ebay inductive heater, carbon crucible arrived.
So now we have a real solder pot:
No load current:
And current with the carbon crucible at teh bottom of the coil:
On Fri, 08 Jan 2016 13:12:43 GMT, Jan Panteltje Gave us:
What is the tie wrap for? A thermal fuse? Hahaha
On Fri, 08 Jan 2016 13:12:43 GMT, Jan Panteltje Gave us:
You could use one of those coils inside a steel box pumped with a huge cap bank for this:
Quickest is to carve the shape in a firebrick.
On a sunny day (Fri, 8 Jan 2016 11:19:23 -0800 (PST)) it happened whit3rd wrote in :
Yes, I think you are right. Next time (was there today!) I am in that shop I will buy ONE :-) Alternative would be to make a copper stand that does not form a closed loop.
On a sunny day (Fri, 8 Jan 2016 11:19:23 -0800 (PST)) it happened whit3rd wrote in :
Yes, I think you are right. Next time (was there today!) I am in that shop I will buy ONE :-) Alternative would be to make a copper stand that does not form a closed loop.
I mean like this: stand:
molten solder:
Actually you only need to apply power for about 30 seconds, and then the solder stays molten for a long time.
I think if you keep the power on, then this stand will melt, so need the firestone anyways.
No idea what the maximum temperature is, but very high, maybe you can melt aluminum with it.
On Fri, 8 Jan 2016 11:19:23 -0800 (PST), whit3rd Gave us:
Quickest is to just buy an off-the-shelf piece from one of these makers around here. Sure they make custom, but they have lots of stray pieces laying around. Likely find one on ebay too.
I am talking about alumina, btw.
On Fri, 08 Jan 2016 19:49:07 GMT, Jan Panteltje Gave us:
40 x 40 mm $30
a teracotta flower pot of the apropriate size.
-- \_(?)_
Jan, you've probably already read it but back in 2014 there was a thread in rec.crafts.metalworking titled "countertop aluminum foundry" that I think you would find interesting. At google groups as:
----- Regards, Carl Ijames
Experiment: glass is insulating, but melted glass is conducting. But what 's the resistivity? Too high for induction heating? Maybe not, since a glass stirring rod, if connected to line voltage and warmed with a torch, w ill spontaneously heat up white hot and pop the breaker. Resistive heating element made of glass alone. Also, there's the melting beer bottles in mi crowave ovens.
Legs of stirring rods, glued with furnace cement? Or just plain furnace cement scupltures.
Or, search CERAMIC STANDOFF
On a sunny day (Fri, 8 Jan 2016 17:43:11 -0500) it happened "Carl Ijames" wrote in :
Link works, nice pictures.
I wonder why everybody goes for _insulating_ the crucible.
My idea was to allow airflow (convection) in the coil.
Was thinking after that experiment how clever my neural net was to come up with the transformer wire solution.
No mazz involved.
Of course solder already melts at about 200 C, the insulation on the transformer wire burns off at 370 C (tested), so if convection keeps it below that, plus bad thermal contact with the carbon crucible, then it is not a shorted turn. If it was a shorted turn the wire would be red hot and burn I'd think? So maybe thicker wire with some other high temp insulation...
Anyways the thing that bugs me all the time is: Where does the 70 W power go when run with no load? The MOSFETs do not get hot, the coil is warm, but not that hot. Is it radiating EM waves at 100 kHz? coil seems a bit small for that...
I mean try to hold on to a 70 W light bulb.
mm maybe that heat is also carried away by convection in the coil spiral. OTOH you can hold you hand above it no problem.
I am doing it just for fun, no intention of starting an alu casting plant :)
On a sunny day (Fri, 8 Jan 2016 20:24:34 -0800 (PST)) it happened Bill Beaty wrote in :
Does not seem to matter much, material needs to be _magnetic_ active, for exampe, a copper wire does not get hot.
Maybe not, since a =
I find glass melting point 1400 C carbon melting point 3825 C so glass in crucible could work.
I posted a link to 3D printable ceramics a few days back:
Because it holds the heat you give it better. Duh.
On Sat, 9 Jan 2016 07:51:08 +0000 (UTC), DecadentLinuxUserNumeroUno Gave us:
Also to keep radiated IR from heating the coil. It has enough problems.
On Sat, 09 Jan 2016 03:35:55 -0500, DecadentLinuxUserNumeroUno Gave us:
Oh, and you can get that coil silver plated (heavy) and get a bit better operation from it too.
The coil is physically to large. I've done coin crushing and played with different coil sizes in the 10 to 20kJ range.
Trying to contain the energy from the discharge in a vessel is just making a bomb. I always absorbed and dissipated the explosion of the coil and coilform itself into other materials. It's cheaper, faster and safer.
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