Silicone Rubber Molds - 3 Ways Part 1

In this video I show you how to make 3 silicone rubber molds using 3 different methods.
What these parts have in common is that they all have holes.
The first mold is the simplest. It's a 1-piece cut mold using a plastic cup as a mold case. This probably the most common mold I make because it's quick, easy and works with most small parts.
The second mold is a 2-piece mold with a flat parting line. The part being cast has screw threads so care must be taken to avoid catching bubbles there. The parting line is created by clamping the part to a waxed wooden base and registration dots made of resin are also attached to the parting surface. This mold is poured in two batches.
The third mold is by far the most complex. It is a hybrid mold using both clay-up and cut mold strategies. It has a long through hole which requires a clay-up parting line in the middle. It has a thin, flat flange and screw threads. This require multiple air vents and cut parting lines that run at 90 degree to each other.
TIMESTAMPS
00:00 Silicone mold making three different ways.
00.38 How to deal with holes in models.
04:03 Setting up a cut mold in a cup.
05:51 Testing the rubber to verify that it will cure.
12:06 Sealing the mold case parts with beeswax.
13:23 Registration dots on mold cases.
15:15 Pouring molds; using mold release on 2-part molds.
20:02 Spruing and venting a complex part.
22:23 Pouring on open mold of a model with threads.
25:12 Pouring the 2nd half of a 2-part mold.
29:09 Pour rubber around a complex shape.
Here is a list of suppliers for the rubber, resins and waxes I use in my videos: www.dropbox.com/s/kz6mhmf7v5v...
Do you have a project to suggest for the channel? Here’s a .pdf with everything you need to know: www.dropbox.com/s/pjb0l6fr7zj...

[@TheGnthreman]

Old school guys, glad I'm one of them.

[@andrescepeda4763]

I am a mold nerd and I love your videos, I always try to imagine how I would approach the problems you present and I learn a lot from your solutions. Thank you so much for sharing every step of your processes!

[@RobertTolone]

Thanks for watching Andrés!

[@TheGnthreman]

Im busy watching your videos while my projects are neglected 😂 😂

[@mossy9227]

Your favorite thing in the word is 5 minute epoxy, mine is starting to be this channel!

[@ryancreasey5833]

Every time I watch one of these videos, I feel as if I learn twenty new things. Topping a mold off with "chunkies"... mind freaking blown.

[@shaunavconnelly9022]

The “Tolone-isms” rock!

[@PamelaBrandonChromeFoto]

I think this impressive gentleman is or use to be in the dental field, just my guessing,I think he’s being modest, thank you for these awesome videos.

[@antystein]

So no one is going to talk about the wax carving pen burning up its own wire sleeve at 25:20? I hate it when this happens to my tools, at it has happened maaany times with a soldering iron, making severe damage in some cases as it takes some time for the smell of burning plastic get to you! At least I am somewhat relieved that it can happen even to a person as methodical as you! I can never get enough of your videos, your approach to problem solving comes very handy in many cases even though I don't make molds or castings yet, but I am planning to do some day for sure! Thank you!

[@RobertTolone]

That's not the first time I've burned something unintentionally! 😳 😢 😀

[@debrajol3585]

I don’t even make molds but I love to watch & listen while I do my prep & resin art pieces. It’s like having an artsy friend in the studio with me 😊 .. and some of the things you show I have been able to use in other areas of problem solving. Always a joyful day when a Robert Tolone video comes out.. and previous videos refresh my mind. Thanks so much for sharing your beautiful art work & techniques 👌💯🤩

[@RobertTolone]

That is awesome! Thanks so much for watching!

[@abrahamazariii5943]

I feel like the most difficult part of making this video was strategically placing his thumb in every shot. I love these, keep 'em coming! I always learn something.

[@RobertTolone]

I failed in one shot and didn't even notice until I uploaded the video. The F bomb can be clearly seen! Oh well...

[@shaunavconnelly9022]

Genius and thoughtful!

[@annekabrimhall1059]

@@RobertTolone 🤣 I saw it!

[@RobertTolone]

@@annekabrimhall1059 Hate when I edit the entire video and miss the obvious mistakes. 😳😭🤪

[@joshuac4961]

Something about silicone mold making is just enjoyable to watch!

[@RobertTolone]

I have been pouring molds for 35 years and I still get a kick out of it every time

[@grimmace2131]

Definitely glad I found your videos. Thank you!

[@RobertTolone]

Glad you like them! Thanks for watching.

[@curbotize]

So cool how you have all these tips an little tricks to make your job a little easier. You can tell the experience. 👍

[@flytrapjohn]

Wonderful stuff, Mr Robert. Thanks for bringing us along for the ride.😊

[@RobertTolone]

Thanks TP! Glad you enjoyed it.

[@markhills3922]

Another interesting tutorial Robert. I look forward to seeing how you address the problem of having a solid mold inside the hole of the pendant.

[@ChempZee]

Excellent content as always. Thanks for sharing.

[@RobertTolone]

So nice of you to comment Matt. Thanks!

[@wollibar5263]

Great video once again and a joy to watch.

[@RobertTolone]

Thanks Wolli!

[@ThatRobHuman]

that's some strategic thumb placement on that F Cancer ribbon, there - well done :3

[@RobertTolone]

👍😄

[@hector4330]

Awesome channel. Please keep making these videos.

[@RobertTolone]

Thanks, will do Hector!

[@PamelaBrandonChromeFoto]

I just came across your videos at 3am, when my mind is clear running on its on time. Love your enthusiasm and how easy you articulate the process. Love learning new ways to do things, I look forward to learning and watching more of your lovely videos.

[@levinebette15]

Great vid, Robert!

[@RobertTolone]

Thanks Bette ❤️

[@ArcticFlies56]

Robert it’s a pleasure to watch you work. It’s very interesting to see how you plan ahead for as many problems as you can. I started in making molds and pouring resin to make replacement parts for vertical blinds that I couldn’t find because they were too old and out of production. They turned out better than I had expected not knowing what I was doing. I found that watching people like you on You Tube helped me get educated in what to do. There is something about making replacement parts and having them work just fine that is very rewarding. After watching you do what you do so well, I subscribed to your channel and gave you the thumbs up. Best regards, Richard

[@RobertTolone]

Thanks Richard. A lot of the people who watch my channel are into restoration and making out-of-production parts.

[@technomicah]

Totally need these tutorials right now for my toy business

[@RobertTolone]

Most of my business has been sculpting toy prototypes for the entertainment industry. Molding and casting is the final step in the prototyping process. Of course nowadays 3D printing and CAD models straight to manufacturing are replacing hand sculpting and mold making.

[@krzysztofmathews738]

This is excellent! The part with you using the already cured rubber to fill in really was a "Holy cow, I didn't know you could DO that!" moment for me! I love learning new things like that.

[@RobertTolone]

And also that you can fill the mold in multiple rubber pours and letting the rubber cure between pours. Makes building a complex mold so much easier!

[@damianpark236]

Rob, Another bonza video

[@RobertTolone]

Thanks Damian!

[@vicyhago]

Always Great , Master! Thanks

[@RobertTolone]

Thank you Vincente!

[@KWKirchhofer]

Very Cool Robert! Thanks for taking this on and giving such a thorough demonstration. I linked to this on my FB page and in the group I worked with in creating that 2 piece part. I think they will like to see this. That 2 piece part, btw, was for a PAPR hood. Ventilated hood that was very popular when COVID 19 became a thing. A local 3d printing group was tasked with making 200 for a local hospital. I changed the connection of the original 3M part in solidworks to this screw on part method simply to make it a cast-able item.

[@RobertTolone]

It was a really fun project Karl, thanks for sending it in. It's amazing that such seemingly ordinary objects can require search different strategies to cast. That's what makes this so much fun!

[@tooncescat8040]

Robert, I am new to casting and molding. I have always been interested in how to DIY produce and replicate needed things without involving a commercial manufacturer. While a lot of what you do doesn’t apply to what I am currently doing, I am amazed and captivated by the innovative problem solving you constantly do from how to mold the item, create a support system for the mold, and placement of sprues and vents. Thank you for all the information and effort!

[@RobertTolone]

Thanks so much for watching!

[@BIGJIM1934]

Hey Robert I enjoyed your video as I do all your videos. When I cast a part that has a high probability of air entrapment I pour the silicone into the mold then put the mold into the vacuum chamber and give it a quick pull. Bubble free every time.👍

[@RobertTolone]

That works as long as the model you're molding has no voids inside it. I have a strict policy of not applying vacuum or pressure to models because I often get models from clients and have no idea how they were constructed. I learned this the hard way and destroyed a couple of models early in my career. But as long as you're sure of the model it works

[@Bren0780K]

17:20 Painting the silicone around the edges is a fantastic idea!

[@RobertTolone]

Pre-painting the rubber is one of the most useful ways to eliminate bubbles and leaks in a mold.

[@mookzmom]

You are magical!

[@RobertTolone]

SO not magical, but thanks for the nice comment Pam!

[@thatguybeardo1279]

That cup bit got my dying 🤣

[@paulhayton3423]

magician..

[@RobertTolone]

Cheap tricks and slight of hand. Not much real magic going on here! 😀

[@jordanhindes769]

Robert how would you go about making a mold or series of molds to effectively overmold another part or shape to a model. Such as a new color resin forming say the jacket on a figurine model or even a different material such as PU rubber or even silicone if that’s possible like the rubbery grip on hiking sticks handles? Just thought it’s would be a challenging task stopping the over-mold pour from running over the existing first cast. Great video once again. Ps thanks for the advice on my molds the other day on my next project I’m going to try to blank the corners out of my mold boxes to save resin like I’ve seen you doing. :)

[@RobertTolone]

Hi Jordan. I have very little experience with that kind of molding. I have done casings where I cast sections of the same mold in different color resins... but it is tricky and time consuming. I prefer to simplify the casting process rather than over complicate it.

[@markdean1500]

Hi Robert! I’m a recent subscriber and I have already watched 8 or 9 of your videos. I am especially motivated because this is exactly what I have been looking for in the metal casting I do in copper and silver! So a huge thanks for the high quality and thorough explanations in this series. Robert, will the MR-150 release agent work between PLA, from a 3d print, and the econosil-25 rubber? Thank you so much!

[@RobertTolone]

Usually you don't need a mold release between silicone Rubber and PLA. What you need is to make sure that the brand of printing plastic you are using will not inhibit the cure of the silicone rubber. The only way to find out is to test your rubber against a sample of your PLA. I don't think mold release will work to prevent mold inhibition.

[@rustianphelps3440]

Hello, Robert. Thanks for another inspiring video. I would like to get a wax pen like the one you have. I found sticky wax and wax sprues online. I also found the Foredom waxer model you have, but it’s prohibitively expensive, especially since I’m just starting to experiment with mold making and casting. There are lots of cheapo waxers available, mostly marketed for dental use, but I don’t know what to look for in a waxer. Can you please offer some insight regarding what makes a waxer suitable for this purpose?

[@RobertTolone]

I have used a number of wax pens over the years. Back in the bad old days before the internet the only place I bought them was a jewelry making supply store. The cheapest way to go is with alcohol lamps they sell. The biggest downside to those is you must constantly heat the tool tip in the flame. I soon tired of that. Then I went through several electric pens that either burned out or wore out. The Foredom Wax pen I have now has been in constant use for more than 10 years. Yes, it's expensive but for me it has paid for itself many times over. That said, be sure to get a pen made for wax that has a temperature control knob. You will often have to vary the heat output of the tip. A lot of people try to use soldering irons or woodburning pens but the heat output is usually too high for use with wax.

[@rustianphelps3440]

@@RobertTolone Thanks so much for your quick and thorough response. I'm glad you warned me about the soldering iron; I did look hard at those. I found a $50.00 jeweler's wax pen, and I think I'll go with that for now. Meanwhile, I'll write Foredom on my penny jar.

[@gremics-gallery]

Hello Robert, The pot you have on the side is that just a standard temp controlled cooking pot you use to keep your wax in liquid form. Then use that to brush onto your wood boxing up pieces? Thanks. Thanks for the reply to my other question - it will be a handy video down the track. Whats your optimum temp on your Fordom for do the wax welding. Got myself a little SJK brand for dental wax molding? Hopefully should do the trick. The Fordom is expensive in comparison.

[@RobertTolone]

Yes, it’s a crock pot - I bought it super cheap from Target. The temperature I run the Foredom tool at depends on the wax. The sticky wax I run very hot, my sculpting wax cooler otherwise it burns rather easily. So you just have to experiment with the wax and the pen to get the right settings.

[@BioMusing]

Both making a rubber mold and then using the rubber mold, the original 3d printing.

[@crowntimber1]

I watch this then later i will be staring at random crap in my house and think maybe i need a silicone rubber mold of that. Ima need some sticky wax.

[@shaunavconnelly9022]

And now I can learn Italian with the subtitles😉

[@RobertTolone]

Life is full of surprises!

[@Anubis30224]

Excellent work, Robert! I've been thinking about molding pieces of raw, natural wood for reproducing aquarium decorations. Should I coat them in beeswax, or would mold release be adequate do you think?

[@RobertTolone]

The only way to be sure in your situation is to test out a small sample to see if the combination of wood, release and rubber works for you. I always test everything! It's a habit born of many disasters, especially in the early days of my career. 😳😢

[@Anubis30224]

@@RobertTolone Thank you! I'll take your advice, and try a few samples to test. I hope you have a happy Easter!

[@joshuadreha6304]

Happy dippy dappy sticky wax

[@RobertTolone]

😄

[@tsujono]

Hi Robert, could you give me information, please, what glue do you use and where you bought it ?

[@RobertTolone]

The glue I am using in this video is five minute epoxy from Zap called ZPoxy. But pretty much any brand of 5 Minute epoxy works fine. You can get five minute epoxy online or in just about any hardware store.

[@nicholekennedy362]

What if you filled it with play dough or use silicone ? Now I’m new at this so I’m sure I’m far off from being correct . Can I ask a very embarrassingly basic question that I’m sure I should know😢. How do you know when your pouring if the 1st pour is the front or the back. I have wasted a lot of money trying to figure this out

[@roger.agburn]

Nice video, Robert. Will the threads unmold easily or do threads make the mold wear out faster? And did I see right that you melt the plug of your soldering iron in a little accident there? ^_^ Happy Easter!

[@RobertTolone]

Sharp edges on any form can make the mold wear faster. Now I have to go back and watch my own video to see the plug melting! Didn't notice it but I have melted things several times by being careless with the pen.

[@roger.agburn]

@@RobertTolone It's at 25:15. ;) You knocked it off the wax and shortly afterwards some smoke rises up.

[@RobertTolone]

@@roger.agburn I went and checked today. That plastic sleeve must be fire proof because there wasn’t a mark on it!

[@roger.agburn]

@@RobertTolone Good thing. It's super annoying to damage your tools.

[@artcraft2893]

Question: How to copy a silicone mold? Suppose I have a 2-3 piece mold for transparent casts, which took a few days to make. How to made mold for molds?

[@RobertTolone]

I have never been successful making molds of molds. Whenever I make a production run of one item I cast between five and 10 copies of the original and use those copies to make production molds from. This works because I always use the cut mold method. It is theoretically possible to make a mold of a mold however. Just be sure to use a good release agent when casting silicone against silicone.

[@ashi1922]

Hello. Completely unrelated. I purchased a silicone tray mold that is meant for resin but I wanted to use it for concrete. The problem is that the fill in part that would be the base of the tray isn’t deep enough for me to pour a good layer of cement. What is the easiest way to increase height of the walls so I can pour a thicker layer of cement. 🙏🏽

[@RobertTolone]

I'd have to see it to really tell. If you want send a pic to [e-mail]

[@scottgperry1]

Where can you get the sticky wax and the heat applicator?

[@RobertTolone]

A link to my suppliers is in the description of my videos.

[@gremics-gallery]

Hi Robert, Can you do a video on filling in holes/bubbles ? time stamp 09.50. thx

[@RobertTolone]

Ok, I'll include that in a future video.

[@CrystalJean157]

What kind of silicone did you use? The stuff I have is pink. Thanks

[@RobertTolone]

It is a tin-based silicone rubber from www.Silpak.com called Econosil-25.

[@annekabrimhall1059]

I can just smell the wax when I see the smoke coming up from your tool. I like to watch to see if you will ever melt or burn anything. If you do, I’ll catch it😆

[@RobertTolone]

You wont have to wait long! One time I caught a rag soaked in acetone on fire!

[@shaunavconnelly9022]

😳

[@annekabrimhall1059]

😱🔥

[@cdertschei]

Is there a special reason you use plastic cups or cardboard tubes for round molds instead of rolled up plastic sheets, where you could make any diameter in an instant?

[@RobertTolone]

Rolled plastic works great too. Plastic cups are the ultimate in speed and convenience for small parts. I'll do some rolled plastic molds one of these days. I try to show as many ways as possible to make molds on the channel.

[@cdertschei]

@@RobertTolone Cool, can‘t wait!

[@johndix6101]

What is the name of the iron called you use to melt the wax its not a soldering iron is it ?

[@debrajol3585]

I’m interested to know what it’s called too. I was thinking it’s either a wood burning tool with a smaller shading attachment.. or a hot knife with an attachment meant for slicing designs into styrofoam. Hopefully Robert answers 😁

[@RobertTolone]

It is a Foredom Wax Carving pen.

[@curbotize]

Will non cured silicone stick to cured silicone? If I wanna make like a stripey mold can I do it by layering? (edit) should probably watch the whole video first😂 I think it answers my question. 🤷🏼‍♂️

[@RobertTolone]

The silicone I use definitely sticks to itself. I do molds in poured layers, brush-on layers and often cut up old molds to recycle the chunks into new molds. But definitely test the brand of rubber you’re using to see if it bonds before using this method in a mold.

[@annekabrimhall1059]

Why did you have to do the second side to the nut? If you just left the one side when you filled it with resin it would be flat on top anyway.

[@glenfisher728]

You would need to place an acrylic sheet across the top of the mould to get a flat finish otherwise you would get a dip due to surface tension or too much that would need clean up.

[@RobertTolone]

It would not be flat. It would be cupped. So I would have to build the part up, overfill it with resin and sand it flat. You know how lazy I am. This was easier!

[@annekabrimhall1059]

If you put the pour spout on the first side and then glued your clear sheet to it, would that work also?

[@RobertTolone]

@@annekabrimhall1059 I can’t see how that would work...

[@t4concepts]

Sorry Robert, but I got distracted when you de-moulded the nut at 25:24 ................... I got too busy keeping an eye on your wax carver burning into it's power cord! I guess wax carvers don't actually get as hot as soldering irons, but still hot enough to burn through plastic. Was there much damage made to your wax carver? TURK

[@RobertTolone]

Fortunately it survived and lives on! Another thing I like about the Foredom waxer is you can replace any of its parts. Worst case I would have had to buy a new handpiece and cord. When cheaper tools die you have to junk and replace them.

[@gaveintothedarkness]

7:05 heh heh heh

[@Isimsiz-pe1nk]

I want to contact you please i want to show some thing can u do it and show us please

[@RobertTolone]

Reach me at [e-mail]

[@dodgeramsport01]

Anyone ever told you that you sound like Red Green?

[@chartle1]

I have a feeling that this whole video is going to be an exercise of how to keep covering up the 🤬 not to the point yet where its getting cut away from the mold. 😄

[@RobertTolone]

I thought I did pretty good at it but in one scene the F bomb is clearly visible 😳!

[@chartle1]

@@RobertTolone I sort of noticed but I think it wasn't close up.

[@jimstanley_49]

"... they both have TWO holes, they're very similar." In fact, they are topologically identical. :)

[@RobertTolone]

That's true!

[@stanleythrewbrick]

3 Molds 3 Ways _*3 Parts_