Kevlar Project update

[stonehollow]

Off the form today! Update at http://www.myrabo.com/k-canoe/kevlarII/off_the_form.htm, but here's a few pics:

Shrink wrap worked great! This is a shot down the inside (ends not closed yet).

Really hard to take a picture of it:


I'm really pleased with the results (again, this is the inside):

[Jim Dodd]

I was pleased with the shrink wrap also, it seemed to cover slight flaws in the mold.
If My outside came out that smooth, I would've been happy!
Keep up the great pics!
Thanks
Jim

[Bryan Hansel]

How would it work if you used shrink wrap on the outside of the hull after wetting out the kevlar? Do you think you could have gotten it tight enough to give a nice smooth outside hull?

[stonehollow]

I thought about that, but you have to heat it up to shrink it, which accelerates the epoxy curing. You also have to find a place to attach the shrink wrap to, which is probably a bigger obstacle. Maybe bungee cords fastened with duct tape underneath? I might try that on a test layup to see what the problems are.

25 lbs at this point, looking at 8 lbs of gunwales, a couple of pounds of ribs (probably offset by trimming the gunwale line), 5 pounds of seats and a finish coat. Should still be around 40 lbs in the end.

[Jim Dodd]

AWESOME Arne!
Great pics, and no sanding on the inside!
Bryan!
I think you're on to something!
Keeping the wrinkles out seems to me to be the problem. The shrinkwrap is flexable enough. but it really likes to stick to the wet resin.
Spring clamps along the shear might work, and no heat gun..
I'm going to give it a try on my last fill coat.
Thanks guys!
Jim

[Bryan Hansel]

My guess is that if you figure this out, you won't need any fill coats. If you can figure a way out to apply the shirk wrap, I bet that it will compress the fabric enough to make your initial saturation coat turn out to be smooth -- sort of like vacuum bagging. Or if the kevlar needs a bit more fill, probably only one fill coat would be needed after this.

If it works, this would solve my only gripe with using a male mold instead of a female mold. That is the outside will look nice and smooth.

I'll be waiting with interest to see what you two come up with. It might just make me do an all kevlar kayak from a male mold.

[Jim Dodd]

Another thought, if you preshrunk the shrink wrap, pulled it off before the resin was applied.
Definitely worth some more thought!
Jim

[stonehollow]

Even if we get the wrinkles out (on an outside application), I see no way to remove air bubbles. Anyone have experience with release films in this type of application?

I got some more shrink wrap film for the second hull; I'd like to improve on the application to the mold. More testing today - it's finally raining!

[Doug]

With using shrink wrap as your interior, next to mold, layer.
Is there a home made way to vaccum bag the exterior layer?
This would seem to be the goal, ....a smooth interior and exterior layer.


Are the epoxies the same as you use for fiberglas?


Doug

[Jim Dodd]

I used the Window heat shrink.
A hair dryer shrunk up the wrinkles.
Jim

[Bryan Hansel]

Doug - Have you seen this article on my website? http://www.nessmuking.com/vacbag.htm

Female or male, it should work with both.

[Jim Dodd]

Thanks Bryan!
I've seen your vacuum bagging article before!
I had planned on doing a lot of the don'ts, so now I'm stalled until I get the equipment, and time.
Saved me! Thanks!
Jim