I just finished my second compsand, just rode it yesterday, and thought I would detail it’s genesis for the record. Disclaimer-if you try any of this sh!t, don’t blame me if it doesn’t work. I don’t know what I am doing.
So anyhoo, I am presently working with an 8x12 room with closet, and a back deck roughly 10 x 12 or so, and a landlord who lives downstairs with his family. Basically, I would be able to use this setup in a well appointed prison cell (although smuggling some of the items in the usual way just woldn’t work). The space constraints have led me to create a fairly compact system, and I thought some pics and a description might be helpful…
My first compsand was made with a rocker bed that slid into a vacuum bag. the room I have now is too small to back the board up and load it into the bag, and I didn’t want to deal with trying to wrestle some rolled up arangement over my board as the resin hardened, so I came up with the idea of using a box with a vac-bag lid that sealed around the edges, basically a veneer press. Or coffin.
The bag material is 20 mil vinyl, the yellow stuff is vac sealant tape (sticky-tack on crack) and the top of the coffin is coated with 100% silicone caulk–nothing sticks to it. The vinyl is wrapped up and over the wooden frame of the lid, so that when the vac is applied, it pulls itself down harder, helping the seal. Also, I left enough slack in the bag so that it could be used without the rocker bed, for flat laminates (pre-formed skins) and such…A major advantage is that work can be done right on the surface, then pumped down with less chance of shifting layers. For test runs I used a wet-out table and some cardboard tubes cut to just fit the bed, and I would wet out the cloth and roll it onto the work all wet out, but I found it’s easier to simply wet it out in the bed. (more detail on that later…)
Problems include the fact that the yellow tape squeezes out a little each time I seal the lid. I had thought that a wide enough strip would just stop, but it keeps going. So every few pumpdowns, I have to pull it off the edges toward the middle, to reset it.
The box itself is made with two 2x4’s laid on edge for the sides, and a base of 3/4" plywood, very sturdy. The inside working area is 7ft. by 22", designed for anything up to 6’10" and 20" wide. The board I want to focus on is more like 6’3" x 19". Vacuum inlet is simply a hole drilled through one end-wall with a barb fitting screwed in and sealed with yellow goo. The box itself is sealed using an old vinyl bag glued up on the sides to just under the lid, on the outside of the box. This arrangement is quite airtight, and “takes in” very slowly, not much faster than just my pump and reservoir. It falls from 28" to 24" in about three to five minutes.
Cont’d…
