I commend you on your ability to make this process look so much less daunting than what I expect it to be lol. I have watched alot of your videos, joined your patreon account, and started planning my first build. THANKS for all the great videos.
Hi Bill, thanks for a great video. loads of good info. Regarding degassing. For tiny parts I use a household vacuum marinading box. Due to the small internal volume it only takes a short time to remove the air. Also they, as we in the UK say, are as cheap as chips.
WOOOO my question made it in (only got part of it answered but that's ok) thanks for being awesome, looking forward to all the upcoming videos for molding.
I'm a beginner mold maker, but from what you've said about repairing silicone is spot on. If it's a fully cured silicone mold, repairing it with more silicone is difficult to do and most often won't work. Making silicone masks or repairing a mold when it's fresh and not quite "fully cured" works great, but something cured fully probably isn't even worth the effort.
There is a silicone available at Reynolds Advances Materials called silpoxy specifically for repairing rips. You will have to clean up the seam on the rip on future casts but it works for fixing silicon tears. Also you totally can pop bubbles in a one part mold with a blowtorch, but it's the CO2 that does it, not the heat. Mold release works just as well if you are worried about the heat kicking the resin too fast.
For the individual that asked how to determine the volume of a mold so you know how much resin to mix up, here is a trick used a lot in the effects industry. Fill the mold with dry/clean rice, and then pour that rice into a measuring cup. This gives you the general volume of your mold. You can do the same with water, but that requires drying time, and you never want moisture in or around your molds when you are casting urethane resin. That's why we mostly use rice.
It shouldn't be too hard to calculate resin needed for a rotocast. Calculate surface area and multiply with the thickness you need for the cast. Having bends and crevices adds to the surface a lot more than one might think though. So keep that in mind.
Hello Bill... Just been watching your videos and they are very informative and interesting... I do have a question in regards to molding things like full characters would a two part mold work or could I just use one master mold? Thanks a bunch.
I want to throw my two cents in on two of those questions. 1. Just to be clear, do NOT pour uncured (or cured I guess) silicone or urethane down the drain. Unless you have a crush on the plumber and want to watch him replace your pipes. That stuff will clog them. 2. For the phone, Smooth-On has Equinox silicon putty that would probably work. And it is food safe if you go through their post curing process so you can make chocolate phones.
one thing i've always wondered. with the question about alternative to expensive silicone. i've seen a lot of tutorials with a single stage mould or a two stage mold, where they pour and completely fill basicaly a box around the object. Would it not be cost effective to make like a matrix mould for things, make a rigid form that fits closely around the object so you need a lot less silicone around it to get a mould.obviously could take more time. but i think it seems to be a superior way to mould things, and with practice could become a quite efficient workflow that saves a lot of silicone.
+Graeme Evans Matrix molding is awesome! There are lots of factors to consider. If time is the top priority, a one-part dump mold is the fastest. Big production companies will even do dump molds on props (and cut the prop free), if they only need one copy. It's cheaper for them to use the extra silicone then to pay for the extra time of a matrix mold. So far, we've only used matrix molds on large items and helmets.
just a tip have learned the hard way silicone glued with the same silicone , like he says kinda works. but you have to clean the surface and even cutting out fresh area for some reason that seemed to work but i got a better result with clear nails, im guessing since its made as a glue and made with silicone its worked so far.
I want to cast acrylic. Mainly for making clear acrylic saxophone mouthpiece. The internal will be machined by hand or by a mill and lathe. Will the this work on acrylic?
I have a few questions that I have been trying to find the answer to. Soon I shall be working on a character project where the final goal is to create a 1/6 scale in a action pose. My plan was to make a prototype out of wax clay then moulding it and making the final piece resin. My main questions are about what materials should I use? How much would I need roughly and how much money would it take?
To answer the most pressing part of that disposal question... DO NOT POUR UNCURED RESIN OR SILICONE DOWN THE DRAIN. If not going with his mini-molds idea for disposal, just have a bucket or something you can dump the resin/silicone in. Once cured, it is safe to throw away with your garbage. Some people will actually combine this method with their razor blade disposal, alternating resin/blades so that they can safely dispose of sharps, which usually require a special container.
I once made a mold for a micro fusion cell from fallout 3, everything went fine. But when I tried to roto cast it with polyester resin the following happened: I filled one part of the mold with resin, closed it with the other half, made sure it wont open accidentally when rotating it. I was rotating that thing for 20 min making sure the whole surface comes in contact with the resin evenly. But the result was only a small amount of resin remained at the molds surface giving the casting a very very thin surface. The rest of the resin bulked up to a ball inside of the casting. My question: are there resins that won't work for roto castings? Or what can I do to prevent this from happening?
That's totally up to you! Sculpting is a great option, but you can also fabricate using many other materials. The key is to prep properly for the molding process - blocking openings, making sure your surfaces are finished the way you want, etc.
i know this is 3 years old now but with regards to the blowtorch to pop bubbles hell no! applying heat in this way to the silicone will cause it to burn up to an ash. talking from experience.
Hey man another new question for a very old video.. you KINDA said something about Eva foam but I'm not sure I understood. I just built my very first arm gauntlet out of Eva and now I'm learning about casting from your videos. I might have missed the answer, but could I use that Eva foam gauntlet as a master? Or would it just get all screwed up in the smoothcast?
You could, but silicone will pick up the surface texture and it could warp, so you'll want to make sure it's well sealed and coated in something like Epsilon Pro to add rigidity and control the surface texture.
Are you wanting to know if you can use epoxy to make a cast or to make a mold? Here's an example of using epoxy to "cast" in a mold: punishedprops.com/2017/12/18/experimenting-casting-props-using-epoxy/
Punished Props I was speaking about the smaller guns, but I'll try that then Sadly can't do it yet because I have no where to do it, I'll try it next year though
In every single video.... all I hear at the beginning is "Hi welcome to the shop, I'm Builder Ann" I think you should run with it. Make a t-shirt that just says "I'm Builder Ann"
