RIB Salvage Project, glue for PVC inflatable.

[Franziska]

Hi,

slowly advancing on the RIB salvage project. See photos below.

Old fittings are off, oarlocks are glued, hull is repaired, new patches are prepared for glueing(two bigger ones are made purposeful looking by adding a logo).

Once I have the patches glued I will paint with two layers of Veneziani Gummipaint.

Still I have glue problems after not having success with the local PVC plumber glue available here when gluing patches I am wondering now what of the following would work best:

-G-Flex, a special flexible Epoxy by Gugeon
-3M 5200
-Sikaflex 292
-Polymarine 2K PVC glue

So, which one should I try next on this old baby?
The Polymarine works, I even used a tin of it for the oarlocks, but it is very expensive, I can only get a small 250ml tin over here and it needs to be ordered online and I have quite a few bits to glue, so the other three or other alternatives are favored.

Suggestions, experiences?
I can glue it and refrain from using it for a few days, but the tubes might still deflate a bit after a while, so that could pose problems.

How do I get the old glue of someone else's attempts off?
Not sure what they used.

[JPA Cate]

Hi, Franziska,

We had success, using 5200, in gluing a pvc bottom over hypalon. The 5200 did work on that pvc surface, in an underwater usage.

To remove existing patches, use a hair dryer or a heat gun, whichever you have to use. The heat breaks down the glue bond, and you should be able to peel the patch off the underlay.

On hard surfaces, you can use a putty knife, heat the glue to moist, and peel it off with the putty knife.

You may have to sand off the last remains of some glues. Maybe someone else knows the best thing to clean it with afterwards, I think I'd limit it to methylated spirits. (my go-to is usually acetone, but it will melt pvc fabric.)

Ann

[Franziska]

Originally Posted by JPA Cate

Hi, Franziska,

We had success, using 5200, in gluing a pvc bottom over hypalon. The 5200 did work on that pvc surface, in an underwater usage.

To remove existing patches, use a hair dryer or a heat gun, whichever you have to use. The heat breaks down the glue bond, and you should be able to peel the patch off the underlay.

On hard surfaces, you can use a putty knife, heat the glue to moist, and peel it off with the putty knife.

You may have to sand off the last remains of some glues. Maybe someone else knows the best thing to clean it with afterwards, I think I'd limit it to methylated spirits. (my go-to is usually acetone, but it will melt pvc fabric.)

Ann

Thanks Ann,

good to read from you. I did use the heat gun and a wooden spatula to get the old patches off. That worked fine.

The remaining glue is the issue, it's probably not all PVC.
Guess I am going to sand it carefully off as you suggest.
Need to sand the tubes in any case to prep them for painting.

I noticed that the acetone attacks the PVC, so I'm probably only use that a little bit just before painting. Could not get MEK over here. The guys in the shop here use Acetone.

Good to hear about the 5200. That will be my choice then, what I like too that it's thick to bridge any minute gaps when a patch goes over another seam.
Luck has it that soon I'm going for a short trip to the US, so I can buy it there.

Thanks again.

[Tupaia]

PVC leaches plasticizer over time, this is what causes it to become stiffer, it also breaks down the bond structure of many glues.

You need a 2 part polyurethane glue specific for PVC
https://www.thegluepeople.co.uk/cont...pvc-p-115.html
This is essentially what Polymarine sell.

[Franziska]

Originally Posted by Tupaia

PVC leaches plasticizer over time, this is what causes it to become stiffer, it also breaks down the bond structure of many glues.

You need a 2 part polyurethane glue specific for PVC
https://www.thegluepeople.co.uk/cont...pvc-p-115.html
This is essentially what Polymarine sell.

Thanks Tupaia. The linked stuff would be great, but they are not selling to outside of the UK as it seems.

[Jim Cate]

^^^^
The problem with 5200 is the long cure time. That was a problem when we did the external PVC floor over an old Hypalon Zodiac's bottom... very hard to keep everything in contact for several days. May not be aproblem for you.

I'd be tempted to try the g-flex... several have reported good success with it here on CF.

Jim

[ttex]

Buy Christy's Red Hot Blue Glue. Buy Oatey's purple primer. Both of these things are at Home Depot.

Clean the spot. Dry the spot. Rough up the spot with 120 grit sandpaper. Rough up the patch with the sand paper.

Apply primer to spot and patch. Wait 30 seconds for primer to dry. Apply a thin amount of glue to both the spot and the patch. Press and hold for 15 seconds. This will weld the pvc together making it one.

I repair pvc pipes for a living and I have already done this on our PVC dinghy. The patch is going to last longer than the rest of the boat. The patch has been on there for two years. I had to patch it after I dropped a hardhead catfish and it's devil spines put holes in my dinghy.

[Franziska]

Originally Posted by ttex

Buy Christy's Red Hot Blue Glue. Buy Oatey's purple primer. Both of these things are at Home Depot.

Clean the spot. Dry the spot. Rough up the spot with 120 grit sandpaper. Rough up the patch with the sand paper.

Apply primer to spot and patch. Wait 30 seconds for primer to dry. Apply a thin amount of glue to both the spot and the patch. Press and hold for 15 seconds. This will weld the pvc together making it one.

I repair pvc pipes for a living and I have already done this on our PVC dinghy. The patch is going to last longer than the rest of the boat. The patch has been on there for two years. I had to patch it after I dropped a hardhead catfish and it's devil spines put holes in my dinghy.

Thanks, I'd try that, but unfortunately there is no home depot with these materials in Portugal.
Getting 2 cartridges of 5200 into a plane is probably ok. That stuff you mention I'm not so sure unfortunately.

[Franziska]

Originally Posted by Jim Cate

^^^^
The problem with 5200 is the long cure time. That was a problem when we did the external PVC floor over an old Hypalon Zodiac's bottom... very hard to keep everything in contact for several days. May not be aproblem for you.

I'd be tempted to try the g-flex... several have reported good success with it here on CF.

Jim

Good point about the curing. Especially as the tube is not 100% ok yet and slowly loses air until all patches are on.

And I can have that tommorow, the boat next to me has some.

[dkenny64]

have you tried PVC cleaner( the kind use on pipes?) then glue together with shower pan liner PVC glue. it stays flexible unlike PVC pipe glue.


just a thought
-dkenny64
I used it my pvc dinghy seems to work well. need to use the dinghy more to be sure

[ttex]

You don't need the exact brands. I was just trying to make it easier. You need PVC cement and PVC primer. that is the important bit. Primer not cleaner. PRIMER. And follow the instructions I gave. You don't need anything else. Good luck.

[Rumpi]

Contact cements: Plastigum 77, Sabacontact 70T, technicoll 8002 They all cost around 30€/l in 1l tins (250g or 350g also available but more expensive) plus shipping (9-30€) available from a variety of shops including amazon.
Cold welding: Bindu AK5, more expensive then the cements, more packaging options.

For local glues and expertise find the truck tarpaulin shop, they have glue and probably also hot air welders. Inflatable boat PVC is no different from pond liners, truck covers and advertising tarps, so the glues are identical.

[qwert]

There is a German co RENIA Köln - Klebstoffe für Industrie und Handwerk who make a range of suitable glues. The one I use is "syntic"You can usually get them at shoemaker/leatherworker wholesale suppliers.

You will find that the glues which work almost always have volatile solvents, mek etc. They aren't allowed on aircraft without proscribed special packaging.and labelled as dangerous goods. Costs an arm and a leg.

When you put the two parts together it is very helpful to have a small heavy roller to effectively squeeze them together

[Franziska]

Thanks everyone, enough food for thoughts.

After all I settled for the G-flex.

The main reason is that it can handle higher humidity levels better than the PVC glues (I work on sunny days outside & onboard the mothership).

Secondly it has some gap filling characteristics, stays flexible and I found a number of postings claiming successful use.
Cures faster than 5200 as well.

If it fails I let you know. Same for the oar locks, which I did glue with the small tin of Polymarine Glue I had.

[Franziska]

Summery for this thread.

I just glued the handles and patches on my PVC dinghy with G-flex. Seems to bond like hell.

Does not mind humidity, the special PVC glue does not tolerate this.

Has gap filling characteristics, the PVC glue has that only for a limited amount.

You need less G-flex than the special two component PVC glue.

So even price wise the G-flex seems better. While the G-flex is slightly more expensive for a pack you only use half of it, while you use a complete tin of the other stuff.

I'm sold on G-flex for inflatable repairs outside of a controlled workshop.