epoxy or polyester resin on aluminum

[mfbear]

Which should I use to patch cracks on aluminum hull? I know about JB weld, Gluvit and 5200 but am thinking of fiberglassing. Anyone know which is better, epoxy or polyester resin?

 

[Uncle Dave]

Re: epoxy or polyester resin on aluminum

Bear:<br /><br />Most of those repairs are not acceptable for an alum. hull. However you need to be a little more descriptive of the problem, Type of boat, welded or rivited , where and how big a crack. The better the description the better some one can offer a suggested repair<br /><br />fitz

 

[beckerdg]

Re: epoxy or polyester resin on aluminum

I'm with Fitz I doubt either are really suitable. Polyester won't even stick to itself, Epoxy might go a season or two, but doubt it will last.

 

[mfbear]

Re: epoxy or polyester resin on aluminum

It is an aluminum v-hull that is riveted. I have been cleaning all rivet heads down to bare metal to apply an aircrat sealer. The boat had several places with fiberglass so in the process I removed the glass to see what had been fixed (?). I found two hairline cracks about 5" and 2" long, and a place that had been welded then they put fibglass over it. All this is below water line. Then I went back out after I posted the question and removed another place with glass on it, now the big problem. I found a hole clear through about 1" X 2" right at the front of a bottom rib. They had put some kind of metal (not aluminum) patch inside then covered it with some kind of sealer. On the exterior they filled in the hole with more sealer and then covered that with fibglass. Hope this is enough info. Thanks guys.

 

[BF]

Re: epoxy or polyester resin on aluminum

I bought a 16' aluminum that had a bunch of old fiberglass/polyester repairs on it when I bought it (on the outside). The resin was cracking/flaking off all over. Some places I could see what had been patched, in other places I couldn't. As soon as I got the boat home, I flipped it over (this is an open fishin' type boat, no windshield etc) and wire brushed/ground all the resin etc off. Once cleaned I turned back up & put water in it. Marked all spots that leaked. There were several (6 or 8) small cracks (an inch or two starting at a rivet) and a few leaky rivets.<br /><br />After that, I took the boat to a heliarc welder I know... he welded several aluminum patches on the outside, covering all the little cracks etc. It took him ~ 2 hours and cost me $120. Lastly I put a dab of fast cure 5200 on all rivets below the water line (on the outside). (I didn't care if there were white "spots")<br /><br />Anyway, I used the boat all season. Doesn't leak at all and it is reassuring to know that the bigger damage is repaired solidly (welded patch).<br /><br />Anyway, that's my experience. And no, I wouldn't use polyester resin, it's too brittle and peels. Epoxy, I dunno. An aluminum patch and a good welder (someone who does a lot of boats) is best in my opinion.<br /><br />Good luck.<br /><br />Brent

 

[boat doc]

Re: epoxy or polyester resin on aluminum

I agree with these guys, a lot of people use fiberglass on metal, but it is not the thing to do. If you are determined to not let someone weld it up for you, in my opinion, jb weld would be your best bet. clean the area that you are going to apply whatever you use real good, give it a little scuffing, and go for it. If you are going to use the boat in some big water, I would have it welded.

 

[pbailey]

Re: epoxy or polyester resin on aluminum

Have the cracks and holes welded or patched with welded plates.<br /><br />Patching leaky rivets is a waste of time. For the leaking rivets. Just reset the rivets. <br /><br />Read this for leaky rivet repair.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=006350 <br /><br />pbailey

 

[walleyehed]

Re: epoxy or polyester resin on aluminum

mfbear, if you would email me, I would tell you how I've done that type of repair.....I'm an Aicraft Mechanic and I've got a simple fix, but would take too much space on this board.<br /> My father and I still run the Marine buis. but after I became an A/C Mech, I've learned many ways to handle alum.<br /> Also, the boys (MEN) above are right about the resin/glass.....It gets you to the middle of the lake, and THEN starts leaking..... <br />ktsanderson@st-tel.net

 

[crazy charlie]

Re: epoxy or polyester resin on aluminum

I had a 25ft chrysler Lone star cabincruiser,alum with rivets.I had to do a repair of a crack and hole in the same spot in 1 day and could not get to a welder.I sanded and cleaned the spot inside and out.the welder told me not to use a wire brush on it and i dont remember why.I wiped it with acetone.I put 3m 5200 all over the outside and inside going past the damage in all directions.then I sandwiched it with 2 pieces of aluminum and wiped up the 5200 that was forced out.I did not sandwich it too tight because the more 5200 left in there the better,it has incredible strength.Well I kept the boat for another 5or 6 years and every year I attempted to take the repair apart and fix it right but the temporary repair was still perfect.I recently saw the boat and asked about the repair and it was still holding great.Not a professional repair,but pretty darn effective!! And less than 20 dollars. Charlie