Vacuum press


Since I want to have more concave/convex shape in my boards, I wanted to use thinner veneer. I bough some 1.5mm thick birch veneer from Hollolan viilu ja laminaatti, but this would cause problems in laminating if I'd use the simple press, since the pressure that it gives is really uneven. And since I didn't really have a time or place for a full size hydraulic press or anything like that, I desided to test vacuum bagging. I bought a Roarockit vacuum press (thin air press) that comes with a manual pump. Another good thing about this, compared to mechanic press, is the fact that only one side of a mold is needed. This allows me to shape the mold freely by hand out of high density foam (I'm using 50mm finnfoam fl-300). Compared to concrete mold or wooden mold this is far easier option. Let's see how it goes...
I used a long filleting knife and sandpaper to shape the mold. With a knife it was easy to slice thin pieces and get smooth result. Sandpaper was just to finish it up. Finally I coated the whole thing with contact paper (plastic), just the same that you may use to laminate books. This is supposed to prevent the epoxy or glue to ruin the mold right away. Dimensions are about 140x35x5.
Mold with plastic coating on it
 I took a test run with just three sheets of 1.5mm birch veneer, and thought that if it looks good, I can the add more together with fibreglass and the base. It was surprisingly easy with a vacuum bag and the mold seemed to be reasonably shaped.
Bag before vacuum
I rechecked the pressure of the bag couple of times to make sure it is not leaking. It seems that atleast for this sort of purpose it is holding pretty well, but I suppose it is worth it to take a look at the bag couple of times.


Bag with vacuum


Outcome seems reasonable, so I think I add couple layers and the base and fibreglass...



Three layers glued
So, I added only two more layers of birch veneer with fibreglass, one set at the top, one at the bottom. And an extruded base at the bottom to finish the whole thing. I'm using SP106 epoxy that I bought from Kevra. Amount of epoxy needed is roughly 4sheets/250ml+50ml, and that is without fiberglass. For one layer of fiberglass between two veneer sheets, the amount I use is roughly 250ml+50ml, or 200ml+40ml depending on the fiberglass. One fiberglass that I have used is from Biltema, just biaxial, and I have no idea about the quality of that. Another one that I have used is triaxial fiberglass from MBM.

But here is the final product, looks nice, feels quite stiff, and rather light. It should be clear from the picture what I meant with the convex/concave shape. Now just some finishing work and grip tape to the top. Oh, and there is one good tip for the griptape that I'll show next...


The grip-tip is simple, and rather cheap: Take a closed-cell-foam, (for example here http://www.vaahtomuovi.net/node/17) and add a normal skateboardgrip on top of that. No icelayer forming, good grip on every weather. 

If you're wondering how to glue the eva-(closed-cell-)foam on top
of the board, maybe you can try one of the spray on glues. I suppose many brands have spray-on-glues. I just tried 4connect glue that is designed for the car tuning guys (I have no idea what they glue, some speaker/foam/whatever maybe). Seems to make excellent bond even to the laminate that I'm now using as a toplayer.