1. Insert die pins
into RTP_Bases with finger pressure only. You are putting a
tapered pin into a tapered hole, the more pressure you exert, the
tighter the pin. A simple test is to wiggle the pin from side to side;
if there is any play the pin is not fully seated.
Remember:
Finger pressure only when
inserting die pins.
2. Use distilled water at room temperature when mixing stone for impressions. Tap water may be several degrees colder and can shock cool an impression, causing it to distort slightly. In addition, tap water may contain chemicals, minerals and calcium that can adversely affect the stone's expansion and overall integrity. Also, weighing the stone and measuring the water for each mix will help guarantee quality and consistency.
3. To clean out small index holes on the bottom of the die surface, do the following: take a round, pointed toothpick and dip it in water, drop the water onto the hole and use the pointed end of the toothpick to work the water down into the hole and let it soak for a few seconds. Then take a high pressure air hose and blow the excess water out of the hole. This is the safest way to clean an index hole. Also, we have been told that a high pressure steamer works equally well.
4. Very few impressions will have the third molar as most people have them removed at an early age. If the third molar is missing in the impression, very often the impression material will get in the way of the third molar pointer on the Pin-Locator. You can cut off about half of the third molar pointer on most Pin-Locators, but keep a few unaltered for those occasions when the third molar is included in the impression. This will save a lot of work trimming away impression material behind the second molar.
5. Stainless steel
die pins can be safely heated in a porcelain oven to
the final firing temperature of porcelain. This means you can pour your
porcelain refractory model just like any other impression without the
need to duplicate the impression or use special pins. Refractory dies
are treated just like any stone die as far as the RTP plastic bases are
concerned.
Caution:
The information contained in item #5 above is feedback from other
labs. We have not personally tested this procedure.