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bobby_hamill

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Anyone have any recommendation for a source for an aluminum 3 part mold ?
It does not need to withstand pressure just retain a liquid until it cures .
Can be aluminum, steel, brass, or even delrin

Thanks

Bobby
 

rharshberger

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Anyone have any recommendation for a source for an aluminum 3 part mold ?
It does not need to withstand pressure just retain a liquid until it cures .
Can be aluminum, steel, brass, or even delrin

Thanks

Bobby

Have you considered making a mold from pourable 2-part RTV silicones? They will handle hot stuff up to molten lead. If you have the original they are simple to make. For metal molds it will require a machine shop to make them.
 

bobby_hamill

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Rich

I have considered it but it will need a 3 part mold and one part of the mold will have an undercut.
see attachments

complete part.jpg


mold sections.jpg
 

rharshberger

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Rich

I have considered it but it will need a 3 part mold and one part of the mold will have an undercut.
see attachments
One of the nice things about some of the 2 part silicones (PlatiSil from Bare Metal Foil is one iirc) is that undercuts are not all that hard as the silicone can stretch quite a bit before tearing, I used to use it to do two part molds of BattleTech vehicles and miniatures. The easiest way to build the mold box was to use Legos and a styrene base sheet, using white glue fillets to attach the the Legos to the styrene temporarily (flex the styrene and the mold box pops right off). From the image on the right the fin would be an easy two part mold using the base as the pour holes and with a tooth pick creating an air release hole from right where the root edge and leading edge meet. Rocking the mold during pouring can also release the trapped air bubbles, many of the urethane casting resins are so thin they pour like water, and the silicone molds with reproduce fingerprints on the original.
 

Rob702Martinez

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That is good stuff. Also consider urethane filled casting resin. Can be mixed with aluminum powder.
 

rharshberger

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mccordmw

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I bought mine from Bare Metal Foil and iirc it was TinSil product with a mixing ratio of 10:1. BMF looks to have changed some of there casting product line over the years.

I don't recognize the product you linked.
I've used that to cast intricately detailed items like gears from watches and other jewelry items. It can capture a lot of details, so I know an undercut will be no problem. It's also really flexible after curing, so I really doubt it would tear. You can buy it in small amounts off Amazon for about $25. Lots of jewelry videos out there showing how it's used.
 
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bobby_hamill

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Here is 2 photos of a 2 part fin mold I had made from MDF ?
It was made by a ShopBot CNC machine
I used it in experimenting with making fins by a fiberglass layup method

black brant fin mold open.jpg


black brant fin mold closed.jpg
 
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