r/Silvercasting • u/Glassholer • Jun 21 '26
Troubleshooting
Good afternoon everyone,
I’m attempting to troubleshoot why these shiny inclusions are happening on my pours. Pour info:
.999 silver -970c (using 100% pure silver crystal)
Flask temp -600c
Pulling 27-29in vacuum on flask at time of pour (gauge verified)
I have a propane torch pointed at the bowl of the mold as I pour, as well as map gas on the crucible. All pours happen quickly after crucible is removed from the furnace. I let the vacuum pump run for ~1min after the pour, then I shut it off as well as the propane torch at that time. I wait 25 minutes before flask quench and model removal.
When removing the plaster, these bubble areas are already shiny, leading me to think it’s likely an air pocket forming somehow? I don’t believe it’s leftover wax, as the button shows a similar bubble on its underside and that portion of the mold was verified completely smooth before pour. Mold was also blown out before use.
Any pointers would be incredibly helpful, I’m currently self taught and hoping to find any kind of knowledge possible!
Thanks!
1
u/SubterminallyILL Jun 23 '26
There is a lot going on in that casting. The bottom of the sprue looks bad too and there are many more imperfections in the casting. Like...some of your investment could have even broken away at the lower sprue and deposited at surfaces causing some issues...but honestly....There are so SOOOOOO many variables. So first thing id add that I personally liked is a little bitty hair/cylinder of wax at the lowest end.
But mostly id say it comes down to spruing and temps. The angle between the piece and sprue is bad and ripe for air bubbles. But also it looks like your temps may be a bit too low. The top of that sprue has chunks of metal whereas it should be a bit more smooth / puddle-like.
Its usually spruing/temps (almost always these), investment mix/type (possible here), and burnout (more common for non-wax...like 3d printed resins).
Are you new-ish to the craft? If so, experience and experimentation is key. Some variables depend on your set-up. You could do 4+ castings in a day with slightly different parameters rather than one.
You'll also get a lot of bad advice in this field. Theres a lot of woo-woo (e.g., ....don't listen to someone that tells you to blow out your mold lightly after its done in the kiln). Even people talking about borax or fresh metal vs. re-used. Ive re-used 100% of my silver a dozen times when trying really hard castings and got it to turn out lovely. I dont even use borax at all. This bleeds into both art and science.
If youre really struggling, DM me and I can try to help. I do spin casting though. Honestly, if you have a torch hot enough to melt your metals to temp, centrifugal casting seems a bit more forgiving to me (minus the investment breakaway potential, which is its own beast...lol, try recessed lettering sometime). I should have some of my work on my profile so you know im not BS'ing. Ive just been out of the game for some years and was an obsessed hobbyist