Carbon Fiber Nokomis

[Jim Dodd]

Well I've been gathering materials to start my Carbon Fiber Nokomis.

In the past, I relied on window heat shrink film as a release agent . Wrinkles were my biggest problem. As a release, it worked fine.

Well I'm trying PVA made by Partall, as my release agent.. The plan is to do some testing before I make the big jump.
I have two coatings of PVA brushed on a test piece.

I want to Thank Alan for steering me to a site, that had a lot of good info, dealing with fiberglass molding ! It was enlightening !

Resin is supposed to be here tomorrow, RAKA's UV-inhibited epoxy. I ordered a three gallon kit with half slow hardener, and half fast hardener.
Going to test with several layers of scrap E-glass, and maybe some Kevlar, as well as some carbon fiber.
The object of the test is to tell me how long I can work the resin, how many layers,, I can easily wet out, and most important, how well the PVA works as a release.
Lastly how well the PVA will wash off the test hull.

These are all things I need to be sure of before I take the leap.

I'll keep posting.

Jim

 

[Canotrouge]

Would you mind sharing that good site about fibreglass moulding??

 

[Jim Dodd]

Would you mind sharing that good site about fibreglass moulding??

<www.boatdesign.net>

www.boatdesign.net

Sorry about the posting, I'm not smart enough to make that an easy link, but that's the site.

Jim

 

[Jim Dodd]

http://www.boatdesign.net

Bingo ! If first you don't succeed. Try try try again.

 

[Canotrouge]

cool thanks

 

[Alan Gage]

It will be fun to watch. This will be your 3rd composite build now, right? Are you doing only carbon or some kevlar too? How many layers? Cedar strip core on the bottom again? What about gunwales and trim?

I've found PVA seems to wash off nice with soap and water followed up by denatured alcohol for good measure.

Alan

 

[Jim Dodd]

It will be fun to watch. This will be your 3rd composite build now, right? Are you doing only carbon or some kevlar too? How many layers? Cedar strip core on the bottom again? What about gunwales and trim?

I've found PVA seems to wash off nice with soap and water followed up by denatured alcohol for good measure.

Alan

Still thinking on the Kevlar, maybe some 5 oz. either on the inside, or maybe between two carbons. What do you think ?

I have enough 4 oz for two layers. Enough 9 oz S-glass for the outside football. And enough carbon 5 oz for two lyers. Lots of 6 oz E-glass. Will need Kevlar.

Yes on the cedar insert. 1/8" thick. I really liked how it turned out on my last Kevlar. I've learned a few things with that one, that really swayed me.

I've got soo much Ash, I'll go with Ash for trim again. Old habits are hard to break, for me anyway.

I would like to bring down the weight, and resin usage.

Did you think the slower hardener, helped in reducing resin required ?

Jim

 

[Alan Gage]

Still thinking on the Kevlar, maybe some 5 oz. either on the inside, or maybe between two carbons. What do you think ?

I think carbon on the inside would be hot when paddling in the sun. Kevlar is strongest in tension so for strength it should go on the inside. But maybe you don't need maximum strength either.

Did you think the slower hardener, helped in reducing resin required ?

Not really. It just made the process a bit more leisurely.

Alan

 

[Jim Dodd]

I think carbon on the inside would be hot when paddling in the sun. Kevlar is strongest in tension so for strength it should go on the inside. But maybe you don't need maximum strength either.

That makes sense ! Express Composites maybe hearing from me again soon. They were out of those scissors we talked about. Hoping they come in.

I washed a spot of the PVA off with just plain water. It left a little green stain. I'll try some soap.

Thanks !

Jim

 

[stripperguy]

Jim,

I'll be watching closely. I will be following you and Alan's footsteps fairly soon.
I had used some PVA many, many years ago...I don't recall that it was so dark.

 

[Jim Dodd]

Jim,

I'll be watching closely. I will be following you and Alan's footsteps fairly soon.
I had used some PVA many, many years ago...I don't recall that it was so dark.

Seemed to me the original stuff was green. I've never used it until now. This purple must be the newer version.
Did my testing today on an old partial hull.
I'll pull things off tomorrow, and try and give a report.

As of today, I had some runs of PVA, that I wanted to take off the hull with just water, and they came off. That's good. Another concern is if the PVA will transfer to the glass, I pull off the mold. Tomorrow will tell.
In the test today, I cut a few strips of Peel Ply. I want to see if there is any thickness difference, with and without.

Jim

 

[Jim Dodd]

Couldn't wait to get down to the shop today.
It was a great learning experience that will guide me along.
Here's a few pics.

The Peel ply doing what it's supposed to do. One wet out coat.

The carbon fiber added significantly more stiffness, but was easy to cut with shears. I'm going to mic the difference between the wetted , and the Peel Ply. More later when I get back to the shop on that.

The PVA release, stuck to the back side of my CF patch, as it did to the E-glass.

Pulling everything off the hull was a success, but there was still more bonding effect than I was expecting ! The patches didn't just fall off like when I used window heat shrink film. And no residual clean up with the window film.

What am I going to do ? Planning on going back to my heat shrink, for now.
The Peel Ply is still tempting me.
More to come.

Jim

 

[Jim Dodd]

OK. I made a quick trip to the shop, brought the test pieces home to mic.
Interesting to me anyway, was the Peel Ply not only left a smoother surface, but reduced the thickness by .002", on the Carbon fiber. Without Peel Ply, .015", with Peel Ply .013" . This was using 5 oz Plain weave CF. That was impressive. And no detectable difference in flexibility.

On the pieces that I double layered 6 oz E-glass, The flexibility really increased. I'm totally sold on double layering the bottoms of my hulls.
Peel Ply also reduced thickness of the E-glass by about the same as the Carbon fiber.

All of the E-glass and carbon fiber were coated with the PVA, and needed cleaning. Running hot water on these diluted the PVA enough to remove it. A step I don't think I want to do to either hull.

It's back to my plastic wrap, and tweeking my technic !

Jim

 

[Alan Gage]

Nice test. How did you apply the PVA? How many coats? Did it go on nicely? Any fish eyes? It looks like it left a nice finish.

Your coat of PVA appears to be considerably thicker than any I've done. Usually after separating the pieces it looks and feels thinner than saran wrap, just hardly anything there, which makes wiping it off easier. Theoretically, as long as there is complete coverage, the thickness of the PVA shouldn't matter.

I've never experienced a part "falling out of the mold" with either wax or PVA, it always takes a little effort. It took a fair amount of effort to get my tandem unmolded. The bond didn't seem to be that tight but when you lightly stick something with that large of a surface area it's going to provide some resistance. When I went over the hull with a rubber mallet I could hear it "snap" as the bond was broken. I've used the same technique for loosening up seats I'm taking out of the mold. Shocking it and causing it to flex a little seems to break the bond better than pulling and prying.

Alan

 

[Jim Dodd]

Nice test. How did you apply the PVA? How many coats? Did it go on nicely? Any fish eyes? It looks like it left a nice finish.



Alan

I brushed it on with a cheap chip brush. Two coats, and lots of runs. Let it dry at least a day. When I laid on the cloth, I tried to move it around, to see if it would get under the PVA. It didn't. That was good.
Good advice on loosening the PVA.

I'm going to try and shrink some window film, and if I can't get it to shrink, I'll go with the PVA.

I'm not going with a seam on the ends ! I'll seal the ends, and come back the next day while the resin is still soft, and just cut right done the center of the stem with a knife. With out the Kevlar, it should cut easy !

Oh I just ordered shears and Kevlar from Express Composites.

With this hard cold coming, I may wait til warmer weather to wet out cloth..
.
Stay Warm !

Jim

 

[Jim Dodd]

Another thought that's been bouncing around in my head (And there's a lot of room to bounce!)

Is the idea of coloring at least the outside. I'm a little worried about what the full sun will do to the carbon.

Years ago we used to graphite the bottoms, of our strippers. Well a friend left his on top of his van one summer, and it bubbled big time.

Thoughts or experiences ?

Jim

 

[Jim Dodd]

I Played with the test pieces of wetted out 6oz cloth yesterday. Was amazed at how much stiffer the double layered cloth was ! I'm totally sold on double layering the bottoms of my canoes !


Finally made it back to Nokomis yesterday. I struggled big time with the window film release barrier. So bad, I tore it back off. Thought about it, and had to try One more time ! Had enough film for one more stab at it.

I realized that my Old blow drier wasn't up to the task anymore. So now I'll be buying another.

So far it's about a 90% improvement over my last build's window film application. By the way, I bought the Duct brand window film treatment. I like it better than the Off brand I used before !!.

So Window film again !
I didn't have my camera, and My Wife's Dad is in his Final days, and so it might be delayed some more.
Thanks !

Jim

 

[latremorej]

Sorry to hear about the family Jim, thanks for posting your results. Interesting!

 

[Jim Dodd]

Sorry to hear about the family Jim, thanks for posting your results. Interesting!

Thank You !
He passed yesterday. One Tough Old Bird !
I'll be happy if my sons inherit his grit !

Jim

 

[Jim Dodd]

Needed to escape for a while from the wife's family. Don't get me wrong I deeply love them all. Just needed out for awhile.

So I got into my comfort zone(Shop) and started working on the wrinkles, in the window film release. I have just a few more to blow out. But all in all. I'm happy.
The neat thing about the window film, it covers up any pinholes, or small imperfections on the hull.

The long scuff mark, is where I feathered the outside double layer, just a little, so it will blend in on the composite. Really it should disappear.
Also one more crease or wrinkle to work on, and I'll be ready to go on with my first layer of cloth.

The black band (electrician's tape) on the stem, is where I will cut to remove the CF Nokomis, from the back of Nokomis.

Plan is to lay 4 oz E-glass on and wet out. I will let it set, then apply 5 oz Kevlar. Next will go 5 oz Carbon Fiber. A layer of 6 oz E-glass. Lastly a 9 oz layer of S-glass to about the 3 or 4" waterline.

I'm thinking if I'm not happy with the stiffness, I can apply more layers ( I'm sure I will), to the inside.

Any thoughts on my madness ?

Jim