Thursday, January 26, 2012

Graphics and topsheet finish


After chatting with Peter on the blog and looking around on kiteforum, I think I've finally got a way to make the finish in the top of the board glassy right off the table.

If you search 'Porker' on the kiteforum board builders forum you'll find a really great looking board with a gloss finish right off the table. The maker doesn't give any details of the actual steps except to refer to it as 'pre-cured'. Eureka!!!

I'm guessing this just means a light ply of glass layed up on a sheet of plastic to get a mirror smooth finish on one-side, the side that will face up. Once this is cured it can be used just like the topsheet material Durasurf or PBT which has proven very difficult to source in small quantities in Australia.

So my thinking is just wet out a think layer of 3 or 4 oz glass on a perspex sheet, place a layer of peel ply over the top to blot away the excess resin and leave the surface rough so that you get a good mechanical bond when you use it as a top sheet. But wait, here's the rub. If you use clear resin first, lay the encapsulated graphics down ( I've printed them on tissue paper) then peel ply it. Give it a few hours and then apply a coat of white resin , peel ply it again. By letting the clear layer cure first, the white resin over the top of it won't infuse into the graphics like happened to me last time when I only left it a half hour or so. Any the opaque background means that you won't see any of the voids etc in the layers of laminate when it placed on the top in the lay-up.

Bit fiddly but it means that the topsheets can be made in advance and stock piled.



  1. Thats a super shiny finish he got on that board. Only thing with pre cured in my way of thinking is that you could only use a basic shape board.

    I'm wondering how when gone off the glass would conform to the shape. You can roll up a single layer of glass but conforming to square/sharper edges might be a pain.
    But i guess if you make one sheet you would have to do it by vacuuming as well, the same way you actually make the bottom of the board. Maybe hand squeegee may be a bit inconsistent.

    I have an idea floating around in this head of mine. But i may try it on a small scale.

    I have to find me some of that foam core stuff now, should start getting my table together this weekend.


  2. How shine is a super shine after some time on the Sun? Is it yellowing affecting a shine?
    If doing the topsheets in advance, I would spray varnish as well for some extra protection!

    Did you see this:

    Nice and tidy:) I might start using a gas cylinder too, when the time comes.


  3. Hey Dean

    I know what you mean but I really like the yellowing effect on wood cores, I think it makes it look less like Ikea furniture:)

    I went to witworths and asked about the varnish. No one at the shop really knew anything about it and the ones that I looked at similar to what you had mentioned were all indoor use. What the brand and product name again?

    The other thing about pre-curing would be that you could make opaque topsheets to cover any potential voids underneath. I'm going to see if I can get more infom on kiteforum.

    I can't remember how, but I have seen that table before - yes very nice setup. I wonder why two bottles? Small buffer and larger reservior? I thought about using a gas bottle or PVC pipe as a reserviour but the problem I had is my vac pump is small flow rate and the amount of time it would take to pump it out if there was a leak woudl mean that the vac pressure would go through long deep fluctuations.

    I used the full bag made of vinyl on the weekend and even using tacky tape to seal it there is still a leak. I'm thinking maybe the seals in the pump are leaking. Problem with the leak is that as soon as it reaches the desired pressure, within seconds its drops below it and closes the switch but the relay hasn't had time to reset. So it end up operating on the heating /cooing cycle of the pump instead of maintaining the pressure.