Metal Casting Zone

When I need to make more than 25 or more castings, in Petrobond, I make up a low cost matchplate for the job.
The example here is a small wheel and holder for an antique gas pump.
The wheel turns while gas is being pumped out.

I will need to make maybe 40 pairs of these parts.
I use an oak cope and drag, with dowel rods for alignment pins.
The aluminum plate is 1/8" thick but you can use thicker metal if you like.
I prime coat the patterns with automotive sandable primer to get them smooth, so pulling out of the sand goes well.
Ram them up, put in pouring gates, slip the aluminum plate onto the drag.
"C" clamp them together and then I pour pewter in to cast the matchplate.
You can then sand the surfaces slightly so they pull out of the sand.
I also polish some areas.
Then clean the cope and drag and install the matchplate onto the drag.
Install the cope and ram sand in as usual.
Trun it over and ram the other side.
Carefully open the mold, remove the matchplate, close, clamp and pour.
These are inexpensive to make and are usable for many parts if you are careful with them.

I had seen this done before but, not with pewter. That's a good idea, easy to repair and put a smooth finish on. Aluminum ones would be a little rough and hard to polish while on the plate. I'm having a little trouble figuring out the size. Is the Al plate about 8" X 6", or am I even close?

Good job, I'll archive this in things to try.

The alum plate is about 8 by 5 1/2".
I have seen larger ones made using a piece of sheetrock (drywall) and they worked great.
Pewter is a lot easier to clean and make smooth.
The small white pins are Teflon, to make the holes in the casting.
Saves a lot of machining time.
That is one of the nice things about zinc.
You can use plaster and Telfon to capture detail.

Well, I was pretty close.
OddDuck has used a similar method.

Does the sheetrock hold up very long. I guess it would depend on how hard you ram it and keeping moisture away from it.

The opening in the sheetrock extends over the opening in the cope and drag, so that the matchplate is supported around the edge while it is rammed up.

The sheetrock just locates the plate, while it is being used.
If handled carefully they will last for a long time.

Sheetrock, eh? Hmm... yes, I have a technique that is very similar, I made up a simple set of patterns to make what I call my EZ-Match System (TM, pat. pend., external use only... ).


I ram these up and cast them in aluminum, and lay them between the cope and drag before pouring. The patterns are just 1/4" mdf, and it works pretty slick. Here's one poured:

The nice thing about doing it this way is that you can have a permanent matchplate without needing a larger flask than the one you already have. Just ram 'em up diagonally in your flask.

That is a very good idea and reusable, if you end the project as are mine.