epoxy and pvc

[john the pom]

Just the first of what will be a few "left field" questions from me.
I've had very little experience of fibreglass/epoxy use, and that little bit was almost forty years ago. This began as a simple question but grew into a four parter. :?
A, Does epoxy adhere to pvc? If not can it be made to with some kind of primer?
B, If it does adhere is there some other kind of primer which would act as a release agent?
C, Does anyone have any experience with any of this?
D, Is the heat from chemical reaction of epoxy and hardner likely to distort or otherwise damage pvc?

 

[hairymick]

G'day John,

A, does epoxy adhere to pvc? If not can it be made to with some kind of primer?

I don't think so. From the little I know, PVC is one of the few things epoxy won't bond with.

B, If it does adhere is there some other kind of primer which would act as a release agent?

Assuming my first answer is correct, you shouldn't nead a realeasing agent but car polish wax should work.

C, Does anyone have any experience with any of this?

Not me.

D Is the heat from chemical reaction of epoxy and hardner likely to distort pvc?

The exothermic reaction is directly proportioned to the amount of surface area of the epoxy resin. (and the volume of the resin) The greater the volume or lesser the surface area, the more heat from the reaction. ie, if you mix the resin and leave it in the pot, it will get very hot. If you take the same amount of resin and put it in a paint roller tray, it won't get nearly as hot.

Hope this helps a bit mate. Sorry I can't be of more assistance.

 

[john the pom]

Don't be sorry Mick, actually it helps a lot. Any information I can steal from you guys saves me from testing ideas or pursuing theories myself, and might steer me in the direction I need to be: and that will save me time and money. Not that I'm in any rush, still won't be ready to begin even for at least a few months. I hope to use that time to listen and learn from anyone that knows more than me. ok that would be everybody

 

[JEM]

Epoxy will not get a good grip on PVC. It will get some grip, but not one that I would trust not to leak.

West Systems claims to have come out with a new epoxy that will stick to plastics. I haven't heard how good or bad it works.

 

[john the pom]

Y'see Mick you just answered one of my future questions elsewhere on the site without me even asking it yet: :shock You said: 1. I thought I would be smart and i used 4mm hardwood bracing ply for the bottom panels and lighter, 3mm pine pl that I think is your luan for the sides. My reasoning was to achieve a stronder, tougher bottom. DON'T DO THIS. what happens is that the lighter ply is not strong enough to force the heavier bottom panelsinto shape. use the same thicknes ply throughout the boat. While I'll still consider using different thickness wood your response to that question certainly made me think about WHERE I could do that without getting into similar trouble to what you did. Am gonna end up owing you guys a few beers
Matt, thanks for that. I don't spose I'll be going to the trouble or expense of specialist high tech stuff but I appreciate your input and hope it will help someone else perhaps. The original idea was to maybe incorporate some fittings into a build rather than add late and have them look like afterthoughts.
PVC and plastic stuff comes in so many useful bits an pieces. I suppose at worst I could "encapsulate" them into where I wanted to if need be with cloth and over a previously glassed area. Mostly am just kicking a few ideas around, and you guys are passing back what you know.
This seems to be the essence of this site and what keeps it swallowing up previously normal people and turning them into.... people like you'all.

 

[JEM]

If you're using them for like a rod holder in a bulkhead or deck, then encapsulate them and you should be fine for the life of the boat.

I haven't heard the prices on West's new stuff. I'm guessing it'll be a little bit more pricey.

 

[hairymick]

G'day John, Only too glad to be able to help mate.

A heavier bottom on a flat bottom boat with no panel twist in the stems works fine. it is only where the panel twist comes into play in boats like Matt's Swampgirl that there might be problems.

Re the prices of Epoxy, International HT 9000 will cost you around AUD$130.00 for a 4 litre pack and West Systems 105resin and 207 special surface hardener will cost you about AUD$160.00 (if you shop around) IMHO, there is no comparison between the two and I will pay the little extra every time. I buy two packs for each build, and every few boats, I have enough left over for a freebee

Whitworths have the best prices on the fibreglass matt. I use the 85 gram stuff. others have raised concerns about its lightness but I haven't had any problems so far. it is about AUD$13.00 per metre.

Mate, have a look at Matt's Touring Pirogue. It might fit ya needs down there nicely.

 

[john the pom]

LMAO! Am willing to bet you KNEW I'd already been looking at the touring pirogue. It's what first led me to this site.