[revenuer95b]

So I have been working on a small Tri Hull Skiff. I have replace the transom using coosa (Laminated 1/2" to make motor area about 1 1/2"). I am looking to start laying out the floors and decks. I like the coosa because its almost just like plywood. I can get 1/2" coosa for about 165 a sheet the Divinycel is about 125 a sheet. I am trying to make the boat light and fast. what should I use? With the divinycel what do I do with exposed edges such as bulk head cut outs and hatch openings? Can they simply be covered with epoxy or do they need to be glassed? I know it needs to glassed on both sides but if I cut an opening what do I do? Which is better

 

[fjmaverick]

I saw a boat a few years ago that was built for a government contract to run in south texas on the rio grande. The seller had a sample of the core material and it was incredibly light and strong. It was dark grey/black in color and I want to say some type of carbon but I dont recall. Anyone know what that stuff is?

 

[Boatbrains]

Coosa good for transom, go with divinycell for the floors/decks. You can just epoxy coat the cutouts, but I would throw a couple layers 7oz on them for some impact resistance.

 

[firecat1981]

I saw a boat a few years ago that was built for a government contract to run in south texas on the rio grande. The seller had a sample of the core material and it was incredibly light and strong. It was dark grey/black in color and I want to say some type of carbon but I dont recall. Anyone know what that stuff is?

Carbon core maybe?

http://www.carbon-core.com/product-category/structural-foam/

 

[revenuer95b]

Can I just lay out the foam sheets and glass them on my carport? Glass one side let it cure then glass the other? Would 1708 be better for the top?

 

[Boatbrains]

Can I just lay out the foam sheets and glass them on my carport? Glass one side let it cure then glass the other? Would 1708 be better for the top?

Yes, you can do it this way. Just lay some paper down first or you’ll have a mess.

 

[DuckNut]

I want to caution you on one thing doing it this way.

IF you are using poly resin (not epoxy) you will need to do something to make it cure flat. Covering with plastic and a sheet of plywood will be fine. What happens is the resin will heat up and shrink a bit and that can curl/warp the panel so you need to prevent this from happening.

IF you are using epoxy forget what I said above.

I mention this as you did not state you were using poly or epoxy. Although you stated using epoxy for the edges and then you said 1708 - so I am not sure which one you are using.

 

[revenuer95b]

Using Epoxy the glass would be 1708. I have some 6 or 4 oz glass. I am not sure which one.

 

[DuckNut]

Lose the 08 and just get 17.

This is why I was confused.

The 08 is necessary for poly resins, not necessary for epoxy.

 

[trekker]

When I built my boat, i routed out the exposed edges (roughly 1/2" deep), filled with thickened epoxy and then sanded to a decent finish.

 

[Flatbroke426]

Coosa is heavy but works great for places such as transoms where it stands up to compression better. But floors and bulkheads and deck I only use core cell or the divinycell.. Its strong and lightweight and so easy to work with.

 

[revenuer95b]

Has anyone heard of Airex T92

 

[Finsleft258]

Has anyone heard of Airex T92

Yes. It's a good product. I use it in my shop often for building one-off hatches and other components.

DuckNut had a good recommendation about watching for shrinkage. Most vinylesters, isophthalic polyesters and some blended othophthalic polyesters have shrink characteristics. These generally fall in the 3-6% range. The thicker your core and layup, the more noticeable it will be. If you want to do a poly to cut down on the cost, I recommend a DCPD resin. They are very low shrink (.5-1%) and excel for reducing print-through on hand-laid parts without a mold.

DO NOT get BOATYARD resin. That is a blended resin of end of batch products from any of the three above. You never know what the shelf-life of that shit will be.

 

[revenuer95b]

Well I got an email today. The company I ordered the foam core doesn't deliver. The closest supplier I can find to Mobile AL is Advance Plastics and they are about $25 a sheet more. They are also only open on week days

 

[revenuer95b]

Does anybody know where I can get Coosa Board or Foam Core around Mobile AL.

 

[FrankZinCLE]

So what did you end up going with and please share the end result !

 

[Flatbroke426]

So I have been working on a small Tri Hull Skiff. I have replace the transom using coosa (Laminated 1/2" to make motor area about 1 1/2"). I am looking to start laying out the floors and decks. I like the coosa because its almost just like plywood. I can get 1/2" coosa for about 165 a sheet the Divinycel is about 125 a sheet. I am trying to make the boat light and fast. what should I use? With the divinycel what do I do with exposed edges such as bulk head cut outs and hatch openings? Can they simply be covered with epoxy or do they need to be glassed? I know it needs to glassed on both sides but if I cut an opening what do I do? Which is better

I only use foam core material n decks and such. Glass both sides and really work the resin into the core. then you can just use resin on ends then using fairing compound to clean up edges before painting. If you want to get high tech use carbon fiber cloth and vacuume bag. I have a friend buidling a new 21' flats boat this way. While others weight clsoe to 2000 lbs his is weighing 750 lbs. Good luck and let us see how your build is going

 

[FrankZinCLE]

Thank you for the feedback and prompt replay, I just ordered a small sheet of Coosa Board 26 .75" 31.5" x 48" for only $122.03 plus free shipping = This I will use this for the new transom and front bow area (18 x 12) mount the bow mount trolling motor and the front foldable 6" inch cleat. and another 12 " x 10 " piece on the floor deck where I can securely mount the grab bar/rail to.