Metal Melter

[Onoff]

Don't rely on EU funding....... Although 2nd to Ukraine in Eurovision is a major acheivement for us now. Most likely drive Putin to Nuke us?

Nepal Biogas Plant -- Construction Manual

 

[prepman]

Nepal Biogas Plant -- Construction Manual

Already have one...it's called a septic tank.....did think piping up compressors storage, gas analysis.....then sod it I'll pay cak..cak...Calor.
73 in June..... Off to play speed Chess....take me down a notch

 

[Kram]

Chopped or melted hdpe/pp/pet plastic would be free fuel. Need a different burner design with some way of feeding/metering a small amount in so that it vapourises and burns fully.

 

[Kram]

Small square cliplock food tubs implode between 6-8 inches of Hg. Tests for doing the plaster cow mould. Im not sure how much vacuum the plaster needs but more must be better. I have a small hand vacuum brake bleeder. Round cliplock tub seems to hold 7 inchesHg but I dont want to push my luck.
Having had a wax explosion last week Im a bit cautious of doing the same with plaster!

Next job is to find a short length of 150mm dia tube to weld up a small vacuum chamber.

 

[DAPPH]

I think a preheated metal cooks syringe is a cheap way but probably works better on a closed mold e.g. silicone type.

I made my own hot wax injector syringe out of a tail gate lifter assister ram .
Lovely job after I got over the big bang of de presurizing it safely in the vice .

The only thing I miscalculated was that the Delrin I used to make the piston , nozzle & top support collar for the ram rod all melted once the 320 oC molten wax had been in the syringe for a few minutes . I gave the syringe a few passes of my small map blow lamp to ensure it stayed nice & hot and liquid
I cut shallow " V" breather holes in one half of the silicone mould so there was no pressure build up , but the hot wax did sometimes also melt the silicone which I was assure would withstand 356 oC .

My next venture into lost wax casting will be to find a harder lower melting point wax to use in my silicone moulds . So far I've used red , green & blue casting waxes in the white & yellow silicone moulds . Every time it has only partly filled some of the more intricate voids in the moulds by not fully going into the sharp cornered small coul-de-sac's aka the tessellated castellated rims & forks of yokes . Another Round Tuit ...... of that I'm sure .

 

[DAPPH]

@Kram , I'm intrigued by your idea of injecting rather than pouring the wax. First thought is how to keep it hot. I did find metal syringes online. Again, pouring from pot to syringe will cool things down unless I pre heat the syringe.

Pouring the wax straight in, as I have been, then the pot that comes with the melter is crap, has no spout etc. Maybe I can form one?

Pouring does work though the tendency is to over pour and then you end up with excess wax on the back. How to take that off without damaging the PVA?

Just random thoughts tbh.

Print in pla , coat it in instatement powder using a spray on water based glue such as diluted Pritt stick or a spray on matt undercoat to make it stick. Once dry repeat several times till you get almost 5mm of in statement powder coating then cast a full cast round the basic one you have just completed . let it dry slowly for a week or so then bake out the PLA in an oven a few degrees above the PLA melting point
Make up a shielded centrifugal spinner so when you pour in the molten metal & release the balanced arm the mould is on , the molten metal in the reservoir will be flung out into the mould .

Look up how dentists make gold tooth crowns & caps .

 

[DAPPH]

Small square cliplock food tubs implode between 6-8 inches of Hg. Tests for doing the plaster cow mould. Im not sure how much vacuum the plaster needs but more must be better. I have a small hand vacuum brake bleeder. Round cliplock tub seems to hold 7 inchesHg but I dont want to push my luck.
Having had a wax explosion last week Im a bit cautious of doing the same with plaster!

Next job is to find a short length of 150mm dia tube to weld up a small vacuum chamber.

Inverted greased rim or silicone sealed wide necked strong glass jar on a metal or metal faced face plate with an extraction tube in it ? Same principle of the old school glass bell jar that you boiled tap water up in under vacuum at 56 oC or so . ? Pop a vacuum gauge in the extraction line and a shut of gas valve .

 

[Onoff]

Next job is to find a short length of 150mm dia tube to weld up a small vacuum chamber.

What about repurposing an old fashioned, kitchen pressure cooker?

The ones with the seal and twist on / clip lid.

I recall Mum not putting the lid on properly once. Didn't half go off with a bang and the stew went straight up into the ceiling!

 

[Onoff]

@Kram , I could knock up a decent timber box type one like the Veg Oil Guy made?

I don't have any thick Perspex though...

 

[Kram]

What about repurposing an old fashioned, kitchen pressure cooker?

Have an old aluminium one but Im not sure it would do it.

Timber one is going to be leaky, fine with a decent size electric pump but not with my little hand thing, much smaller than his plastic pump.

Should I buy a proper vac pump?!

 

[Onoff]

Have an old aluminium one but Im not sure it would do it.

Timber one is going to be leaky, fine with a decent size electric pump but not with my little hand thing, much smaller than his plastic pump.

Should I buy a proper vac pump?!

I think a domestic kitchen pressure cooker operates at about 1bar. Must I'd have thought be rated to more than that for safety. No good?

You'd have to fit a window and take off / shutoff valve.

Sem to remember at school we had vacuum pumps that ran off the mains water taps.

 

[JMS1972]

I made my own hot wax injector syringe out of a tail gate lifter assister ram .
Lovely job after I got over the big bang of de presurizing it safely in the vice .

The only thing I miscalculated was that the Delrin I used to make the piston , nozzle & top support collar for the ram rod all melted once the 320 oC molten wax had been in the syringe for a few minutes . I gave the syringe a few passes of my small map blow lamp to ensure it stayed nice & hot and liquid
I cut shallow " V" breather holes in one half of the silicone mould so there was no pressure build up , but the hot wax did sometimes also melt the silicone which I was assure would withstand 356 oC .

My next venture into lost wax casting will be to find a harder lower melting point wax to use in my silicone moulds . So far I've used red , green & blue casting waxes in the white & yellow silicone moulds . Every time it has only partly filled some of the more intricate voids in the moulds by not fully going into the sharp cornered small coul-de-sac's aka the tessellated castellated rims & forks of yokes . Another Round Tuit ...... of that I'm sure .

Have you got the right temperatures there? Casting wax melts somewhere between 32 C and 66 C!

 

[Onoff]

Really can't see why a vacuum chamber can't be made well, like the VOG does. No need for it to be leaky if expanding pu glue is used.

 

[prepman]

Remade the burner nozzle to give more adjustment and rigidity and got a discharge flume temp of 1166C. Down the bottom near burner nozzle inlet straw colour. So 1300C ? propane without blower. Refractory's looking good, so pleased.

 

[Kram]

Really can't see why a vacuum chamber can't be made well, like the VOG does. No need for it to be leaky if expanding pu glue is used.

Theres an easier way more suited to my abilities...

https://www.mig-welding.co.uk/forum/threads/short-length-of-5-6-dia-tube.121487/

 

[DAPPH]

What about repurposing an old fashioned, kitchen pressure cooker?

The ones with the seal and twist on / clip lid.

I recall Mum not putting the lid on properly once. Didn't half go off with a bang and the stew went straight up into the ceiling!

I was putting things away out the dishwasher this morning , putting Pyrex dishes & bowls in a lower cupboard , when it struck me that a decent 12 inch dia clear Pyrex mixing bowl inverted on a ventable base plate would make a tremendously strong & successful vacuum dome for things that will fit in it , and with sealed shaped possibly printed interlocking curved side parts the height could be extended with the inverted bowl sealed in to the top with silicone to attain 18 inches high or so .
Adding a 10 mm Allen key . small end in a chuck to a zip tie tied on trigger on a securely clamped / attached to the bench battery drill ought to make a suitable vibrator to bring the bubbles up through the e liquid instatement mix when its still liquid and under the vacuum .

For longer items a charity shop fish pan /poacher some 16 inches by five inches inverted could be used .

 

[prepman]

Print in pla , coat it in instatement powder using a spray on water based glue such as diluted Pritt stick or a spray on matt undercoat to make it stick. Once dry repeat several times till you get almost 5mm of in statement powder coating then cast a full cast round the basic one you have just completed . let it dry slowly for a week or so then bake out the PLA in an oven a few degrees above the PLA melting point
Make up a shielded centrifugal spinner so when you pour in the molten metal & release the balanced arm the mould is on , the molten metal in the reservoir will be flung out into the mould .

Look up how dentists make gold tooth crowns & caps .

Expensively

 

[prepman]

I was putting things away out the dishwasher this morning , putting Pyrex dishes & bowls in a lower cupboard , when it struck me that a decent 12 inch dia clear Pyrex mixing bowl inverted on a ventable base plate would make a tremendously strong & successful vacuum dome for things that will fit in it , and with sealed shaped possibly printed interlocking curved side parts the height could be extended with the inverted bowl sealed in to the top with silicone to attain 18 inches high or so .
Adding a 10 mm Allen key . small end in a chuck to a zip tie tied on trigger on a securely clamped / attached to the bench battery drill ought to make a suitable vibrator to bring the bubbles up through the e liquid instatement mix when its still liquid and under the vacuum .

For longer items a charity shop fish pan /poacher some 16 inches by five inches inverted could be used .

Your pushing the frontiers of R&D to a new dimension!

 

[DAPPH]

Have you got the right temperatures there? Casting wax melts somewhere between 32 C and 66 C!

It all depends on what grade you buy & who makes it , colours schemes are whatever the manufacturer chooses theirs to be , I can assure you the Delrin & silicone melted .

 

[Onoff]

@Kram , would something like this work, you attach to a compressor seemingly:

ZH15DSA-02-03-03 | SMC Vacuum Generator, 1.5mm nozzle , -90kPa 58L/min, ZH series | RS

uk.rs-online.com