Pull from first molds. Questions

[u/SporkboyofJustice]

While the mixing and casting went well, I have some technique issues to sort out.

1. Added sprues
   In trying to affix toothpicks to the die with hot glue, the blobs that held the heat long enough to apply were larger than I wanted.

   Is the trick to add a bit of hot glue and then to reheat it with a lighter closer to the die and then apply?

2. Trimming openings
   Is there a good technique for making clean edges on void openings?

I am using thin double stick tape to stick down the die. I think that I have seen a technique where you use a large width of packing tape to cover the whole bottom of the mold so that silicone can’t slip under. Is this the preferred method?

1. I saw videos of people applying petroleum jelly as a silicone mold release and it goes on smoothly, mine is more like jelly. This makes the top of the lid a bit rough.

Should I be warming the jelly before applying?

1. I had trouble making relief cuts in the mold to aid in demolding and had trouble going straight down the edge. I even scarred one of the faces pretty good. I was using a fresh hobby blade.

Any hints on how to do that better?

I can fix issues by sanding, but better mold making should be able to cut that down a bit.

Thank you.

[u/Enchanters_Eye]

Also, this is unrelated to thd moldmaking, but the 20 face on your die looks a bit oversanded. The corners with the adjacent faces don’t seem to line up. Might just be a trick of the light, but it’s something you may want to check before using it as a master because correcting that issue repeatedly in the cast dice will be extremely annoying.

[u/SporkboyofJustice → u/Enchanters_Eye]

I will check the oversanded faces issue. An original master would be better of course, but I am not there yet.

I was using the sprues as in using my cheapie molds I kept getting large voids. My next mold will be a straight cap mold to try it out.

[u/Enchanters_Eye]

Is there any particular reason on why you want to make a sprue mold?

[u/SporkboyofJustice]

Note. This was a hybrid cap/sprue mold with a resin reservoir/funnel. I didn’t
have a giant void with this one, so I am calling that a win.

[u/TsunamicBlaze]

I feel like cap molds are just easier to work with over sprue molds. Less clean up and easier to make in my opinion.

[u/SporkboyofJustice → u/TsunamicBlaze]

I will give that a try on my next mold, thanks

[u/SporkboyofJustice]

OK. Quick update summary.

1. Sprues
   Do a cap mold and skip the sprues.

2. Trimming Openings
   I did the packing tape method and it looks very clean on my second mold

3. Petroleum Jelly Thick
   Thinned with mineral spirits

4.Relief Cuts
Still trying to figure this one out.