My Mal Pistol Project
- Thread starter DrewSmith007
- Start date
I turned the thumbscrews today. I switched from stainless steel to mild steel and it was MUCH easier to machine. Here they are. I still have to solder them together.
dirtyharriet
Well-Known Member
Not surprised at all with the brass shrinkage issues. We ran into really bad problems with this ourselves while trying to made solid bronze golden snitches. Even though we are pulling a massive vacuum on our casting system... we finally gave up and had to made it make in two thick wall hollow pieces. If you rework the wall thickness... you may be able to find a proper balance that will yield clean and sharp castings.
Emmet
Member
Well, if you already have 3D-files, why not get them printed in brass through shapeways?
https://www.shapeways.com/materials/brass?li=nav
The model will shrink by roughly 10% so you have to make it around 10% bigger before you upload the file
This will be cheaper than any cast and their surface quality is really good now.
I actually considered it, but it would be $1750 at a minimum, and for that I can buy the vacuum casting machine, furnace and have enough left over to build the burnout oven. Then there's the problem of what happens when the shrinkage isn't correct? I would have $1700 worth of useless parts.
For brass, shapeways prints in wax then does the same lost wax method I will be doing, although they skip the silicone mold process and directly invest a printed part. I also originally tried to have shapeways print them in white, strong and flexible so I would have good prints to use as my masters, and they refused to print it because it looked too much like a gun. I highly doubt they would print it in the future, especially in metal of any kind.
Plus, there's the fun side of melting the metal myself and the added benefit of a skill that I'll be able to bring to those here on theRPF.
For brass, shapeways prints in wax then does the same lost wax method I will be doing, although they skip the silicone mold process and directly invest a printed part. I also originally tried to have shapeways print them in white, strong and flexible so I would have good prints to use as my masters, and they refused to print it because it looked too much like a gun. I highly doubt they would print it in the future, especially in metal of any kind.
Plus, there's the fun side of melting the metal myself and the added benefit of a skill that I'll be able to bring to those here on theRPF.
I guess I missed your post when you first made it.
My shrinkage rate is about 5%. I determinded that from the pieces that I've already cast. The walls are as uniformly thin as I could make them, which should help the shrinkage issues.
There's also the factor of having space to shrink into. If you were to cast a shot glass for example, it would shrink far less than an equal sized cylinder. The investment in the glass keeps it from shrinking as much.
My shrinkage rate is about 5%. I determinded that from the pieces that I've already cast. The walls are as uniformly thin as I could make them, which should help the shrinkage issues.
There's also the factor of having space to shrink into. If you were to cast a shot glass for example, it would shrink far less than an equal sized cylinder. The investment in the glass keeps it from shrinking as much.
codered11343
New Member
Got to ask Drew, are you interested in maybe releasing your files for this? I have been searching all over the internet trying to find a 3d model of Mal's pistol...then it dawned on me. "Of course, the RPF!"
Sorry, but I won't be releasing the files for this. At least not in the near future and definitely not until I get my gun done.
There is a reason this has only been done once. I spent most of the holiday weekend working on a burnout oven and vacuum casting setup. I vacuumed this batch of the investment, but I didn't vibrate and it left some bubbles on the surface. I've been using homemade refractory, but I think it's time to switch to a professional. That, and the steel can I used as a flask allowed the bottom part of the mold to separate when under vacuum. Needless to say, the casting didn't turn out that great. Here's a before and after:
So I'm still at it, and I'll finish it one day.
I'm considering turning this into a tribute to the magazine that was lost in production in a creek. It kinda looks like a creek bottom...
There is a reason this has only been done once. I spent most of the holiday weekend working on a burnout oven and vacuum casting setup. I vacuumed this batch of the investment, but I didn't vibrate and it left some bubbles on the surface. I've been using homemade refractory, but I think it's time to switch to a professional. That, and the steel can I used as a flask allowed the bottom part of the mold to separate when under vacuum. Needless to say, the casting didn't turn out that great. Here's a before and after:
So I'm still at it, and I'll finish it one day.
I'm considering turning this into a tribute to the magazine that was lost in production in a creek. It kinda looks like a creek bottom...
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