Does anyone mold or cast their own stuff?

[thecrusader]

I've been trying to get into molding, tried to make a mold
yesterday with expander foam and it didnt work. I'm thinking of
trying silicone now.

Do any of you guys mold parts or anything or cast engine parts?

I find the whole thing pretty interesting.

I'm trying to make a 2 piece silicone mold. It isn't easy.

I would be keen to hear if you guys are molding
or casting stuff. What your mold's are made out of and what
the thing that your molding is made out of.

doesnt have to be RC stuff.

 

[MadMax]

This is the stuff i use to make the moulds.
http://www.tiranti.co.uk/EdgeImpact...with+original+T30+catalyst+25g.+This+catalyst

And the casting i use this.
http://www.tiranti.co.uk/EdgeImpact...?Division=555&Content=F31+Polyurethane+Resin+

Steve.

 

[BUBBA069]

I use stuff from Smooth-On for molds, casting, and epoxy. I like their 2 part epoxy when I layer up stuff. It can be dyed so it easy to make sure you have an even coat.

Smooth-On, Inc. - Mold Making & Casting Materials Rubber, Plastic, Lifecasting, and More

Now, if you don't want to spend the money on the high cost stuff, you can do it ghetto and use silicone caulking you can buy at the hardware store. Plenty of videos on YouTube for this method. https://youtu.be/-OB8zLKdp_Y

But if you are wanting good parts to sell (assuming you are) spend the money for the good stuff.


Depending on what the final part is for will dictate what you material you cast. Most urethane resins are shore 80D, and don't shrink up like polyesters tend to.

If you are going to do stuff with fine detail, I would look at making up a vacuum chamber to degas the silicone for the molds.

 

[MountainStorm]

Bubba nailed it and I've watching a ton of "Brickyard" videos on YT about how to work with Smooth-On but for my own cheap experiments I've had decent results using craft casting resin and making latex molds reinforced with bandage gauze. I make whatever I want to replicate from oil based clay and paint latex over it. After a couple of coats to capture the detail I paint on more but press gauze into the wet latex and build it up till it is stiff enough to hold its shape. Then I spray the interior of the latex mold with mold release and pour in casting resin. This will allow you to cast intricate ins and outs as the mold is very flexible. Yes there will be bubbles...but if you are planning to paint it the surface bubbles that leave craters can be filled with thickened epoxy like West Systems G or whatever you like and spot sanded. Only epoxy sticks to epoxy...styrene based products like auto body putty will not adhere.

 

[Hoosierdady]

I too have been getting into making molds. It's an art for sure. Certain pieces are ok to make putty molds for while others require silicone. I've made molds for brake boosters and resorvoirs, windshield wiper blades (kept losing them so I made a mold to replace them with my own pieces instead of having to spend $8 a pop) tail light lenses, tailgates and a stepside bed. Those are just the recent attempts. Next up is a mold for a cowl hood scoop.

 

[BigSki]

I've been experimenting with casting parts for a few years, it's a non-stop learning process. I use the Smooth-on products for the mold cavities and I've tried a dozen different resins for casting the parts, each brand has it's own plus and negatives.

I've used everything from poster board to acrylic to Lego's to build the dams that encase the part to be molded. Some of the best books for learning the basic techniques come from the Model Railroad hobby. You could visit some local art studios and ask for pointers, I've found that most folks are willing to help if you show them a part or 2 that you've made.

Best advice that I have is to start with small, uncomplicated parts. As you get into bigger parts with multiple surfaces, you have to start thinking about draft angles on the parts so that they can be removed from the molds.

 

[Duuuuuuuude]

<iframe width="420" height="315" src="https://www.youtube.com/embed/sIDNbPu7lYY" frameborder="0" allowfullscreen></iframe>

 

[thecrusader]

Wow, thats a lot of information. Thanks guys.
I'll have to re-read this thread a few times as i know
stuff all atm and dont understand all of whats being said.

For what i want i have to use silicone as i'll be casting with
chemicals,apparently latex is no good.

That chevrolet tub tray came up a treat!

I'm going to have a go with the tube silicone i have lying around and try to do a glove mold
or whatever it's called. For the record i'll be first trying to make a mold for a small
ornamental Buddha. about fist size.

Any more molding/castic stories or advice chime in.

 

[thecrusader]

What are you guys using as a mold release? are you using a specified
product or something else like a household product? I've been using dishwasing soap
as thats what ive been using to make this silicone mold in that very basic technique.


Heres a couple of photos of my first effort that i stuffed up pretty well.
didnt use enough oil on the mould and shouldnt have used foam but anyway.bit of fun
and all in learning. I won a popularity contest that day, just after i emptied 3 cans of
expander foam into a box on the patio.
Screwed up one of the ornamental ducks from the garden pretty good too.
Luckily i'm using sacrificial ornaments that no one gives a shit about.

Then i had a go at casting a buddha ornament. Stuffed up the first one because i read that
i didnt need any realease or barrier with the silicone. The first buddha is in a ball of silicone somewhere.

Then i had another go and covered the buddha in the soapy water then put my silicone on. Success!
Got one air bubble in there put i'm pretty damn chuffed it worked. i cut it in half with a razor and bam.Buddha mold.
When i do bigger stuff i'm going to have to make a fiberglass outer mold to keep its shape when it's filled.

I'm tempted to put some pins in this mold and whack some concrete in it just to have a go but i dunno.

Here's some pics anyway.

It picked up some detail pretty nice, i'll pour some shit in there and post the results.

Cheers.

 

[BUBBA069]

Silicone before its cured needs release agent of some kind. Once done, you can get away with pouring parts with out it, but if you want the mold to last always use release agent.

Actual mold release is best. Easy release 200 (again from smooth-on)

I know some that have used hair spray and spray furniture wax.

If making a two part mold, brush a THIN layer Vaseline on the first half of the mold after its cured, then make the other half of the mold.

 

[BigSki]

I 2nd the mold release from smooth-on, however I've also used good 'ole WD-40 with great results. You will need a way to positively align, or 'locate' the 2 halves of the molds. It's easiest by carving out "keys" in the first half so that when you pour the 2nd part of the mold, it will fill in the "keys" and become a part of the 2nd mold.