I want to make a mould of a nice paving stone/slab i have,I plan on making concrete replicas of it.Can i just make it with fiberglass or do i need to use rubber if so which shore?
HI. are you making a patterned slab then rubber would pick up the detail but if you want to make plain ones then you can make them without rubber or fibreglass
I think its limestone so there is a bit of detail on top,like a cut stone texture.Any recommendations for rubber type?Im new to this so any advice is appreciated.Iv used fiberglass for repairs in the past but not for moulds so was unsure if it would work for this idea.
HI. if your stone is just a straightforward shape and glassfibre will not stick to any undercuts. that's what i would go for in this case.you would first give the slab a couple of coats of g4 varnish available from your glass supplier. when it is dry a couple of coats of wax release agent. when that drys a couple of coats of nice thick gelcoat.when that sets but still tacky. layup resin and fibreglass when that sets your in business whip it of coat the inside with wax release agent before each cast.
anothere tip for slab making is to use a vibrating table for a business. but if it is for yourself just tap and beat the living day lights out of your mould. to rid those bubbles and furthere to help you. buy some liquid polymer from special plasters type them in on your computer. it will make a top quality slab for you if you want to colour them buy plaster pigments from the same company. it can be used for concrete as well and you can get any colour you want blue green red or white or mix colours together 5.ltr of polymer is £17. £18 but mixed with water you can turn it in to 20.ltr. and it will help rid those bubbles and give you a better slab.
Appreciate the advice,il be giving it a go this weekend.This could be the start of an interesting moulding hobby!Thanks.
make slab moulds from wood build a wooden frame around plywood.