Monday, February 25, 2008
Friday, February 22, 2008
Can withstand high burnout temps.
Made of gypsum-a white mineral, calcium sulfate, responsible for the hardening of the plaster; silica-white and colorless mineral, quartz, to cushion while expansion and contraction (this is the main material that is harmful to breath in (wear a respirator) ; cristobalite-pure silica, enables to withstand the high temps. Some investments contain fiberglass for strengthening.
Store in resealable bag to avoid being exposed to moisture--use within 6 months or less.
If you suspect it has been exposed to moisture, measure it against some investment you know is fresh. (throw out if its more than 20% heavier than the new)
Never pour investment down the drain and use rubber mixing tools that the investment will easily crack off of to be thrown out.
When mixing, you want to get a proper ratio between powder and water, mix it evenly, make sure there are no air bubbles, and do it within a specific amount of time.
Before mixing, make sure the model is clean, renove all dry investment from flask and mixing container, check to make sure the the fit is watertight, make sure the sprue is in tact, paint the model with debubblizer-denatured alcohol can work too but a debubblizer is not neccessary.
Investment has a working time of about 9 1/2 minutes. Hardening too slow will not give the investment time to properly settle around the mold. Hardening too fast will cause the investment to separate and bubble.
Use water of consistent temps.
Mix investment in a ratio of 38-40 parts of water to every 100 parts of powder by weight. Always add powder to water and not visa versa. Mix for about 4 minutes. Consistency should be a little thinner than sour cream.
A vacuum machine can be used to shake out air bubbles. Prepare this ahead of mixing. Tape a piece of paper to the top of the flask to catch any investment that might spill out while in the vacuum. Bubbles can also be vibrated out by a massager.
Wednesday, February 20, 2008
A rod that supports the model while making the mold; provides passageway for wax to leave; entrance for molten metal; positions the model
Round soft wax wire is preferred for the sprue.
Plastic sprues are not recommended.
Attach to the thickest section of the model; where they cannot damage surface texture and can be easily removed.
Leave 3/8" clearance on all sides of the flask; for several models leave 1/8" between them; leave 1/2" between model and investment.
Try to get your model situated to flow completely downstream to avoid air bubbles and backflow.
As metal cools in contracts.
To avoid pits make sure to attach the sprue at the thickest portion and make sure there is enough molten metal supplied.
Choose a flask just the right size--too small can cause it to burst and too large is wasteful.
Use a sprue wax slightly heavier than the average section of the piece.
Heat the wire and lower to attachment site--hold there until it hardens; check the joints and trim the wire if needed.
Enlarge mass and round off opening at joint for smoother flow.
To thicken, heat needle with wax and drop off at joint.
Electric wax pens work well for this.
Determining amount of metal needed
Weighing-calculate ratio between gravity and weight of the model and the metal being used.
*Multiply weight x gravity of metal*
Use pennyweight or gram scale.
Weigh model with sprues.
If scale is not available, use the water displacement method (not as accurate)
Submerge wax in jar filled with water; mark how high the water rises with wax; take out wax; add metal until reaching the same point and maybe add a little more for the button.
Wednesday, February 13, 2008
riveting-basic, tube, spacer, flush, nail head
liver of sulphur patina
cold forging-aluminum, silver
lampworking glass beads
diamond/gemstone identification certification
various stone setting techniques
chain-making-chainmaille, double loop in loop, etc.
Tuesday, February 12, 2008
I thought I would look up bullets because of the relationship of the diamond craze serving as ammunition or 'fuel' for war. It turns out there are some really lovely shapes accompanying the bullet image. I was considering making a bullet referenced neckpiece with a noose going through it and also binding the hands, touching on the slavery issue--maybe with some interlocking wrist braces.
I like the antiquity to these old mining carts. The first one looks secretive because of the trunk-like shape to it. The various gears and wheels in the second one are nice, just not sure how I would work these into a piece yet.
In researching scars I decided to investigate a more dramatic type of scar--a keloid. Keloids are overgrown scar tissues that have regrown abnormally outside the boundary of the original wound. I like the imagery here in that they are 'deeper' scars so to speak. Something more unforgettable. I would like to use this as texture detail in my piece.
Wednesday, February 6, 2008
I will come back to this...
Monday, February 4, 2008
The metal (final product) will weight between 10 and 20 times the wax model, so don't hesitate to make the model thin. The mass can be reduced by scraping or hollowing out some sections.
Pieces of wax can be reused as long as they are not contaminated.
Denatured alcohol or Lamp fuel are the only fuels to be used for this kind of wax working.
Soldering irons with a dimmer switch are good replacements for electric wax pens and offer much control.
Make etchings to press hot wax into, through a vice, to produce an imprint.
Files, sandpaper, and steel wool are inappropriate finishing tools for modeling wax.
Dripping wax will produce interesting shapes and effects.
Pressing forms into clay, then filling them with hot wax will also make interesting shapes. Use potter's clay or any clay mixed with water. Modeling clay will melt when hot wax is poured over it.