Need help with fiberglass/epoxy repairs

onecoolair · Nov 11, 2012

Piotr said:
So my 12-year-old son got the sailing bug. So he wants an Optimist for his B-Day. Wisely, I told him: "Your Dad spent all his money fixing a 1984 Mac 25 and cannot afford a $1,500 boat for you. Be happy with your $200 25-year old Eli." And what do you know - one of my coworkers has 2 teenage sons who just outgrew their Optis, and she was looking to get rid of them (Optis, although the sons are on their way out, too). So now my son is a proud owner of a pre-1995 Optimist. He is a 3rd (or the 10th) owner, so there are a few things to take care of, and this is where I need help:
1. The deck is coming away from the hull, at the bow - I will put epoxy in there and clamp it, but is there anything else I should know about? I read about using fiberglass strips to strenghten the joint from the inside (between deck and hull) - do I need to sand down the gellcoat all the way before putting fiberglass there?
2. As all Optimists, this one has a cracked bow. It's not a hole, but the crack is big enough to be through (the edges are actually displaced via each other). Do I sand it down along the crack and built up the thickness again with fiberglass? or just sand off the gell coat and put a few layers of fiberglass from both sides?
3. I fixed the sail (ripped near the mast) with a "super tape" - a clear vinyl-like patch with adhesive for "permanent" repairs. Is it worth it going to a sailmaker? It is a class-legal sail, and they go for $500 - used! does any one have a 1 ft sq. piece of dacron they could part with so I could make a patch?
Any thoughts will be appreciated and considered.

Make sure your son is part of the repair process. Better yet make him pay for part of the supplies.
My first year learning to race j24s at the local yacht club my crew and teachers was the local 12 and 15 year olds from the kids opti and sunfish fleet...I was mostly rail meat. I also learned fiberglass and gel coat repair from them. It was a lot of fun watching these guys beat there parents out on the race course. After that first year I was mostly on my own because most of the parents switched over to the newer j22s and gave the kids the old j24s to race.

finding41 · Nov 11, 2012

Check YouTube for fiberglass repair. You will be able to tell if the video is good by the comments below it. if you see: Your going to kill someone, you don't know s...., etc they aren't the ones to learn from.
One that is informative is from Tap Plastics.

rgranger · Nov 12, 2012

finding41 said:
.... you don't know s...., etc

MrBill_FLL · Nov 12, 2012

I would suggest polyester resin for repairs vs epoxy.

the reason is epoxy doesn't like to stick to epoxy, as much as polyester resin likes to stick to polyester. and I doubt this will be the last time you need to repair this boat.

pic's would help for a specific repair

the challenge is light is fast, but thick is strong.

take a look at the bi axle glass mat - really strong. kid tough material.
http://www.fgci.com/bp_productlist.aspx?subcatID=2532&level=4

http://www.fgci.com/buyproducts_catalog1.aspx

ps - Opti's are great! your son's 1st boat. you should show him how to glass. never too young to learn! LOL!

Barnacle Bill · Nov 12, 2012

First of all, use polyester. It is cheaper, as strong as you need it, if you do the repair properly and has no incompatibility with gelcoat, unlike epoxy. Epoxy is more hazardous to your health. You must protect your skin and lungs when applying it or sanding it. If you get sensitized to epoxy (it takes a while, but happens), then you cannot even get in the same room with it for the rest of your life. So, for your kid, polyester is safer to work with. In addition, epoxy has to be mixed perfectly for perfect curing. Polyester isn't so critical. You said you glued the deck to the hull with epoxy. That might not hold if you didn't use a filler as well, as a thickener, or adhesive thickener. Again, as someone mentioned, without pictures, it is hard to tell you exactly how to approach the repair. Cracks, as you describe, usually have to be ground down and if it goes through the hull, you should repair it from both sides for best results.

MrBill_FLL · Nov 13, 2012

you can thicken resin with talc power, or specialized thickeners like micro balloons or silica powder. mix with the resin, THEN add the catalyst. thickened glass takes a bit more hardener than normal resin.

joker460 · Nov 18, 2012

On my West System Hardener can, it says that the min recommended acceptable temp is 60 degrees. You might to apply some heat to the area and it might cure quicker.

Good luck

rgranger · Nov 18, 2012

Piotr said:
Ther temps were in the high forties and low fifties. Any thoughts? Help?

I have had trouble with fiberglass repair (both polyester and epoxy) as well as paint jobs anytime the temp is below 65F.

You might try taking the job into a warm place... heat lamps ...

Next time you have a job and the temp is ify... try bringing the resin indoors overnight to warm up. The reaction itself is exothermic so once it gets going it will stay at temp.

kbstrand · Nov 18, 2012

Barnacle Bill said:
First of all, use polyester. It is cheaper, as strong as you need it, if you do the repair properly and has no incompatibility with gelcoat, unlike epoxy. Epoxy is more hazardous to your health. You must protect your skin and lungs when applying it or sanding it. If you get sensitized to epoxy (it takes a while, but happens), then you cannot even get in the same room with it for the rest of your life. So, for your kid, polyester is safer to work with. In addition, epoxy has to be mixed perfectly for perfect curing. Polyester isn't so critical. You said you glued the deck to the hull with epoxy. That might not hold if you didn't use a filler as well, as a thickener, or adhesive thickener. Again, as someone mentioned, without pictures, it is hard to tell you exactly how to approach the repair. Cracks, as you describe, usually have to be ground down and if it goes through the hull, you should repair it from both sides for best results.

Epoxy is no more dangerous than polyester resin and one would use the same safety precautions in processing repairs with either resin. Epoxy is not as uv resistant and needs to be painted to prevent chauking. Both systems have advantages and disadvantages. I would consult experts on fiberglass repair if you are unsure.

finding41 · Dec 9, 2012

Piotr said:
Mystery solved. At issue is the insistence of Americans to use an antiquated system of measures (I'm joking - kinda). It turns out that while I estimated that I used about 1 ounce of epoxy, in reality I used probably 5 or 6 ounces. Consequently, I used too little hardener. I asked my wife for a measuring cup and did it right this time. No problems. Oh, btw, the epoxy adhered to gel coat just fine. Thanks for all of the advise.

What did she say about the measuring cup when you gave it back? You got all the epoxy off right? You did give it back...?
Here's a great Christmas gift idea...

sandpiper10471 · Dec 10, 2012

The epoxy may be adhered to the gelcoat just fine for now. Won't necessarily remain that way. Generally, whether using poly or epoxy, you must remove the gelcoat or you won't get glass to glass adhesion. Gelcoat has little structure or strength and separation can occur. Also, all mold release waxes as well as maintenance waxes must be removed prior to grinding or adhesion may be compromised. Make sure, please, you and your son wear really good masks: particulate filters for grinding, organic for applying resin. I recommend the 3M rubbery face masks.

Barnacle Bill · Dec 10, 2012

I do not agree with kbstrand. I have been doing fiberglass repair for many decades and you CAN GET SENSITIZED to epoxy. Any epoxy manufacturer will give warnings about this. It is not something that will happen in a short period of time, but it can happen. If it happens, then you cannot get in the same room with it. He/she is right when it comes to UV degradation. Epoxy does not hold up to sunlight so that it will discolor or get chalky or hazy. That is why if you want a plane wood finish, you should varnish over epoxy adding UV protection (which, BTW, is temporary, so you need to replenish the varnish UV inhibitors every now and then). Of course polyester can have some health issues if used improperly, but nothing like Epoxy because of the sensitivity. I have never heard of anyone becoming sensitive with polyester.

Barnacle Bill · Dec 10, 2012

Mixing epoxy must be exacting to prevent failure. You mix the hardner in the recommended volume with the resin. Adding a filler does not change the ratio. You are catalyzing the resin, not the filler.