Poly, Resin, Epoxy.....and a stringer question

[SnowHunter]

Ok, I think I've been reading wayyyyy to much over a short period of time

I dunno if I've got the differences between everything....

So I'm replacing stringers, actually, just one that I can see right now. Uniform contact with the hull? No contact? I can't tell if I'm relaying it right through my brain, or just jumbling all the information I've read.

All wood to be marine grade, then coated in....um....poly resin on all sides/edges then installed?

Lawdy...can yall help unconfuzzle me? :redface:

 

[boatflipper]

Re: Poly, Resin, Epoxy.....and a stringer question

Ok, I think I've been reading wayyyyy to much over a short period of time

I dunno if I've got the differences between everything....

So I'm replacing stringers, actually, just one that I can see right now. Uniform contact with the hull? No contact? I can't tell if I'm relaying it right through my brain, or just jumbling all the information I've read.

All wood to be marine grade, then coated in....um....poly resin on all sides/edges then installed?

Lawdy...can yall help unconfuzzle me? :redface:

I know how it feels to read and read and read and read and read on here....it gets to ya!!
Sounds like you are on the right track though.
If you have a tri-hull, chances are it is just one stringer running down the center. The wood doesn't actually contact the hull-it is bedded in whatever the factory used. When you replace it, PL Premium Construction adhesive will work fine. Just lay a good bit of it up all the way down the center where the stringer will go. (I haven't actually replaced a stringer before-this is just what I have gathered after reading through endless threads) I am sure someone else will chime in on what to do.
As for the wood, I wouldn't spend my money on marine grade wood. it sounds good but if you get the highest grade exterior ply (ACX works good) it will work just as well once you resin coat it (as you already have a grip on)

Hope this unconfuzzles ya!

 

[tallcanadian]

Re: Poly, Resin, Epoxy.....and a stringer question

Poly or epoxy, doesn't matter. The differences are usually the following...1. poly is a fast cure and you have to be fast to get it in place. 2. It stinks to high heaven. 3. It's cheaper to use. Epoxy is 1. slower curing, so you have longer to work with it. 2. Virtually no smell but you still need ventilation. 3. It's about 3 or 4 times more expensive than poly. Epoxy is suppose to be stronger. It will adhere to almost any surface including poly. Poly will stick to most surfaces except epoxy. LOL...confused more? Your wood should be marine or exterior grade. Coat your stringer before you install them , then wrapped them in fiberglass. Some people put something between the floor and the stringer, some don't. I didn't. Anywho that's a start. Welcome by the way. Pics would be awesome.

 

[SnowHunter]

Re: Poly, Resin, Epoxy.....and a stringer question

Thanks for the info yall!!!

Ok, so if I got this right....bed the stringer, coat with resin (2 layers or???)

Does it have to be wrapped in the cloth fiberglass stuff if its going to get fiberglassed over? Or am I confusing things?

The stringers come in contact with the floor, if I got it right...and do you use anything to secure them together?

Tryin to get some basics down...before diving in and messing up. We plan to have this boat for a looooong time, so I want to get this right!!!

 

[osborn159]

Re: Poly, Resin, Epoxy.....and a stringer question

bed the stringer in adhesive, wet it down with resin let sit to soak in a bit, wet it out again apply csm to stringer and onto the hull a few inches, wet it out again if your into overkill like me apply another layer of csm to the stringer and onto the hull a few more inches further than the last ply.
to attach the floor i will use pl premium adhesive and deck screws about every 18in or so
oh and youll probly want to use laminating (unwaxed)poly resin, not general purpose resin it allows you a little more time to come back with the next wet and ply.
think you where confused b4, keep asking ?? the mud in your head will clear.
where are you located??? that may help someone help you that is local to you.
good luck D

 

[SnowHunter]

Re: Poly, Resin, Epoxy.....and a stringer question

Thanks Os

I've got a MUCH better idea now... reading more after getting a better grasp of all this helped me out a bunch!!!!

I'm still unsure of what to make the stringer out of. Mine is so far gone that its pretty well impossible to take accurate measurements, aside from total length.

I'm up in the NE part of Georgia, pretty well smack dab between Lake Lanier and Lake Hartwell; not far from Lake Oconnee. I'm sure there's places to get marine supplies round here, bein the location I'm at. That'd be pretty cool if there were other iboat folks round here too!!!

 

[osborn159]

Re: Poly, Resin, Epoxy.....and a stringer question

btw if you use pl adhesive to bed the stringers or anywhere else it may come in contact with resin, let it cure well, depending on how thick a bed you lay it can take a few days to cure thru, i set my stringers in it and it took 2 1/2 days for it to cure to hardened, the tube says 24hrs but i think thats for like laminating something that doesnt require a great deal of product, like a header for a window or door

 

[osborn159]

Re: Poly, Resin, Epoxy.....and a stringer question

i made the keel stringer out of plywood, the next outer 2 are doug fir, and the next outer 2 are pine, all to be encased in poly and csm before the 1708 goes over that.

 

[erikgreen]

Re: Poly, Resin, Epoxy.....and a stringer question

Poly or epoxy, doesn't matter. The differences are usually the following...1. poly is a fast cure and you have to be fast to get it in place. 2. It stinks to high heaven. 3. It's cheaper to use. Epoxy is 1. slower curing, so you have longer to work with it. 2. Virtually no smell but you still need ventilation. 3. It's about 3 or 4 times more expensive than poly. Epoxy is suppose to be stronger.

I just realized I've never posted any numbers for this.

So let's go with the ones for adhesion for now.. that's what matters for things like composite panels, stringer and bulkhead tabs, basically anything that's attaching to existing boat parts.

Polyester 100psi
Vinylester 500psi
Epoxy 2000psi

Bond strength refers to the force required to delaminate the cured epoxy from whatever it was applied to.

There's a less impressive comparison of tensile strength and stiffness (epoxy is about 20 percent higher in each) you can look at too.

Erik

 

[SnowHunter]

Re: Poly, Resin, Epoxy.....and a stringer question

Wow thanks! I'm on a better understanding now with everything, and reading some more with a clear head (read light bulb kicked on ) sure helped a lot too!!!!

Yall have been a big help! *cheers*