Ventilation solutions for poor cast emerald green

A lost wax capable resin tuned for 30 - 70 micron slice thickness
bronzeloch
Newbie
Newbie
Posts: 6

Ventilation solutions for poor cast emerald green

Post#1 » Thu Jul 20, 2017 3:36 pm

Trying to solve the same casting problems that it seems like a lot of other forum people are experiencing. But I can't seem find any of the one that had problems that actually admit success following the prescribed burn out at 1400 + degrees, proper curing, and ventilation.
I think my resin is cured enough. I use an Asiga UV light box 6 min. I have also cast prints that have been sitting in a window for days with same result (see attached photo) Prints are crystalline, almost brittle, not flexible. Ventilation is the one thing that I have not made a permanent change to try and resolve the problem. I have propped my door open slightly to increase air flow. I have a Neycraft Vulcan 3-550 120 v, chimney in top but no fan. Max ramp is 70 degrees/min. I set my temp to ramp to 300 for 1 hour, 700 for 1 hour, 1425 degrees for 2 hours same results as my initial program, 700 for 4,1350 for 4, 900 for 2 . So short of drilling holes in the bottom of my oven, which I am about to do but don't know where to drill, the ceramic removable tray will be covering the holes so that seems counterproductive. Meanwhile I have waxes stacking up and customers wondering where their jewelry is. So if there is someone that had this same problem and found the cure I would appreciate the solution.

I had another company that printed resin for me and I didn't have any problems casting at all. Did it for 8 years without a hitch. HELP!!!!!
Attachments
bad castings emerald green.jpg

User avatar
Robert Howle
B9 Creator
B9 Creator
Posts: 6629

Re: Ventilation solutions for poor cast emerald green

Post#2 » Thu Jul 20, 2017 4:24 pm

It's obvious that u are ok with the metal (clean good buttons). Has to be cure or air flow. U can't over cure the resin, so do it longer. and get the air flow. Are u raising the flask above the floor of the oven. I use expanded metal and stack two 3/4 in bolts to make my 6 risers. U don't need the ceramic wax tray. Need the flask at least 1 inch off the floor (little more will be even better).

Add more sprues because it aids in removal of the resin. On the ring add one to the center. Myself and hundreds of others cast the b9 resins everyday. It's just cureing, airflow, and reaching the high end temp for 2 to 3 hrs.

Have u calibrated the oven to make sure it is getting past 1350F. you should be ok at the 1425 to 1450 on the settings for the high end. Won't hurt flask or the oven. That way u make sure u get to the temp required even if your thermocouple is off.

Robert Howle
Dance like nobody's watching!

bronzeloch
Newbie
Newbie
Posts: 6

Re: Ventilation solutions for poor cast emerald green

Post#3 » Fri Jul 21, 2017 12:23 pm

How do you tell if the resin is cured. When I cut the supports they are brittle/ crystaline.

Where did you drill holes in your oven? Depending on your brand, I have housing I guess I will have to remove to get at the bottom, not sure I have room to drill from the inside. I have been saving drilling the furnace as a last resort. I have propped the door, elevated my flasks, raised the high temp to 1450 for 3 hours with no improvement. I just did another casting this morning, same results.

The frustrating thing is that I have cast hundreds of resin printed pieces from Malakan without any problems at all. Now with this resin I am getting beautiful prints but worthless casts. What is so different about the resin that I have to revamp my whole operation to get a usable product.
Attachments
RG BC 2.jpg
RG BC 1.jpg
RG BC 3.jpg

User avatar
Robert Howle
B9 Creator
B9 Creator
Posts: 6629

Re: Ventilation solutions for poor cast emerald green

Post#4 » Fri Jul 21, 2017 12:56 pm

There are no electronics or wiring in the bottom of my 8 x 8 oven. I laid it on it's back and drilled 12 holes 3/8 diameter (4 rows of 3 evenly spaced). Drilled through the metal bottom and the fire brick. Allow for wall thickness when marking for layout.

Robert Howle

Those castings are horrible. Are u sure they are cured? If u want send me a "cured" print and I will test cast in my small oven.

Robert Howle
550 Spears Creek Church Rd.
Suite B
Elgin, SC 29045

803-736-4441 Shop
Dance like nobody's watching!

bronzeloch
Newbie
Newbie
Posts: 6

Re: Ventilation solutions for poor cast emerald green

Post#5 » Fri Jul 21, 2017 1:48 pm

Seems cured based on other resins that I have cast, How would I know for sure? Never used this stuff before.

I am sending you a couple of prints to test cast.

bronzeloch
Newbie
Newbie
Posts: 6

Re: Ventilation solutions for poor cast emerald green

Post#6 » Fri Jul 21, 2017 2:02 pm

I noticed that you said that you ramp at max 999 degrees per minute. My oven max ramp is only 72 degree/min. This resin whether cured or un-cure is sticking to the sides of the investment as a carbon solid/ash. It won't blow or suck out. If your oven ramps up that fast then that could be a variable that I can't reproduce without a different oven. Is there anyone that has success casting this resin in the same oven that I have?
Ney Vulcan 3-550 120volt Its is only 2 years old.

User avatar
Robert Howle
B9 Creator
B9 Creator
Posts: 6629

Re: Ventilation solutions for poor cast emerald green

Post#7 » Fri Jul 21, 2017 6:34 pm

If u have black resin ash then u are not getting hot enough and or not enough air flow to oxidize the residue. Have u tried to test your oven temp with kiln test cones. I'll send u a couple if u give me your address.

Robert
Dance like nobody's watching!

User avatar
Metalcaster
B9 Wizard
B9 Wizard
Posts: 1293
Contact:

Re: Ventilation solutions for poor cast emerald green

Post#8 » Fri Jul 21, 2017 7:56 pm

I just looked up your oven and programer on Gesswein site. This has the capability of going from room temp to 1000 oF in 15 minutes.

"Model 3-550 with Programmable Temperature Control: A powerful built-in controller has 9 three-stage programs and 1 single-temperature hold program. You can link programs together for a maximum burnout of 6 temperatures, 6 hold times and 6 rate settings. Temperature, countdown time and program number are digitally displayed at all times. Also features delay start. Membrane keypad and LED indicators make this controller easy to program and operate."

I think you need to read the instructions carefully. I have used this oven when I teach at Metalwerx . It is a bit confusing to program it correctly, but it can definitely climb much faster then 72oF per minute.

rkundla
B9 Maker
B9 Maker
Posts: 82

Re: Ventilation solutions for poor cast emerald green

Post#9 » Mon Jul 24, 2017 3:28 pm

If your oven can go 72°F/min, you can get 4320°F in an hour. Which corresponds to 1000°F in 15 minutes.

Maybe like you said a programming error? Fahrenheit to Celsius conversion or vice versa?

That black char is definitely incomplete burnout due to lack of high end temp or an anaerobic (no oxygen) environment. I wonder if the top of the flask in the metal funnel was bright white or it still had some carbon residue on it?

bronzeloch
Newbie
Newbie
Posts: 6

Re: Ventilation solutions for poor cast emerald green

Post#10 » Sat Aug 26, 2017 10:00 am

So, finally success. This post is for all those that may be experiencing the same problems as me. From the previous posts in this string you will see that B9R-3-emerald resin was not burning out properly. From other post and strings on this topic you will arrive at the same conclusion I did. Three factors seem responsible. Ventilation, Temperature and resin cure. If you are like me and have been burning out other resins without a problem and then when you start using emerald green and immediately have unusable results it can be quite frustrating. From the posts that address this issue it was hard to tell if their problem was solved or not. Helpful people, like Robert Howle and others tell what has always worked for them but the question is... Do they have better equipment? Is it the burnout oven? Is it the UV cure oven? Do I really need to drill holes in my oven? Do a need an expensive UV Box to obtain proper resin cure?
Here is what worked for me. Of the several things that I have changed to get these results I haven't yet tried excluding any of them to find out if they all are needed or if just one is the solution. If I get time I may experiment, but for the time being I am just happy to be back in production.

Here is what has worked for me, I have included some pictures of equipment for reference.
UV cure in a ziplock bag with 50/50 water glycerin,in UV box pictured for 8 min flip over and then 8 min again
Blow off excess glycerin from model.
Investing in R&R Ultra Vest per mixing instructions with tap water. Setup for 2 hours before putting in oven.
Presently, I do a 3 stage programmed burn out. 3.8 degree/min ramp to 300 degrees (resin bake cure stage, may be overkill)Hold for 4 hours
Max ramp (72 degrees F/ min) to 1450 degrees hold for 4 hours.
Ramp(25.5 degrees) to 900 degrees hold 2 hours to casting temp.

As pictured, per Robert Howle's suggestion I have raised the flasks off of the oven floor about 1.75 inches, I also prop the door for additional ventilation as opposed to drilling holes in the bottom of the oven, I put a small piece of ceramic about 1/2 inch thick under the door to hold it open.

I had previously tried the above 3 stage burn out at 1425 degree without the raised flasks,glycerin cure method,this rendered the bad casting pictured in this string earlier.

So for now I am getting usable casting that are near perfect. Any casting flaws I have been experiencing have been normal stuff easily repaired. The most flasks I have burned out at one time so far has been 3 small, As I said before, any one of these steps may be unnecessary but at this point, I don't have time to play around.

Hope this is helpful to someone.

Thanks to all those that helped me get here.

Robert, Sorry I didn't return your call, Thanks for being so willing to help!!!
Attachments
B9R-3-Emerald cast.jpg
Oven setup.jpg
UV cure box.jpg

Return to “B9R-3-Emerald”

Who is online

Users browsing this forum: No registered users and 1 guest

Close Menu Shop Forum