RR epoxy peeling off on Repairs

General Discussion
1 
On more than one occation I have had my repair work not get a very good mechanical bond and peel off.

I post cure my board to 120 deg F

They are all sanded finish boards which no gloss or sealer

All dings and repairs are sanded with 60 git and then whiped down with DN alcohol with a clean rag

I do not use Add F on repairs

I use gloves to do repair work

What am I missing?

Never have a problem during production

I am tempted to use a heat gun on the repairs to try and get a chemical bond between the old and new.

CJ

2

I see on your profile that you’re in N. CA. If so, cool air may be your problem. Are you warming up the room to 70+ degrees?

3

If its peeling off, rather than cracking, maybe you could go with a less-flexible formulation for the repairs?

4

Drop the alcohol. Sand to 80 grit to get a good finish the resin can “key” into.

5 
    Thank you for the promp response Greg.

Should I just wipe the dust with a dry clean cloth?

Is the alcohol never to be used for prepping a surface?

CJ

6

For Greg L…

You say to sand the repair with 80 grit. Does 80 grit give me the best bond?.. or is 60 grit just overkill?..Both would work fine???

For cj3…

How long before your epoxy repairs show up with problems?

I have only one personal board with epoxy repairs so I’ll beat the crap out of this one in the name of R+D. I love surfing without a leash in small waves !!!

Having fun!

Ray

7

Obviously, it presents like a contaminant issue. Different source of alcohol, no alcohol, contaminated resin, different gloves, etc.

Take some of the epoxy used in a repair batch and let it set on a piece of paper to see if the cure is ok (ie: is the contaminant on the board or in the resin)?

If it is on the board, look to your surface prep. Don’t use the alcohol. Change the type of gloves you use. Try waiting longer after applying alcohol and before applying resin to ensure it is dry. etc.

If it is in the resin, you attack the resin. Or just replace the bottle you are using.

Divide and conquer. Some resin/hardener contaminant issues are mind-bogglingly tough to find, some are pretty easy.

HTH.

8

Just wondering,

on the repairs, are you using resin to cloth 1:1, or a resin rich mix? I’d like to check out that board of J’s I repaired to see if it’s holding up, because although I brought over some of my own resin, I used the DNA over at your place to clean if off prior to putting the patch on. But I used a lot of resin, and told J to sand it down afterward since he wanted to get back in the water right away.

Pat

9

http://www.grainger.com/Grainger/items/2UV86?BaseItem=2UV84

I’ve used another one that was like 3 bucks from Lowes, with real good results, comes out white and sandable, but you have a visible-ish patch…

10 
Pat

That one is in two pieces now so you should be able to get a good look at the repair from the inside out. I have not seen it but apparently it broke at the repair site.

CJ

11

lovely.