Laminating plywood

[johnny be good]

Hello all again, demo went great on my transom repair after cutting inner shell with an 3" air cut-off tool [works great] if you use a fan its not bad at all mask and coveralls are a must. Anyway after reading all the answers to my old post I am going with poly resin and exterior glue plywood. I will first preseal the plywood with resin only but my question is when I laminate the first layer of ply to the outer shell do I use mating in between and when I laminate the second sheet of ply to the first sheet do I use mattihg there also or do I just use the matting after both sheet are in place to cover it all and tie into the rest of the boat? Will those cheap foam paint rollers work to spread the resin or will they melt? If anyone is interested in progress pics. they are in my old post titled "plwood help needed quickly" Thanks for all the help I wouldn't have even started this project without this site full of info.

 

[Greg Mrozinski]

Re: Laminating plywood

Jonny,

Yes use a CSM layer in between each. Resin the two pieces of ply together first then glue to the outer skin of the transom. You should wet down each side of the wood with resin. Let it start to tack up. Then put on the CSM. Then add resin to the CSM and then smash together align and clamp. Once that is done and hardened, do the same process for the wood and transom skin. This will provide a good chemical bond of everything. Good luck and post some pics.

 

[johnny be good]

Re: Laminating plywood

Thank you for the quick reply I don't know what CSM is but I am assuming it is the fiberglass mat name brand. So I understand to use the mat inbetween. Do you know if those cheap foam paint rollers will work and throw them out? I posted pics. in my other thread but don't know if they can be moved here if not I will find my disk and repost them, we all like pics.. Thanks

 

[Greg Mrozinski]

Re: Laminating plywood

Sorry. CSM = chopped strand mat.

No don't use the foam rollers. They come apart fairly quickly when they absorb the resin. Use a short nap roller or a roller specifically for resin. I used a 7" short nap roller to lay my glass. Work well. Just don't over roll it because the roller can draw resin back out of the glass when the resin is still wet. I tried to keep the roller well wetted with resin when rolling the glass out.

 

[PiratePast40]

Re: Laminating plywood

Another technique for clamping while the resin sets up is to use screws to hold the ply together. Remove the screws and fill the holes with resin before laminating the next piece. That way you're also squeezing the center portions of the wood that you can't reach with clamps.

 

[johnny be good]

Re: Laminating plywood

Thanks again I will try and see if I can move my pics. from my other post if not I will redo.

 

[Greg Mrozinski]

Re: Laminating plywood

Yup. I used PL Premium and then screwed my two pieces of ply together. I didn't bother taking out the screws since that side went against the outer skin. Used PL to glue the transom in against the outer skin/hull. Then I glassed in everything nice and tight. It will take an A-Bomb to remove that transom.

 

[johnny be good]

Re: Laminating plywood

Is that PL the construction adhesive sold at lowes or is it something boat related? If it is the constructoin adhesive it will probably have to be done before sealing the ply with resin so it can soak into the wood to bond right?

 

[johnny be good]

Re: Laminating plywood

After thinking aboult the PL adhesive I was just wondering since my transom rotted from water comming in from the top engine vents maybe I am better off using the resin because it will seal any water from getting to the wood again. Am I thinking right. I know its alot of questions but I am ready to start the rebuild and don' won't to go through this again. I am going to try to make somekind of cove for my vent that will still let the air through

 

[bugzy_1]

Re: Laminating plywood

The PL Premeim adhesive is a brand name that can be bouhgt at Home Depot. It is polyurethane const. adhesive. Its water/weather proof. Im useing it to bed my stringers/bulkheads to the hull then glassing over. Its cheaper to buy the big tubes.
You can also seal the back of the ply. then glue the trams. in with thickened epoxy res. ie. "peanut butter", a strong epoxy mix. There are several good threads on the site about it.
Good luck
Scott