Hi, i would like to try my luck in building my first compsand board. It will be 3mm poplar skins and paulownia rails on 1# eps foam. Thare are few things that i have trouble solwing. I will shape eps and vacuum bag skins on to it, thing that bothers me are bottom contours. Will contours from eps transfer to poplar skins? And is there a way in any of board shaping softwares to print outline of skins. Something like board outline minus 5 cm rails to get the skin size. Becouse software prints straight line board outline not the stinger line board outline.
the search term produces quite a few results though Bert’s thread seems to have disappeared. That is a shame. Do some more research in the archives, hopefully the info is still there. A rocker bed will ensure that the vacuum does not press out the concaves (or change your rocker) therby having them not transfer to the skin. Do not go high on your vac pressure.
Thanks for the link Bob. I was watching videos on youtube and almost nobody seems to use contour mats when vacuuming ply on eps.People rarely use rocker tables also. Is it realy necessary to get the contours right or is it just precaution?
3 mm is too thick. Poplar twists and warps, especially when wet. Yes, the contour mats work with corecell and thin veneers, but not with 3 mm wood. You might like a heavier foam, and only skin the deck.
From what I’ve been able to gather about their methods they use 2-layer veneers for their decks/bottoms, not planks of balsa or palownia like Sunova or the compsand guys.
The guy who makes the Golden Tigger boards in the UK apparently uses those, too; except he doesn’t glass the exteriors.
It should be mentioned that the original title has a misspelling of “vacuum” (vacumn) which has been misleading people for years. The link that bgreen posted is it but some (certainly not all) pics are missing. Of course there were a few mysterious pics that Bert himself removed after he had second thoughts, but not quick enough. There are a few rogue images floating around that most of us missed even before the remodeled website resulted in many photos missing from various threads.
Nice of you Oneula to have saved and reposted those.
Do you have actual URLs for the Bert.txt links? The text links you posted do not work for me using Chrome and Explorer, disappointing. Your effort is appreciated regardless.
1/8" ply will bend around bottom contours if they are mild. Channels with hard edges will not work.
We have used contour maps to create double concave bottoms with 1/8" balsa, but not ply. Oneula has posted our process more than a few times. It is not the same as Danny Hess’ method, he makes his rails first then fits the EPS into the center. We bend the rocker into flat sheets of 1lb EPS foam while we add the bottom skin (one pull). Then we add the rails, then we shape the deck. The rails hold the rocker in place.
We lay the skin on the blank then draw out the shape and cut it. I don’t of any easier way.
