DIY Manufacturing Process Using RTV Silicone 

By the way, if you want a cheap and easy way to degas resins, grab the biggest syringe you can. Put the plunger in, and suck up the resin to about half way. Put your thumb over the tip, and then pull it back the rest of the way. It will create a vacuum, pulling all of the air out of the mixture, then you can use the syringe to fill your mold. Something like a 150mL syringe will do, it looks silly at first, but really works and will save you the need for a vacuum pump.

Don't mix silicone with a spoon, it introduces a ton of bubbles. Also if you are using a tin cure such as this, pour the non viscous part in the cup first, then the viscous. It will ensure you can thoroughly mix the entire cup and not have to worry about unmixed materials.

Really cool project, integrating 3D modeling, printing, and silicone casting 😉

2:24 use a vibration pad to get bubbles to the surface faster.

Easier than vacuum degassing the silicone is to pressure cast it. Don't worry about bubbles getting in when mixing, the air pressure will crush them and drive air into permanent solution in the silicone. A Harbor Freight item number 66839 Air Pressure Paint Tank is big enough for a wide variety of molds. What you get with RTV silicone without pressure casting it, even if you vacuum degass it, is bubbles in sharp inside corners, which can be seen in the mold in this video. Only the thinnest viscosity, low durometer, RTV will flow well into those tight corners. But that softer silicone wouldn't be suitable for "pack and hold" injection molding. It might work for injecting until the mold is full then immediately releasing pressure. But then that method isn't suitable for plastics that have a lot of shrink as they cool. For some reason, tiny bubbles in the silicone like to cling on vertical surfaces, just beneath the surface of the mold cavity. The mold surface can look great but pressure cast resin or injection mold thermoplastic into the mold and those subsurface bubbles collapse. That produces bumps, spikes, or if the bubble ruptures, little balls of plastic on the surface of the casting. Those defects will then be rough on the mold when removing the casting. Never use tin cure RTV. It's not worth the small cost savings, not even for one off projects, especially when dimensional accuracy is important. Platinum cure RTV molds can last for decades if taken care of. I've been making silicone molds and resin castings for over 24 years and most of my molds from the early years are still in use, including a few that I didn't pressure cast the silicone. I just put up with the issues that came from that because those molds don't get used often. A few molds I have made enough castings to where they got worn and I've had to make new molds once. I have learned a lot about making silicone molds in over 24 years, especially how to make them faster, easier, lower cost, and better performing. I started out with a background in slip cast ceramics and plaster molds, and fiberglass mold and part making. Much of the molding techniques for those types applies to silicone molds. I started with the typical methods found in books published in the 80's and 90's, and still promoted in this century in countless RU-vid videos. Tip from this pro, they could be doing it better. When I found that a traditional / historic method was difficult to do or produced results I wasn't happy with, *I figured out a better way*. I've often figured out a better way than my original better way several times. I am happy to share what I've learned through a lot of experience *for free* because I want other people to have the best experience making molds and castings by taking advantage of my years of experience to "short cut" from the old school techniques of 40 years ago to how I make molds now. Use my knowledge and learning so you can skip all the in-between development I've done from what's in books like The Prop Builder's Molding and Casting Handbook (still a good book to read for anyone making silicone molds) to making *better molds and castings* than what you'll get following the old books.

Amazing for small production or home business.

Gr8 job guys!! Always inspiring.

For those of you on a budget. Vibration also helps bubbles rise to the surface. You can achieve this simply by holding your mould as it dries on top of your washing machine when it's on full cycle

What was the diameter for both the holes where the injection took place and the escape hatch?

Love this concept, I really have to try it to make joysticks and throttles for flight sims.

The legends are back 🎉 and amazing video

How many injections can you do before the mould wears out?

Good fast drying silicone "epoxy": Silicone I (not II) mixed with a little baking soda. There is a good tutorial on Instructables.

Have you tried injecting any PP HDPE or similar polymers into silicone? How well does it work?

Last time I tried using sla printer to create a silicon mold, the silicon didn't cure in contact with the resin. You need to use specialty resin for this and/or spray them with polyurethane.

What silicone are you using is it tin cure or platinum cure if platinum cure what resin are you using?

Does this mean there is a 2.0 verion of the WEDM coming? please :-)

Could ABS plastic be injected just as easily?

for small parts like this you can degas using a large syringe

can you use pet plastic instead of hot glue ?

Damn you RU-vid. Now I want to try injection moulding 😱

വെരി ഗുഡ് very good

7:27 Looks like one halve was flipped?

7:22 hoopsie did you flip the mold in the first try? 🙈

I dont have a injekto 2.0

Great video, although I think some of your sound effects of choice (namely 1:38) are a bit annoying and not very well suited to an informative piece of content like this.

Super! This is a super amazing super detailed super done super duper superdiliocious super idea!