I bought a board second hand with a good sized ding, pretty sure it was not fiberglassed with epoxy - can i fix it with epoxy?
Josh
Yes you can. But I always try to fix a ding with the same resin used to make the board. But yes, you can use epoxy to fix just about anything if it’s all you have. Just make sure you sand and rough up the area round the ding because you’ll be relying on a mechanical/physical bond to hold the two materials together, rather than an chemical bond.
I have used epoxy to fix an older board I know wasn't glassed with epoxy. I haven't finished the work, but plan on glossing with poly, as per my usual protocol. I have another board I need to re-gloss after some remedial work, I'll probably catch up on all my glossing then. Once I get to it, I'll try to post up some pics.
I just fixed up a few PU/PE boards using quik kick epoxy a few weeks ago. One had a large pressure ding between the fins and a large ding on the mid rail with some slight discolouration.
Just used some 4oz, as nothing needed filling with the ceramic bubbles. I think the white bubbles would have been really noticeable so stayed away from using them.
Used 60 grit to sand down to the weave and allow the epoxy to key-in. Worked up to 400 to finish sand the final coat.
The epoxy blended in better than my past PE ding repairs. Can’t really see it at all. Mixing small quantities 2 to 1 is really easy and there were three different temperature ranges on the bottle with the approx pot life.
You’ll pretty sure see a difference, but to fix the ding it’ll work.
I just wanted to chime in here. If you are fixing a ding on a polyester board, use polyester resin. Epoxy will be very clear and look nice, but wont give you close to the strength of a poly on poly bond. If you are really fixed on using epoxy, do like the others said and MAKE SURE you sand down the place you will patch as best as possible (don’t leave any smooth spots). Hope that helps.
[quote="$1"] I just wanted to chime in here. If you are fixing a ding on a polyester board, use polyester resin. Epoxy will be very clear and look nice, but wont give you close to the strength of a poly on poly bond. [/quote]
Couple of quick questions: How do you know this; and Why is it so? Are you saying Poly bonds chemically with cured / hardened poly? I ask, because my understanding is that once resin is cured, the only bond the next coat gets is physical, not chemical. I have used epoxy / fiberglass to repair dings on a poly board, and it seems very strong. So are you saying its gonna fall off after awhile, or that poly / fiberglass is just stronger than epoxy / fiberglass?
As far as I know, you are right… Once resin is cured, be it poly or epoxy, you are talking about a mechanical bond only. It used to be thought that if you soften poly resin with acetone you’d get a chemical bond with a poly repair, but that is not so with todays resins, which have better cross linking, and few “open” molecule ends to create that chemical bond you’re after. Everything I’ve read about the mechanical bonding properties of epoxy say it’s superior to poly when using it for repairs on poly laminates and coatings.
I suggest using the same resin for a repair as used to build the board because it helps make the repair disappear, not because it’s a better bond.
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Epoxy resin will not bond to uncured poly,and poly resin will not bond
to uncured epoxy.There is a difference between cured resin and just
hardened resin.If your bro has done “tons” of glassons then he should
have known there would not be a chemical bond only mechanical.Sounds like
the resin on the board was hard,not cured when the fins got glassed on
with epoxy.Then it wouldn’t matter what grit you prepped the area with.I
have to call B.S. o n your claims of not being able to fix a ding on a
poly board using epoxy,I’ve done plenty with great results.
I should have said that all the advice I have read is to use the same material to fix dings as the original construction.
However, I have been banned from using polyester resin where I live, so it was epoxy ding repair or no ding repair.
I was very sceptical about using epoxy on PU/PE.
If you get any epoxy drops on a sealed shiny surface then it is usually possible to get it off. When the boards were sanded with course grit then the epoxy appears to have a very good bond and could only be sanded off. How it lasts over time I don't know.
Surfboard epoxy is supposed to be more flexible and durable than polyester, so it will in all probability last a long time.
Without wax solution polyester resin does not harden at the surface. Epoxy on a poly laminate won’t stick because that laminate surface will never harden at the poly/epoxy interface. But to a cured sanded surface it will. Interestingly epoxy sticks to a surface that contains wax solution while polyester won’t. Polyester will bond to a polyester surface that doesn’t contain wax solution but epoxy won’t.
Polyester hot coats on epoxy are just a bad idea. They eventually peel off. We did this in FL 20 years ago and after about 3 years stopped. California followed and now most there have stopped for the same reason. Australia got hot on the idea and now people there are stopping as well. It sorta works but in the end it’s just a cheap, low quality short cut. Can create yellowing as well.