Casting metals,guards, pomels, etc.

Mark Behnke

Mark Behnke

Joined
Apr 16, 2008
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814
Anybody here cast? I'd like to do guards in bronze, embellishments in silver, etc.

Seems to be quite and investment in tools. I did pick up a couple of centrifical units to spin the molten metal. no crucibles though.
I'm a little familiar with wax work, not so much with the investment process.

Anyway looking for help getting started from those who have experience.

Thanks Mark
 
What Mark, tired of carving? ;)

Just kidding of course, I'll be following this closely. Some of the designs that are bouncing around in my head would greatly benefit from this. Carving has it's limits.
 
You probable know this Patrice, you can carve wax, then cast, then you have to clean up your casting. Lots'a carving involved.

But yeah, I want to do it all, just can't learn and move fast enough.
 
markb said:
I want to do it all, just can't learn and move fast enough.
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You and me both. :(

I am sorry I wasn't implying that casting was that easy. Still lots of carving involved but some of it of wax as you say, much easier than steel.
 
Casting is as simple or complex as you want to make it. Sand casting with Delft Clay is a cheap easy way to start, I still use it sometimes for simple things

http://www.contenti.com/products/casting/173-015.html

requires sand, mold frame, model, and some way to melt and pour metal

the next step up is lost wax investment vacuum casting (you can use the vacuum pump you use to de-bubble your investment for casting) I did it for a few years but do not use it for anything that fits in my centrifuge as it had filling limitations

needs vacuum pump, burnout oven, investment scale, casting chamber, bell jar, melting crucible, vacuum flasks, means to melt and pour metal

I now mostly do lost wax centrifugal investment casting

needs centrifuge, burnout kiln, bell jar, vacuum pump, investment scale, casting flasks, metal scale, centrifuge crucible, melting torch, and splash shield to catch molten metal splatter

-Page
 
Patrice no implication taken.

Thanks Page
I think I'm making this process too hard. I have about half of the items you listed for centrifugal investment casting, I'm good at collecting tools and materials but have a problem starting new process on my own.

I'll start looking for the remaining tools and materials and break down the steps.
 
markb said:
Patrice no implication taken.

Thanks Page
I think I'm making this process too hard. I have about half of the items you listed for centrifugal investment casting, I'm good at collecting tools and materials but have a problem starting new process on my own.

I'll start looking for the remaining tools and materials and break down the steps.
Click to expand...

Casting is essentially easy, make a hole, fill it with metal, it is the details that bog you down. To do it well commercially and repeatably you need good tools and good process with as much variability controlled as possible. The finer the detail of your model and the finer you can get your hole to hold detail the less cleanup you have to do and the smaller your defective casting losses will be. I have probably $3000 invested in casting equipment and supplies, when I was doing delftclay casting I was working with a torch and a delftclay kit and a homemade sifter and homemade mold frames and getting good castings, though they were sometimes porous under the surface

-Page
 
Thanks for the link Page I'm going to look into the delftclay, it may do just what I want.
 
Hey Mark and Friends,

Lost wax casting is a real blast! I first started as a pup and made my own burn-out oven, vacuum jar and centrifuge. For the burnout oven I made a small box with soft insulating firebrick and used old stove top elements and range knobs for the heat. Used tin cans and pieces of muffler tail pipe for flasks. Used a compressor from an old frig or freezer to pull a vacuum for an investment chamber. Cut the bottom off a glass gallon jug to make the chamber ("bell jar") placed on a sheet of rubber. Use a one hole stopper in the jug's mouth to introduce the vacuum. You have to pull a vacuum on the liquid investment (refractory plaster type stuff) you pour around your wax model to get all the air bubbles out or you end up with lots of metal beads on your casting.

I just dug around in the crawl space under the house and found the centrifuge arm a friend welded up for me way back when ('78ish?). A saddle for a narrow flask is on the right in the pic. Saddles could be swapped out depending on flask size. Just to left is the holder where the crucible (with a nipple to fit up into the opening of the flask) sat and the metal was melted. The axis went through the table with the large sheave underneath which was driven by washing machine motor with a loose belt. On the left side different lead counter ballasts could be put on to balance the whole affair depending on the size flask and metal melt. The whole arrangement was surrounded by an old enameled washing tub with the inner rim at the top to catch any escaped metal. The reason the belt was loose was so that the arm could be held once the metal was melted and the power switch thrown on. The belt would slip until letting go of the arm (and clearing the hell out of the way, never had a prob) then grab and bring the arm up to spinning without spilling the metal. Make sure the direction of spin is such that the axis doesn't unscrew! The whole turnkey setup was one of the joyful adventures of my youth. Sold LOTS of stuff. At some point started injecting wax into rubber molds for various designs. Eventually got real equipment. Now I have stuff Stacey sourced and shipped out to me. (What a guy!)

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Here's an old pic of some trees of sterling castings straight out of the flasks.
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I've tried a little silicon bronze casting of knife hardware and believe it has a LOT of potential. If some folks wanted to do a casting BBQ WIP thread sometime, that would be a real learning opportunity for us.

All the best, Phil
 
My brother and I have been melting beer cans to make machine parts lately. :D

Basically we have an old wood stove, an air compressor and some simple tools I made out of scrap iron. The melting pot (crucible?) I made out of a piece of pipe, and some channel. The molds we make out of builders sand and clay soil.
So far it's saved us about $450 in parts for an old lathe.

The beer cans tend to produce a lot of 'Slag' which has to be scraped off the top before pouring, but so far we have not had a single impurity in anything that we have poured.

I'll try and get some pics of our set up.
 
Remember- your casting weill come out about 5% smaller than your master model.
 
Bill DeShivs said:
Remember- your casting weill come out about 5% smaller than your master model.
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Yup, that's a factor for sure. Wish I knew a way to get around it preemptively, particularly with the inner negative spaces, like around the tang. I had a buddy who modeled gold crowns. They had a way of factoring in the shrinkage with some sort of coating on the cast tooth stub model that they built the wax crown up on. Wish I understood that process.
 
On anything but the most precise parts, the shrinkage is not an issue. If your tang hole is .980 by .187, and it shrinks 5%, it only ends up .950 by .178 . You have to file it anyway to clean it up. On the outer dimensions, you just make it a bit thicker/wider to allow for shrinkage, filing/sanding, and polishing.

I met an old Russian man once who was a mold maker and caster for the Soviet rail road (steam) in the early 1900's. He made the wooden models that the wheels and train parts were cast from. He had a wall in his living room with a dozen 6' long "yard sticks" displayed on it. I asked about them, and he said they were model making rules. Each was proportionally larger (scaled in units) according to the type of steel/metal they would cast the wheels and parts from. That way, if 4140 steel has an 8% shrinkage, the measurements were 8% longer on the 8% ruler.

A great book to get you started on casting is:

"Centrifugal or Lost Wax Jewelry Casting for Schools, Tradesmen, Craftsmen", by Murray Bovin .
http://www.amazon.com/Centrifugal-Jewelry-Casting-Tradesmen-Craftsmen/dp/0910280053
 
If you want to give a try in the most basic cheapskate way,

you can carve a model, form the mould in plaster of paris, and use a torch to melt some old copper penny's
 
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