[hobbyrich]

First this has to be the BEST Forum on the Net!!!

Hi this is my 1st post, not sure if this is the place for it.

Was wondering if anyone has made there own spin casting equipment for metal alloys like tin,lead,zink ect ?The type of equipment used for jewlery ,figures, small scale models ect.Tekcast,Conquest and Conley are some of the manufactures of these.Anyway would like to see some pic. plans for this, if anyone has any. Thinking of making a spin caster and vulcanizer to make parts for HO scale models.Trying for a low budjet .Any info ect would be a help!

Thanks Rich

[Robin Hewitt]

Only ever seen one at college. It span forwards freely but if you wound it backwards you hit the spring which acted for about 90 degrees before it latched vertical against the trigger.

We never used it, cuttle fish moulds were so much easier to make. If it needed any help filling we used steam, a damp leather pad on a wood block placed over the hot sprue

[hobbyrich]

Robin
Thanks for you reply.Im not sure how the cuttlefish bone method works,sounds interesting.Is this some kind of actual fish bone?

Thinking the machine you saw at college was the one-shot type,that uses the lost wax method of casting.I have heard them called broken-arm spin casters and spring driven casters ect.Actually I have one of these that my Dad (retired Dentist) gave to me.He refered to it as a Jelenko spin caster.I have used it to make a few rings ect.

Anyway what Im wanting to do is build a centrafuge type machine that uses silicone or vulcanizing rubber for the pattern mold,into which metal is poured into the center and forced outwards into the mold patterns by the spinning action.The advantage is that the rubber pattern molds can be used 100s of times and multiple parts made for each pour.


I think and hope it won't be a lot of trouble to make the spin casting machine (front load type).Looks like I'm going to use a variable speed tred-mill motor for revolving power and possibly a air cylinder for clamping the mold in position.Kinda in the hunter gather mode at the moment,looking for some used bits and pieces for a telescopic shaft that will be used to move the platen in position.

The vulcanizer will be another story.Looking for heating elements thermocouple and temperature control for under $800.00 us.These would be in the 18" diamater range perferably.I might be better off buying a used vulcanizer.

Made a vacuume forming machine (Hobby-Vac 12x18) a few years ago had a lot of fun with that. Went a little over board with it ,made the cabinet out of oak with dove-tail joints.

Thanks Rich!

[Robin Hewitt]

Thanks for you reply.Im not sure how the cuttlefish bone method works,sounds interesting.Is this some kind of actual fish bone?

Cuttle fish is a sort of squid thing, the 'bones' litter the beach and are sold for cagebirds to sharpen their beaks on.

You can press your pattern in to a cuttlefish bone, needs a bit of scraping if deep. The bone crunches down and forms a wonderful porous mould for casting metal in.

You start with two bones, sand them flat on one side, impress your pattern, add a couple of rods for location, scratch in a sprue with a wide mouth, remove the pattern, tape the two halves togther and you have a mould ready for pouring.

It is amazing stuff, if it didn't exist someone would have to invent it

[beone]

I built one with a variable speed motor from surplus supply(the treadmill one) and simply made a turntable to clamp on the shaft. three wingnuts clamped my rubber mold to the turntable with another piece of ply, hole in center. Then just experimented as to rpm and how hard to clamp the mold- too fast or not enought clamp and the metal(i used pewter) squirts out(all over the kitchen cabinets-it comes off). too slow or too much clamp and the cast is incomplete or distorted. Think simple and just try it.

[drescher3]

Rodney Grantham has a video of centrifical casting here:

http://www.youtube.com/group/hobbymetalcasting

I believe he made this centrifical caster I could be wrong about that though.:banana:

Dave Drescher
http://metalshop.homestead.com

[mc_n_g]

If you go the rubber route there is a lot of older heated hydaulic rubber presses out of eastern Ohio when the major rubber industry collapsed into smaller shops which over time have eventually closed. Larger presses are normally 220 3phase and have very heavy iron castings.
The rubber is different durometer(hardness) and you buy appropriately. Once it is vulcnaized (heated) there is no turning back. To work with and understand how the rubber flows under heat and pressure is learned over time with experience( and failures). The rubber under pressure finds it way into the smallest of holes and slivers which may bind your part into the rubber. Make sure your pattern can be easily extracted from the completed rubber imprint. The imprint must be completed in the rubber with the part inside the rubber. Make sure the pattern can withstand the pressure and heat(300 - 375 F) of the press for anywhere from 5-15 minutes. For easy extraction a moulding silicone spray should be LIGHTLY used on the pattern.
I would suggest you come up with a containment system to deal with splatter from any liquid metal which may escape while you refine your process.
Always allow for good runners to feed metal to the cavity so it will not solidify too soon.

[2muchstuff]

I made one out of a furnace blower motor and a few parts. Mounted the motor with it's shaft vertical and attached a large belt pulley to it. Attached to the pulley was a round piece of 3/4" plywood. The mold was sandwitched between a top piece of plywood and the one attached to the pulley with long bolts. The top piece of plywood had a hole thru it which the metal was poured thru as the mold spun, center sprue. You will have to experiment with how tight the mold is sandwitched. Tight enough to keep the metal in but loose enough to let the air escape.


CAUTION....... Use a splash ring around the spinning mold. If you miss with the molten metal, it WILL go flying. Ruined a set of blue jeans and have the scars on my shins to remind me.

[drescher3]

Do you have any pictures of this?
Dave
Http://metalshop.homestead.com

[Harryman]

I've spun cast pewter alloys for close to 20 years and the basic machines are just that, pretty basic.

I've had several machines like their Digital caster and a 18" 3 post vulcanizer similar to theirs.

http://conleycasting.com/machines.php?cat=2

A fixed bottom plate with a hollow shaft leading down to a rotary union.

A movable clamping plate attached w/springs to the fixed bottom plate and a shaft/piston riding inside the hollow shaft.

A removable top plate fixed by interlocking pins to side posts connected to the bottom plate. The mold gets clamped between the movable plate and the top plate, pins spaced at varying heights on the post allows for molds of different thickness.

The air system is essential IMHO, you need to be able to remove, empty, reload and fill the molds in a short and repeatable amount of time to keep the mold temp correct and get good parts. I've seen old machines with mechanical clamping systems and they don't work well, too slow and too inconsistent. With air you can get the clamping pressure just right for the speed you're running and ths molds you're using.

A variable speed motor or a using a variable pitch pulley is a must. The motor drives via a belt/pulley the hollow shaft and the plates. A rotary union at the bottom of the shaft allows the assembly to be pressurized and still rotate.

Vary the metal temp, speed and clamping pressure to get good, clean castings.

Vulcanizers are pretty simple to make too, but I agree that you might be able to find stuff used pretty cheap. A lot of that work has gone overseas. : (

18" vulcanizers, casting machines and molds are pretty big, heavy and hard to handle, unless you really need them, go with 12", it's much easier to deal with.

[jgro]

I looked into this a couple of months ago and found these sites:
http://members.aol.com/__121b_eALsAp...ArQzdWlga2COc=
http://www.granthams.com/Spincast/

Hope this helps.

jgro

[sonicwonder2000]

I looked into this a couple of months ago and found these sites:
http://members.aol.com/__121b_eALsAp...ArQzdWlga2COc=
http://www.granthams.com/Spincast/

Hope this helps.

jgro

Awesome links! Thanks.