Introduction: The Crucible Mold.
In my next instructable I'll show you the items and method I used to create a mold for my clay crucibles as all the "stainless steel" ones I used have failed (drinking bottle, drink shaker and 3 x steel milk shake containers.) these have all oxidized and failed, thus the clay/ceramic crucible is the next bet.
So the items needed are as follows:
1 x 2" PVC Coupler.
1 x 2" ABS Cap.
1 x 3"-1 1/2" ABS Adapter.
1 x 3" ABS Cap.
2 x 3" ABS Couplers.
7" x ½" Carriage Bolt.
• Rotary tool (Dremel).
• Reciprocating saw.
• 5 Min Epoxy.
• Sand paper (fine grit).
Step 1: The Core. - 1x 2" ABS Cap. - 1x 2" PVC Coupler. - 1x 3" > 1½" ABS Adapter. - JB Weld, Kwik Weld, 5 Min Epoxy.
Grab your sand paper, Dremel, epoxy, adapter, cap and the 2" couple (white one, pvc).
Now very carefully with much precision center the 2" PVC coupler in the center of the 3" ABS adapter on the 3" side not the 1-1/2" side it will have a slight cone shape making it difficult to keep centered.
Once this is figured out mix up a batch of epoxy, start by applying a thin layer on the edge of the couple attach this to the adapter while pliable correct straightness and squareness. Finnish by filling in the rest of the groove. if you mixed a large batch you can add it around the opposite rim of the coupler and as well on the 2" ABS cap and squeeze the two together hold making sure to have them perfectly aligned. using some more epoxy I filled in the logo and other text on the cap to create a smooth inside wall of the crucible.
After about 5 mins the epoxy should have set, so now we can sand it I used my Rotary tool with 2 different sized drums and started sanding hours went by. After I had sanded it square with out damaging the white coupler wall
Step 2: The Outer Shell. - 2x 3" ABS Coupler. - 1x 4" PVC Coupler. - JB Weld, Kwik Weld, 5 Min Epoxy.
Here we will be attaching two of the 3" ABS couplers together by way of some epoxy and a 4" Coupler.
First we cut one of the 3" couplers in half just so the inner seam is still on one of the halves. the second 3" coupler needs to have the inner seam removed I did this again with a rotary tool and sanding drums. once removed the coupler must be attached to the other half of the 3" coupler piece (without the seam) the same way as before, then sand all excess epoxy making it nice and smooth. For extra support I cut the 4" coupler in half removing the seam then removing a 1/2" section allowing it to fit around the 3" Coupler tightly. Apply epoxy to this piece before applying it to the outside wall as a support holding long enough to dry.
Step 3: Rammer - 1x 3" Cap. - 1x 7" Carriage Bolt.
This step is pretty basic, we will start by cutting the top of the 3" cap clean off, drill a large hole in the center big enough for the threaded rod to fit in now tighten down the washer with the nut creating a handle.
Step 4: The Crucible
Start by spreading a light coating of vassaline all over the core and the inside wall of the outer shell as well as the plunger. Putting to much vassaline will cause it to collect in places the are inconvenient but we still need to have enough to allow a release, (i'm not sure if anything else will work as well or better if any one does know don't hesitate to comment and tell us what you used).
After a release agent is applied its time to pack the form/mold using a plunger this will ensure all clay is forced down and all the air is pushed out we don't want any air pockets or bubbles. This will continue till you reach the top of the mold, with the plunger add the bottom layer and whit all your might press down on the mold pressing all the clay down.
When things all look good its time to press the crucible out of the shell by way of the nicley formed plunger it should pop right out. Next we remove the bolt from the core this will alow air into the cavity that will form once we start removing the core.
after everything goes to plan you should be left with a nicley formed clay crucible that NEEDS TO DRY the best way is to let the item set over night and the to bake it in the oven I do this as a precautionary measure to ensure all moisture has been removed.
Step 5: Firing the Crucible With Coal.
Start by getting your favorite foundry and add a layer of coal put the DRY clay crucible next then cover with more coal light the fire and wait when all is red about 30 mins turn on the blower keep the foundry hot by adding coal every 15 mins it needs to bake for at least an hour and then allowed to cool over night.