PVC board as stringers??

[Dquinn]

Dear gentlemen, the day has come. Haha. I've ripped, torn, snorted, cussed, brushed, grinded, cussed, sanded, planned, planned, cussed some more, planned, and over cleaned all I can do. Next time I work on the boat it will be to build back! Pulled it out today and washed it with some simple green and measured for materials. I have a few questions around some other threads I've read and "knowledge" I've pulled from them.

1. I have planned to bed stringers and motor mounts in PB since I started this project and then read something on a poly based bedding material for more flex.. opinions? PB seems like a better option to me.

2. Are " hard spots" a concern under pb? Saw Frisco boater put some foam squares every so often under his stringers so that the actual wood didn't touch his hull. Also why some folks saw use poly bedding.

3. Penetrating epoxy? Can I thin down the resin I have with some acetone? Is thinning even necessary? As I understand it it's best to soak a good bit of resin into the wood before laying up so it doesn't wick the resin out of your mat and make the layup go dry.

4 what is y'all's opinion on boat foam? Bore holes and pour or spray and trim before floor goes down?

(Edit) 5. Best way to seal the plywood decking? Soak it with resin or paint? Glass mat the top? With a sheet of csm? Biaxial?

 

[matt167]

IMO, PL Premium is cheap and easy to work with. It works fine. BUT you need to let it cure for a few days or a week for it to out gas before you glass it. PL is a polyurethane construction adhesive, hence PL.

Poly resin works fine. You can't put poly over epoxy, but you can put epoxy over poly. If you do your boat in epoxy, it will theoretically last longer, but it may or may not hold true. It adds cost and changes material selection a little bit as you don't need anything with CSM in it as it does not require the styrene to work correctly

 

[Dquinn]

IMO, PL Premium is cheap and easy to work with. It works fine. BUT you need to let it cure for a few days or a week for it to out gas before you glass it. PL is a polyurethane construction adhesive, hence PL.

Poly resin works fine. You can't put poly over epoxy, but you can put epoxy over poly. If you do your boat in epoxy, it will theoretically last longer, but it may or may not hold true. It adds cost and changes material selection a little bit as you don't need anything with CSM in it as it does not require the styrene to work correctly

I've been wondering on this for a while about my boat, but how can I tell if it was built with epoxy resin or poly. I've bought some poly, and the whole boat is a yellowish tint which after looking at a lot of stuff makes me thing it's epoxy, but I for sure has a lot of csm used in the construction of the hull and glassing/bedding in the old stringers

 

[Dquinn]

I've been wondering on this for a while about my boat, but how can I tell if it was built with epoxy resin or poly. I've bought some poly, and the whole boat is a yellowish tint which after looking at a lot of stuff makes me thing it's epoxy, but I for sure has a lot of csm used in the construction of the hull and glassing/bedding in the old stringers

Boat is a 1984 Harris kayot floteboat if it helps. I feel a manufacturer would use poly for the costs but I don't really know

 

[matt167]

I've been wondering on this for a while about my boat, but how can I tell if it was built with epoxy resin or poly. I've bought some poly, and the whole boat is a yellowish tint which after looking at a lot of stuff makes me thing it's epoxy, but I for sure has a lot of csm used in the construction of the hull and glassing/bedding in the old stringers

99% chance that it was built using Poly. You CAN rebuild it with epoxy for a higher cost, but not much gain

 

[Lectro88]

PL makes a marine adhesive called... PL Marine..
it cures in said 24 hours, and I have been kicking around the idea pretty steadily to spring for it and save my epoxy for glass work.
**All this pivots on if the stores have it. damn covid has everything so screwed up and as if we didn't need more reason not to do anything.

thinning epoxy is not the best of ideas "chemically" or with solvents, have I done it.. yes, makes a rubbery finished product after a few weeks or month.
if you stay down in 5% or less dilution it may work better. I was doing that before I found this site. and others advised against it.
There is a product for thinning epoxies,., I think it's geared for epoxy paints. Xylol or Xylene. it's with acetone and other solvents in box stores.
The best way to thin epoxy is with heat. warm water bath about 120 degrees, but it makes epoxy kick off and cure faster.
CPES clear penetrating epoxy is a thin product that does well.
I know of another epoxy I like that takes forever to cure, but its pretty thin and slow cure allows it to leech in pretty good, Fasco Epo Steel 103 LVX "summer"/slow is my top shelf epoxy followed by total boat 5;1

Hard spots, pay attention to keep wood off or from direct contact with hull.
I never did grasp the difference in PB and wood touching hull, they're both hard,. I kinda get the glass flexing around and the concept but its still a little muddy.
space it off, run a paint stir stick under as feeler gauge to check clearance, before you PL.
Using spacers is what I'm doing and removing afterwards and filling with PL for total Bed.
To clarify how not to adhere spacers while bedding. Don't PL all the way to spacer. leave a inch gap on each side and fill the 2" gap later. (so it takes an extra day)big deal. I'm now a 4yr project.

csm is wasteful with epoxy, it soaks it like a Hog and doesn't even melt the binder in csm.

flip a coin as to which is easier for you on foam.
Watch some youtubes on the subject.

I'd say your boat was polyester ,., 99% sure.
I myself am going back structurally with epoxy,. thats just my choice.
It bonds stronger, turns water better all for a little extra expense, however epoxy and gel coat don't mix if you jump to exterior.
polyester doesn't stick/bond well to epoxy.
however, reversed, epoxy will grab to polyester or about anything if the surface is clean and sanded.
The guys that know polyester and work with it often,. do fine with it.
I have not yet gained that trust... yet.. for me, as I have not worked it enough to learn its quirks. to each their own.

 

[todhunter]

Hard spots, pay attention to keep wood off or from direct contact with hull.
I never did grasp the difference in PB and wood touching hull, they're both hard,. I kinda get the glass flexing around and the concept but its still a little muddy.

It's not hard spots you're watching out for. It's hard (supported) spots beside soft (unsupported) spots that are bad and will cause a stress riser. Raising the stringers up just gives you enough gap to completely fill the area under the stringer with bedding and leave no voids.

 

[racerone]

I did an outboard cowling repair with polyester resin.-----The smell / stench of that stuff made me appreciate epoxy resin just that much more.----Epoxy for me.

 

[Dquinn]

Thanks for the info fellas. Bout to dive into it head first! Sorry for the late reply but you know... Life haha. Will keep y'all posted and post some pics of it. I wish I had more of the year down but I'm horrible about documenting with pics. I get in go mode and forget all about that stuff.

 

[Dquinn]

Hey there friends. Project is marching along. Stringers are bedded in and am a day or 2 from starting some glass work! ( It's currently 81⁰ here is SE GA). New question. Thinking on saving my resin for the glass work and need to build a decent radius (fairing) in the corners with the stringers. Went with the PL glue for the stringers and have plenty left. Thinking I might fair them out with the glue. Anybody ever tried this? I'm concerned with the glass/resin bonding to the PL. It feels super slick where it's exposed.

 

[Lectro88]

Congrats on your progress.
Weather in nc yday was maybe almost 70. So I understand the itch for progress.
I’m going to be using marine pl when I bed my stringers, bought 12 tubes already just in case we get another lazy streak or availability issue with goods.
I can’t tell you about the capability of bonding since I haven’t used it yet.
But there is a number on the tubes and the folks there are real helpful. I have talked with them several times.
So I’d reach out to them since you haven’t gotten a reply yet.
Best of luck.