Metal Melter

[Onoff]

Can the pva stand molten wax at 70c? I would guess it will deform?

Damn, good point!

 

[Dr.Al]

I know nothing about any of this, but just wondering: can you use the PVA (or PETG or PLA) as a pattern and make a silicone mould from it (cutting the back off after it has set to get the pattern out of it)? You then might be able to use the silicone mould to make something else that can be used as a brass casting pattern maybe?

 

[Onoff]

Im not sure what hes using as slurry

"SuspendaSlurry" I think. US product, again, I think.

Did find this:

Molochite Suspension Flour 200 Mesh 1.5kg for Ceramic Shell Cast

Molochite -Suspension Blend - (200Mesh 75micron) (Product will be shipped in a heat sealed plastic bag.) Molochite -200 is a suspension modified calcined clay used in the production of ceram...

www.artisanfoundry.co.uk

 

[Onoff]

Just because we can...

We could print a mould, would take about 5 hours:

& with some material lopped off to allow a bit quicker print:

We probably won't as can't think of why we would at the moment.....

 

[Kram]

 

[daedalusminos]

I bet that fish didn't come out in one piece!

 

[Onoff]

At last, I now understand about the burn out process! Found this article, albeit for wax casting, that explains the cycles gone through.

Wax Casting Burnout Cycles - Ganoksin Jewelry Making Community

When casting, the burnout cycle is an important step that is often treated with indifference. Learn more about the lost wax casting burnout cycles.

www.ganoksin.com

I've been touting round locally and even as far as Southend & Devon for brass casters and what they could offer as a quick service. No luck with what I want. Tbh I'm not really sure what I want, somebody to take our 3D printed models and do the investment then pour or we do the investment and give to them?

If we do the investment casting here then I think a vacuum chamber build is a must to get the air out. This investment powder I have here is supposedly air permeable hence suited to the vacuum process very well.

I think in reality I need to consider an electric furnace build. To then use as a burn out oven, my lad reckons he could use a Pi or similar to make a suitable, programmable controller instead of spending out £££ on a CAL 9500P.

On the look out for Grade 28 or similar fire bricks now.

@Kram , seriously, how are you fixed for doing this pour? Would the investment survive posting or would I need to careful transport it and drop it to you? On top of that is your furnace design good to go yet / something we could copy?

Cheers

 

[daleyd]

At last, I now understand about the burn out process! Found this article, albeit for wax casting, that explains the cycles gone through.

Wax Casting Burnout Cycles - Ganoksin Jewelry Making Community

When casting, the burnout cycle is an important step that is often treated with indifference. Learn more about the lost wax casting burnout cycles.

www.ganoksin.com

I've been touting round locally and even as far as Southend & Devon for brass casters and what they could offer as a quick service. No luck with what I want. Tbh I'm not really sure what I want, somebody to take our 3D printed models and do the investment then pour or we do the investment and give to them?

If we do the investment casting here then I think a vacuum chamber build is a must to get the air out. This investment powder I have here is supposedly air permeable hence suited to the vacuum process very well.

I think in reality I need to consider an electric furnace build. To then use as a burn out oven, my lad reckons he could use a Pi or similar to make a suitable, programmable controller instead of spending out £££ on a CAL 9500P.

On the look out for Grade 28 or similar fire bricks now.

@Kram , seriously, how are you fixed for doing this pour? Would the investment survive posting or would I need to careful transport it and drop it to you? On top of that is your furnace design good to go yet / something we could copy?

Cheers

I may be able to help with a programmable controller if you get to the point of needing one.

 

[Onoff]

I may be able to help with a programmable controller if you get to the point of needing one.

Cheers. Don't tell my lad that! It's my mission to push him to do these things and build his confidence.

 

[Onoff]

Oh well, a Kent based jewellery casting place came back to me with this:

"Morning,

Thank you for your email, PLA does not burn out and cast well, it is awful stuff.

For me to do these I would have to either mould the prints you have then wax them up and cast them or re print them. Either way due to the size it would be a very expensive process.

I also would have to do the investing my end as I do not use machines that are a case of melt and pour it is all specialty equipment that has specific can dimensions and sizes etc etc

Thank you! "

Interesting even if they can't assist. When he says he would have to re-print...I wonder what material that is? I'm thinking now then to do a lightweight, shell, PVA mould, pour in low temperature wax and soak the PVA off.

The saga continues!

 

[Kram]

@Onoff I have said I'd do it, infact I want to do it .
If you want I will make up a clay form* so you can have your own melter, and get the other bits sorted. You'll need a steel cylinder or similar, propane bottle. I have plenty of perlite etc..

* While my melter works I havent been in a rush to do version2. I am very happy the design is excellent. For an easier/quicker version you could buy a bag of dense castable refractory which would likely stand up much better than clay in terms of thermal shock/cracking. I'd still use perlite for the outer insulation, it is excellent stuff.

Controller, use a cheap rex-c100. There may be better ones but ignoring my calibration issue it works perfectly.

@Kram , seriously, how are you fixed for doing this pour? Would the investment survive posting or would I need to careful transport it and drop it to you?

I think PLA is our best shot. If you send me a PLA print I'd firstly make up a sillicone mould and try wax, and then try burning out the PLA in plaster or sodium sillicate sand. I have some normal plaster to mix with sand or you could send a small amount, it wont need much.
I could use one of those test print bits you sent to test with before hand.

I can have the melter running this week..
Im messing about with anodising today so I can get the control box reassembled. The lid will be cherry red

 

[Onoff]

@Kram cheers for that. I've a 5kg bag of investment plaster here. I'll happily give you half. As for posting...would it be easier for me to deliver? You're not a million miles away from me. How btw are you doing for brass? I must get the rest of the scrap brass I've been told I can have.

When you say a silicone mould...as in out of a silicone gun/tube any particular type?

 

[Onoff]

@Kram this sort of castable refractory?

Dense Castable Refractory (25kg)

Castable refractory material suitable for those constructing ovens and for hot face lining in kilns and furnaces. We stock various grades of this

www.castreekilns.co.uk

 

[8ob]

Skip to 5 minutes.. and speed it up, lo g video but useful stuff. I guess lost foam is pretty similar to lost pla/wax in a shell.

High density foam gives off evil niffs when it's burnt, I think its was cyanide gas or something equally unpleasant. Something to consider when working in close confines.

Bob

 

[500e]

@Onoff I have said I'd do it, infact I want to do it .
If you want I will make up a clay form* so you can have your own melter, and get the other bits sorted. You'll need a steel cylinder or similar, propane bottle. I have plenty of perlite etc..

* While my melter works I havent been in a rush to do version2. I am very happy the design is excellent. For an easier/quicker version you could buy a bag of dense castable refractory which would likely stand up much better than clay in terms of thermal shock/cracking. I'd still use perlite for the outer insulation, it is excellent stuff.

Controller, use a cheap rex-c100. There may be better ones but ignoring my calibration issue it works perfectly.


I think PLA is our best shot. If you send me a PLA print I'd firstly make up a silicone mould and try wax, and then try burning out the PLA in plaster or sodium sillicate sand. I have some normal plaster to mix with sand or you could send a small amount, it wont need much.
I could use one of those test print bits you sent to test with before hand.

I can have the melter running this week..
Im messing about with anodizing today so I can get the control box reassembled. The lid will be cherry red

@Kram
May be of interest re. anodizing

Chromic Acid Anodizing Tape That Works

Masking for Type I anodizing has always been a challenge. This new tape is designed to withstand the harsh chromic acid process, reducing masking and removal time without leakage.

www.customfabricate.com

 

[Kram]

@Kram this sort of castable refractory?

Dense Castable Refractory (25kg)

Castable refractory material suitable for those constructing ovens and for hot face lining in kilns and furnaces. We stock various grades of this

www.castreekilns.co.uk

I havent tried it but I think its the right stuff. This lost foam guy made a similar style furnace using it. I remember they are quite helpful if you phone them - ask what its like for drying and cracking.

Furnace Fail & Reconstruction

Well bad news/good news. Bad news: The resistive coils and refractory insert for my electric furnace failed. Good news: Now I get to build another...

forums.thehomefoundry.org

I need a round to it and register there to see pictures properly and read his threads.

High density foam gives off evil niffs when it's burnt, I think its was cyanide gas or something equally unpleasant. Something to consider when working in close confines.

Bob

There are many types of foam. Avoid any PU types as they will give off isocyantes and might have Mr Parm looking for you..

@Kram
May be of interest re. anodizing

Chromic Acid Anodizing Tape That Works

Masking for Type I anodizing has always been a challenge. This new tape is designed to withstand the harsh chromic acid process, reducing masking and removal time without leakage.

www.customfabricate.com

Interesting but looks hard to get, expensive and possibly not suited to wrapping wires and lumpy connection welds.
I think I could get away with epoxy using more hardener than recommended. Needs testing..

 

[Kram]

@Onoff Making silicone moulds, skip firat min or two. I'll see if I can get some proper 2 part silicone.

 

[Onoff]

@Onoff Making silicone moulds, skip firat min or two. I'll see if I can get some proper 2 part silicone.

Silicone won't be any good for brass temperatures though will it?

Definitely going to try a 0.1mm layer, PVA, female print like the two "black" renders above then fill with wax. Then soak off. Figure if the print infill is quite high it might work. Wax temperature is a little under when PVA melts.

 

[daedalusminos]

Myfordboy recently did lost pla..

 

[Onoff]

@Kram the previous cow/ice cream prints were done at 0.15mm layer height. Going to re-print now at 0.1mm for hopefully better accuracy.

What do you think ref infill percentage? A fuller infill or lighter? Lighter i.e less internal lattice might burn out easier.