Plaster moulds?

[Talonmotorsport]

Has any body here ever used pink wall plaster to make a fibreglass mould? I'm using the blue foam used in model making and taxidermy, then sealing it with PVA and fibreglassing over the top. At this point I'm only looking at making one so I don't need a reusable mould. Whats the best thing to use as a release agent to put on the plaster mould when I come to laminating the new part?

It shrinks so no it's no good. There is a special plaster type stuff but canny remember what it's called, it's used by modellers as the mould can be made quick and used same day. No special tools etc but costs 3 times that of using fibreglass...

Best stuff to use when making moulds even if only for a one off part is gel coat and fibreglass, but even this can shrink if you do too many layers at once.

[Talonmotorsport]

Is it perchance called 'modrock' The stuff they use on broken arms?

nearly yeah you slap it on by hand but it's not very stable and beggar all will stick to it so if it cracks etc you cant really repair it...ooo and it;s like mdf, it acts like a sponge and soaks up damp so goes all shapes.

believe me it's easier to use grp it really is and it's cheaper too especially as you intend making a grp part from the mould. If mould is to make a one off part just make the mould using 4 layers then add wood to stiffen it.

What are you after making?

[Talonmotorsport]

My first project is making my own nose cone for my roadster FB (fat b***ard) as nothing else will fit. If I just cut and shut one it could end up looking alittle odd as it's a convex shape and I've changed all the angles. The next one is making a stretched escort cosworth type bumper for my transit (yes sounds silly but the kid in me says sod it).