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Time to build again - Short solo/kid's tandem

Looks good !
So what is on top of the carbon ?

Also, what did you use for a release, between the mold, and carbon?

You will likely have that hull done, by the time our river is back to normal .

We will need to paddle !

Jim
 
So what is on top of the carbon ?

A couple layers of fiberglass at the stems.
what did you use for a release, between the mold, and carbon

PVA.

The morning after laying down the first layer of fiberglass I at least separated the edges before laying the carbon on top. If I would have been thinking I would have put down tape on the mold at the edge. As it was it was a bit more difficult than I would have liked to achieve separation. I'll find out Sunday how the rest of it releases.

Alan
 
I was able to separate the composite copy from the stripper used as a mold....but not without some challenges.

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The biggest problem was at the edges. They did not want to release! In hindsight I should have ran a line of tape at the edge and my life would have been much easier.

I started with a layer of 6oz fiberglass and the next day added a layer of carbon.
Just before putting down the carbon I decided to separate the edges, figuring it would be easier with the flexible single layer of fiberglass. Even then it was difficult because the epoxy had run under the edge of the sheer and this needed to be sanded off before I could get the fiberglass pulled away.

I figured I would be home free after putting down the carbon but unwittingly I had made it worse. When I separated the edges this damaged the thin layer of PVA. Epoxy was able to wick up into the gap between the fiberglass and the hull of the wood canoe while wetting out the carbon and because of the damaged PVA it was stuck pretty hard.

There were 3 small locations where the fiberglass was pulled away from the wood of the stripper. I sanded away the damaged areas and applied small patches. I covered them with peel ply and will add a couple fill coats before sanding them flush.

I might set the record for how many different ways you can screw up a stripper.
I have no doubt it will turn out fine though.


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A question for those of you that have put wood or foam cores in your composite canoes:

How did you support the canoe to keep its shape? This thing is like a wet noodle right now. I put a few stretchers in place along the sheer and this seems to be doing a pretty good job but I worry a little there might be imperfections in hull shape that I either miss or that occur during the process of laying in the core.

And what have you guys been using to adhere the core? Straight epoxy or thickened?

I know @Jim Dodd weights his cores down. Has anyone used vacuum bagging for this? Anything in particular to watch out for?

@stripperguy: didn't you just build yourself a composite with a foam core? Did you use foam sheets or did you use scored and scrimmed foam? Any tips?

The foam I have is scored and scrimmed. Seems like it should be easier but what do I know.

Alan
 
PVA will hold things together, put it should release, with some persuading.

Next time for me ?
I will add plastic, just on top of the football, and PVA on the side

Looking good !

Jim
A question for those of you that have put wood or foam cores in your composite canoes:

How did you support the canoe to keep its shape? This thing is like a wet noodle right now. I put a few stretchers in place along the sheer and this seems to be doing a pretty good job but I worry a little there might be imperfections in hull shape that I either miss or that occur during the process of laying in the core.

And what have you guys been using to adhere the core? Straight epoxy or thickened?

I know @Jim Dodd weights his cores down. Has anyone used vacuum bagging for this? Anything in particular to watch out for?

@stripperguy: didn't you just build yourself a composite with a foam core? Did you use foam sheets or did you use scored and scrimmed foam? Any tips?

The foam I have is scored and scrimmed. Seems like it should be easier but what do I know.

Alan
Buckled one of my composites. Fixed it, but you can still see it.

I built with more layers, gave the epoxy more time to cure, before removal.
Put 1X 4s on the sling saddles to support the hull, from the underside. With over 300# of sand you need support.
With the insert in place, and positioned, I laid the plastic, strapped in the forms, and added sand
Hind sight I should have clamped temporary outwhales to add even more support.

IMG_4031.JPG


I would highly recommend vacuum bagging !

Thickened my epoxy with Cabo-sill or micro ballons. The stuff, that makes epoxy thicker, no ground glass.
Spread it with a notch troll, and laid in the formed insert.
Had a few spots that you can see a bridge, but not bad.
That is why I would vacuum bag.

They make a vacuum set up, using a venturi, and an air compressor. Not sure if they would work.
I know you have a vacuum pump, for Air Conditioning service. That would probably be your best bet.

Anxious to here how you handle this next phase !

Jim
 
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Alan,
I used carefully placed supports, 3 of them, and measured the gunnel width at those support locations. I also temporarily screwed in place a few thwarts, which I removed after the foam was firmly adhered. The plug was laying nearby and I made sure to duplicate the dimensions before adding the stiffening bottom piece and ribs.
All of that 1/8” H80 foam was heat formed in place to match the compound curves of the hull. It forms quickly and easily with a heat gun set at 500F or so, don’t overheat it. Foam stuck in place with Cabosil thickened epoxy. Bottom stiffener held down with zip lock bags filled with sand. I had good conformance so it didn’t take much load. Ribs adhered with the same thickened epoxy, held temporarily with tape. Again, they matched the hull shape so well that tap was just insurance.
Then a layer of 6 oz was layed in, after beveling any edges of bottom stiffener and ribs, most were pre beveled, but some needed massaging.
I’m sure my hull was just as noodly ( is that a word?) as yours, but was stiff enough after that I could have paddled it without gunnels or thwarts!
Son josh and I have been struggling to come up with better methods for the next ones and yes, we have discussing vacuum bagging. He wants to do a full foam core, but I have trouble to see how to hold it in place on a non sacrificial plug.
 
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