Fiberglass Repair?

[johnson1st]

I have a Larson semi V that has a crack on edge of side / bottom just behind driver seat, on outside of boat. Last winter I tried patching by grinding out 1/2" wide and at least 2" longer than original crack. Stuffed the crevice with resin/cloth until it came out flush. Even used wax paper to have semi smooth finish between layers. Covered side and bottom with at least 4 layers of resin/cloth, at least 2" past opening. Looked like it would work. 2nd outing to lake, I took on about 20 gallons of water, and crack came right back thru. Any ideas how I can fix for good? My son wants the boat and I want him safe on the water...thks.

 

[craze1cars]

Re: Fiberglass Repair?

Check out the "boat restoration and building" section of this forum and maybe post your question there. Your method sounds OK to me, but if you used Poly resin and didn't get everything perfectly clean/dry AND get the hardner/resin ratio exactly 100% perfect, the bond strength may have been poor. Epoxy resin is much more forgiving with regard to cleanliness, more pleasant to work with, and is generally stronger than Poly. Also if you can gain access to the inside of the hull, a two-sided repair would be significantly better. Plus it would reveal if you have a hidden structural problem (broken or rotted stringer?) that's causing excessive flexing at this location.

 

[LubeDude]

Re: Fiberglass Repair?

craze1cars has hit on some good points, also, many make the mistake of using too smooth of a finish before doing the glassing. 40 grit grinder makes about a perfect rough finish for glass resin bonding. Anything less may result in a less than desirable repair.<br /><br />Just reread your post, noticed that you said you ground out the crack 1/2 inch. Sorry, thats not nearly enough. If the glass at that point is about 3/8 inch, you should have tapered it out to about 1 1/2- 2 inches on each side of the crack.The edge of the crack should be paper thin and then beveled out the distance I said. Your repair might have held if you would have backed it up on the inside to a measurement of about 4 inches total.

 

[johnson1st]

Re: Fiberglass Repair?

thanks craze1cars and lubedude, but, i ground this out 1/2 wide all the way thru the hull. Then packed with cloth/resin. After I made it to outside of hull, I covered 2" up and down, and at least 3-4" past in length. The crack came back, and about 10" long...but, I'm going to take new floor back out, and check on inside. I know there was about a 6" ledge above hull bottom, and only about 3/4" between the 2, that's why I stuffed cloth/resin in from the outside...must not have been enough support...anymore ideas, are appreciated...thanks

 

[Terry H]

Re: Fiberglass Repair?

You really need to do a structural patch from both inside and outside leaving room for a gelcoat type decorative patch on the outside. If you can't get to the interior side of the damage the repair will never withstand any stress. Chief

 

[jaxsun]

Re: Fiberglass Repair?

everything mentioned before but also remember to use the resin lightly...you need just enough to saturate the cloth...to much resin is brittle...the method i use when glassing is to cut out the strips of mat and fray the outside edges...mix your resin and hardner then take a cheap 1-2" paint brush and coat the repair area...then you apply your pre-cut fabric and brush with just enough resin to saturate the fibers and work out all the air bubbles...do that till you built up enough or your resin starts to harden....should you need to apply more grind the repair area with a 40 grit disk...concentrate on knocking down all your high spots first making the area flat as possible and make sure you kill ALL the shine then repeat the process...oh and another thing...moisture and glassing dont mix well

 

[johnson1st]

Re: Fiberglass Repair?

thanks to all, maybe I better check out someone who does this for a living. I've got two to work on now. But, still want to get this one ready for my son. I found a business about 30 miles away that does fiberglassing, I think I'll call them next week. You guys have scared me out of trying again. I don't think I want to cut a hole 4" wide and 18" long out of the hull and try to fill, if I'm understaning right. thanks again...

 

[jaxsun]

Re: Fiberglass Repair?

actually you dont cut a hole in it...what you need to do is bevel the edges all around the damaged area...what your trying to achive is a gradual slope about two inches wide on all sides of the crack...but if you dont feel comfortable there are people that do it for a living...good luck

 

[johnson1st]

Re: Fiberglass Repair?

jaxsun,thanks, I think I know what you mean, but the hull isn't real thick. Probably less than a 1/4"...if I did try, between the bottom and the 6-8" shelf about 3/4" above bottom on the inside...how would or could you put some strength in there? would you fit a piece of wood and wrap it with fbgls/resin/cloth??? maybe I should see what the fbgls guys would charge...????<br />besides, when I did it the first time, the 1/2" I cut out was all the way thru the hull, I just don't see how it could have cracked in the same spot...thanks.

 

[ondarvr]

Re: Fiberglass Repair?

Don't only use cloth in the repair, it with not bond well, you need to use mat as the first layer to make it stick well. Don't "pack with glass and resin", the fiber glass needs to lay flat on the surface, it can be shaped around a corner, but not folded or packed. If you were able to do it the first time, with a little help this time you should be able get it right.

 

[jaxsun]

Re: Fiberglass Repair?

it wouldnt hurt to check out how much they'd charge you first...it might be worth it