Amy's notes from lesson with Mike
Casting shopping last—freezer zip lock bags new better tongs for handling flasks sandwich spreader for leveling flasks
let people know if doing casting these are the buttons you push for burn out. others cannot edit other than the shop captain
equipment—do we have all, use spatula for mixing investment Mike has provided de-bubbleizer so we likely need to order some ProCraft vacucoat—coats wax prior to investment—invest right after while wet.
investment—fold with spatula so that you don’t get air on model then vibrate heck out it then vibrate flask
if this gets popular, you vibrate then evacuate with a vacuum just a little, not to boiling, bubbles then pause (don’t go to far as can ruin investment.
with vibrator—wait till don’t see bubbles and not too much or you can break model off sprue
do not put any of this down the drain (it is a combo of clay and plaster of paris)
investment ratios are arbitrary pancake batter viscosity is ideal, keep a little water on the side to get to this viscosity
don’t have a short flask, always need more than enough investment material use ratios table and adjust mathematically as needed, investment material is not cheap. store in freezer quality zip lock bags once opened.
Use flask liner—mitigates shock factor for flasks and hairline cracks in investment—if too wet, not adequately aged (at least 24 hours)—idea is need water to evaporate from investment or chemically reacting. Don’t want to put soggy. If over 24 hours put in zip lock bag for up to a week. There is always a little moisture there that steams off and finishes chemical reaction with investment (clay locked into matrix in plaster-mechanical process that occurs gases to release) and creates channels for gas to escape. Flask liner—synthetic replacement for asbestos, cut it, wet it and line flask with a little undercut. No need to line crucible—when breaking anneal , melt lots of flux in and keep
resin casting, in holder for resin, can make a three d print then drill the hole out, cold flask totally constable filament that can burn out in kiln—can we get it off thing averse
crucible must line up to middle of flask, stirrups can be made to create the alignment
flasks are made of stabilized stainless that can take the heat buy with sprue base from supplier so they match up can be a v-shape so centers align
safety equipment—face shield, oven mitt
spruing—have investment as close to button end as possible so it can immediately get into model, though if your model is wide (having metal go right angle) does not work and may need to have longer sprue—this is the art of spring. use largest sprue as you can. If you have a shape that is linear you can use a single sprue. or three distinct sprue with object on a ramp (angle) so bubbles flow off during investment and metal flows. Need to have large enough base in model to feed the thicker area. In design elements make sure you can chase design into sprue cut off area.
Iff you add up the sprue and group them they should add up to cross section visually. Where sprue touches object fillet it into object for smooth flow.
make each batch of investment separately for each flask
for pouring flask at angle, on vibrator with vibrator on. touch lip to flask and vibration will cause it to flow. then tip back to horizontal at end and let overflow slightly
take spatula and cut across it before burn out or can flatten with coarse sand paper (all after 24 hour set up time)
or can burn out during night and cast in the morning
put flask in sprue down on fire brick and let it drip out, start it (ramp heat up per program), then a couple hours later, turn flask over drive all chemical water out, then wax model drips out, then no liquid wax left, though wax coating on model, then when turned over turns into a vapor-and gases. If done the other way-creates ash.
have everything heated up, melt the metal have it cocked and ready to go, go over and get the flask, then reheat to puddle and go
8 hours is the minimum though can go for longer though has to be at max heat for casting
before anything, balance machine, put flask into stirrup (after 24 hours and before burnout , close up and loosen center nut (cross pin nut)—straighten arm out and add weights to counterbalance flask. Be sure to tighten nuts on weights and then center (cross pin) nut.
figure out start position, wind and it will catch at a certain point. Wind clockwise, then go three turns and be sure you are in a good position to be able to melt your metal. Three turns then engage cocking pin with bolt head right on top of arm to fully support the bolt. cock arm 90 degrees clockwise before you start metal metal melting (critical as this is what does the casting (the flipping back to 180 degrees), then heat metal, torch in left hand moving torch back and forth to uniformly heat it* then on weight side with right hand pull weights away when molten and pull torch hand and weight had away at same time.
- start by heating crucible, add grains and little flux, as it turns to a puddle of metal