RIB repair. Hypalon and ?

[KD8NPB]

Originally Posted by Scout 30

I'd also like to know why & what exactly do you recommend?

The chemistry of 5200/4200/4000 is not formulated for this use. It is not plasticizer resistant. After the plasticizers from the PVC attack the caulking, it will debond again and the caulking will have a "gooey" consistency, but will be extremely difficult / impossible to remove without damaging the CSM/CR.

///

The correct technique for rebonding PVC/TPR plastomer to CSM/CR elastomer is to lightly sand, solvent wipe, then halogenate the surface of the CSM/CR elastomer. Within 8 hrs of application of the halogenation primer, glue the piece on utilizing polyurethane type adhesive formulated for use with inflatable boats mixed with ~5% of the correct isocyanate type reactant (Bostik Fixdur 100 / Desmodur RFE / RC or equivalent).

Halogenation primer is available in industrial designations as "Bostik Actisol SPW" and "Kiilto TR-Primer" . It is not available to the general public.

It can be formulated by making a solution of approximately 1L technical grade ethyl acetate to 5 gr sodium hypochlorite (chlorine, pool shock powder), then applying the solution with a rag to the area to be glued.

[skipmac]

Originally Posted by poiu

Bostik 2402 is the correct stuff. There are lots of other re-packaged suppliers of it or re-formulators out there, which may well be just as good and cheaper if you want to chance it. I used to mess about with 3M glues until I learned they were rubbish the hard way. I and others have posted this before, so I am surprised people still want to make the same old mistakes all over again.

If I recall (from research three years ago so I could be fuzzy on the details), the info I found on the internet for 2402 was based on bonding Hypalon to Hypalon and I did not find online information referring to 2402 bonding Hypalon to PVC.

[poiu]

Originally Posted by skipmac

If I recall (from research three years ago so I could be fuzzy on the details), the info I found on the internet for 2402 was based on bonding Hypalon to Hypalon and I did not find online information referring to 2402 bonding Hypalon to PVC.

Yes it is. You are quick off the mark. I had posted that, realised my mistake after a minute and deleted, but too late though.

[skipmac]

Originally Posted by poiu

Yes it is. You are quick off the mark. I had posted that, realised my mistake after a minute and deleted, but too late though.

You have to get up early in the morning to be as fast as I am.

[poiu]

Originally Posted by skipmac

You have to get up early in the morning to be as fast as I am.

The early bird got his worm.

[skipmac]

Originally Posted by KD8NPB

The chemistry of 5200/4200/4000 is not formulated for this use. It is not plasticizer resistant. After the plasticizers from the PVC attack the caulking, it will debond again and the caulking will have a "gooey" consistency, but will be extremely difficult / impossible to remove without damaging the CSM/CR.

///

The correct technique for rebonding PVC/TPR plastomer to CSM/CR elastomer is to lightly sand, solvent wipe, then halogenate the surface of the CSM/CR elastomer. Within 8 hrs of application of the halogenation primer, glue the piece on utilizing polyurethane type adhesive formulated for use with inflatable boats mixed with ~5% of the correct isocyanate type reactant (Bostik Fixdur 100 / Desmodur RFE / RC or equivalent).

Halogenation primer is available in industrial designations as "Bostik Actisol SPW" and "Kiilto TR-Primer" . It is not available to the general public.

It can be formulated by making a solution of approximately 1L technical grade ethyl acetate to 5 gr sodium hypochlorite (chlorine, pool shock powder), then applying the solution with a rag to the area to be glued.

Hi Richard,

Thank you for posting the detailed instructions for the correct method for bonding PVC and Hypalon.

NOTE: Hypalon for those interested in the minutia, is the Dupont trade name for CSM (a synthetic rubber, chlorosulfanated polyethylene). Dupont I believe is no longer making Hypalon but the trade name (like Kleenex) has entered the language as a commonly used term for the generic material. Since there are several manufacturers of generic CSM the quality may not be as consistent or reliable as it was when dinghy makers used genuine Hypalon.

Unfortunately I didn't locate this information about the adhesives and technique you gave when I was researching the repair so went with what I found at the time.

I understand the issue with plasticizers (which in this older dink was probably DOP largely replaced today with DINP), however so far, three years on, I haven't seen any separation of the rub rail from the sections where I used the 5200. Could be that due to the age of the dink much of the plasticizer had leached out (the PVC rub rail was getting a bit stiff) or the action on the 5200 is proceeding very slowly.

I have verified that getting 5200 off the Hypalon is almost impossible (guaranteed to pull the surface off the Hypalon) where I tried to clean off a couple of drips so anyone trying 5200 should understand that applying 5200 to a Hypalon dink will be an irreversible process.

For cruisers in remote locations with no access to the proper materials I think 5200 would be a workable solution but not the best nor the ideal.

[Westerly31]

My update how to clean rubbing strake from glue residue.
Today I use Circa1850 and it was easy, fast, and almost perfectly clean.

http://www.cruisersforum.com/forums/...attach/jpg.gif

[JPA Cate]

@skipmac:

One time, we used 5200 to bond a pvc fabric (Herculon) to a hypalon dinghy bottom, and it never failed during the time we used the dinghy. It was 13 yrs. old when we got it, and it was sold 7 yrs. later.

I believe the rubstrake is pvc, so 5200 should do for you. Use just enough, don't slather it on too heavily, or it will be a hard spot when you roll it up.

Ann

[skipmac]

Originally Posted by JPA Cate

@skipmac:

One time, we used 5200 to bond a pvc fabric (Herculon) to a hypalon dinghy bottom, and it never failed during the time we used the dinghy. It was 13 yrs. old when we got it, and it was sold 7 yrs. later.

I believe the rubstrake is pvc, so 5200 should do for you. Use just enough, don't slather it on too heavily, or it will be a hard spot when you roll it up.

Ann

Hi Ann,


When I was going through my repair I found a way to test it and confirmed the rubstrake is indeed PVC.



NOTE: The fumes from this test are TOXIC. Be very careful, do this outside, good ventilation and DO NOT BREATH ANY OF THE FUMES.



The test is to take a piece of copper wire, heat it in a torch (and for the Brits out there I'm talking about a thing that makes a flame, not a flashlight) like a small butane or propane torch, touch the copper wire to the plastic piece you want to test so you melt a small bit onto the wire, then put the wire back into the flame of the torch. If the plastic is PVC the sample will burn with a green flame due to the chlorine in the PVC (polyvinyl choride).


Years since I used the 5200 to glue my strake back on and it's still perfectly attached and has seen a lot of use, abuse and tropical sun.