Anti Shrink hole Paste
To obtain completely dense castings with the Lost Wax Method, not only is a gas free and micro crystallizing alloy necessary, but permanent pressure of molten metal from the sprue to the casting required. With this newly developed Anti Shrink hole Paste it is now possible to control differences of temperature during casting where the premature hardening of the sprue can be hindered. Through the warmth conduction of the sprue, a temperature spread occurs between the casting and the main tree exactly at the critical temperature point between the molten and solid state of the alloying metal. This spread creates the effect of dense crystallization in the casting even though sprue´s are thin and the casting is composed of thick and thin parts, normally tending towards shrink holes.

 

Advantages
Shrink hole free castings with solid objects. Less work with thinner sprue´s as well economizing on metal.

Anti Shrink hole Paste is simple to use. After the tree is assembled, a little Anti Shrink hole Paste should be added to the points where the sprue is to remain longer molten, the Anti Shrink hole Paste should be liquid enough that it adheres to the wax surface without blistering (if the Anti Shrink hole Paste is too dry, some thinner should be added in the tin and stirred thoroughly before applying). The wax tree should dry for 30 min before covering with investment and burning out. Oven temperatures over 750° Centigrade for gypsum bound, and 850 ° Centigrade for phosphate bound investment should be avoided in the interest of investment quality also. As the cast molten metal comes into contact with the Anti Shrink hole Paste, a chemical reaction takes place, heating the contact points for approx. 1 min., the sprue´s sink in and the contact points show shrink holes thus allowing the cast object to become dense. The Anti Shrink hole Paste is in its dry form a silvery red color, should it become brittle and intensive red after ca-sting , this denotes inadequate drying out after investing. With correct drying out it should be hard and black after casting.

 

Smelting Alloys brilliant castings

To replace alloys with a high zinc content (0.5-2%), we have developed an alloy additive that increases both the ductility and malleability of the metal.

 

With the alloy AC 9.105,
we have an additive that

1. Releases surface tension thereby allowing a sharper more detailed result with just 0.2 - 0.3% additive.
2. Through the micro crystallizing construction of the alloys the malleability of the metal is increased.
3. By reducing metal oxides during smelting, dryness and micro porosity is eliminated. The residual dross (waste) sits as skin on the molten surface.
4. With correct usage and temperature of CASTIN, the contact points between metal and investment give not only a smooth oxide free surface but also a high metallic shine.
Poisonous cleaning baths can be eliminated. We recommend that a maximum of 0.3% is added to the molten alloy 1-10 minutes before casting, giving enough time for the cleaning process to take place. Analysis of alloy conditions will be practiced during the seminar.


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Degassing Porous Alloys
Degassing Flux

Porous casting are the result of melting alloys under less than optimum conditions. Now there is a new chemical that flushes the gases out of the molten metal. With smaller amounts (0-5 kg) the result is obtained by just sprinkling the powder onto the metal and then covering the crucible for 1 - 2 min. By larger amounts the procedure should be repeated, or with the aid of a graphite stirring rod to submerge flux to the bottom of the molten mass. The effect is so thorough, that it flushes not only gasses but the Zinc and AC alloys too, these should be re-added after the cleaning process. With the regular usage of degassing flux, Zinc and AC, not only the castings will be improved but the returning of sprue´s etc. to the refiners is no longer necessary. 4 Analysis of alloy conditions will be practiced during the

 

MOLD COMPOUND
Transparent Blue - Hard is delivered as a two part liquid Room Temperature Vulcanizing compound. After hardening, it remains elastic with a high durability and offers NO SHRINKAGE. It copies surfaces and forms perfectly, even details that are only discovered under the microscope are reproduced. For more than 10 years this type of compound has been chosen for highest quality precision casting, Both compounds, due to the transparency are easier to cut open than the conventional rubber molds. Errors in pulling the wax can be discovered immediately, when glass instead of metal plates are used for holding the form.

 

Additional Tools
For mixing, a is necessary, obtainable in four different sizes,

Nr. Ø H
1 65 mm 54 mm
2 86 mm 72 mm
3 116 mm 100 mm
4 128 mm 140 mm
comes complete with filter and adapter. The mixed and vacuumed mass is purred over the jewelry piece and with the help of vacuum bell jar, vacuumed for a second time.

Offered in sizes 6 x 6 mm & 3.5mm high, with an additional insert smaller forms can be made 5 x 5 mm & 1.5mm high. For stabilizing the model in the Form Box, a special sticky wax and pre-formed wax sprue´s (right).


MOLD MAKING

To make a rubber mold the model should be first thoroughly cleaned. Should the model have already been copied by the usual vulcanized mold rubber technique , the surface must be cleaned of the sulfur compound and amino acids. The simplest way is to anneal, pickle and then dipped in a warm sulfuric acid mix, (scratched or scraped with a brass brush to get all nooks and crevices clean).Waxes, Insects, Plants, Metal, lacquer objects etc., can all be used as models. Sticky wax is melted onto an easy to clean point of the model with a hot wax knife or a soldering iron.
On this point, the point of the ready formed sprue is melted just enough to bind the parts together, after cooling, the connection point is hard and strong.
The soldering iron is dipped into the sticky wax again, and a little wax is melted onto the flat side of the sprue in the middle, the still warm sprue and model is pressed onto the inner wall of the mold box. The model should be positioned with a minimum of 2 mm under and above, and a 4 mm border on all sides.

For larger models the corresponding size of box should be used. The sticky wax cannot break, but can deform under the weight of heavier pieces. A small piece of silicone from a previous time should be placed under the model to support it, when the silicone support is not too old and well cleaned it will bind together with the newly mixed material After the form has been prepared, the rubbercomponents should be weighed up, to fill a small box, 110 grams of ground mass, for smaller pieces less material.
The empty vacuum beaker is placed on a trainable scale and turned to zero, the necessary amount of milky transparent ground mass is weighed up and 9% from this amount of the dark blue hardener is added. Exactness is not important w hile best results are obtained even with differences between 7 and 13% hardener.
Now the cover should placed on the beaker with the tube and filter attached to a vacuum pump, (97% vacuum should be reached ) it should be stirred slowly for approx. 3 minu tes under running vacuum. One turn per 1 - 2 seconds is optimal.

Look also onto our new developed Injekion pump were you can press out first time, the mixed components without vacuumpump and air bubbles.

 

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