Casting question?

[Powder keg]

When I pored the cane heads I had a hard time keeping the sprue full while I was poring. I've seen tapered sprue formers before but I cant figure out how they are used? I usually cut the sprue after I have the sand rammed up. Those tapered formers look like they would have to be rammed in place then removed?

Thanks for any input, Wes

[GGaskill]

I think you push them in from the top.  The taper compresses the sand while the hole takes away the middle.  Cut the sprue first, them connect the cavity and sprue with a runner.  You end up turning the cope over a few times.

[Max Caliber]

Wes, I make sprue formers from wood on the lathe in two pieces and put in nails to hold them in alignment. I put them in with the pattern when I ram up the flask. Cutting them after the flask is filled works also but the finish is rough and the rough sand may be washed into the mould when pouring. I use a tapered sprue about 3/4 inch in diameter at the top, 1/2 inch at the bottom and about 1 inch long for most castings. The idea of a tapered sprue is to keep the sprue filled while pouring to prevent air and dross from entering the mould. Max

[Powder keg]

So you slide them over the nail so they stand up on their end? I might try that next time. I never thought about sand washing from my sprue's? I use a thin wall brass tube to cut them. I'll give the tapered sprue's a try.

I've been filing these castings a bit and the inperfections seem to be on the surface.

Wes

[Cat Whisperer]

We used (in college some 30 years or so ago) a solid sprue that was tapered and had a pin.  The pin (narrow end) would fit into the match plate.  After ramming it was easy to just pull it out.

[Max Caliber]

Wes, I usually pour brass/bronze through the top or side of the flask whick gives a longer sprue/risers and thus more weight to the casting. The sprue type I described is one running along the parting line of the flask from the pattern to the edge of the flask. Cat is right on the process for sprues through the cope. You can use a piece of turned wood or piece of tubing or whatever for the sprue pattern and hold it in place until you get enough sand in the cope to hold it. If you don't have enought height in your cope you can add a pouring basin on top in the form of a piece of metal tubing pressed into the cope or make a conventional pouring basin. Max

[Powder keg]

It would be neat to see a flask like that. I think I've got it. I was doing these loose and cutting the sand down to the parting line. I think That the only way to do it like this would to be to pore through the cope. I imagine that your flasks have a door that comes off to allow you to pore from the side? You are probably using a match plate also?

Thanks for your help, Wes

[Max Caliber]

I usually make my patterns in two parts that come apart in the middle so they part the sand better. This goes for the sprue and riser patterns as well, I don't use a match plate. I make flasks of wood with one end made of 1/8 inch thick steel stock with a 1 1/2 inch or so hole for pouring the metal.The hole is covered by two pivoting covers, one on the cope and one on the drag, which are closed while the flask is being filled with sand.

[Powder keg]

Got it!!! That sounds like a great Idea. I'll try that on my next pore. I would like to see some pictures if you have any. I went to a guys house last fall and he had some flasks made out of sheet metal. I've made a couple of sets so far.  I could cut the poring hole in them easy.

Max, What kind of stuff have you been poring?

Thanks, Wes

[Max Caliber]

Wes, The metal flasks are the way to go. I started with wood flasks and have found them to work well so I have continued to use them. Most of my casting has been for muzzle loading rifle parts, under hammer pistol frames, lots of cannon parts, small machine parts, belt buckles and other stuff. Latest castings have been five 1/3 scale Coehorns. Am experimenting with lost foam casting now in hope that I can use it to cast an early breech ring for a small breech loading cannon, my first test with aluminum looked promising.


Here is a picture of some parts I cast along with the casting patterns.

[Powder keg]

That is great work there Max!!! You should share more of your work. There are people here that love anything Cannon. I like to see how others build things. Many times I learn things to make it easier next time I build something. I sure like those mortar handles.

Wes

[Powder keg]

Those bronze castings sure are a lot harder to clean up than the aluminum I've been poring. I decided to try some discs for blending stainless. They did the trick!!! I tested them on my brake/clutch levers. They got down through the cast finish in no time. I can now polish them easily. They are made buy 3M and look like compressed scotch brite.



Now back to cannons, Wes

[Max Caliber]

Wes, Thanks for the tip, will give them a try. Good looking work. By the way, that lever would also pass as  a lever for a cannon lock chain.
Max