What I Did on My Summer Vacation:
An Alpine Board Construction Primer

by Chris Couse

 

Bruce Varsava of Coiler generously offered me an opportunity that most of us only dream of: the chance to construct a snowboard with the benefit of his shop, his guidance, and his generous assistance. I have tried to document my experience here because I think it will be of interest to the community.

I hope this article can put into perspective the enormous resourcefulness, creativity, passion, and artisanship that every custom board builder brings to his craft. I have not visited or worked in the shops of others (although I’m always open to invitations) so I can’t offer a truly balanced perspective on various approaches to custom alpine board construction. If I occasionally sound like I am trying to hype Coiler, it is not intentional. My simple aim in writing this article is to raise the level of understanding about what goes into building a custom board. What I have learned only intensifies my sense of awe that we are able to obtain and enjoy (at what seem bargain prices) such intricate hand-made objects in this era when everything we encounter seems to have emerged from some mechanized hell on the other side of the Pacific.

Not Just Another Day at the Coiler Factory

“Hello Coiler.” Bruce Varsava, Mr. Coiler, answers the phone in his shop and a typically affable conversation begins. The caller is a fellow custom composite builder like Bruce but his product is skis and he’s returning Bruce’s call. Bruce has been going through his contact list trying to sort out a typical headache for custom builders: sourcing exotic materials on a small order basis. Today’s crisis: rubber foil, a product made only by one Austrian manufacturer and seemingly unavailable anywhere in North America right now except if you want to order a container load. No rubber, no boards. ‘No sweat’ says Bruce and shrugs it off. Just another typical day-to-day challenge in the custom alpine board world. And if you’re a Coiler customer awaiting your board, relax, a new supply of rubber foil is now in Bruce’s hands.

The telephone conversation moves into casual territory as it inevitably does with Bruce. He explains more about the nature of Coiler to Luke, the ski guy, who obviously has trouble imagining what Bruce is explaining because it makes no sense in terms of his experience of making skis. Luke makes approximately 1,000 pairs of skis per year based on standardized designs and lengths. Bruce explains that he builds every board to varying specifications based on the weight, abilities, and preferences of the rider, often creating new board shapes in the process. He keeps volumes low so that he can focus on the quality of the product and so that he can maintain a healthy work-life balance (building only about 100 boards per year means being able to catch the best days for kite boarding or pursuing other simple pleasures). Luke questions Bruce about his production machinery. “CNC machines?” Bruce laughs, “I haven’t got any CNC but I do have a ‘C Squared’ in the shop today.”

I’m spending part of my summer holiday in the Coiler shop with Bruce Varsava finding out firsthand what it means to put together a custom alpine board. Others have witnessed parts of the process at Coiler but Bruce has invited me to get my hands dirty (or at least very sticky with epoxy) producing a board so that I can experience each step of the construction. In my naïvete, I had imagined this would consist of Bruce explaining the construction process while I would wield the tools, shaping a core and slapping epoxy about. I now understand how the sorcerer’s apprentice must have felt. Building an alpine board means more than having the right tools and templates, it requires the finesse of a violin maker and the deftness of a blacksmith. I certainly had a hand in making a board but the real magic came from the magician himself. You can’t become a great chef by reading a recipe book and you won’t learn how to create an alpine board by reading this article. I can only try to give you a window into the intricate complexities of the process that will hopefully give you a sense of the craft that goes into a custom board.

Boards Beget Boards

The process starts as it starts with every Coiler: a friendly dialogue with Bruce about what you dream of in a board and what conditions you would like to ride it in. Though I have savoured the qualities of the Coilers I have owned (180 Racecarve, 184 Pure Race Superboard, 186 J J Anderson GS model, 178 J J Anderson Boardercross model), I have sometimes felt on East Coast ice days with crowded slopes that something damper, less crud susceptible, and more maneuverable would raise the fun quotient and lower the fear factor. As many have discovered, the answer to this need is in metal boards because of their suppleness, inherent dampness, light weight, and responsive flexural behaviour. A promising direction has been the application of Titanal to Bruce’s All Mountain design, offering the crud-eating flex pattern of this ever-popular all-round board with the supple ice-holding characteristics of Titanal construction. As Bruce put it: “Frig man, you’re going to want to put your other boards away for good once you ride this.” The board will be a second generation prototype using the AllMountain 172 shape adapted to suit Titanal construction and will require more time and care than usual to produce. The assembly process will use the press during lamination which holds some special interest for me because of my involvement in its design. Bruce builds many Titanal boards using the press while all his fiberglass boards and some of his Titanal boards use the tried and true vacuum-bagging process.

Did he say vacuum-bagging? Isn’t that for surfboards? Well yes, some of Bruce’s techniques are influenced by his roots as a sailboard builder. Prior to last year, all of Bruce’s boards were laminated in vacuum bags using vacuum equipment that always made me think of props from a Mad Max movie (an air conditioning compressor and a reconditioned medical stomach-pump). In fact, all of his glass boards are still made this very reliable way. It is important to understand that every custom builder uses different methodologies (there are no real conventions in the business). I also mentioned above that Bruce has no CNC machines. While Bruce has the requisite skills to use such equipment, he

has never felt that they would enhance his boards. He will often joke that he uses almost no power tools apart from a bandsaw and a router (there are actually a few others but nothing you couldn’t buy at Home Depot). I would characterize Bruce’s approach as being like that of a musical instrument maker: short on mechanical process/engineering and long on hand tools using his innate knowledge of the materials and how they go together as composites. Doing more of the steps by hand also permits a great deal of latitude for customization of length, shape, flex pattern, stiffness, and construction.

Core Values

Once a shape and construction for the board is chosen, the process of building begins with the selection of a core composition. As with most snowboards, the cores of Coilers consist of parallel laminated wood strips using four or more species of wood to achieve lightness where possible while providing the strength required to retain inserts and support the compressive pressure of binding plates elsewhere. The varied grains, strengths, and densities of the woods also tend to balance the behaviour of the core when subjected to temperature or humidity changes. Among the woods Coiler has used in the past are White Pine, Red Cedar, Douglas Fir, Sitka Spruce, Poplar, and Ash. Bruce buys dimensioned lumber in 1” nominal thickness (3/4” actual) rather than the veneer thickness materials that are customarily used for cores. Using thicker plies for his laminations permits him to cut the camber into the plies rather than pressing it in (more about this below). For his ‘World Cup Construction’ option, Bruce adds strips of a composite material into the tip and tail areas to enhance lightness while improving vibration dampening. The species used for the core of this board were specifically selected to suit the Titanal construction and are positioned to address specific stresses. However, like “the Colonel’s secret blend of eleven herbs and spices”, the composition will make the board tasty but must remain a secret.

Using a tempered hardboard template that draws a slightly oversize version of the sectional profile of the running length portion of the board, we layout shape cuts on the wood planks for cutting on the bandsaw. This is a Coiler methodology that most builders do not employ (typically cores are profiled on top by various methods with the bottom left flat) because it is more expedient to mold the camber into the board during the pressing. I asked Bruce why he has always used this method to obtain the core shape given that it adds considerable time and fussing to the construction. His response was:

“I went with the precut camber as it actually adds life to the core and since it always wants to return to its natural shape it theoretically should have a better life expectancy as long as it is not over-bent. It allows you to add more dampening to the lamination as you get more liveliness from the core itself. You get the best of both worlds! Makes assembly easier too. Only negative is that it is hard to do and also when the board is really bent as in a crash, the wood fibers will break down sooner as they start from a higher position than a flat core.”

Here is a bit of expansion on the topic if you didn’t quite catch some of Bruce’s explanation. When a core is built flat, it has to be pressed into the camber shape. During pressing, the board is moulded into an exaggerated camber shape because the ‘memory’ of the wood core will cause it to try return to its original flat profile (it can only partially return because of the glass plies that resist it). This means that the core itself does not resist flexing until it is de-cambered beyond flat. The life expectancy issue relates to the wood constantly being under tension after pressing because it is forced out of its original flat shape by the added glass plies. De-cambering of a core by over-bending is rare but more than just a theoretical possibility. This was the fate of my Coiler Racecarve 180 as a result of a crash that involved running off a trail and auguring the board into an embankment like a pole-vaulter’s staff, bending it so significantly that it retained a reverse camber from the shovel to the front binding for about an hour afterward (eventually it settled to a no-camber shape indicating that the wood and glass had both exceeded their elastic limits but did reach the point of failure).

But I digress. After the core strips are cut to profile, they are set up on pipe clamps and laminated side-by-side with epoxy. Because the strips are crudely cut on the bandsaw they need to be trued to the base by tapping them down onto the clamp pipes to make them as uniform as possible on the bottom. The core pieces are cut long and thickened in profile beyond the final core length to provide a robust flange at each end. For further added stability and strength, Bruce laminates a pine stringer across these flanges to resist working pressures during the final shaping of the core.

Once the epoxy cures, the core is removed from the clamps and the first step in refining the core profile begins. The core thickness is about 90% responsible for the eventual stiffness and flex pattern of the board and it needs to be shaped to within 1/10 of 1 mm (~1/250”) of the targeted thickness. This is especially true for a Titanal board where the amounts of adjustment that are possible after lamination are very small. In addition, the core thickness of a Titanal board is significantly less than that of a traditional fiberglass board so 0.1 mm can represent 5% of the core thickness toward the tip and tail of the core. Sure, a CNC machine could probably perform shaping to this level of accuracy but when you start to reduce wood to such a negligible thickness things become very fragile and hand tools permit a higher level of care and finesse.

To begin the shaping, basic core profile templates made of veneered particle board are screwed to both sides of the core using the bottom as the set-up guide. The template edges are perhaps 20 mm offset from the actual core profile so they stand above the core surfaces on the top and bottom. Locating the template correctly is very critical because the screws that secure it to the core are virtually the final thickness of the core at the ends and can easily turn up in the router cuts, damaging the router bit. The templates are used as the guide for a router that has been fitted to a plywood bracket long enough to span between the profile templates. The bottom of the core is trimmed first with a relatively shallow cut (+/- 2.5 mm) to true up the base as this continues to be the reference surface. This preliminary base cut takes the bottom profile to within 1.5 – 2 mm of the intended shape. The router is run longitudinally in overlapping cuts along the base using care not to let the bit pull the router away where the cut is running in the feed direction. Once the bottom router cut is complete, Bruce checks the core thickness with a modified vernier caliper and sets the router for the preliminary top cut. We discover that the top cut will be a relatively chunky 4 mm to get to within 2 mm of the final shape on top. Cutting is slow and careful with the router tugging and threatening to pull away at any moment as it tears into the hardwood strips.

Next we get to the final shaping steps for the core. This will be done by taking one further cut from the bottom and then the top that will bring us to within .5 mm of the target profile. These cuts are done with care because errors at this stage mean writing off the core. These router cuts are only about 1 mm deep and are done by running the router in both directions because the core is now very thin and vulnerable to small differences in temperature from the heat of the router tool (ie the core will tend to bow upwards as the tool creates heat locally resulting in different depths of cut). This becomes apparent when the direction of the router cut is changed and very slight ledges become visible at the router tracks. This is also when the router can get hung-up on the screws that are holding the profile templates on the sides of the core, causing the tool to chip and vary the depth of the cut. The screw locations are avoided until the rest of the cut is completed and routered as a last step. With the ends of the core now shaved down to less than 3 mm (1/8”) in thickness it seems miraculous that only one screw becomes visible in this last stage. We are now within .5 mm of the final thickness of the core and it is time to remove the templates, and cut the core to its final length on the bandsaw, removing the additional thick material which has helped to keep the core stable and protect it from damage while thickness routing was performed.

The Art,, Science, and Zen of Core Shaping

This is the point at which the core starts to be transformed into something reminiscent of a snowboard. Using a tempered hardboard template, the shape of the board is traced onto the core for rough cutting on the band saw. The cut is offset to allow for the ABS sidewall material that will be bonded to the edges of the wood. The core is then sandwiched between the template and a particle board backer and clamped. The edge of the wood core is cut to its final shape using a router that maps the edge of the tempered hardboard template. The accuracy of cutting at this stage is fairly critical as this step will effectively determine the final shape and width of the board. Note again that the core is only about as thick as a pencil at the waist at the waist, thinning down to plywood veneer thickness at the ends and it requires extreme care to avoid damage. A very light touch with the router is required to avoid pulling pieces off the side of the core near the ends where the thinnest areas occur. The core emerges unscathed and looking like some breath-taking modern sculpture: “Turd in Space” we’ll title it.* We epoxy on 6 mm ABS sidewall material and trim it flush with the top and bottom of the core finishing with a 7 degree side bevel trim, all using the favourite tool at Coiler: the humble router.

The next step in making the core is trimming it to the exact thickness profile that will provide the desired flex and stiffness. This is the stage at which high accuracy is required in order to bring the core to within 0.1 mm (1/250”) of the target thickness. Bruce records construction data on each board he builds documenting extensive core dimensional data along with other key details of the construction and, perhaps most importantly, the stiffness in Coiler units (sorry no BOBSI’s). Collectively Bruce’s data sheets comprise a huge body of empirical knowledge about board construction involving over 1,500 boards. Bruce locates the data for a board or boards he has built previously that have as many similar characteristics as possible to the one being constructed. Using this data as a guide, he establishes final thickness targets for the core that will address the rider’s weight and flex preferences. Higher mathematics are not involved in this operation: the process is a black art. The differences between one flex pattern and another, between a heavy rider and a light rider are only 1/10ths of a millimeter and Bruce adjusts by dead reckoning. When Bruce is feeling creative, he will design core profiles using a graphic method where the Y-axis on the paper is scaled to 10 times full size and the X-axis to 1/10 full size to exaggerate the shape. Once the sketched shape looks like it will produce the flex pattern Bruce is looking for, he plots the Y-axis values to get thicknesses at 3” intervals and builds it. If you use the word ‘CAD’ in Bruce’s shop, you get a look that says “CAD?: We don’t need no stinking CAD.”

Whereas the core shaping process up to now has been quite methodical and controlled, the final shaping actually becomes somewhat fluid and freestyle. The core is gauged with a vernier caliper at 3” centers measured from each end. Bruce writes the differential between the target thickness and the gauged thickness in 1/10ths of a millimeter on the top of the board at the 3” center points (the board starts to look like a child got loose with a marker). Using a router, Bruce sets the depth to take about .05 mm less than the required thickness at each interval and plows several quick passes across the top of the core in each 3” region. This sounds a little crude and it is but speed and deftness are important: the core is now so thin that slow action with the router can cause the top of the core to heat up and ‘crown’ resulting in non-planar surfaces. Of the final stage I can only say “Don’t try this at home.” Although the final cut is done by sanding, if done too slowly with fine paper the heat build-up would cause distortion so you need very course grit paper and a sure hand. For best results, Bruce goes at it very briskly with a sander using 40 grit paper. This is very unforgiving and a second too long in any location could destroy the core which is negligibly thick at the ends. Thirty seconds of sanding and a few minutes rechecking the vital statistics at the 3” interval points and Bruce declares the core within tolerance. Bruce does a check of the core on his board stiffness test-bed using a smaller weight than is used for final stiffness testing. Although the core itself does not contribute much to the stiffness, its deflection under a load is indicative of the flex pattern of the finished board.

Time to prep the core for inserts: a steel plate drilling jig is located and clamped to the board and holes are drilled from the bottom side. Using two bit sizes, the holes are slightly graduated with the larger hole on the bottom to make the starting of the insert easier while the top side hole is tighter to maintain registration and contain the movement of epoxy. The holes are then counterbored with a router bit to take the t-flange of the inserts.

I don’t know why, but I always find the finished cores of Bruce’s boards very striking and aesthetic (Bruce is immune to it). Bruce’s cores are made up from clear dimensioned lumber and the grain and colour of the wood are very visible and tangible. The wood, of necessity, is so flawless and the shaping so precise that it cannot help but have sculptural qualities. It almost seems a shame that all of that beauty will end up encased in several layers of other materials but that is its fate. There is a kind of zen-like experience in knowing that your board has an inner beauty that remains hidden but is perhaps expressed in the poetics of a well-carved line.

One step remains to complete the core: attachment of the tip and tail core materials. Bruce uses ABS or PET sheet materials for these areas of the board (in lieu of wood which is sometimes used in production boards that are pressed to their profiles). Rolls of core material come approximately 1.8 mm thick and the wood core needs to be tapered slightly by sanding to provide a flush butt joint at the splices. After rough-cutting to profile, the plastic is cleaned with acetone to ensure adhesion then flamed to open pores in the material that will enhance the mechanical bond. The tip and tail plates are spliced to the wood core by epoxying a strip of fiberglass to the top and bottom and clamping them in jigs to maintain their shape and position during curing.

Where the Rubber Meets the Road

Time to get our base and edges in order. A length is cut from a role of p-tex. The p-tex must be cut to the exact desired profile as it will virtually determine the final shape of the board (this becomes more understandable once you read the succeeding steps). The p-tex, which is very pliable and difficult to work, is clamped between the tempered hardboard template and a particle board profile to support it from below. Cutting to profile is done using a router that maps the tempered hardboard template. After deburring the p-tex with course sandpaper, alignment marks are made to position the wood core during the lay-up and the base material is placed on the lay-up bed which maintains the camber, tip, and tail shape of the board.

Lengths of carbon steel edge material (standard Rockwell 48 hardness) are selected. The familiar square profile of the edge that is visible on the finished board has a thin flange approximately 3/16” wide that tucks behind the p-tex and is milled into a series of ‘T’ shaped anchor slots to permit bending and to lock the edge into the composites. The edge will be made up in four pieces: two running from tip to tail and two that close the final 4 – 5” at each end. The side pieces are bent by hand into the approximate edge cut curve and the tip areas are roughly pre-bent using a slotted bending jig. Forming the edges to the final curvature is maddeningly difficult because of the two-dimensional bends involved. Bruce uses a set of vice-grips with the jaws ground to make finger-round surfaces. The edge is progressively bent by squeezing it in the vice grips at +/- ¼” increments with the strength of the squeeze creating a tighter or looser radius. At the tip and tail, the edge must bend vertically as well as in plan but working the bend in one orientation, alters the bend in the other orientation. It’s tinkers’ work and requires extraordinary patience and intuition to achieve an exact fit between the p-tex (exactly profiled to the board shape) and the steel edge. The four pieces need to come together with hairline joints when applied to the p-tex. However, the size and shape of the p-tex can change as the p-tex relaxes (it has been kept in a roll since being manufactured) and the edges may require further adjustment before being bonded.

Unnatural Ingredients

Three days or about 15 hours of shop work have been required to reach this point in the board’s construction. In production mode, Bruce could reach this point in about half the number of hours. Left on my own, it would likely have taken me twice the number of hours with markedly less successful results. I note the elapsed time because it represents a distinct first phase that will be succeeded by a session which cannot be interrupted once started. We have reached the point of no return: the lay-up. Not only does the epoxy have a best-before date that is in the minutes, but also some of the materials, notably the Titanal sheets, rapidly oxidize in air and begin to lose their bondability. This step will require from 5 to 6 hours of dedicated time: the assembly time from mixing of the epoxy only requires about 1 ¼ hours but about 4 hours is required for set-up. If you are ever wondering where Bruce is when the answering machine comes on at Coiler, it is likely that he is laminating a board and your call does not come close to the urgency of the procedure underway.

The next steps would be familiar to anyone who has ever tried to cook something ambitious: measuring and preparing the ingredients that have to be instantly available as they are needed. We cut lengths of rubber foil for the top and bottom of the board. The rubber foil, which is the most expensive material in the board, is only about .020” (.050 mm) in thickness and is textured on the top and bottom. Although the material comes ready to laminate from the manufacturer, this roll is past its best before date and requires very careful scuff sanding (the material is about as substantial as peach skin) to raise a nap for bonding. Why rubber foil? In simple terms, the foil provides a resilient discontinuity between materials in the core that enhances damping. Damping helps to suppress vibration and absorb energy so that the edge of the board can remain in intimate contact with hardpack and ice surfaces. There are other helpful factors at work in a Titanal board including the range of natural vibration frequencies of the individual materials (Titanal, fiberglass, carbon, wood) that tend to suppress one another. But the rubber is the major player.

Fiberglass is selected for the top and bottom. Bruce keeps a whole arsenal of fiberglass types in his shop for different purposes. S glass is sized and cut for the base and top, rolling the strips and putting them aside. Strips of carbon are cut for the side rails and rolled for easy handling during the lay-up. A nylon ‘peel ply’ sheet is cut to size for the top of the board to provide a sacrificial layer that will permit air movement but contain the excess epoxy resin that percolates up through the fiberglass.

Now for the glamorous stuff - Titanal, the word on every alpine rider’s lips these days. So what is this stuff? I recall a hilarious a sports broadcast two years ago in which it was stated that the new generation of alpine boards were machined from some mysterious solid metal. Titanal is the proprietary name for a solution annealed aluminum alloy with very high tensile properties produced by AMAG Rolling of Austria. It has been in use in the ski industry for 20 years. Bruce must make major investments from time to time to keep Titanal on hand because it is typically only available in fairly large quantities. Donning white cotton gloves, we remove two precut strips of the exotic metal from Bruce’s stock of material. TheTitanal is very delicate (about the gauge of a soft drink can) and is anodized to enhance bonding. The anodized bonding coat is only a few molecules thick making the surface very vulnerable to contamination and it must therefore be stored and handled with considerable care. Using snips, one of the sheets is cut to fit precisely to the inside perimeter of the Rockwell 48 edge while the other sheet is rough cut about 1” oversize all around for the top sheet. Insert holes are laid out on the top sheet using a template and drilled using a wood boring spade bit (the concentric cutting tooth on the bit scribes a low-friction score in the metal and does not hang-up like a twist drill would, tearing and distorting the metal).

The Joy of Cooking

The ingredients are ready, time to start cooking. The p-tex is unrolled and cleaned thoroughly with acetone. We lay the p-tex on the profile template and discover that it has twisted approximately 3 mm in plan since being cut (as noted above, this is just the plastic relaxing once it is off the roll). The steel edges are fitted to the p-tex and clamped in place very 2 – 3” . The p-tex is coaxed back into the correct shape by pulling slightly in one direction while progressively clamping. Once the edges are properly fitted and clamped, a drop of 5 minute epoxy is used to tack the edge every 1 ½”. When cured, the epoxy is razored off flush with the top of the embedment flange.

While we are waiting for the epoxy to cure on the edges, we are installing the inserts and the fiberglass reinforcement panels in the wood core. A batch of epoxy is mixed and the recessed area at the inserts wetted-out. The batch of epoxy is then brought to a more molasses -like consistency by adding filler and this material is trowelled into the counter-bored holes for the inserts. Twenty 7 mm inserts are selected with white gloves and the remaining epoxy is thickened further to a peanut butter consistency. Each insert is buttered with the epoxy and pushed gently into a hole in the core. The inserts are then ‘set’ by driving them the last 1 – 2 mm into the tight portion of the insert hole that was made with a smaller drill. Finally, a ridge of the peanut butter consistency epoxy is trowelled over each line of insert heads which have been set just below the bottom surface of the board. Just as one would apply drywall compound to a crowned gypsum board joint, the slight ridge of epoxy is feathered out on either side. All of these steps are needed to provide maximum engagement and pull out strength for the inserts. Turning the board over, almost no epoxy has bled through around the inserts (because of the tight bottom in the holes) and yet they are fully embedded in epoxy with no voids.

A mold sheet is prepared for the base of the board using an 0.060” (1.5 mm) aluminum sheet and applying a wax release agent to the surface (something like a giant cookie sheet). The mold sheet is laid on an adjustable length mold bed and the mold sheet is aligned with the core end mark in the mold bed to accurately position the board with the shovel profile in the bed. A loose tail lift profile is placed under the tail end of the board (the tail form is used on boarder cross and all-mountain boards to create the tail riser and is loose to suit varying board lengths). The p-tex base with metal edges attached is placed on the mold sheet with the core end marks at the tip aligned. 1/4” square by 1” long pine blocks are bonded with hot-melt glue to the mold sheet at the ends and mid-point of the running length, tight to the metal edges to provide alignment guides between the base and the core during lay-up. Final cleaning is done on materials that could have become contaminated or oxidized. The PET tip and tail cores, now spliced inseparably to the wood core are flamed again to open the pores and are then cleaned with acetone. The p-tex base and edge assembly are re-cleaned with acetone.

Now for the magic of epoxy - for the lay-up Bruce uses a 2:1 mix (epoxy resin to hardener). After mixing the epoxy, we pour and squeegee the resin as thinly as possible over the surfaces. To save time, I build from the p-tex up while Bruce builds from the top of the core up. Once the surfaces are thoroughly wetted-out with epoxy, we squeegee off as much epoxy as possible from the substrate with plastic spatulas. You can’t apply epoxy thinly enough that the press won’t find it and squeeze it to some other location so to discourage pooling of epoxy exceptional diligence is required when removing any excess. Particular care is also needed to ensure that epoxy fills all of the ‘T’ anchors on the metal edges. The bottom sheet of Titanal is wetted-out with epoxy and squeegeed thin with a spatula before laying it over the p-tex. The Titanal sits tightly within the steel edge flange. The top of the Titanal sheet is now wetted out and squeegeed thin before applying the rubber foil. After the rubber foil has been wetted out, it is gently squeegeed from center to ends and from center to side to work out bubbles and wrinkles (the foil is so thin that it can tear at the slightest strain). The bottom glass ply is laid over the rubber, wetted out, and squeegeed. Meanwhile, Bruce has built up the top of the core with rubber foil, Titanal, carbon strips along the edges, S glass over top, and finally the stripping sheet. Like a giant Dagwood sandwich coming together, the two assemblies are joined and checked for alignment of the layers.

Before the board goes into the press, Bruce applies a multi-layered panel that will help to reduce pressure points and spread the pressure more uniformly. The mold bed, mold sheet, board, and pressure panel are slid into the press from the side and the tie-rods reconnected. Using a high-powered flashlight Bruce leafs through the oversize plies of the board to check that the various layers of the board are correctly aligned before pressing. The press head consists of hose-like bladders which have very high pressure ratings. The bladders inflate like sausages when filled with air from the type of pneumatic pump and reservoir tank one would use with air tools. Pressure is spread using a caterpillar track of 1” x 1” (25 mm x 25 mm) aluminum tubes threaded together with cables. Bruce inflates and cycles the air in the bladders a few times before inflating the bladders to their final pressure and the board is left to cure for 17 hours. The aggregate pressure applied over the area of the board is perhaps as much as 75,000 lbs (34,000 kg).

At these pressures, magical and terrible things happen. When all goes well, the epoxy continues to flow through all of the permeable materials and makes its way to the sides, top, and bottom of the board. The quantity of epoxy left in the board is perhaps ¼ of the amount in a vacuum-bagged fiberglass board resulting in extraordinary lightness and strength. If you are unlucky, bubbles don’t escape and epoxy bogs down in lumpy pools. Bubbles and pooling can lead to delamination and irregularities in the board’s flex pattern.

Hot Off the Press – A Steaming Coiler

The next morning we open the press. After removing the pressure panel, we remove the stripping ply to expose the glass surface of the top. The edges are pretty shaggy with materials that were cut oversize protruding all around. Bruce drags a fingernail over the board listening for a tell-tale rasping that would indicate hollowness but the board is sound. The excess materials are trimmed from the board with a jigsaw using the steel edge as a guide. Its looks like the jungle-fighter version of an alpine board: crude but lethal.

Although the epoxy is still curing, we put the board on the Coiler ‘Stiff-o-meter’™. We have been targeting a 7.7 level of stiffness and Bruce impresses even himself when it measures 7.6 (additional curing will bring the board up past 7.7 from where it can be de-stiffened by sanding the top glass. The board is substantially complete. The rest is all frivolous stuff like a top sheet and tuning.

_______________________________________________________

If you never have a chance to participate in building a board (and chances are you won’t) I am hoping that this article will have given you some idea of what is involved. Although I have probably provided too much detail in some spots and the article is unforgivably long, I have still had to omit a lot of significant detail both for brevity and for proprietary reasons. I hope the article will spark interesting dialogues among riders and perhaps inspire some to invent new approaches to the craft. If it only helps you to enjoy the board under your feet, I think I will have accomplished something.

-csquared

*This refers to a bit of Coiler lore that goes back to the origins of the Coiler name. Without telling the whole story, a ‘coiler’ in one man’s parlance refers to a dog turd. If you still don’t get it, Google ‘Bird in Space’

Image Captions:

1 The core, laid up and ready for the start of the shaping process.

2 The core on the router/sanding table ready for the installation of guide templates which will be fastened to the sides with wood screws. Note the thickened end for stability and damage resistance while working.

3 Bruce installs a guide template.

4 Bruce checks alignment and gauges the distance from the guides to the bottom of the core to set the first router pass depth.

5 First pass with the router. A plywood bracket supports the router. Placing a finger against the outboard edge of the guide provides a simple means of setting the path of the router on length passes.

6 After two depth cut passes with the router, the author rough cuts the core to shape following a line traced from the board template. Thickened ends are also cut from the core using the bandsaw at this point. The author does not recommend using a camera and a bandsaw at the same time (but he still has all his fingers).

7 The core rough cut to shape.

8 A view down the edge of the core. Note the camber.

9 Bruce uses a router and the shape template to fine cut the core shape.

10 The core on the laminating bench ready for ABS sidewall material.

11 Rolling on epoxy to bond the sidewalls.

12 Adding ¼” (6 mm) white ABS sidewall material. Once cured, the ABS will be router cut to a 7 degree bevel.

13 The author router cutting a sheet of p-tex which has been sandwiched between the board template and a particle board backer.

14 The author, a happy apprentice to have been given a responsible task by the master.

15 Bruce deburrs p-tex using course sandpaper on a block.

16 Mischievous master gives miserable apprentice the task of shaping metal edges.

17 “See, its easy. Ya’ just apply the vice-grips like this, and this, and this. Done.”

18 The magic vice-grips. Note the illegal modifications.

19 The author thins the end of the core by sanding to match the thickness PET tip and tail material.

20 Laying out thickness check intervals along the core. Thickness is measured with a vernier caliper at standard 3” (76 mm) intervals and compared to statistics from past boards as a means of predicting final stiffness. A matrix of target thicknesses for the core are interpolated from the precedent data.

21 Top of board with notations indicating excess differential between target and actual core thickness in 1/10ths of a millimeter (approx 1/250”) as measured with a vernier caliper. These values will be used to set the router to trim the board to within 1/20th of a millimeter (approx. 1/500”) in the 3” (76 mm) band to which the number applies.
22 Cutting shallow quick passes across the core to limit heat build-up. The router depth is reset as noted above for each 3” (76 mm) region along the length of the board.

23 Checking router depth on a preliminary cut. Depth setting gauges on routers are too approximate for comfort with the level of accuracy required at this stage. The depth is checked after a single pass.

24 Checking the core thickness at 3” (76mm) intervals with the vernier caliper after router trimming. Both edges of the core are checked to ensure planar uniformity.

25 Local idiosyncrasies in core thickness are sanded out by hand to bring the core to exact target thickness along its entire length.

26 An steel template is clamped to the core to act as a drill guide for insert holes.

27 A router tool is used to counterbore the insert holes on the bottom side of the core. The counterbores accommodate the ‘T’ flanges on the inserts.

28 Bottom of core with one set of completed insert holes.

29 Tip and tail cores cut from heavy gauge polyethylene sheet. Cores are cut oversize initially as excess material can be trimmed later. Masking tape limits extent of epoxy coverage at splices.
30 Tip of core with splicing jig / clamp in place on bottom ready for installation of fiberglass splice tape on bottom surface prior to positioning core material and splice tape for top.

31 Fiberglass splice tapes for PET tip and tail cores. The strips of glass fabric are sitting on squares of polyethylene where they will be wetted with epoxy before they are applied.

32 P-tex base with one edge positioned and clamped in place.

33 P-tex at tip with one edge positioned and clamped in place. Edge is bonded to p-tex with dots of epoxy applied intermittently to ‘T’ flange portion of steel edge material. The p-tex effectively serves as the template for the board at this point and sets the final shape of the metal edge. Only enough epoxy is used to retain the edge in the desired shape. Structural retention of the edge is dependent on embedment of the ‘T’ flange into the full lay-up of the board.

34 P-tex base complete with edges is positioned on the waxed aluminum mold sheet (sitting on the shaped mold bed) and retained in position with small blocks of wood bonded to the mold bed with hot melt glue. Ready for lay-up.

35 Locating the ends of the wood core on a sheet of Titanal. These lines will serve as important registration marks during the lay-up.

36 Making holes for inserts in the top ply of Titanal. A wood boring spade bit works well for this task because the concentric ‘tooth’ on the bit scores the Titanal and takes out a plug of metal whereas a twist drill would likely jam close to the end of the cut and tear the hole or distort the metal.

37 Working with Titanal requires careful procedures to prevent contaminating the surface and spoiling the epoxy bond. Hand oils are a major threat and white gloves are the best precaution (preferably on your hands not under them).

38 The aluminum mold sheet.

39 The mold sheet installed on the mold bed. Wood positioning blocks, set up using the p-tex base with steel edges attached, are visible. Tail of bed is toward lower left hand corner of photo, tip is to the upper right. Note the tail mold which is a loose piece only required for AM and BX board profiles.\
40 Test fitting the pieces to the mold bed. P-tex base with steel edges has been positioned on mold sheet between positioning blocks. Core sits to one side for test fitting over base.

41 The lay-up begins. The p-tex base is wetted out with epoxy which is then squeegeed off as thoroughly as possible. Tip of board is toward lower left corner of image.

42 The bottom ply of Titanal is inlaid between the ‘T’ flanges of the steel edges. At this point, I have to stop shooting the process because the work must proceed quickly and the camera is getting covered with epoxy every time I pick it up.

43 The tip of the board with the lay-up complete: The nylon peel ply is visible on top (under the green work sheet) with the carbon rail reinforcement plies visible through it.

44 The board laid up and ready for bed – press bed that is.

45 The press awaits its next victim.

46 The board in its uncured state inserted into the press on its mold bed.

47 One last check to make sure nothing has shifted out of alignment during insertion.

48 The pneumatic piping and pressure gauges for inflation of the press bladders.

49 Seventeen hours later the board in all but finished state. The stripping ply has been removed, excess materials have been trimmed to the steel edge.

50 A quick check on the Coiler ‘Stiff-o-meter’™ and the board is determined to be on target for exactly the desired stiffness. The epoxy is still curing so the board tests very slightly low. As the epoxy strength increases, so will stiffness. Using both glass and Titanal together offers the advantage of being able to reduce stiffness after lay-up by sanding out the glass ply (you gets what you gets if you have Titanal with no glass).

51 Like new-born baby pictures, this could start to get a little boring.

52 Me and the T.