Whats causing this?

[mranum]

I have a consistant issue with this result using a resin saver mold. I have a single tube mold I made from silicone putty that holds 2oz of resin and I never got this result with that mold. I did have air bubble issues but nothing like this.

Is it not generating enough heat? My shop temp is generally in the mid to upper 60's and I am using PR.

 

[jttheclockman]

I will give you the same answer I use to give people who I had to troubleshoot their electrical problems with. I always asked what was the last thing you did when the problem occured and 9 out of 10 times it lead me to the problem.

If you have been doing this type work and using this type mold in this type conditions, you must stop and think, what is it I am doing different. Is the resin new or old, is the mold contaminated from oils or mold release (not good to use), am I using the same amount of additives and so on. In there will be the answer. To me I suggest heating your resin before you add the catalyst. (now you did not say what resin is it you are using) So this maybe a moot point. Did you coat the stamps or decals with CA and if so you must and I mean must allow that to off gas. It does take time. I will allow more than 24 hours.

We need more info on your procedure to help you.

 

[mranum]

The resin is Castin Craft, and I did heat it in a water bath that was about 150 degrees. The labels were coated with lacquer spray 48hrs before casting. I have used Krylon acrylic spray with similar results. It was put into a pressure pot at 30 lbs of pressure for 12 hours. No oils or mold release was used.

 

[m4skinner]

I've seen that the Castin Craft resin could be old from sitting in store, I have not used lacquer spray or Krylon acrylic spray so can't help you there. is there a reason you only use 30lbs of pressure ? I use 50lbs. also do you have a filter on your air compressor ? could be moisture from the tank getting in your pot/resin, I had that before.

 

[mranum]

Well as far as old resin, it is nice and thin/pourable. I forgot to mention it earlier but I used 6 drops of catalist to 1.5oz of resin

The reason I was only using 30lbs is that at 50lbs, my molds tend to deform. They are not designed for pressure but instead open air cure. I'm in the process of making a couple vertical molds to try.

I do not have a filter on my air at this time. Although I do not get any noticeable moisture from my blow nozzle even if you blow into a paper towel. My air travels from a 20 gallon tank uphill a few feet through 25' of plastic air line to get to the pressue pot.

This issue in the pics above I only get when casting labels. Feathers do not have this issue. I am using Avery shipping lables # 15264 with TrueBlock.

 

[jttheclockman]

Anyone who does labels will always tell you that air can get trapped under a label or decal. The label or decal needs to be sealed well all around it. Many methods used to do this. Not a fan of using lacquer under resin. A poly or CA would be better. Lacquer takes longer than 48 hours to cure. Poly can also. CA needs to outgas too. You should not need pressure with that resin. It heats quicker and hotter than Silmar 41. Feathers can cause problems with air bubbles too.

 

[Mikeyt]

I have had similar problems with using resin saver molds I tried everything i have gotten much better results from vacuuming the resin to get all air bubbles out then pour into Mold and put under pressure. Since doing this I have not had any issues at all doing it this way. I was almost to the point of not using the silicone molds. I believe even with the high pressure the tiny bubbles may settle on the label and cause this issue.


Sent from my iPhone using Penturners.org mobile app

 

[Kenny Durrant]

My 2 cents worth are that 150 degrees sounds a little warm. I also used 3 drops of mepk per ounce. I think the blanks were not as brittle using the fewer drops of catalyst. Maybe between the higher temp. of the resin and more drops of mepk the resin might have started to set faster trapping the air. Also if the humidity was higher than normal maybe there was moisture still in the tube when you cast them. I would try lowering the drops of catalyst to 3 per oz. and not get the resin so hot before mixing. 80-90 degrees should be plenty. You might try putting the tubes in a toaster oven around 125 degrees for 15-20 min to make sure they're dry as well. Good luck. And by the way I like the Duck Stamps also.

 

[mranum]

Thanks for all the input guys, really appreciated. Its frustrating as hell. :frown:

The only duck stamp I had turn out was the very first one. Go figure. Been either crackled paint, air bubbles, fogging from Mod Podge or the issues posted above ever since. This one was done with Mod Podge with no issues.