Poly Resin works

[Intermediate Mariner]

Just wanted to share this.

A poor man's (self employed so always broke!) solution for boat building.

Yesterday I was prepping part of my transom and sealed a coat of glass over the inside exposed piece... this is the piece I will tab to hull.

I noticed on another thread someone said to let it get tacky first before applying cloth.

Well, I didn't do anything and the cloth peeled right off the plywood like a candy wrapper, would have never held in a million years!... BUT, I did notice one thing: the cloth peeled right off but the resin stayed on the board! Hmmm. Have used before I know that the resin saturated cloth sticks to existing clean glass like nobody's business. And I had not even prepped the piece with acetone.

So I peeled the glass off the piece of plywood and sanded mostly bare (took awhile). I then prepped good with acetone and simply coated with resin and now man it's on there good! It will not lift or scrape with razor blade, it seems well soaked in - don't want my darn motor falling off you know.

What I found: prep the plywood with acetone first... then apply a sealing coat of resin and let dry, sand, acetone again and you're ready for layers.

I plan to watch the hull tabs and if I see deliamination I will cut it out and go with epoxy.

 

[CarTuner]

Re: Poly Resin works

What type of resin did you use as the first coat on the plywood that allowed the cloth to just peel right up, waxed (ie, finishing resin) or unwaxed (laminating resin)?

 

[Intermediate Mariner]

Re: Poly Resin works

It was the cheap stuff, the gen purpose with wax in it. Finding the other is like finding a needle in a haystack. I finally found a fiberglass supply but they only have 5 gallon buckets.

I have no problem with thorough sanding a acetone before each layer. And you can sure feel that wax too on the surface. Wish they would simply give you another little bottle of it instead of mixing it in for you. WTF

 

[Shife]

Re: Poly Resin works

Secondary bonds are weaker than primary bonds. Wetting out the properly prepped plywood and doing your layup in one shot would have created a stronger structure than wetting out the wood, letting it cure, sanding, and then completing layup on top of that. Doing the layup in one shot makes the resin soaked plywood substrate the likely failure point. Building on top of a cured layer of resin means the bond is only as good as the key in the surface you provide. When using waxed resin the layup must be done in one shot. Otherwise the surface must be wiped with a damp cloth to remove wax and sanded to further remove the wax and provide a keyed surface to secondary bond to. Failing to properly prep the surface causes the vast majority of 'glass layup failures.

 

[Nugglet]

Re: Poly Resin works

http://www.mertons.com/ has poly laminating resin with no wax by the gallon for $27.50 (you have to specify that you want the no wax resin)

they also have the wax (polyester surfacing agent) in a 2oz bottle for $4...

great store,,, great prices,,, great service,,, fast shipping... i will for sure be using them again for any fiberglassing needs

sounds like it was the wax that caused the delam

 

[Intermediate Mariner]

Re: Poly Resin works

Holy cow thats a good price for poly! Wally world stuff is $11.42/Qt.

 

[oops!]

Re: Poly Resin works

actually that is expencive......im buying 5 gals at 109. waxed or inwaxed.

resins whole sale price is really cheap....so shop around.

as explained a little earlier....people add resin and glass to an area and the glass comes off and the say poly is bad.
its the application that is bad.....not the product.
uasually if you look at the failed bond the surface will be waxed...or has oil in it or other contaminants.

the area must be prepped well....
scuff with 32 grit....vacuum and clean with acetone.

apply first layer of resin to the substraight...let tack...(the reason you wait to tack is to let the resin penetrate the wood and start a bond and seal.

apply second layer of reisn and glass....just enough to saturate the glass.....50/50 ratio is best.

apply the second layer of glass.....this soaks up any residue or resin from the first layer....and work it in with a air roller.

with un waxed resin....you can add to the cured layer for a few days and still have a good bond with the substraight with out re scuffing.
the bond wont be as good as a chemical bond....but you wont pull it apart with plyers.

cheers
oops

 

[martin6651]

Re: Poly Resin works

I don't think that Mertons are all that super. I sent them an email last week about one of there products and they never answered my mail. I may live on the other side of the ocean but an answer is not a lot to expect.

 

[system-f]

Re: Poly Resin works

I found some boat building guys that sell me unwaxed poly and as much MEKP as I want for $20/gal. I think composite one only wants $80 for 5 gallons, but there is a $125 min order and they are local so no shipping.

 

[oops!]

Re: Poly Resin works

if you can get comp one stuff......GET IT