Alternate Format of Castable Wax Burnout Schedule

I am beyond thrilled that Formlabs has released the new Castable Wax resin, and I finally have a few pieces in flasks that I will burn out tonight. (I’ve been tied up with remodeling my parents’ house to sell for many months, and I’m anxious to get back doing some jewelry…and I miss you guys, and my little CurlyBee.)

I’m using two different Paragon kilns for burnout, one with a 3-key controller and the other with a 12-key. I’m primarily a glass artist, and our kiln schedules look nothing like the one in the Castable Wax burnout information. I was not able to easily translate those tables into practical programs for my kiln, so I have created a different table that makes more sense to me. Hopefully it’s helpful to others.

When we program kilns, for each programming segment, the kiln accepts a number for the ramp that is in degrees per HOUR, not minutes. We arrive at a certain temperature, then we hold for the specified hold time. I did put both °F and °C in the chart. Anyway, here it is:

And here is the article from which this information is derived…it also talks about the difference between the 8-hour schedule and 14-hour schedule. The 8-hour schedule is for pieces weighing less than one gram, a flask under 6”/150mm (I’m assuming height?), and using a stronger investment that can withstand the faster heating. Check the article for additional information.

Additionally, and I have not tested this yet, but in the cool down phase of the 8-hour schedule, there may be an issue with the ramp. That’s a pretty fast drop, and depending on the kiln, it may not be able to achieve that ramp, especially if it’s loaded with flasks that want to hold that heat. If that happens, it may throw an error in the final segment. You could try an AFAP/9999 (as fast as possible) ramp down if it’s not able to achieve that rate. This should prevent the kiln from throwing an error.

Here’s an example of a fairly common glass fusing schedule with a computer controller that shows the format I’ve described above:

Hello @katkramer!
I am using a Paragon kiln to but I cannot get good results with the purple wax filled. Have you tried it?

Hey there!

I am unfortunately still remodeling my parents’ house (STILL) but I did get a chance to do a quick casting run with the new Castable Wax.

I did have some issues with what appeared to be residual ash, but I have not had time to fully test it. I do a little more testing before coming to conclusions, so my results could have been a problem with improper spruing and burnout.

I also got a larger Paragon burnout kiln a little while back…unfortunately I ended up working on this remodel right about the time I had an aelectrician come wire the 30 amp break for it. I know that airflow seems to be key, so this would definitely give me room for airflow.

Which Paragon do you have? How many flasks, and what size are they? Are they crowded in the chamber—i.e. is their good airflow? Are they lifted up on stilts on sitting on a burnout tray? Is it a large tree or just a few pieces? Perforated flask or solid? Vacuum or centrifugal casting machine?

Also, did you treat the prints with anything? (I don’t, but I know BlueCast recommends using PTFE spray on their resin prints).

You can also PM me, but I’ve been really bad about checking.

(Hmmmm…I just had a thought…our crappy tile installer did a horrible job lining up some expensive tile with an unusual pattern…maybe I should 3D print a spacing tool to use after I RIP IT ALL OUT! Grrrr…I want to be playing with my printer again!)

Hi there! Thank you very much for your reply!
I wrote Formlabs and sent some pics. They said the problems I had appeared to be ash.

I bought mine from Rio Grande. It’s exactly like this but it has the Paragon name on it. I has a ventilator, so I thought it would do the job just fine…

Usually we fit 1 to 3 2.5" by 3" solid flasks or one 3.5" by 4" perforated plus one 2.5" by 3". We never get it to crowded in there. The sit on a burnout tray and we usually fit 4 to 5 pieces on the small flasks and around 10 pieces on the perforated flasks. We cast with a vacuum machine.

We did not treat the prints with any spay (I used BlueCast a few times, but the resolution is not as good and they shrink a bit).

Did your results with Castable wax where like this?

You made me laugh with that last comment about the horrible tile. My first thought was: that will be quite expensive spacing tool if you cast it in 14k gold and mount some pave diamonds on it! haha!

Let me know if your results were similar! Thank you again for your reply!


I have done quite a few casts with Castable Wax resin and I am still getting variable results more poor than good i have to say. The surface is often poor. I am also finding other issues. I had only printed 1/3rd of a litre and I had to throw the new tank away because it was badly fogged and the castable wax resin was sticking to the surface of the tank so hard it was destroying the surface. The other problem I am having is that it is very brittle. So cutting off the supports becomes a nightmare because its very easy to break prongs and claws. I am thinking of going back to the old Castable resin because I was actually getting better results with it and I have put 3 litres through the same tank without serious fogging issues.

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I have been using the Castable wax resin regularly since i first received it about 2 months ago. My Castable wax cartridge is almost empty now and i will be ordering a new cartridge soon.

I personally feel that casting the castable is more stable compared to the castable resin as prior to this, i have been experimenting with castable resin for almost a year. I have tried so many different nail spas and trying to UV cure for different lengths of time but I still do not get a good casting regularly enough. My definition of a good casting is when i can still see the fine layer lines of my resin on the jewelry pieces.

Coming back to the Castable wax burnout schedule, i started off with what was recommended by Formlabs as well. However, i would like to add that there are so many more factors which can determine the result of the casting such as:

  1. Clean resin
    Resin cleaned with resin saturated IPA will result in uncured resin still on the surface of the printed parts. The uncured resin will react with the investment later on and cause surface issues.

  2. Investment drying time (before placing into oven) should be determined by the size of flask (or to be more exact the volume of investment used in the flask)

  3. Investment brand and type
    I have many times achieved good castings using my Kerr Satin Cast 20. However, my castings turned out badly when i tried casting slightly thicker parts recently. Therefore, understanding that the weaker general investments can still be used but there are limits.

  4. Burnout schedule should be adjusted according to volume of investment used again. You can increase the peak temp period to ensure total burnout, or you can also increase the peak temp if your oven and investment allows. I am typically casting 3" x 5" flasks and my burnout schedule is as follows:
    i) 170-C 60 mins
    ii) 370-C 120 mins
    iii) 730-C 280 mins
    iV) Casting temp 60 mins

  5. Another consideration is air flow (oxygen flow) into the oven. If your oven is not vented, you may want to consider adding a fume hood to increase air flow to ensure more efficient burning of the resin in the flasks.

I have just finished going through the Formlabs webinar on Castable wax resin and what i shared above is based on experience and a lot of it is covered in the webinar and i would highly suggest that you go through the webinar as it has not only taught me new techniques but it as also reminded me of some of the good practices.

Keep on casting everyone!