Botched seam repair

Dudlet · 09 July 2016, 21:28

I had a seam come loos on my Brig PVC inflatable RIB. I used proper PVC repair glue to fix it. However, I stupidly forgot to deflate that chamber before doing the repair! The fix didn't totally take as there was a small leak and air bubbles under the seam where air separated the seam piece from gluing to the rest of the tube. I have since glued again along the seam - this time with the chamber deflated - and it appears to be holding. However, I'm sketched out by the air bubbles under the seam piece where it didn't glue. I'm afraid one day the whole seam might give out because of this.

If it is holding air, should I do anything at this point? If so, what? Or should I just wait it out? I thought of putting a patch over it, but that seems tricky because I don't know how well it seal over the crease of the seam. I also thought of using a medical syringe to carefully inject glue in between the seam piece and the rest of the inflatable. Of course, that would create a small hole in the seam piece.

So, what do you think I should do?:

spartacus · 09 July 2016, 22:07

Think you've answered your own question. Seams are safety critical. Haul it apart, and do it properly.

idsebby · 09 July 2016, 23:54

You can cover the whole thing with a large patch and use storm sure to bridge the gap that the seam leaves. Is it still leaking or did you fix the leak. If it's still leaking do it all over.

office888 · 10 July 2016, 03:27

The only safe way is to completely unglue and reglue the defective seam. Or replace the boat.

Glued PVC has a life expectancy... You eventually reach a point where literally everything is ungluing.

Dudlet · 10 July 2016, 05:06

How would I un-glue and re-glue it?

office888 · 10 July 2016, 05:20

Quote:

Originally Posted by Dudlet

How would I un-glue and re-glue it?

With a heatgun.

Then, chemicals to remove the old glue. Either MEK and a lot of scrubbing or methylene chloride.

It sucks, but it's the best way. Everything else is a band-aid.

Dudlet · 10 July 2016, 07:06

Yikes! I'm afraid if I do that I might go too far with the heat gun and MEK or methylene chloride and unglue the whole seam. Any suggestions on how to do it without making things worse? BTW, where do you get methylene chloride?

idsebby · 10 July 2016, 16:16

If you slowly heat up the area it will only come apart where you pull at it. I would use a blow dryer. It's not as powerful as a heat gun and makes you work slower. Take your time don't rush.

jyasaki · 11 July 2016, 16:04

If you're sure you got the adhesive covering the entire area (talking about where the bubbles are), you may be able to adjust the integrity of the bond. Use a heat gun to warm the area (you're trying to use heat to soften and reactivate the adhesive) then burnish the area down while warm. A thin roller (like a 1/4" wide wheel) is ideal, but you can get away with any smooth rounded object that is long enough to get good pressure on.

jky

Dudlet · 12 July 2016, 00:36

Wow, you can reheat the glue and it will still work afterwards? Then, yes, I will definitely try this option first as I know I got plenty of glue in where the bubbles formed.

cgoing · 12 July 2016, 12:19

You may have too much glue in their which is never a good thing. The other issue that can cause difficulty in repairing is material
Degradation. If the material discolored and getting stiff or tacky then it is starting to break down and will typically not bond well.

jyasaki · 12 July 2016, 15:00

Quote:

Originally Posted by Dudlet

Wow, you can reheat the glue and it will still work afterwards?

Yes, it's a regular practice if you coat the material and get called away for longer than normal (like days.) Some also add a wipe with solvent, but just heat works as well.

Quote:

Then, yes, I will definitely try this option first as I know I got plenty of glue in where the bubbles formed.

It's simpler, and if it doesn't work, you're out a couple of hours but not much labor.

As cgoing mentioned, too much glue is as bad as not enough. For PVC, the glue melts the fabric surface and welds to it. You need just enough surface adhesive to allow the two layers (one on each repair piece) to stick to each other; a barely perceptible layer should do fine.

jky

Dudlet · 12 July 2016, 19:06

Hmmm. I don't think I got too much in there, but now you have me worried. Assuming I originally used too much glue, is there a chance that by heating the glue back up I could make things worse? For example, could the reactivated glue start eating away at the PVC?

jyasaki · 14 July 2016, 15:00

Quote:

Originally Posted by Dudlet

Hmmm. I don't think I got too much in there, but now you have me worried. Assuming I originally used too much glue, is there a chance that by heating the glue back up I could make things worse? For example, could the reactivated glue start eating away at the PVC?

I doubt it. It's the solvent in the adhesive that softens the PVC for the bond. Once that flashes off and you apply heat, you're just softening the remaining adhesive so it will stick to itself (or in this case, the adhesive on the other piece.)

jky