PR vs EPOXY casting resin

[its_virgil]

I am often asked, "Why do you cast snake blanks using polyester resin and not epoxy?" I like using epoxy for casting with dyes and pigments: easy to cast and turns and polishes well after fully cured. The blanks on the left and right were cast in 2019 with one of the epoxy resins we all use and have been in a shoebox on a shelf since then. The center blank was cast with polyester resin and has been in the reject bin for a few yrs also. I got it off the bottom. The picture answers the opening question. I'm not ragging on epoxy just relaying information.
Do a good turn daily!
Don

 

[jttheclockman]

I believe you brought this up not long ago with the same examples. At that time I believe my question was do you think that the skins have a reaction with the epoxy resin as opposed to it yellowing in all cases? Because I have been using epoxy resins for 2 years now at least and have not seen a difference in the castings. I like to use epoxy because of less bubbles when doing blanks like I do. I have used silmar for some blanks and still sometimes get a crazing for a lack of a better word and with epoxy none.

Maybe other have seen this with something other than skins. Interesting.

 

[its_virgil]

I believe you brought this up not long ago with the same examples. At that time I believe my question was do you think that the skins have a reaction with the epoxy resin as opposed to it yellowing in all cases? Because I have been using epoxy resins for 2 years now at least and have not seen a difference in the castings. I like to use epoxy because of less bubbles when doing blanks like I do. I have used silmar for some blanks and still sometimes get a crazing for a lack of a better word and with epoxy none.

Maybe other have seen this with something other than skins. Interesting.

I have mentioned this before, yes. Shown other images of unturned blanks. This is the first with a turned blank that had yellowed. I have bottles of unused epoxy, both Liquid Diamonds and Royal Palm where one side has yellowed just sitting in the cabinet. So, no, I do not think it is the skin. Epoxy just yellows. I really like using it for non-clear casting. It is easy to use but it isn't, in my opinion suitable for tube in clear casting.
Do a good turn daily!
Don

 

[Kenny Durrant]

I agree with Don on this. A few years ago I tried several different epoxy resins. They all yellowed on the shelf and after casting. I bought a rather expensive one figuring that since I'm only using an ounce per blank it's still cheaper than buying them plus I have more control over a specific look. I'm trying out another one that supposed to have an additive to stop or slow the yellowing. I guess we'll see.

 

[JohnU]

I was told a while back by a company who manufactures resin that all epoxy resins will yellow with age. I've had the same results with yellowing but I haven't tried any of the new ones that advertise "non-yellowing" or UV prohibitors yet.

 

[jttheclockman]

I have mentioned this before, yes. Shown other images of unturned blanks. This is the first with a turned blank that had yellowed. I have bottles of unused epoxy, both Liquid Diamonds and Royal Palm where one side has yellowed just sitting in the cabinet. So, no, I do not think it is the skin. Epoxy just yellows. I really like using it for non-clear casting. It is easy to use but it isn't, in my opinion suitable for tube in clear casting.
Do a good turn daily!
Don

I do not get it. Epoxy is more expensive and being you use Silmar for other casting why not stay with one. It has been proven Epoxy is a softer resin when turning and is more suspect to correct mixture than Silmar.When adding colors that has to be taken into account. I have been using LD for clear casting and Silmar for colored. On occassion I use Silmar for clear also. I think I will have to do an experiment with both for clear casting. But I would not waste the money on colored casting with epoxy. Unless I am making a blank that other objects in it that I need the adhesion capabilities. That is what makes the decision for me. Watch parts is a main one. Just my opinion.