Instructables
Picture of Making Designer Toys Part II (better molds)
As a follow up to my first self produced designer toy the ice scream man http://www.instructables.com/id/How-to-manufacture-your-own-designer-toy-or-start-/ I decided to design another plastic part that i could self manufacture but this time using a slightly different process.

This time i wanted to do a single solid cast part rather than a rotocast part.
this would require a different type of mold and casting in a pressurized environment.
I also wanted to experiment with a new technique for mold registration that i thought would make my process much more efficient.

Since i and many others have covered 3d print finishing techniques, silicone mold making and resin casting in the past i will skip over some of those details to focus on the more innovative portion of this project.

For the design I stuck with a melting theme but this time worked in the idea of melting weapons as i thought it suggested a sentiment of anti violence.

 
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Step 1: Realize the concept

the first step in my process after some sketching is to refine the concept in 3d software and check the details for manufacturability.
My software of choice is solidworks.

the knuckle design was a few simple extrusion commands, the first from the front plane to build out the actual knuckle portion and the second from the ground plane to create the general shape of the melted puddle. I added a few chamfers around the edges of the knuckles and a lof of filleting to blend the puddle in to the knuckle portion in a convincingly melted manner.

after the 3d work was completed the file was exported to an objet 3d printer.
after a significant amount of high grit sanding and a light gloss coat i had a pattern ready for a silicone mold.
baysel2 months ago
Is it just me, or do they look a lot like knuckledusters?
BLR_RAVI2 months ago
wonderful.with coloring it realy looks great..
are you selling these i need this. what else do you make?
bryanbrutherford (author)  Flaky_Jay's1 year ago
www.brutherfod.com will answer all your questions

Think you mean brutherford.com!

bryanbrutherford (author) 2 months ago
the one thing i will say about pewter casting and my magnetic molds, my molds were originally intended for resin. When i was casting the pewter the relatively thin mold walls absorbed heat very fast and the magnetic closer gave out as the mold expanded and flexed from the heat, usually after a minute or two and the pewter had already solidified. Once the mold cooled again they worked fine but this meant that i couldn't cycle through castings as fast as i could with resin because the molds needed a significant cooling period between each cast.

I'm not sure if much heavier walls would have helped or not.
gumiponi2 months ago

Did the magnets pull and rip through the silicone?

I've worked with MoldMax60 before and I found that it tends to fall apart after maybe 30 casts (pewter casting - so heat and detailed parts definitely played part). I'm just wondering how much the magnets may shorten the life of the mold?

bryanbrutherford (author)  gumiponi2 months ago
I never noticed any issue with the magnets stressing or damaging the silicone.

Thats fantastic news, Bryan. Thanks for this instructable. This sort of ingenuity is inspiring!

I really like your product and packaging.. Did you farm out the boxes or make them yourself? The pewter idea and the rare earth magnets is an excellent idea. I think that this will really help me out. Thanks for posting.


I just read your other instructions on packaging. The sleeve idea seems great. I need to find someone in Idaho whom prints packaging sleeves.
Do you mix the pigment in the "a" part of the resin and after each cast? Or in the entire "a" bottle? Or do you mix the pigment into the "a" and "b" mix? I have been using smooth-on 320 casting resin with so strong black and silver bullet powder to achieve a silver/chrome look and have been getting very inconsistent results.
bryanbrutherford (author)  timrwallace1 year ago
it depends on how much I'm planning on running, when i make the ice scream men from my previous toy making instructable i mix the color by the gallon in to part b.
the problem with metalic powder pigments is that there will always be strange knit lines from the way the powder disperses and mixes based on the flow of the resin.


What products are you using to tint the resin? Or are you painting them?
bryanbrutherford (author)  timrwallace1 year ago
no paint, all the color is in the resin. i use smooth-on pigments.
bryanbrutherford (author) 1 year ago
the production molds ended up having 24 0.5" x 0.125" rare earth magnets in them, 12 in each side.
Rob3111 year ago
good idea. how many magnets did you end using in that mold? magnets on both sides, or just metal in one?