How can I thin epoxy out?

[zoltan]

I have a board who's nose has delaminated in on one side. The plan is to use wedges to open it up, put epoxy in the gap, and then clamp it together. I plan on using two part epoxy purchased at the hardware store. So, is there anyway to thin the epoxy out to make it flow better, and allow it to penetrate deeper?

[fin]

Zoltan,

Do NOT use the epoxy you find at the hardware store. Especially the "5 minute" stuff. It is strong but is very rigid and does not flex. It will eventually crack and fail if you use it. Get some epoxy for skis and snowboards from one of the ski tuning supply companies.

Thinning: just add heat. Apply the epoxy into the delam, put board on side, then put a hair dryer on it and watch the epoxy flow into the delam. Works great.

[Donek]

Follow fin's advice. Another trick is to simply pry open the gap and then work it open and closed (twist your screw driver a bit and then relax). This works a bit like a pump and moves the epoxy around very well. Once you think you are there, add a bit of heat and repeat some more. You'll have it all the way into those hair line cracks in no time. If you have a laser thermometer, put a clip light a few inches from the clamped repair. Keep it between 150 and 180 degrees and you'll get a better bond and the epoxy will be cured in about an hour. Look up fiberglas/boat/plastic suppliers in your area to get good epoxy. A lot of guys will use West Systems very successfully. If you can find G2, that's good stuff as well.

[kipstar]

ok, bear in mind that I am coming from a boat buildnig backbground, not a snowboard one, so what i advise should apply, but in boats, the margin for error is a bit different.

I would suggest you should first attempt to pry the gap open, and if you can, attempt to clean the surface on the inside with acetone. It will air dry, so you can do this a few hours before. I would personally attempt to get a nail file or similar in there and rough up the surfaces so you get a good bond.

I would recommend that you use a flexing epoxy product from westsystem called G-flex, which will give you the best possible flexing repair. Just straight epoxy is not giong to be ideal, but it will probably do the job, it sounds like it is not particularly structural.
http://209.20.76.247/ss/g-flex-epoxy/

this is the link off the west system site. I am sure Westmarine or someone can sell to you.

If you do use epoxy, then I can suggest you would be well advised to use brown packing tape, and tape up the board, so then any running drops won't adher to your pride and joy.

You could consider to use a syringe to squirt the resin in; use gravity so it flows in there. If you clamp, then use moderate pressure, as you need a certain amount of resin to just hold things in place.

Resin loves warmth, so yes, do it in a hotter room, but bear in mind the curing time as hotter resin will also cure faster. Make sure the mix is exactly as specified, epoxy needs to be mixed precisely so don't go flicking in extra hardener.

After your job is finished, you should wait a day, then flick the board into a drying room or something; ideally you want to hit 60 degrees celcius at 8 hours on west system so the epoxy will postcure, which is a secondary cure which makes it strengthen about another 20%.

If you do have to apply resin again, to the same repair, you cannot apply epoxy on top of epoxy without sanding or washing off the amine blush; you can do this by sanding or washing with water and wiping with paper towels.

It's pretty simple, I would check out the way we build stuff out of epoxy in boats, and use the same techniques for your board repair.

BTW epoxy is pretty toxic, so I suggest:
- wear throwaway surgical gloves
- mix VERY small amounts as in 20g at a time
- you can use the small throw away paper cups or plastic cups for this, with a mixing stick
- the syringe and everything else can be thrown after you finish
- there is heat created when the epoxy goes 'off' which should be on time as designed with that brand of epoxy; so make sure you are aware of this
- if you use a brush, try to use a good one so the bristles dont fall out into your job and ruin it
- if you insist on attempting to apply liquid resin onto surfaces that defy gravity, consider using a thickening agent of some sort eg. silica, glue powder, filler, as otherwise it will just run off and make a mess

[Donek]

I would suggest you should first attempt to pry the gap open, and if you can, attempt to clean the surface on the inside with acetone. It will air dry, so you can do this a few hours before. I would personally attempt to get a nail file or similar in there and rough up the surfaces so you get a good bond.


STOP!

Keep the acetone away from the board unless you know exactly what it is made of. Many snowboards have sidewalls composed of ABS plastic. ABS plastic is soluble in acetone. Applying it will disolve the surface and polish it. ABS will also absorb a large amount of acetone and continue to release or outgas for at least a week. Heating it during this time will result in foaming of the material. ABS plastic must be sanded and flame treated prior to lamination. Application of acetone will render that treatment useless and your epoxy will never stick to the ABS again without resanding and flaming. That's nearly impossible with a board you are attempting to repair. Never use acetone near the sidewalls or tip extensions when repairing a snowboard.

[bjvircks]

There is a an absolutely huge range of epoxies to chose from, but a relatively small number available to individual users like us. A choice like a flexy marine or ski repair specific product would be a best choice if a board mfg can't be persuaded to provide a small 'sample'.

on epoxy A:B ratios... some products do provide a range of ratios for A to B parts, but you've got to know what you are getting into to be messing with those.

mixing... mixing just enough but not too much can be very important for some epoxies. Mix too little and the A and B components are like a swirl cake and poor % combining of A to B results in weakness. Too much mixing and the batch becomes mechanically worked, accelerating the cure, prematurely increasing viscosity and decreasing pot life (working window for using the epoxy).

and batch size..... If you've got a long pot life epoxy you may be OK working in a couple of small batches, applying one batch and working it in and then mixing up a second batch for finishing up. However, if you've got a quick set material and a bunch of puttsing around has to happen you may not have time to put the work down and mix a second batch.

more batch size.... as others have mentioned, these materials are exothermic. The curing releases heat. Heat accelerates cure. And so on. If you've mixed up a large container of some materials thermal runaway can occur causing what appears to be boiling but isn't. If you need a large amount you might be better off mixing it as a spread out sheet to avoid a large concentrated mass of material and heat. I've had runaway occur. It can be scary if you don't expect it.


some, all or perhaps none of this may apply to your repair. The advice for disposable stuff and hand protection is spot on. Maybe even eye protection... a bit of this stuff accidently wiped in or near the eyes is bad news.

[kipstar]

STOP!

Keep the acetone away from the board unless you know exactly what it is made of. Many snowboards have sidewalls composed of ABS plastic. ABS plastic is soluble in acetone. Applying it will disolve the surface and polish it. ABS will also absorb a large amount of acetone and continue to release or outgas for at least a week. Heating it during this time will result in foaming of the material. ABS plastic must be sanded and flame treated prior to lamination. Application of acetone will render that treatment useless and your epoxy will never stick to the ABS again without resanding and flaming. That's nearly impossible with a board you are attempting to repair. Never use acetone near the sidewalls or tip extensions when repairing a snowboard.

my bad!

Just for knowledge, with the ABS plastic also have problems with the styrene in polyester/vinylester resins?

must be a swine to laminate with the plastic if you can't easily clean surfaces; we go through litres of acetone in boat layups/repairs.

mo' respect for the board builders aye!