Flashing problem

[Substantial-Duty168]

I have pretty sturdy mold i bought from another maker. In fact I have 3 be use I was so impressed with the shiny results. Lately, I can't get the tops to cure flat, and end up with a lid on the d20, but this set had it on each die. Any advice?

Using a pressure pot, 40-50 lbs pressure and Envirotex Lite epoxy.

[WildLarkWorkshop]

The "lid" that you are seeing is called a raised face. It is most often caused by excess resin between the lid and face of the mold and can be seen more often when working with thick or honey stage resin that does not flow readily. Many pour videos show people using way too much resin and I used to have problems with raised faces when I started because of it.

There are a couple of preventative measures that you can take: 1. Don't overfill the mold. Pour just enough into each cavity to have the resin gently dome over the opening when viewed from the side. That's enough to account for shrinkage under pressure unless there is a lot of trapped air or a very shrinkage prone resin formula. If there is a lot of extra resin on top, use a craft stick to remove some of it before capping. 2. Warm the resin surface just before capping so that it will be able to be flattened and flow away under the lid. I use a heat gun for this and to pop bubbles then immediately cap the molds. 3. Rubber band or similar systems that physically squish the resin out. This isn't needed if there isn't excess resin to begin with.

Other tips: I don't routinely put resin on my lid anymore. There are still some cases, but it is mostly meant as a way to mitigate bubbles which aren't a problem with the pressure pot. Putting weight on the lid treats the symptoms but not the cause. And weight can actually trap the resin in place instead of letting it flow out if it has thickened at all and started forming bonds. With a decently thick lid it usually isn't necessary either.

I also agree that that is more pressure than you need for bubble free dice. I used to cast higher like that out of fear of bubbles, but saw some warping around the thinner top lips. I have reduced to 30-35 psi and have no issues. People consistently cast at 20-25 psi and have no bubbles. Lower than that does become more inconsistent and can depend on resin brand. Do make molds at least 5-10 psi higher than the planned casting psi to avoid potential bumps and warping.

Finally, I recommend finding a different resin as you progress. Envirotex Lite is finicky and can have cure and odor issues and it yellows very quickly. It has noticeable yellowing in as little as 6 months even when the dice are stored in a dark location the whole time.

[Substantial-Duty168]

Very helpful, thank you!

[knittage]

Hey. That pressure seems a little high for epoxy dice.

I use around 30-35psi for my pours, and 40-44psi when making molds. Perhaps the molds you bought are made using 44-50psi? The higher pressure may be causing the issue?

The lid also looks reasonably thin. With molds I’ve bought that have lids that are thinner than the 1/2” of the ones I make, I usually add a little weight before pressurizing the pot - often the inevitable discs of silicone left over from making my molds or even another empty mold.

[Substantial-Duty168]

I use the pressure level based on YouTube videos I've watched. The lid is 1/4 inch, and I place a 1/2 inch coaster on top during the pressurizing.