clear resin is a good idea, Tho I want to design something specifically to be cast in rubber so I think Its going to be a while before I do this again. and thanks for the videos, MAN is it a long series haha but I have started watching it
I used Mann ease release 205, came with my smooth on molding and casting kit. yeah, I wouldn’t do it with a hard figurine, but I think it works pretty well for a flexible one like what I did, especially if I can get it perfect~
those food containers are out of stock everywhere D: but I am looking around for something similar. I discovered my family has a vacuum sealing storage container (you plug the vacuum in on reverse) and if I can’t find anything thats going to be my last resort.
Getting vacuum to draw the air out of the container isn’t as much of an issue as maintaining the pressure.
The commercial vacuum pumps like the Gast one I have and similar one on Harbor freight will work really nice but they range from $99 to the thousands and are probably too powerful for ordinary plastic containers for any kind of continuous use so you need to regulate them so the container doesn’t flatten out or you pop a seal. Then you need to keep that pressure.
I ended up making one because I couldn’t find the ones I showed you, all sold out. I did a cold casting in it though the part is just an emblem it did raise the bubbles to the surface.
I use a urethane parafilm (Price Driscoll Ultra 4) release agent on my parts so the finish parts are paintable.
Not sure of the one Smooth-On sells, might be the same thing.
As an option what I used to do is tap the hell out of the mold which will also raise the bubbles.
Cutting in some air vents will also be a key factor for those ears and tail that aren’t filling.
ooo I was wondering if there was a way to paint the casts without priming them. so that mold release lets you do that? because thats great! thanks so much ken, you have been so helpful. I got the silicone putty and plan on making molds with it (and smooth on liquid silicone) maybe next week
Some mold releases use oils or silicones which will resist paint. Paintable release won’t transfer to the casting.
I think the big key for your castings is to create some air vents where it isn’t filling.
That putty silicone is pretty slick stuff, there is a platinum cure version you can use for food molds, make chocolate versions of your characters.
I thought about that, but shipping food seems like a pain but maybe making custom molds for candy stores or something? Food grade does open up new possibilities. Guess I should just focus on getting a perfect mold first haha.
I wouldn’t get into selling either the mold or candy, the liability insurance needed would put you in the hole before you start.
ugh its so annoying, I wanted to make kids toys but the more i looked into it the more I saw what a legal pain that was So I just stick to making things for adults~
@Sasha, one method of molding that is used in industry is to cut the pattern out of the molding material. This method works by supporting your pattern in a box and pouring clear or translucent silicone around the pattern. De-gas if you can to remove bubbles. Once cured cut through the silicone along the desired parting line. Create a jagged pattern when cutting to make a keying surface between the mold parts. With this method you can make complex molds more quickly. Use a sharp Exacto knife to cut through the silicone and be careful. If you use steel or glass rod, as the patter supports they will pullout of the silicon making spures and vents in the mold, just make sure to put them in logical places.
For mold making strategies regarding vents, parting lines, and filling… I would recommend this video which addresses a lot of that (it’s making a silicone mold, but the techniques still apply to rigid molds):
Hi all i have printed a four piece mold and the detail is very good. I want to put the mold together while it cures to minimise any chance of leakage after it cured. My thought is to put some food wrap between the pieces of the mold before i put it together to stop it sticking together. Has anyone tried this before?
I’d recommend testing this out with some of the supports you may have clipped off/out first made of that same uncured material. This way you can make sure there’s no undesirable reaction between the plastic wrap’s composition and your mold making resin. You’d not want to damage your carefully printed part if it turns out that the plastic wrap reacts to the curing resin in some unexpected way. (Like fusing the mold together or becoming some kind of goo from some offgassing of the curing resin.)
Depending on which resin you used for your mold, there’s also a possibility that the resin could shrink up a minute amount around the plastic wrap during curing. I’d check the materials datasheets for that information. This could even cause some slight stress on just the assembled mold alone if there’s any factors that might cause things to cure at an uneven rate.
if you don’t have a vacuum chamber- then pour silicone for molds in a pencil lead thin stream… very slowly- this will burst 99% of air bubbles in the mix.
If you are casting resins without a pressure chamber- the mold must be carefully vented to ensure it doesn’t entrap air- and you should lightly dust the interior cavity of the mold with talc. The talc prevents bubbles from adhering to the surface of the cavity by acting as a wicking agent, so that air is subsurface- or rises to the vents.