Another noob question- delicate/thin part removal from mold

I just made my first attempt at creating a silicon mold to pour a wax positive. I’m trying to recreate a trigger guard from an old .22 rifle. The silicon mold turned out well, and has awesome detail. The issue is, I can’t get the wax positive out of the silicon without breaking it. I’m zero for nine.
I’ve tried paraffin and soy wax with no joy. It always breaks in the same spots, which is across the thin bridge by the sprue.
Is the brown wax I see folks using more pliable to allow removing delicate items from the mold?

 

Paraffin wax is really fragile while beeswax is more like a super thick grease so for a one off possibly a mix of the two would work. Failing that, buying the proper wax would be the best option. Personally I would make a split pattern and sand cast it but I'm a sand casting guy with access to really fine silica sand and suitable sand binding resin.

 

That’s kind of my question. What is the proper wax? I’m not very far on my learning curve... Is red wax “hard” ? As in HARD? And brown wax is not as hard? How hard is hard?

 

I don't do any wax work so that's a question best left for the lost wax guys on the forum here. I just use it for other purposes where the lack of flexibility of paraffin makes it unusable.

 

Thanks ... I’m ready to buy something, just need to zone in. My total experience with wax to date has been blowing out birthday candles.

 

Try Pink Filigree. Soft and pliable but hold it shape.

Freeman Flakes Filigree Pink 1 Lb Injection Melt Wax Gold Silver Platinum Alloys

 

Looks like this. The one vent is to an arch like the ones in Moab Utah Arches National Park. very hard to release from the mold without breaking until I tried the pink wax.

 

Hard wax can be machined with tools like dremels and drills, files and other tools where soft wax will clog the machining bits..

 

But still melts at a relatively low temp to be poured into a mold?

 

I think 160-165F. I use a turkey baster sort of to inject the wax. there are other soft waxes as well. I little higher than some paraffin. google says 115-154F

 

I would go with DavidF suggestion. I guarantee there's a reason for the tuffy green. Never used it myself but that's not saying much. I will check it out myself.

 

HOLY CRAP BATMAN... I just received my bag of tuffy green in the mail. I had no idea wax can be so variable. My total wax experience was pouring candles back in the 70s. ... far out.
This stuff is more like plastic than wax. I can’t wait to try again in the next day or so.
Thanks for tolerating a total newbie that doesn’t know enough to ask an intelligent question..

 

And make sure you have plenty of draft in your mold.

 

Draft? What's that?

 

Just as an aside, silicon and silicone are two very different things and are both frequently mentioned here. You're using silicone.

What are you planning to do with the wax once you successfully get it out of the mold? I'd guess it's for a lost wax casting? Just wondering. Some lost wax guys might chime in to tell you if there will be any challenges in melting your invested wax out, I don't really know much about it. Hopefully your new wax will come out of the silicone mold successfully but if not you may have to return to your silicone mold design. Possibly cutting some relief slits in the mold would help. I notice from your original photo that most of your part is captured in one half of the mold and merely printed onto the other half. If you have the cavity split evenly between the two halves of the mold you would probably have better luck extracting you wax intact. That lends to your question about draft.


I don't know if your silicone can be poured in two sections like the urethane in the video, you would probably already know that, but this would certainly improve you're chances of getting the wax part out.

Just my 2 cents.

Pete

 

AGELE55... I think the wax models will come out fine with the new wax, but how are you going to cast the piece? Lost Wax or Ceramic Shell?

 

Why is it not an issue in getting a brittle wax pattern out of a silicone mold? It appeared to me that the mold was not releasing easily.