Help with thermarest patching problem

I need some advice on patching my ProLite3: I accidentally ran my knife on top of my ProLite3 and left a 1.5" gash on the orange side. I dug out my 6- to 8- year old patch kit (previously unused) and followed the instruction religiously. Unfortunately, the patch just did not stick to the hot bond AT ALL. I applied the hot bond 20 to 30 seconds after I removed it from the hot water, put the patch (smooth side facing mattress) down, and put the still somewhat hot pot of water on top of the patch/mattress. I removed the pot from the mattress 5 minutes later, and I was able to peel the patch off the mattress. All the hotbond glue (which had hardened) stuck to the ProLite mattress and there wasn't a trace of glue on the patch.

What happened? When I called Cascade Design, Chris (who answered the phone) said the only reason is that the hot bond is too old but that doesn't make any sense to me.

Chris is sending me a new patch kit but I am concerned that I am screwed already. I have this layer of plasticized glue around the gash which I cannot remove. (Chris suggested I try chipping it off with my fingers but I can't. I tried heating up the plasticized glue with a hot pot but that didn't fluidize the glue. have access to every imaginable solvent but Chris admonished me against using any solvent because it may dissolve the urethane[sic, isn't it polyurethane] away.) I am very worried that if I put new glue down, it won't bond with the old plasticized glue. Could I please get some advice on how to remove the old plasticized old bond? If acetone won't work i.e. it will probably dissolve (poly)urethane, will chloroform be OK?

Thanks,
Alfred (alfred.kwok@pomona.edu)

This may or may not help much, but I've been putting together models of various types for years and in that time I have learned a little about glue. Yes it is possible for glue to get too old to be of good use, this usually happens after you've opened it. That may be part of your problem. I've not had to patch a termarest yet and haven't had to use the type of glue you're using yet, but part of thinks that the new glue might be able to bond with what you've already got applied depending on how the glue works.

For instance as I understand most "superglues" generally dissolve part of the item being glued so the bonding agent can "weld" the two pieces together. An epoxy works differently.

The fact that you mentioned that the glue bonded with the matteress, but not the patch is kinda curious. Why one and not the other? I'd have been tempted to apply a little of the glue to the patch as well to see if it would bond a little better. Hopefully the new glue they're sending you will help.

It sounds to me as though you had a bad patch. Or, possibly, you put the wrong side of the patch against the hot bond. I would try re-heating the glue that you have applied and putting on a new patch after checking to be sure the right side is down. I have had several occasions to patch my thermarest and if properly done with good materials the patch is bomb- and leak-proof.

If all else fails, you can send it back to Cascade Designs along with $15 (plus shipping) and they will patch it for you, or replace the pad if they can't do it. This option is available no matter how old the pad or how bad the damage. I'm surprised Chris didn't mention that to you...

I would admonish you to not use any solvents or chemicals on the pad. This will cause irreversible damage, effectively removing the PU coating which is what bonds the foam to the outer material. If you can't remove the old glue by chipping it off, I would try using the new patch kit without removing it. Although not the most ideal situation, this is your best option.

I would agree with Chris that the glue or the adhesive on the patch was old. The Hot Bond glue is amazing stuff and if it is working properly you get a permanent repair. I'm betting the new patch kit will work. However it's nice to know if in the unlucky chance that it won't, you still have the $15 option <img src="/forums/images/graemlins/smile.gif" alt="" />.

I, too had a bad experience with an old hot bond kit. It failed completely. I ended up sending that one back to Cascade designs for repair. Since then I have had excellent results with Seam Grip. Works like a charm, both for small pinholes - just smear some on - and for bonding Velcro to the Thermarest for pillow anchoring.