Casting TT parts

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Hello ppl

i got a few old TTs that i want to get playing again but some parts are broken or beginning to brake, i have been looking on eBay but no new parts only old going to brake parts.
then i thought take the part i have and make a cast of it may work better then an old used part that may break when i reinstall it.

but don't know how to cast plastik parts and what materials may work best.

anyone in here got any previous experience casting parts or got some info i can start with i have been looking at some youtube casting vids and god kind of an idea :)

hope someone can help

best regards
DDraabe
ps don't know if its the right place :)
 
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I have a bit of experience with casting. I used to to teach bronze casting and other sculptural techniques. In the foundry we used a lost wax investment process and actually poured both bronze and aluminum. It is a very long process, and the quality of the final cast boiled down to good mold making technique.

Since I doubt you want to smelt aluminum or bronze in your garage, although it’s possible, I would assume you will want to replicate parts in some sort of liquid polyester resin.

It is important that you read up on how to make a good mold that not only obtains excellent detail, but also one that vents air properly so that your castings avoid trapped air and the defects that result from it. You need to consider undercuts on your object that might cause issues with the mold releasing from the original and casts, especially if you use a more rigid mold material. You also need to avoid air bubbles clinging to your original that will form pockets on the inside surface of your mold that will result in positive ‘pimples’ all over your castings. Proper use of mold release and some vibration during mold creation and casting can help with these issues.

One of the companies that we regularly sourced mold making materials from was Silpak (no affiliation). They have an extensive line of mold making materials for casting all sorts of materials. Some of the best mold materials I’ve used have been their softer silicones. They retain excellent detail, are very flexible, have fairly low shrinkage and a decent life span. This would probably be a good choice for small detailed turntable parts.

The other consideration you must account for is that every casting material will have a certain amount of shrinkage. You will need to find a final casting material for your parts with as low a shrinkage rate as possible. It is possible to compensate for shrinkage sometimes by dipping your originals in a molten wax bath a few times, but detail will be affected and if they are ‘fitted’ parts that mechanically interact with other parts you may have to re-work or machine the castings to get them to fit and work properly. I have done this before when my friend asked me to help him reproduce some parts for antique cars.

I would check out Silpak’s website, I believe they have some resources to help people out that are interested in learning more about mold making.

Silpak, Inc. - Polyurethane & silicone mold materials and casting plastics for making rubber molds to cast concrete, plaster, wax, resins & foam from Silpak, Inc.
 
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May be take a look at 3d printer the parts or using the plastic filament they use to melt and pour into your mould.

Sounds an interesting project

thats what i did for some parts for my EMT928, there is a free software called designspark mechanical, and i did send the files to shapeways.com who have many materials in their offering. i used aluminim-filled nylon with great results....
 
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