Molding with silicone from the diy store question

[RvanAken]

I hope I,ve put this question in the right place

I found a tutorial on youtube on how to use silicone bought from the diy store for making molds. https://www.youtube.com/watch?v=tBClhbrGR7w by BigboogieING and it seems a cheap way to experiment with molding pieces. has anybody used this methode and what where the results?

I made a mold of an mando helmet ear as a test piece and got a good result for a first try, but not a mold i can use. the mold isn't smooth and has lots of bubbles in it. could ot be that i use to much glycerine or to little? I'm not sure what the glycerine does to the silicone so I don't know to use more or less.

As I live in the Netherlands i can't buy smooth-on products in a store and have to buy it via the internet. as I wouldt like to see the products i buy and want a "cheaper" way to experiment with molding I would like to use this methode.

any tips?

-R-

 

[HaVoC373]

Living in the Netherlands I share your frustration. I have also looked high and low for mold silicone in stores and in the end I'm just gonna have to end up going to http://formx.nl/ for the stuff I need. But i am very interested in hearing more about this. and seeing your results, since silicone is expensive as hell.

Sadly i have no help to offer since i am currently in the stage where i am learning how to do silicone molds etc.
Good luck

 

[Sym-Cha]

Hi guys,

well HaVoC373 already mentioned it formx is the only place I've come across that has all the stuff professionals use ... still need to visit it though. I'll check that video thanks for posting

Chaim

 

[CB2001]

When it comes to DIY molds there's many methods, which includes the video you've posted the link for. For cheap method, the closest thing you can get is buying the silicone from hardware stores, as mentioned in the video shared, which includes glycerine. In fact, regular hardware store silicone was also used in this video, which I think was done by another member of the RPF:

The same type of 100% silicone caulk can be used in this method without glycerine, just caulk it into soapy water with a bit of alcohol to continue be malleable so that the silicone doesn't stick to your hands, but allow you to apply it to a positive, similar to this.

So, it really depends on what you have available around you and what you'd with it, as well as how much you really want to spend to make the mold. I myself am trying out a mixture of 100% silicone, cornstarch, baby oil and acrylic paint to make what is referred to as Oogoo, primarily for smaller projects. So, getting it from the hardware store could be the best method, as some of them offer them in bulk. I'm sure there are others here who can give you other places you can check to see if you can get the silicone caulk at cheaper places.

 

[RvanAken]

That oogoo sounds interesting, and I happen to have some cornstarch.

For anyone here in the Netherlands who would like to try this, I found a cheap place to buy the silicon caulk. The action sells it for around €2,- instead of the €7,- to €12 you would pay at a DIY store

 

[CB2001]

That oogoo sounds interesting, and I happen to have some cornstarch.

Well, as I've said, it's primarily for smaller projects. And I will admit, when it comes to the use of baby oil, it's something I picked up from this video tutorial. It's from my experimenting and some researching I've learned the baby oil apparently thins out the silicone a bit.

 

[RvanAken]

So, I took the plunge. I started to mold my mando bucket using the YouTube tutorial I posted in the first post. First layer is on.

-R-

 

[Strode]

So, I took the plunge. I started to mold my mando bucket using the YouTube tutorial I posted in the first post. First layer is on.

-R-

I wanted to thank you for the tutorial but never got around to it. Please update us on how it goes. I'm in the same boat so i am very interested in the results. Thanks!

 

[RvanAken]

Will do.

Just put the third and final layer on, I hope it's thick enough. I'm going to let it dry/cure for a few days before I'll be making the mother mold. I'll be making it from expendable foam. Yes I'm going the cheap way all the way.

The helmet itself I'll make from fiberglass. But that would probably be after Christmas. I haven't got any free time until then.

 

[RvanAken]

First pic is of the mold ready with the Mohawk on, ready for the mother mold.
Second pic is is my first attempt making the the mother mold using expandable foam. I ****ed up this part. When I bought the foam I forgot to check if the spray nossel was complete, it wasn't. So I had to improvise spraying it on. It didn't work as I intended. I hope I used enough Vaseline so I can get it of for a second try.

I will be buying new foam tomorrow after work but ain't sure when i have the time to make the mother mold a second time. Probably somewhere next week.

-R-

 

[RvanAken]

Second attempt at the mother mold. This time I'm going to make the different sides one at a time instead as the two at once. This allows me to position the mold on its side so the foam won't slide of as I did the last time.

Learning from my own mistakes is quite fun. I learned a lot about using expandable foam for a mother mold. The foam follows the glove mold quite good and the mold becomes quite rigid when dry.

Tonight I'll make the second half and when that's dry I can finally de-mold the the helmet and see how the silicone worked.

-R-

 

[Strode]

Thanks for the updates. After a long search i finally found a fiberglass supplier so I'll probably be using fiberglass myself. Let us know how it turned out! By the way, what will you be using to make casts?

 

[RvanAken]

Update with a lot of pictures.

I'm using tapatalk so putting the pics where they belong in this update is impossible, at least I think so..

First pic is one finished side of the mother mold. I used aluminum foil as a barrier to make the second side. I couldn't use the "mowhawk" I put on the sleeve mold because the expanding foam didn't cure straight. I used the opportunity to cut some keyholes in side one.

The third pic is the second side drying.

Taking the mother mold of was really easy. I used lots of vaseline on the sleeve mold and the cardboard box I used as a base.

The second side of the mother mold warped a little, bit luckily not to bad. The fit together good enough to hold the sleeve mold right.

The last few pics show the sleeve mold in the mother mold and a detail pic of the key slot.

This was also the first time I've seen the inside of the sleeve mold. It really isn't perfect. The imperfections in helmet I molded can't be seen but there are new imperfections within the silicone. But the are easier sanded of the cast than filled.

All in all I'm pretty proud of my first ever mold. It isn't perfect, not in a long shot, but good enough for a cast or three.

In total mold, including the ****ed first mother mold only cost me around €15,- / $18,-. If that isn't budget than I wouldn't know what is.

I'll be making the helmet out of fiberglass, because that's the material I can get locally and have some experience with. I'm hoping to get at least 3 helmets out of the mold so I can do one custom, one boba and one jango. I've got a mold for one ear but will probably make the ears from xps foam.

Update from the first cast will probably be after Christmas, I'll be making long hours starting tomorrow because of the holidays.

-R-

 

[ILL GREEN]

Yes. I too to live where no molding and casting products to be found. I had to use Bondo Fiberglass resin and regular bondo which irritated my nose from the "stench".

Anyway I found specialtyresin.com and they ship worldwide where paypal is accepted. Their products are excellent and cheaper than smooth on. Shipping only costs me $18 for all their products.

I recommend their 25T RTV silicone. Its so versatile, its made for the pour-on method but I use it for brushing on. I recommend the brush-on technique as well to eliminate the bubbles. But if you pour, you'll have to pour it from a high point and allow a small stream to fall into the mold chamber to prevent bubbles. Or get a pressure pot which is 3x faster than a vacuum.

Don't mean to spam but once again its http://www.specialtyresin.com and they truly ship worldwide and their resins and silicones has a sweet odor

 

[Gixxerfool]

This is really cool. I'm not familiar with molding at all so I'm confused as to how this works. You made a mold from an existing piece using the RTV silicone. Isn't that all you need? Where does the mother mold come in?

 

[HaVoC373]

This is really cool. I'm not familiar with molding at all so I'm confused as to how this works. You made a mold from an existing piece using the RTV silicone. Isn't that all you need? Where does the mother mold come in?

The mothermold or mold jacket keeps the very weak and floppy inner mold from deforming when you pour resin in.

 

[Gixxerfool]

The mothermold or mold jacket keeps the very weak and floppy inner mold from deforming when you pour resin in.

Ok. That makes sense. I will research further as to not derail the thread. Thanks for the reply.

 

[RvanAken]

Another update, you shouldn't use expanding foam for a mother mold, it shrinks. It shrinks a lot as you can see from the pictures. I'm making a fiberglass mold just to see how it turns out but I think I need too make a mother mold from fiberglass because the mother mold I have now will probably no work as intended. The sleeve mold warped in using the mother mold I got now and I had to use pieces of xps foam to resize the mother mold to get a decent shape.

I've got two layers of fiberglass in and am waiting to see how it turns out.

-R-

 

[RvanAken]

@ gixxerfool I'm trying to go as budget as possible with the stuff which are readily available in the Netherlands.

I'm using a tutorial I found on YouTube but substituted the mother mold made of fiberglass with a mother mold made of expandable foam. This was/is a real learning experience. If this doesn't work (and it probably won't because of the shrinking foam) I'll make a mother mold with fiberglass.

-R-

 

[Strode]

That's a shame. Lots of work gone down the drain. Best of luck for the rest. Waiting in anticipation to see how it comes out.