Thanks Rabbit, Actually I dont blow my own foam blank and just guess the methodology of making blank mould. Anyway thanks for your reply. Regards, Crabie
I know that everyone on here says to not try to blow your own foam, but i am going to try it anyway and post the results up here. Before i do it, let me tell you what i am going to do. If any expert would like to correct me on how it's done, then your help/input would be greatly appreciated.
I am going to make a 2-part fibreglass mould of a board (deck and bottom) using gelcoat,chopped strand mat and my offcuts. I am then going to glass on some scaffold poles to each half, and re-enforce that with concrete, attatch hinges and a counter-weight. Togethor with clamps, this should be able to withstand the pressure of the foam.
I am going to glass each side of the moulds with epoxy resin (2x 6oz on the deck and 6&4oz on the bottom) Then pour in the 2-part foam, clamp it shut and watch it blow.
When it comes out, i will sand off and glass the rim running round it.
Now i don't see how this could go wrong. It should be a basic epoxy sandwich board that pops out.
The only foam that i can get my hands on is the PU 2-part foam from the fibreglass store, and this is my main concern. If anyone knows where i could get any better foam suitable for this project, then please post me in the right direction.
I poured blanks for Midget back in the 70's and each half of the concrete mold was about 12 inches thick and weighs about 500 kilos. To make a 6'6" board you'll need to make a blank 7 foot and the concrete mold needs to be a foot longer at each end, so now you need a 9 foot mold to make a short board. There's a starting point for you.
its not impossible to do it but you have to think Industrial size !!
great, well concrete is cheaper than fibreglass, so that's good. I'm not making a blank, just a popout/epoxy sandwich board. The board is 7"6 so a 9"6 mould would do. This is what i was expecting, cos that foam's strength needs to be resisted. If you have any more hints/tips on making the mould, then it would be much appreciated. Man, this forum is brilliant. thanks swaylocks
I have made one half of the mould. The fibreglassing part was just like making any normal 2 part mould, then i built a box around it and i have poured the concrete in. It's gonna be heavy, but i can't wait to flip it over and do the other side. I will post it up when all is done. It deffinately looks industrial, but wasn't very expensive at all.