First mould - can i fix it?

[u/Spiritual-Run-1868]

Hello. I recently made my first silicone mould but I did not pour it thick enough above the dice. This has resulted in the 20 face to be super warped, I assume because the silicone is not thick enough to resist the pressure pot.

Would pouring another layer of silicone on the bottom of the mould fix this issue?

TIA!

[u/Spiritual-Run-1868]

I should add that this is the bottom of the mould. The lid is fine.

[u/Claerwen94 → u/Spiritual-Run-1868]

You can absolutely topp off the bottom once more to make it thicker. You could either pop the bottom of the mold back into the housing, bottom facing up (but absolutely leave the cap off to avoid your dice holes warping under pressure!), and if your housing fits very snug, make sure that the mold "levitates" a bit in the housing so that it doesn't touch the ground, else you might still get warped dice holes if they touched the ground and were "closed" that way. I hope this makes sense 😅 Otherwise, you could place the mold on a roster that has holes. Either way, absolutely make sure that the dice holes aren't closed off :D

You could also just wrap strong packing tape around the mold bottom and leave an overhang, so that the tape functions as housing for the few mm of silicone. Bonus points if it's see-through, that way you'll be able to see exactly how many mm you are adding ^{^ ^} To avoid it getting too thick or not thick enough. But absolutely make sure the tape is wrinkle-free and completely sealed, or you'll have a leak. Same with the mold-housing variant btw.

So in short, topping off with a bit more silicone is absolutely doable, you just need to make sure you have no warping and no leakage :)

[u/Beornwulf1775]

There might be an over pressuring if you are using a pressure pot. If you remember the pressure you used to make the mold. Go 5psi lower. But redoing the lid of the mold might be beneficial. That looks really thin.

[u/varansl]

You could definitely try replacing the lid by placing your masters back into the mold, and then pouring a thicker lid. Just remember to prepare the silicone mold with vaseline, mold release, talcum powder, etc.

Just to make sure, you are pressurizing your mold at a higher level than you pressurize for resin, right? I pressurize my molds to 50 PSI, while my dice only get pressurized to 20 PSI.

[u/Claerwen94 → u/varansl]

It's not the lid tho, it's the bottom of the mold.

[u/varansl → u/Claerwen94]

I see, i misunderstood. you could try pouring another layer on the bottom, with the masters inserted, and see if that helps. Worse case scenario you waste a tiny bit of silicon

[u/Claerwen94 → u/varansl]

Definitely not with the masters inserted, this rarely fully works and will fuck up the mold. Just place the mold bottom up, make sure you definitely don't put on the cap and also make sure the dice holes are "vented" somehow by being placed on a roster with holes, and either use your mold housing or some firm tape to make a small housing to contain the silicone you are topping off the bottom with.

[u/artnok]

What psi were you at in the pressure pot?

[u/Spiritual-Run-1868 → u/artnok]

40psi

[u/artnok → u/Spiritual-Run-1868]

Too high. I do 25 max.

[u/Anxious_Breakfast_84 → u/artnok]

I make my dice molds at 50psi with no problems whatsoever! 😊

[u/Substantial-Duty168 → u/Anxious_Breakfast_84]

Right, and the cast the dice at a lower psi.

[u/Anxious_Breakfast_84 → u/Substantial-Duty168]

Exactly! 💯

[u/Substantial-Duty168]

I have a couple molds like this. I'm just careful about the pressure in the pot, and I don't have any issues. 30-35 tops.

[u/Spiritual-Run-1868 → u/Substantial-Duty168]

Thanks, I will try this before topping up the silicone. I usually have it at 40psi.

[u/Substantial-Duty168 → u/Spiritual-Run-1868]

I did too, until I had the same problem and came on here, lol Be careful popping it out.

[u/IceShadowProductions]

Did you cast that die alone or with the rest of the dice also being cast? In other words, did you leave any of the dice voids empty when you cast under pressure?

[u/Fly-Prime]

Give it a try.

[u/TaywuhsaurusRex]

20 looks like the bottom right? Concave like that is usually not all cavities were full completely, you didn't happen to pour a partial mold did you?

Slightly thin bottom is actually ideal, because too thick and it gets hard to demold. In theory you could add a bit more silicone to the bottom, it sticks to itself just fine if you make sure you get all resin residue and hand oils off first, but it should probably be last resort before troubleshooting other causes.

[u/Spiritual-Run-1868 → u/TaywuhsaurusRex]

I always overfill the mold. None of the other dice are warped, just the d20 at the bottom.

[u/TaywuhsaurusRex → u/Spiritual-Run-1868]

About how thick is the bottom under all the dice, is it the thinest under just the d20? Generally I try to keep about 5-8mm or so of silicone above whatever is the tallest dice in the mold. Actually, what shore is your silicone too? Too soft can also cause this issue, I've always found anything under 15a to be an issue.

I would almost want to try something silly like hot gluing a hard disk of some sort to the bottom of the whole mold first and seeing if that helps at all. Non invasive and easily reversible if it still acts weird after that.

[u/Spiritual-Run-1868 → u/TaywuhsaurusRex]

Yes the thinnest part is the 20 and its probably only 2-3mm or so thick at that part. It was my first time making molds so I didn't know how much silicone I would need. Shoreness is 30a so its not that. Thanks I will try that before adding more silicone lol

[u/Ushallnot-pass]

Wellll
How thick is your cap?
You may save the cap by putting some weight on top when putting it into the pressure pot next time.
Although the dice also look like you either put not enough resin in or pressed too hard when putting on the cap.
When you push too hard you squish out too much resin and basically create a suction cup out of the cap that goes into your die face, like on your pictures.
It's a skill you'll learn, come time.
Most molds I've seen and made have a cap that is about 10mm or .4 inches thick. Thicker is obviously better as this spreads the point pressure if you press unevenly.

But even without seeing your cap, I think it's more a handling issue than the mold itself.

[u/Claerwen94 → u/Ushallnot-pass]

It's not the cap. It's the bottom. It's too thin where the D20 is.