Hello all

Finally I have been able to cast FTX green without porosity.



The process is to cast as if you where casting platinum. The secret lies in the investment and its expansion capacity. To get a good expansion capacity ( to avoid internal fractures), you need to use Phosphate bonded investment.

In countries where you cant find this in jewelry supply stores, look for this in dental supply stores because it is the same investment used for dental casting.

I used the fastfire 15 from Whipmix and the process I followed was the following.
http://whipmix.com/product/fastfire-15/

1. Prepare the investment as per instructions (per 100 grams, 27 mils of the binding liquid sold with the investment). I did not add any water. Be very quick while mixing since it gets hard very very fast.

REMEMBER TO PREHEAT THE OVEN AT 730 DEGREES CELCIUS

2.Vacuum the investment mix

3.Put some tape around the top of the flask because while vacuming it rises a lot. Use liner inside the flask . (liner is sold by Whipmix - and it is an asbestos paper to control thermal expansion.
Pour the investment mix and vacuum the flask again.

4.It will become very hot while it hardens due to a chemical reaction of the mix

5.Hold still and dont move the flask for 20 minutes

6. Put the flask in the oven (remember you had preheated it!) fo 1 hour and 15 minutes at 730° celcius

7. Lower temperature to your metals recomended casting temperature (ej. white gold with palladium at 490° C) and stay at that temperature for 30 minutes

8. Cast (I use centrifuge)

10. The investment gets very hard , I used a hammer to help me crack it. If you need, buy the investment remover also sold at dental supply stores.



The results are great, hope you get as good a result as well. I will post pictures soon



Lina