[Keir]

Hi. Im using a rather large square block silicone mold (a baking mold) that is about 19 fl ounces (aprox 3.5 in x 3.5 in. x 2.5 in. deep). Im using polyester clear resin. Ive tried different amounts of catalyst (30-50 drops) and keep getting an alligatoring effect on the sides. Any thoughts? Is it because of temperature outside? Im usually doing it outside at around 68 degrees. Or is it the catalyst amount? Or because the mold is not stable on the sides and pulls away? If I go over 50 drops it seems to have a yellow tint to the resin. But around 40 drops I can get it very clear but with a lot of the alligatoring. Im trying to do it in one layer of about 18oz. Thanks!

[Katherine Swift]

Keir,

How thick are you pouring the polyester resin?

[Keir]

 Im doing a first layer of just 1.5oz (with 6 drops catalyst), waiting till that gels and then laying in an object. After that Im pouring in the whole next pour of 16oz (with about 40 drops catalyst) which I know is a large pour but Im getting great, clear results, except for the alligatoring effect on the sides. Im really trying to get it so its just those two layers, with the 16oz pour, but maybe thats impossible to avoid the problem?? Driving me crazy!

[Katherine Swift]

Keir,

How thick are you pouring the polyester resin?

[Katherine Swift]

Keir,

I think youre using the right amount of catalyst, but I think the problem is that the second layer may be getting poured to thick.  Polyester really only likes to go on about a 1/4 inch at a time.

[Keir]

Yeah, that was my fear. I guess I was trying to cut too many corners! Thanks so much for your response. Ill try doing a few more layers and see if that gets rid of the alligatoring. Thanks again!

[Keir]

 Hi Katherine. Doing my project in thinner layers has helped immensely. Thanks!! My new issue is that from certain angles I can see the lines from each layer. Is this avoidable? Im thinking Im either letting each layer set too much before continuing, OR perhaps not letting them set enough?? Thoughts?

[Katherine Swift]

Keir,

I dont know that there is a good way to avoid seeing the layers.  Is it really noticeable?  I ask because maybe youre like I am and obsess over stuff that no one ever sees.

Are you putting in inclusions or using colorants?

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