Hey there fellow Composite Nuts!

I have been making various parts however now i am needing to create a perfect flat panel with a perfect gloss finish... currently looking at various panels/sheets that will be strong enough not to warp or ripple at all and keep scratch free so that either a large fiber glass mold could be made from or infuse off directly.

What economical CHEAP ways do you guys go about obtaining this surface finish?

I have been looking at acrylic panels (although getting a large one isn't very cheap) and whilst writing this post i think later i will have a look at large mirrors.)

Cheers,
Dave.

Glass panels of any sort speak to your local glass place, I don't know how much big sheets cost.
Or what about hunting down old patio windows or alike.

We had and sold a massive piece of toughen glass for pennys at the time was just in the way how I wish we kept it now!

I'm also interested in tips from the pros but I think the answer is toughened glass.

Agreed. Glass with a semi-perm release is the way to go.

Be careful not to use laminated glass though, ideally some of the fire resistant stuff strong stuff (with the wires going though ) will be good, but again costly. When i used laminated glass, the resin pulled up some of the glass, even with layers and layers of wax and pva.

Toughened glass is your friend. Best results are always gonna cost money.

i use an old white board as a base for moulds and to produce flat sheets, just need to make sure its not got ripples

As a mould surface for flat sheet you simply can't beat glass. It's flatter, glossier, much harder to scratch and widely available.

If you use a chemical release agent you will have no problem releasing composite sheet from any type of glass. Neither wax or PVA will go properly onto glass which is why Alex had problems with his sheet sticking to the glass. It doesn't matter whether you use cheap standard glass (float) or toughened glass in terms of a release but you will find that float is very easy to accidentally break so unless you have a good frame and base to place it into for protection then you're better off with toughened glass. We use a company called Express Toughening for all our toughened glass, they're really cheap, will make the glass to any size and will deliver too!

--Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Cheers for the advice everyone! I ended up infusing onto a standard mirror from a big diy store with great results. I was a little worried that the force of the vacuum bag might try and flex the glass but all was good. As for the finish well.... it was literally a mirror finish! If anyone is interested i will post some pictures later.

Thanks for the tip Matt i will have to check them out for when i want to make larger panels!

Dave.

Has anyone tried a 1/4" (6.35mm) Piece of polyethylene plastic? I was thinking of trying this. The piece of plastic is cheep enough and the resins will not stick. Just concerned with two things....1. will it give a good enough finish and will the Gum tape stick to it for vacuum infusion. Anyone have answers?  I really don't want to go buy a large piece of glass. I don't have a good place to put it when done.

Thanks,

      Dennis G

ive used polypropelene sheet to make flat panels before.

works perfectly fine with a good surface finish.

BUT it is not very durable and can be scratched easily in storage etc.