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Steam wax

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Steam wax

Postby oglassart » Fri Jun 05, 2015 3:16 am

Hi
Please write your advice on the lost wax casting I did.
1. The basic model is from kind of wood
2 . I made negative mold from rtv.
3 . To the RTV mold I poured wax.
The wax is combine between Parafin and paper bee wax.
And let it cool.i must say that this bee wax is new to me , and it take more time to be cool.
4 on the wax mold i made plaster+silca mold.
Left it overnight.
5 . Steam the wax . I put the mold above boild water pot.
Until the mold is clean. In this case , it open mold so I saw it look clean from wax.
6 for the first day I dried the mold above the kiln , and then put it inside the kiln for 7 h at 93 c.
7.fill the mold with glass and began to fire .

100 93 4h
100 667 2
With kiln a little open . At around 300c , there is a lot of smoke, to much., and the top of the old becom brown
Friend advice me to close the lied and go on.
I 'm waiting fire to be finish, and see what happens?
But why it happens , and how to privent .
I did this mold twice and it happens both.,
I uploaded photo of the mold around 300c after I stop the firing and take the glass out.
Thanks
Osnat
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Re: Steam wax

Postby marykaynitchie » Tue Jun 09, 2015 9:50 am

The standard wax we use at Bullseye is brown Victory wax, not beeswax and paraffin, so I am not sure what advice we can give. How did your piece turn out?

Mary Kay
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Re: Steam wax

Postby oglassart » Tue Jun 16, 2015 11:12 pm

Hi
The top glass have devit/haze, and the glass color are stronger/darker.
Do you think the smoke occurred because of the wax or something in the process?
I Read somewhere , the plaster mold need to be emptied from the wax as soon as possible . Because the wax got into the water place in the mold ,
Does it correct?
Thank
Osnat
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Re: Steam wax

Postby Chris_Petrauskas » Wed Jun 17, 2015 3:36 pm

Osnat,

From what you describe and reading about your set-up I see a few likely factors at play here:

First off, you mention all of the smoke. That sounds excessive. I'd guess that you missed some amount of wax in the steam-out. You describe putting the mold over a pot of water. That method may not force enough hot steam deep into the mold. We use an off-the-shelf steam generator like used for wallpaper removal. We run the steam through a tube up into the mold and it works very thoroughly.

Secondly, I can't vouch for the wax recipe you use. As Mary Kay mentioned above, we use a type of wax called "Victory Brown Wax". It is a type of material known as a "microcrystalline wax". It is purpose designed for use in models for lost wax mold-making. It steams-out well and what amount remains to burn out does not contain significant contaminants. Additionally,its dark-brown color makes it easy to see when you're assessing the remaining residue during steam-out.

Regards the statement that you should remove the wax as soon as possible, I absolutely agree. If the plaster were to dry then the freshly melted wax would tend to wick into the investment. A wet mold would not have that problem. As soon as the plaster has completed its heat-producing chemical reactions and cools off, you can go straight to steam-out without delay.

The last item I would note is that you say you "fill the mold with glass". I may not be understanding what you describe but generally-speaking we do not recommend putting cold glass into a lost-wax mold. Instead, we use a method where a remote crucible of glass is built above the mold using an inexpensive terra-cotta flower pot. This is advantageous for a number of reasons: It allows the mold to shed its remaining water and wax residue away from the glass, reducing the potential for contamination. Secondly, it created a clean stream of molten glass that flows into an already hot mold reducing bubbles and more reliably picking-up details.

I recommend our lesson 'Lost Wax Kilncasting' which shows the whole mold-building, steam-out, and crucible casting process.:

https://videos.bullseyeglass.com/videos/lost-wax-kilncasting/

Good luck and please let us know what happens!

Thanks,
Chris
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Bullseye Glass Co.
Portland, Oregon, USA
http://www.bullseyeglass.com
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Re: Steam wax

Postby oglassart » Sat Jun 20, 2015 8:19 am

Chris,

Thank you for this comprehensive answer.
Please , to be sure I understand your recommend:

In this case , the mold is open face mold ( Jewish symbol-Menora) ,the reason for the lost wax process is that the original is hard material.

If I dried the mold in kiln , (or if "clean " the mold fr organic material) by separate firing, and only after that begging the firing with glass.

So my Q is,
When the mold is created by using lost wax processe but actually its open face mold and drying process was separated , do you also recommend to use "pot met" ,or its fine to fill the mold whit cold glass ?
Thank
Osnat
עוד
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Re: Steam wax

Postby Chris_Petrauskas » Mon Jun 22, 2015 4:08 pm

Osnat,

The fact that you have an open face (single-sided) mold does change things.

Does it have under cuts? If not, I would recommend against using lost-wax method and just go with an rtv postive taken off of the negative. It would then peel right out of the investment with no issues of contamination.

If that isn't the case and you do need to use lost-wax then I think you should re-examine if the wax you're using is designed for the purpose.

The advantage of using the crucible method is that it lets your mold pre-fire up into working temperatures with organics burning off well before it makes contact with the glass.

For open-face molds that do not have to burn away wax we do load them directly with billets but I think you would still have the contamination issue.

If you have any photos to share it would be helpful.

Thanks,
Chris
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Bullseye Glass Co.
Portland, Oregon, USA
http://www.bullseyeglass.com
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Re: Steam wax

Postby oglassart » Tue Jun 23, 2015 12:11 am

Chris,
First , and again I wan to thank you for you answer , there are very helpful.
You right, and I should do it from the beginning , att. pictures.
I don't have pic. Of the model ( but it from wood) .
I understand what you write , but to be sure :
Do you think it was the right way to do it?
Thank
Osnat
Attachments
image.jpg
Mold around 300c
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Re: Steam wax

Postby oglassart » Tue Jun 23, 2015 12:17 am

One more pic
Attachments
image.jpg
Rtv megativ
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Re: Steam wax

Postby kwaale » Tue Jan 31, 2017 7:31 am

If my mold has been complete for 3 days--still a little damp--should I soak it in water before I start steaming to prevent molten wax from wicking into the plaster mold?
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Re: Steam wax

Postby marykaynitchie » Thu Feb 02, 2017 6:56 pm

Your mold should be fine to go directly into the steamer.

Mary Kay
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