Going from epoxy to poly resin on transom. Bonding question

[farmer9009]

I have read that poly resin will not stick to epoxy. Is this 100% true? The question is that I installed a transom using epoxy and am now running low on epoxy resin. Is there anything I can do to finish a couple of tabs using poly resin? Is there some prep that can be done to allow the poly to bond to the epoxy resin? I ask this because poly is available locally and epoxy is not.
Thanks.

 

[Cadwelder]

Re: Going from epoxy to poly resin on transom. Bonding question

Nope, polyester resins just don't adhere to epoxy.....you'll need to buy some more epoxy.

 

[88BLiner]

Re: Going from epoxy to poly resin on transom. Bonding question

Yes it is 100% true. Poly will not stick to epoxy.

 

[erikgreen]

Re: Going from epoxy to poly resin on transom. Bonding question

Well, sorta.

It's not recommended because it's tricky, and you won't get even as good a bond as when using poly on ordinary materials like wood.

If what you're doing is only cosmetic, you can sand the epoxy with 100 grit or so and get the poly to adhere enough so it won't fall off. This isn't anything close to a strong enough bond for structural work, especially in a transom.

There are also some "tie coat" type products where you can paint the epoxy with the product. The poly bonds to the tie coat at least as well as poly bonds to anything. Some of the duratec products do this. It would work, but it would be cheaper to just buy more epoxy.

I'm guessing you want to skip buying more epoxy because of the price? Where did you get your first batch? I recommend US Composites as an inexpensive, quality source for epoxy. Cost is about $50 a gallon including shipping.

As an alternative, Vinylester will bond to epoxy ok if it's clean and prepped well. Not as good as epoxy, but stronger than poly and a little cheaper.

Erik

 

[Yacht Dr.]

Re: Going from epoxy to poly resin on transom. Bonding question

I have read that poly resin will not stick to epoxy. Is this 100% true? The question is that I installed a transom using epoxy and am now running low on epoxy resin. Is there anything I can do to finish a couple of tabs using poly resin? Is there some prep that can be done to allow the poly to bond to the epoxy resin? I ask this because poly is available locally and epoxy is not.
Thanks.

This is a loaded question ..

What Poly and what epoxy are you using ??

Without data sheets Nobody can answer you question farmer..

Got links on what you used .. or what you plan on using would be more informative then just suggesting that Epoxy/Poly bond is possibly incompatible ..

YD.

 

[farmer9009]

Re: Going from epoxy to poly resin on transom. Bonding question

I am using epoxy I purchased from www.uscomposites.com. After reading Yacht Dr.?s post I realized I might find my answer on their web site. This is what I found
?27. Can I put polyester gelcoat or polyester resin over epoxy?
There are conflicting opinions on this subject. We DO NOT recommend applying a polyester gelcoat over epoxy. The polyester based resins/gelcoats do not offer great bonding strength to the epoxy. Instead of gelcoat or polyester we recommend using an epoxy or urethane based primer and paint to finish your epoxy made part. Some industry leaders for these type of finishes include Interlux, Pettit and AwlGrip.?
So to be safe i will just stick with Epoxy.
Thanks for your help.