[Tracy]

Hi, can you tell me whether the mould material can affect whether your resin sets or not?

I mixed and poured a batch of epoxy resin (Gedeo crafting resin mixed in a 1:1 ratio) yesterday.  I used some in the harder plasticky type resin moulds and I also poured some into a silicone mould.

After 24 hours the resin in the harder moulds had set perfectly but the resin in the silicone mould was not cured at all and was really gummy and flexible.  It is still that way now after another few hours.

How can the same batch of resin have set in one mould and not the other..?  both moulds were perfectly dry and, in fact, the silicone one was brand new.

Can anyone shed any light?

[Katherine Swift]

Tracy,

Are you sure your mold was silicone?  I ask because I know epoxy resin does not play well with polyurethane or latex molds.  Since it sounds like you mixed your resin correctly (since it cured in the plastic mold), that is my first guess.

Did you use a mold release in that mold?

[Claire]

 Hi sorry tried to reply on my mobile but guess it didnt work!!

Im having the same kinda problems as tracy…

I bought some gedeo epoxy resin which is great – low odour great to cure etc but its quite expensive so i purchased some polyester resin from a local merchant (im in the uk)

this has an awful smell and it just wont cure in my silicon molds ( well i bought novelty ice cube trays) i have a load of this stuff as in 1kg!!

I have now bought plastic molds which have been recommended to me – i now have a whole batch of resin stuck in these molds….(possibly chocolate molds)

im really just looking for the "perfect" resin i guess polyester or epoxy!?!

I have loads of molds but now im just confused – should I just throw the polyester away and go back to epoxy if so where can i get this slightly cheaper than the gedeo stuff??

Thanks

[Katherine Swift]

Claire,

Are your polyester resin castings uncured throughout or only on top?  Im  afraid to say that polyester resin will remain sticky on the surface exposed to air.  You can sand that side down just a bit to get the stickiness off.

At least in the U.S., polyester resin tends to be a lot cheaper, but the smell is heinous.  Epoxy might be your better bet.

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