BCD Patching Question

[pwscottiv]

A friend just gave me his Sequest Spectrum 3 BCD because he hasn't been diving in several years. It's in excellent overall condition, as he only put a few dives on it. However, while it was in storage, a mouse/rat chewed a small hole in it. The hole is about 0.5" x 0.75" on one side and about 0.25" dia on the other side (it chewed through both layers of the bladder to the other side). I washed/flushed and inspected the BC thoroughly and that was the only damage I could find. I'm pretty sure I can get patch material in through the vent valve hole and move it over to the damaged area without too much difficulty. Here's my questions:

1. Is it considered "safe" to patch a BCD with this sort of damage?
2. What materials/adhesive or patch kit would you recommend?
3. Is it standard practice to patch on the inside and outside (two layers), or can you just put the patch on the outside?


Thanks!

 

[fisherdvm]

My guess is it is safe until the patch blow when you need it the most. I wonder if you had good dexterity, you could fasten a mallable piece of aluminum or similar material to sand the inside of the BC bladder. Then apply contact cement or aquaseal to the sanded area. You can cut a round rubber and insert it by rolling it into the hole. Then somehow paint that rubber patch with contact cement and let semidry. Now manipulate it to center over the hole from the outside with a forcep or hemostat. Then gently stick it to the hole. I imagine that if you painted the opposite side with petrolateum it would prevent the contact cement from sticking....

Then you fill the hole with aquaseal, and apply aquaseal to the outside, and apply another patch on the outside.

With this, I would imagine a failure to be very low.... But would take alot of time and meticulous effort.

The quick and fast method would simply involve applying a patch to only the outside. It probably can be done within 5 minutes.... But it would blow if you inflate your BC.

You probably can also enlarge the hole and insert a standard dump valve in it... Might be a goofy place to have a dump valve though.

 

[fisherdvm]

Oh, how about a poor mans patch. You know those friction foam pads .... If you can roll one of those and insert through the hole, and peel the nonstick backing off... It might work, if you sanded the inside of the BC enough. Then fill in the defect with aquaseal till it cover the outside. I might even let it dry. Then reapply aquaseal, then apply a rubber patch on the outside.

 

[pwscottiv]

My guess is it is safe until the patch blow when you need it the most. I wonder if you had good dexterity, you could fasten a mallable piece of aluminum or similar material to sand the inside of the BC bladder. Then apply contact cement or aquaseal to the sanded area. You can cut a round rubber and insert it by rolling it into the hole. Then somehow paint that rubber patch with contact cement and let semidry. Now manipulate it to center over the hole from the outside with a forcep or hemostat. Then gently stick it to the hole. I imagine that if you painted the opposite side with petrolateum it would prevent the contact cement from sticking....

Then you fill the hole with aquaseal, and apply aquaseal to the outside, and apply another patch on the outside.

With this, I would imagine a failure to be very low.... But would take alot of time and meticulous effort.

The quick and fast method would simply involve applying a patch to only the outside. It probably can be done within 5 minutes.... But it would blow if you inflate your BC.

You probably can also enlarge the hole and insert a standard dump valve in it... Might be a goofy place to have a dump valve though.

That's pretty much what my plan was, except the petrolateum stuff... What is that? I was planning to put in some sort of temporary barrier material to make sure I don't glue the bladder halves together in the middle... That would suck.

The dump valve idea is good, except for the fact that I have two holes (because it ate through BOTH layers... Two dump valves would be ridiculous.

 

[pwscottiv]

Oh, how about a poor mans patch. You know those friction foam pads .... If you can roll one of those and insert through the hole, and peel the nonstick backing off... It might work, if you sanded the inside of the BC enough. Then fill in the defect with aquaseal till it cover the outside. I might even let it dry. Then reapply aquaseal, then apply a rubber patch on the outside.

I noticed that OMS makes a patch kit... Do you know if it works well, or if there's any other kits available?

 

[Scubakevdm]

I recovered two bodies once. The guy had a patch on his BCD that let loose, the girl was entangled with him.

 

[pwscottiv]

I recovered two bodies once. The guy had a patch on his BCD that let loose, the girl was entangled with him.

Hmm, that would suck. Do you think it's due to the fact that it was a crappy patch job or is it just unsafe no matter what? Did his patch have an internal layer AND an external one, or was it just the latter? Why the hell didn't he dump his weights?

 

[fisherdvm]

I would refrain from doing a crappie patch job, as it would be very hard to remove the crud if it failed. On second thought - the petroleum jelly is probably a bad idea. Hard to keep it from getting across and contaminate your good surface. I was just thinking that you would use contact cement on the inside patch job, and aquaseal on the outside. Contact cement dries faster and has instant strenght, whereas aquaseal is flexible, has alot of strenght, but takes 24 hours to cure (unless you mix with croton - but it makes it more brittle).

The petrolateum will let you put pressure on the inside patch without getting the excess glue from binding with the opposite side of the bladder. Certainly this wouldn't happen if you hadn't cleaned off all the crud and mould before you did your patch job?

I think in theory - you would really have 3 patches - 1. The inside patch that would bear some of the internal pressure. 2. The middle patch - aquaseal alone. 3. The outside patch - which does not contain pressure on the inside verywell, but will protect the aquaseal/inside patch from external pressure. In my opinion - it can be very strong if done right.

Now if it is in a location where you can insert a string to pull through either an open dump valve or elbow - you could attach a piece of nonstick wax paper or tin foil to it. Use aquaseal on the inside. Put some heavy weight on it. Then pull the paper/tinfoil out afterward. Or a place where you can bend up a piece of waxed cardboard and insert it under the patch, and still be able to grab, reroll it, and pull it out. Aquaseal should be alot stronger than contact cement.... But it is sticky and a pain in the butt to get off.

 

[fisherdvm]

On the thought of failure.... I guess I would probably never dive steel doubles with a patched BC and non releasable weights!!

 

[mrlipis]

How about this, call Seaquest and see if they will fix it. If they won't take the liability, why would you? It can either be fixed safely or it can't and I'm sure they will give you better advice than anyone on this board can. We would prefer not to read about Scott in the Incidents and Accidents forum.

Bruce