Great work on the copies. Thinking about doing one myself.
More questions.......
How was it to work with poly resin - viscosity, working time etc.?
Did you do any heat bending of the divinycell ribs or core? How did you form them?
Would you save any weight with 2 layers carbon and only 1 of the glass?
Mark
Mark,
The polyester resin is easy enough to work with, with some caveats.
Even with excellent chem vapor masks, it still stinks badly. For weeks! Good thing my shop is a driveway away from the house.
Working time was adequate, but we had to always be mindful of working a sharp wet line. If we had a sloppy line, there could be a situation where the resin would kick at the surface, but without fully saturating the layers below. So whenever we ran low on resin, we had to be sure to keep a crisp line, should the next mix take longer than anticipated.
The viscosity was quite low, so penetrating all 3 layers was easy enough, probably took about half the time as epoxy resin would have.
We initially chose the polyester due to low cost, but my son bought a total of 9 gallons of RAKA epoxy resin for not much more per gallon than the polyester. Quantity purchases are key.
Heat forming the H80 foam for the ribs was easier than I expected. We used a Harbor Freight heat gun, set on about 500 F. The ribs were especially fun to form, just hold in place, waft over with the heat gun for 10 seconds, and the rib just shlumps into shape/space. Hold it for maybe 30 seconds, and done. The bottom stiffener took more time, but it was equally easy to do. We have been messing around with more complex, compound curves, and that looks promising as well.
More carbon and less glass for weight savings? Dunno. While the carbon itself is low density, it is also fairly thick, so resin weight goes up too. Glass, more dense, is thinner, so less resin, but the glass itself is heavier. I'd have to run some numbers, but my gut tells me it's a wash. So it then becomes a fiscal issue...With carbon at roughly 4 times the cost of glass, you can see where I'd go next. The strength advantage of the carbon can easily be surpassed by adding section (the H80 foam) to a glass/foam/glass laminate. Besides, next build will have black pigmented resin, so we can
tell everyone it's all carbon. As they say in the RV industry, as long as it looks good in the brochure...
