Repairing the end-cap seams

Question · 16 September 2016, 08:52

Hello,

I need your expert opinions about repairing a leak at one of the caps [those small plastic (PVC?) conical pieces at the rear ends of the tubes].

I'm thinking about to bring the SIB to the service at the end of our holiday for a proper repair, but now I'm looking for a temporary solution that would last for a few weeks : )

I couldn't find a 2 component PVC adhesive locally and only could find single component a PVC-U (Tangit) glue. It's for hard PVC pipes actually and since that cap in question looks like a hard(ish) PVC, I thought it might work.

I've made an experiment on a piece of repair patch and it seems glued on itself well (hard to peel), but no idea about how long it lasts : )

Should I give up the in-home repair idea? Would I make the final service repair more difficult?

It's the piece marked with a number 12 in the pic. And looks like a 1 cm wide area is detached all the way there (approx 5 cm long).

I tried to attach the pic but here's a link in case...

http://images.jamestowndistributors....MMON/25189.png

Cheers

office888 · 16 September 2016, 13:14

Incorrect glues and adhesives can leave residue behind which permanently destroy the material by making further gluing with the proper glues hard or impossible.

I'd order the correct stuff.

Question · 16 September 2016, 16:14

Thanks for the reply

I also thought that I better leave the idea of experimentation aside, and I've ordered a 2 component PVC glue (Adeco, Adegrip) from a marine shop. And I'll wait till it arrives : )

But just out of curiosity, do you think a single component PVC-U adhesive would be completely incorrect for gluing a semi-hard piece of PVC (cap) to a soft one (the tube)or what would be the perfect one for these semi-hard to soft connections?

Regards

Quote:

Originally Posted by office888

Incorrect glues and adhesives can leave residue behind which permanently destroy the material by making further gluing with the proper glues hard or impossible.

I'd order the correct stuff.

office888 · 16 September 2016, 18:40

Quote:

Originally Posted by Question

Thanks for the reply

I also thought that I better leave the idea of experimentation aside, and I've ordered a 2 component PVC glue (Adeco, Adegrip) from a marine shop. And I'll wait till it arrives : )

But just out of curiosity, do you think a single component PVC-U adhesive would be completely incorrect for gluing a semi-hard piece of PVC (cap) to a soft one (the tube)or what would be the perfect one for these semi-hard to soft connections?

Regards

It would likely be too brittle and would fail the first time the joint is flexed.

spartacus · 16 September 2016, 21:15

End seam repair process covered here: http://www.rib.net/forum/f50/zodiac-...irs-52694.html

2-part PVC glue on Polymarine site.

Question · 17 September 2016, 14:58

Thanks Spartacus

Actually I’ve searched the site before posting and noticed that topic. At the moment my cap seam didn’t look that bad, with no visible abrasion, wear etc. But when I checked it again today to take some photos I noticed that cap to fabric adhesion is somehow deteriorated (without any visible abrasion and wear on the fabric), and it was easy to peel the cap away with my fingers. Luckily, all fabric to fabric seams/adhesion looks pretty strong and I can’t remove the ring like enforcement strip (glued over the main tube-to-cap joint) from the underlying tube fabric.

Now I have a more complicated gluing task. Hence more questions : )

a) I think I shouldn’t remove that ring (no 5 in the pic) like fabric from the tube, and glue them over the cap altogether, carefully aligning them through indentation (6) on the cap. What would you suggest?

b) There are four enforcement strips, two of them are over and other two are under the lateral seam of the tube. One white top strip (1) which looks like made of the same material with the tubes. Under it there’s a narrower and thicker grey strip (2). These two are outside edge of the tube’s lateral joint. And there are one narrow (3) and one wide grey (4) enforcement strips inside of the tube. Inside ones are extending under the cap, should I glue that extension (3, 4) under the cap? I wonder if some little gremlins worked from the inside to make the original glue job for that part : )

c) And one last question, how much glue is needed for that job? 125 ml? Or should I order a 500 ml one?

Regards

spartacus · 17 September 2016, 16:20

Thanks for posting the pictures. Looks a little more complicated than I thought. The tube material looks very clean, so I'm assuming that whole area was thermabonded.

This is probably a little more specialist in terms of repair, however I wouldn't treat it as a temporary fix. Once 2-part PVC glue sets, it's rock solid. If you're not confident with this type of repair, then leave it to a professional shop. Having said that if you're relatively good at DIY, then it's possible with preparation, decent ambient temperature and patience.

On closer inspection on Polymarine's site they say to prime rubber with hypalon glue. I'm assuming you'll have to do this to the end cap. You can then apply PVC glue to end cap and tube material for it to stick.

Dry a dry run without glue to see how everything goes together. Lightly abrade the end cap inside ridge on (6) and the area where it will affix on (5) with sandpaper. Degrease both areas thoroughly with MEK. Allow it to flash-off before applying glue.

The secret to this type of repair is to do it in sections. Yes it's going to take time, but if you're doing both end caps, allow a couple of days.

Wear gloves, common sense I know and make sure garage or area is well ventilated. I'd glue the lower inside section of (5) and section of cone end (6) to higher ridge say to 180 degrees in circumference, effectively half the repair.

Apply glue, (not too much), but enough to cover PVC. Leave half an hour until it's dried, then apply another layer, again leaving 30 mins. The glue will be tacky at this point. Fit into position and apply pressure to remove air and make sure you get a good seal. Hold tube in position and end-cap with gaffer tape. Make sure any excess glue is removed with MEK. Leave for 6 hours.

The top section will be a little more tricky as you will have to glue the strenghening seam (3 and 4) to the underside (5) in one go. The last section, seam (1 and 2) will be done last after you've given it another 6 hours. Use masking tape to protect the tube from glue as you'll see this area on the final repair.

Good luck.

Question · 17 September 2016, 19:13

Spartacus, many thanks for your time : )

Quote:

Originally Posted by spartacus

The tube material looks very clean, so I'm assuming that whole area was thermabonded.

Actually the whole thing came off very cleanly (odd, as if the glue is degraded somehow on one tube end, and the other tube end looks intact), so maybe only those grey reinforcement strips are heat-welded to white PVC fabric but not to the cap itself, because I can see a brownish thin residue over and under the cap's seamed areas (plus an 3 or 4 mm evenly extending over the edges of the seams).

Quote:

Originally Posted by spartacus

… if you're relatively good at DIY, then it's possible with preparation, decent ambient temperature and patience.

I’m supposedly not bad in DIY, having made my own speakers, amps, guitars, pants and hats haha… but gluing a vehicle with a remote risk of drowning is another story : )

Quote:

Originally Posted by spartacus

… prime rubber with hypalon glue. I'm assuming you'll have to do this to the end cap.

Do you think that the cap is made of rubber and not PVC?

Quote:

Originally Posted by spartacus

Dry a dry run without glue

Do you mean just checking for correct positioning of things prior to gluing?
And yes I intend to do it in separate sessions. First, gluing that inside extension (3, 4) to inside of the cap. I guess this is the most difficult part. I hope I could find a way to push it up from the inside.

Also, do you think applying a certain amount of positive or negative air pressure to the tube would help during the curing period?

Thanks again for your valuable suggestions and sorry if my explanations were a bit of difficult to decipher, I'm not a native speaker as you might have guessed already : )

Regards

Q

spartacus · 17 September 2016, 21:26

Quote:

Originally Posted by Question

Spartacus, many thanks for your time : )

Actually the whole thing came off very cleanly (odd, as if the glue is degraded somehow on one tube end, and the other tube end looks intact), so maybe only those grey reinforcement strips are heat-welded to white PVC fabric but not to the cap itself, because I can see a brownish thin residue over and under the cap's seamed areas (plus an 3 or 4 mm evenly extending over the edges of the seams).

If it was glued, then it's failed, either heat, UV degradation, pressure extreme, etc. Best you know about it and can sort it.

Quote:

I’m supposedly not bad in DIY, having made my own speakers, amps, guitars, pants and hats haha… but gluing a vehicle with a remote risk of drowning is another story : )

That's quite a DIY resume. There's no reason for the repair to fail, but if you're in any doubt, then leave it to a professional. I can't see the repair failing catastrophically, as the joint will be strong if done properly, in the right temperature.

Quote:

Do you think that the cap is made of rubber and not PVC?

Not familiar with Quicksilver SIBs, but it looks rubberised. I'm only knowledgable about Zodiac having repaired my own MKII CGT. The end caps are polyethelyne or similar, in effect molded parts.

Quote:

Do you mean just checking for correct positioning of things prior to gluing?
And yes I intend to do it in separate sessions. First, gluing that inside extension (3, 4) to inside of the cap. I guess this is the most difficult part. I hope I could find a way to push it up from the inside.

Yes. A dry run to see the best way to complete the repair, which part goes where and in which order. Use external pressure. Either that or feed a wooden pole/rod into one of the valve openings to provide rigidity to press onto.

Quote:

Also, do you think applying a certain amount of positive or negative air pressure to the tube would help during the curing period?

No, resist the temptation to inflate the tube. It takes 6 hours minimum in a dry atmosphere. Any humidity and the glue will bloom. If you know there is no glue overlap, then pressure in the form of G-clamps on blocks of wood gives constant pressure.

Question · 18 September 2016, 13:06

Thanks again for detailed instructions and sorry for many questions (looks like I have a well deserved nickname)

In terms of humidity... I was planning to do this in the garden 10 meters away from the sea : )

According to weather report the temp will be around 25°C and there'll be a 85% relative humidity here nowadays. Do you think these values are OK or should try using a room with AC to achieve a cooler and dryer atmosphere : )

Cheers

PS: I've made a tiny roller to be able to push that inside strip to the inner surface of the cap through the remaining opening around the cap. I hope it works. Because I kind of feel anxious about removing one of the valves to insert a long rod all the way : ) Maybe I can use a small sandbag placed inside to apply constant pressure until it cures then remove the bag and glue the rest of the cap.

spartacus · 18 September 2016, 16:35

Question - there's a good chance the glue will bloom given the relatively high humidity. Temperature ideally between 18-25 degrees, and humidity less than 60%, shaded and well ventilated. MEK and glue are both highly flammable, so don't work near naked flames. The glue smell is strong, so if area can be closed off after gluing then go for it. The roller looks good but I doubt you'll get it in the tube with the valve out. Again, it's just to be able to press against to ensure you get a good bond. A rounded pole or broom handle will do the trick.