How would one go about doing a full foam core in a hand layup?
This is not strictly conjecture...a few years back I did a few numbers based on some sample sections (back when I still had access to all sorts of lab equipment) that I had performed load deflection tests on. Theory is the guide, empirical data is (or should be) proof of the theory. Composites are very difficult to fully characterize without full testing.
Double layer of 6 oz E-glass on the outside, 1/4" H80 bottom transitioning to 1/8" H80 sides, double layer of 4 oz E-glass on the inside. Yes, full foam core. All hand laminated, squeegeed but not peel plied (plyed?)
Gunnels (gunwales, gunwhales) thwarts and seat pedestals double layer glass over foam, painted to look like carbon.
If you do the calculations, it's much more beneficial (from a strength perspective) to add section rather than layers, and whatever section should be as low of a density as practical. Again, I must admit that this is my fully biased opinion.
Modern production boats are made of many layers of assorted materials, not necessarily chosen by design purpose alone. The production guys have all sorts of constraints, from material costs to marketing demands. A backyard builder hopefully has unlimited freedom, within the laws of physics.
As a side note, I had many years of R&D design experience, often interfacing with major national and international entities, corporate, government and military. Often the best suited designs were not utilized to due various factors such as cost, cultural reluctance (we've ALWAYS done it that way), political pressure, marketing constraints...the list goes on.
My point is, freed from the constraints of those that limit the production guys, why not build your hull to be the best possible for your desired use? There's no need to follow traditional build convention...
Now down to the nitty gritty. How to do a full foam core hull?
OK....I'm a bit torn. H80 can be heat formed to conform to complex curves. Heat mold as large a section as possible over a male pattern? Strip build with foam strips? Build inside out, with a glass shell over a plug that then has added foam and inner layers? I haven't got that far yet. I'm still finishing my new house and need a few more months before I can dive into my own full composite build. If I had the time and money I would build heated male-female molds to form a full H80 foam core all at once, or at least a half hull at a time.
Nah, probably strip foam build over forms, then glass inside and out like any stripper.
I'm anxious to hear what others would do.
