Polyester Resin & "Marine" 2 part epoxy adhesive

[itstippy]

I've gotten my hands on an old Starcraft 14' shallow V with bent oak gunwales instead of aluminum. There are rotten spots in the gunwales from old screw holes, water pooling between the sandwiched boards, etc. The rotten spots are "cavities" from the top, with good wood on either side and the bottom. To get a couple more years out of the old gal I dremmeled out the rotten spots like a dentist and packed them with 2 part Marine Epoxy adhesive - it mixes to about the consistencey of toothpaste. To my astonishment the repairs are GREAT! That white stuff filled the voids, got hard as Heck, and it now looks like it's worth doing a real repair job using the old wood vs replacing it. The sides are MUCH more ridgid. Bonus city! I've srtipped off all the hardware (oar locks, tie down guides, weird brackets, anchor brackets . .). I've wire-wheeled off the old paint that would come off, and the rotten surface wood, and dremmeled out the remaining small rot cavities. I'm about to mix more Marine Epoxy Adhesive to fill the rest of the screw holes and minor rot cavities. Then I plan to seal the wood with "bondo" brand polyester fiberglass resin minus the hardener. I've got 2 gallons of the stuff from a friend. Then I'll apply more "bondo" polyester fiberglass resin , with hardener this time, and lay overlapping strips of fiberglass cloth over the entire gunwhale, bow to stern. That should make it very strong and water tight. So . . .

1) How soon after I fill the voids & screw holes with 2 part Marine Epoxy Adhesive can I seal the wood with the raw poly resin? Does the epoxy have to cure entirely or can I just start slapping on the poly as soon as the epoxy adhesive is set?

2) How soon after sealing the wood with the raw poly can I start laying my overlapping fiberglass cloth pieces saturated with poly & hardener? Does the raw seal coat have to cure first or can I just get going with my glass layers right away?

Any tips are much appreciated!

 

[itstippy]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

 

[Bondo]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

I can see a couple of Issues with your Plan,........

1,.... Polyester Doesn't like to stick to Epoxy,......So you'll need to Sand it to a Course finish for somewhat of a mechanical Bond.......

2,.... Don't cover it with uncatalyzed resin,..... It Won't Harden....At All....
You can Reduce the amount of Hardener,... But you Can't totally eliminate it.....

You can start laying the Cloth,+ more resin at Any time,....
But,....
If the layer Under the 1 you're putting down is allowed to totally Set-Up,...
It's got to be Sanded again......To remove the Blush that forms as it Hardens....

 

[itstippy]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

Thanks. I knew one doesn't stick to the other well, but I couldn't remember which and which. So epoxy sticks to poly, but poly doesn't stick to epoxy, correct? Or are the two completely incompatible?

I'll rough it up and hope for the best. The Marine epoxy hardens to a very glossy surface.

 

[Bondo]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

So epoxy sticks to poly, but poly doesn't stick to epoxy, correct?

Ayuh,.........

Epoxy was Designed as a Glue,........

Polyester is Designed as a Casting Resin........

 

[Old Salt Oz]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

Poly resins will not stick to timber for the long haul, so it's just as well this will be just a temporary repair.

Epoxy resin sticks to timber very well, you can even thin it to improve penetration and make the timber even stronger.

Avagoodweekend......

 

[itstippy]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

Well, then, I guess my free bondo poly is out. I want a lasting repair. I finished getting out all the bad wood (spent many hours). The epoxy "marine" glue does such a great job of filling the rot cavities and screw holes that I'm convinced if I do this right it will last forever. It's like Seacast in a transom the way it's filled and set. I went over everything again with an abrasive disk and 50 grit and got the shiney "skin" off the epoxy glue that's exposed. Got off all the old paint, too. Next I'll epoxy paste the remaining holes and cavities and when that's set I'll rough it too. Then for the glassing. I need a source of epoxy resin to do the glass. They don't have it at Farm & Fleet where I got the cloth and mat. Maybe an online source?

 

[Bondo]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

raka.com,........... Larry will Fix you Right Up.......

 

[itstippy]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

Thanks! Looks good.

14" boat. The gunwales are about 1" wide and 2" high so figure 6". 6" X 14' = 7 square feet for one side; two gunwales equals 14 square feet total to cover with 2 layers of cloth. The transom is about 3 square feet. It won't be clothed but will be given a coat or two of resin. About how much do I need to buy?
1 1/2 qt kit
3 qt kit
6 qt kit

I bought two fiberglass material products at Farm & Fleet:
Fiberglasss cloth - Use where thickest repairs are required - 8 sq ft - 0,74m2
Fiberglass mat - Use where thichest repairs are required - 8 sq ft - 0,74m2
It's not that I 'require thickest repairs". I bought what they had. I think the cloth makes for more strength and the mat is for filling? I'm thinking two layers of cloth and forget the mat. Is there something better I should use for this application?

 

[Bondo]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

After you Finish Filling all the Holes,.........

I think that a soaking layer of Resin,.. Followed by a single layer of Cloth,+ a covering coat of Resin,............

You Should be Good to Go........

 

[sdunt]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

For cloth and you'll go broke buying the 'bondo' packages, check out: http://stores.ebay.com/Tordoff-Supply

For 'poxy I uses US composites: http://www.uscomposites.com/epoxy.html

They have a nice thinned 'poxy that is designed for fiberglass work.

Also, you now get to PAINT the entire boat. Epoxy is NOT UV stable and so it needs a top coating to protect it from the sun. Ever seen those yellowed epoxy repairs on something outside? Thats what happens. Thats also why the guys would build those really shinny canoes are always varnishing them, to protect the epoxy..

 

[itstippy]

Re: Polyester Resin & "Marine" 2 part epoxy adhesive

I've got my epoxy and cloth and will finally be ready to glass the wood rails & (new) transom soon. I got delayed by Scope Creep - that happens to about all the projects I take on. I have spent at least 20 hours scraping old carpet adhesive off the bottom with a putty knife. FINALLY done. The plan for the wood is one "soak coat" of epoxy, one layer of epoxy & saturated cloth, and a final finish layer of epoxy. Should I:
A) Do the entire "soak coat" and let it cure, then rough it with 50 grit sandpaper, then do the glass coat and let that fully cure, then rough it with 50 grit sandpaper, then do the final coat? Or
B) Do all three layers under a pot life or curing timeline, working from the bow to the stern and creating a finished 3 layer product as I go?
I've never worked with epoxy & glass before but I'm anxious to try.
http://forums.iboats.com/showthread.php?t=199076