Plastic Welding for boots.

[No.2]

Hi all. One of my my SB 325s is starting to split over the toe underneith the tounge. It's about one inch long and hasn't gone into the thicker side wall of the boot yet. Has any one experimented with plastic welding, as with Motorcycle fairings on, Hard boots?

Any thoughts would be greatly appriciated.

[SEJ]

Done a fair amount of airwelding for work. You can airweld ANY thermoplastic. Getting the correct rod is another matter. You have to know what the boot's made of.

[www.oldsnowboards.com]

In regards to stopping a crack from progressing, I recall drilling a small hole at the point where the crack ends will help stop it's progression. Perhaps doing this prior to the welding might increase the odds of success?
Photos? Keep us updated with your success in the future please.

[No.2]

Thanks guys. Ill try to get some photos up.

Who do I talk to to find out which plastic my Red Raichle SB325 are made of?
Can I just use a sliver of another boot that feels the same?

[Donek]

I'm definitely no expert on boots, but I'm pretty sure they are made with thermoset resins. This is a less expensive approach to short cycle molding that is common in the boot industry. Thermosets also offer better control over flexibility. A thermoset resin is not weldable as it can not be melted. They will frequently soften up under heat, but never reach a point at which they can be welded.

[yyzcanuck]

Without revealing the exact material currently being used by DeeLuxe (which hasn't changed in quite some time), it can be best described as a "TPU-Thermoplastic Polyurethane Elastomer". Different model boots and components of those boots use different grades of TPU. Some of the components that require more flexibility use Nylon 12 material.

BUT... I have witnessed failures of that particular shell you describe (Dark Red, SB325) due to aging. Repeated heating / cooling cycles and exposure to ultraviolet light combined with high stress cycling can cause cracks. Once cracking begins in one spot, count on it happening in another spot soon. The heel ledge is the most common failure point on old boots. The bail wire of the standard binding puts incredible loads on that area.

Do yourself a favour... buy NEW(er?) boots.

[bobdea]

Without revealing the exact material currently being used by DeeLuxe (which hasn't changed in quite some time), it can be best described as a "TPU-Thermoplastic Polyurethane Elastomer". Different model boots and components of those boots use different grades of TPU. Some of the components that require more flexibility use Nylon 12 material.

BUT... I have witnessed failures of that particular shell you describe (Dark Red, SB325) due to aging. Repeated heating / cooling cycles and exposure to ultraviolet light combined with high stress cycling can cause cracks. Once cracking begins in one spot, count on it happening in another spot soon. The heel ledge is the most common failure point on old boots. The bail wire of the standard binding puts incredible loads on that area.

Do yourself a favour... buy NEW(er?) boots.

he speaks the truth, generally when a older boot cracks in one place if you look around there are already others or there will be soon. happens with old ski boots all the time. skier notices a crack on the cuff or tongue, drills to stop the crack and it works but the boot fails somewhere else. with newer boots that something crazy happened like getting hit full force with a ball peen hammer in a cold day(yes, I have seen this) or a boot with a inherent design flaw drilling may get you years more of use.

I'm convinced that the biggest killer of shells is the sun, makes them brittle.

[John E]

I would agree with Sean - themoset plastics cannot be welded. You may find an adhesive that will stick to it but this is often very difficult.

Drilling a hole at the end of the crack helps eliminate a "stress riser". It takes the stress that is concentrated at the tip of the crack and distributes it around the circumference of the hole. A bigger hole (1/8" - 1/4") would probably work better than a really small one.

[SEJ]

X3 for Sean. If it's a thermoset it's unweldable. I also agree with the concept that if it's cracking here it won't be long till it cracks there. Thermo cycle and UV exposure will eventually kill any plastic. Hmmm, sunscreen for boots? Aerospace 303!

[No.2]

Ok so here is what I've done. I drilled the crack. (Interesting point about bigger is better there) Then I took it to an air welder and he chickened out when I showed him this thread. :) So I "welded" it my self with a soldering iron useing slivers of the cuff that I cut off whilest modifying my cant mechanism. Then I got a piece of TPU, shaped and ground it to form a patch and then used 3M 5200 flexable adheasive to glue the patch over the top (Taping it on around the boot). Watch out for the glue in the tape. It can delay the setting of the 5200 as it is water cured.

I realise that this is going to happen some where else. And am now looking for some new boots. http://www.bomberonline.com/VBulletin/showthread.php?p=203862#post203862 I managed to shove my wide and high arched size 11US feet into a mondo 26 so as you can imagine the boots have seen a few heat cycles.

Thanks again for all your help.
Jason.

[Dave ESPI]

I give ya props for being smart enough to take some plastic off the other area of your boot and atleast giving it a try, but you are better offgetting new boot. Both for sanity and safety sake. Peace of mind is worth a lot more than risking TBF (Total Boot Failure!)