plywood choices for floor and transom

[Kracker Jack]

I know where theres a couple sheets of that form plywood at, but they slapped diesel fuel on it a couple times to reuse for concrete forms and keep the crete from sticking to it. I looked into some at my Grandaddys house after reading one of your thread responses.


Back to this "hot coat" technique one of you guys posted on here about treating a cdx with raw resin and letting it soak in and then putting a Hardener/resin batch over that then sanding then applying to transom. Is this true? this sounds fairly plausible to me. Im probably gonna go with marine ply. But just curious about materials that some backyard builders use and are sucessful with.

[spareparts]

I don't like the idea of having resin without any catalyst under cured resin. I don't think the under coating will ever kick, I could be wrong as I've never tried it. I usually lay down a thinned coating of resin with catalyst, thinned with acetone, (you have to add more catalyst when you thin with acetone), the thinned resin gets into the wood pretty good. Don't thin more than 10% as it won't kick

[RidgeRunner]

Yep, That is a hot coat. With Vinylester it helps to penetrate into the wood and gives it some bite. Essential on Kiln Dried PT Plywood IMO. With PT plywood the cells of the plywood that would ordinarily be open for penetration are actually full of preservative, metals like chromium copper and arsenic. It can give a case hardened effect making penetration difficult, that is why I recommended you grind it with some 40/60 grit before laminating with glass.(It helps the mechanical bond) Always wear Personal Protective Equipment when working with PT or any time you grind or sand on glass.
If you seal any type of plywood properly it will work for a long long time. I do not consider Wellcraft's glasswork to be that outstanding. My hull had lots of voids and buggers once the foam was removed.
ACX Fir seems to be a lower cost alternative to Marine Plywood and is available at most of the Box Stores. You need dry and without contaminants.

I have always mixed the hardener in with the resin. I'm like Spare, how does the resin underneath harden. I try to keep the ratios of hardener to resin consistent at the low end of the scale so I can have the most potlife and work on larger areas. (Mind you I glass in 95 degree weather) I threw out more kicked up in the bucket resin than I care to admit trying to find balance.

[Kracker Jack]

I will be glassing in a controled temp warehouse. but in va beach we are averageing 75degrees and high humidity. fellas thank you so much for the help so far, keep it coming im like a sponge soaking up info.

[spareparts]

Originally Posted by RidgeRunner

) I threw out more kicked up in the bucket resin than I care to admit trying to find balance.

I know all too well about that, had to scrape off uncooked resin as well
Kracker, start making some small repairs, check temp and humidity, make accurate measurements of the hardener to glass. don't use the that looks about right method that my self and Ridge probably use. Check the time it takes for the resin to kick. Don't forget that you can cut off excess glass while "green" with a knife or scissors before it kicks completely. Once you get a handle on the time frame it takes, start making bigger batches. Keeping the batch together in a cup or bucket makes it kick faster, spreading it out over a surface slows it down, heat will get it to kick when its slow(hairdryer). Putting the mixed batch in the fridge will slow it down(makes your food taste funny to). Acetone will require more MEKP(hardener), don't go over 10% with the acetone. Wear gloves and long sleeve shirts, its better than picking resin out of your arm hairs later, and acetone makes your skin itch

[spareparts]

one other trick, if you have to reinforce something on the back side, take a piece of pvc, cut it in half down the middle, lay on it the piece your glassing after a layer or two, lay the next layer(or two) over the pvc, it will create a chamber that will make it stiffer. I know some guys that build racing sailboats(yes I used to race), they have a rubber oval shape hose they lay inside the molds, they glass over them, then after it kicks, they pull real hard, the hose gets smaller from pulling it, and it slides out, leaving only the glass in a shape that makes it stiffer.

[Kracker Jack]

I have a couple more questionn for you guys while we are on a roll here. What kind of cloth should i use for the transom and floor? 1708/45? how many ounces? waxed or non-waxed resin? I have noticed the non waxed is more of a laminating resin but stays kinda tacky even after it kicks. thanks fellas. Im asking these questions not because i have not done my research im asking them because im curious how different people do things.

[spareparts]

don't know the names or numbers for glass, I usually use what I find a deal on, if its thin, I use a bunch of it, if its think, I use less.
Yes, laminating resin doesn't have wax, it allows the next layer to stick better, keeps the glass in place