Kiln

[Nigel (egi)Participant @nigelegi]

I bought a Prometheus Mini Kiln, plan is to use it for heat treatment and enameling. Now the chamber is quite small at just 115mm wide, 70mm high and 130mm deep. But this actually isn't bad for the small parts that I make. Plus as it's an electric kiln and only 700W it runs off a normal plug.

Also, it's programmable with 5 steps where you can set rate of heating, final temperature for the step and time to hold at that final temperature.

Me just indicating the size of the chamber. This little unit is rather well made.

My plan though is to also have a go at silver soldering in a controlled way, my initial attempt wasn't good, but I think I effectively dried out the flux – I'll have some more goes at different settings to see what I can achieve.

This was my initial go at firing the chimney together using silver solder paste – note that I put a hole in the washer to ensure no trapped air. However, my slow ramp dried the solder flux out and I ended up with a gritty joint that was in no way fixed.

[Nigel (egi)Participant @nigelegi]

[not done it yetParticipant @notdoneityet]

As you say, it is quite small. My (our) Paragon SC2 seems small enough for me, but if yours is adequate for your needs who’s to worry about it. I can’t just pick up the SC2 and move it around too easily!

I tend to programme mine for night-time running as I watch the power consumption, although I do have a power supply that can run mine for several hours off grid if I really wanted to. Even so, the modern kilns are quite economical – they are well insulated. I think your programmer is much the same – probably used industry wide?

l use it mostly for heat treating, annealing, hardening and tempering (the kitchen oven also gets used for tempering) of larger items that will fit. I’ve not dared to try silver soldering. I do intend trying powder coating (at some time?) and case hargening.

Also on the list is burning out casting patterns, but it would need better ventilation if I do that!

I liked your review. Who is your leccy supplier? Octopus?

Edited By not done it yet on 26/01/2021 14:20:43

[VicParticipant @vic]

It looks very well made.

[JAParticipant @ja]

Nigel

Can the kiln be purged with an inert or reducing gas?

JA

[Nigel (egi)Participant @nigelegi]

Posted by not done it yet on 26/01/2021 14:18:19:

As you say, it is quite small. My (our) Paragon SC2 seems small enough for me, but if yours is adequate for your needs who’s to worry about it. I can’t just pick up the SC2 and move it around too easily!

I tend to programme mine for night-time running as I watch the power consumption, although I do have a power supply that can run mine for several hours off grid if I really wanted to. Even so, the modern kilns are quite economical – they are well insulated. I think your programmer is much the same – probably used industry wide?

l use it mostly for heat treating, annealing, hardening and tempering (the kitchen oven also gets used for tempering) of larger items that will fit. I’ve not dared to try silver soldering. I do intend trying powder coating (at some time?) and case hargening.

Also on the list is burning out casting patterns, but it would need better ventilation if I do that!

I liked your review. Who is your leccy supplier? Octopus?

Edited By not done it yet on 26/01/2021 14:20:43

Leccy supplier is British Gas, quite frankly though it is probably cheaper to run than the blow torch. Especially as the torch is running on medium size gas cans.

The size is about right for me and the weight makes it easy to move around. I haven't found a permanent spot yet and so still returning it to the delivery packaging to store it under the bench when not in use. Also, I do quite a bit of woodwork and nervous about it collecting dust in the vent slots.

I will post more as I try out different things, I had a first go at enameling and that was fun.

[Nigel (egi)Participant @nigelegi]

Posted by JA on 26/01/2021 15:07:22:

Nigel

Can the kiln be purged with an inert or reducing gas?

JA

Not really thought about that, I imagine you could, probably easiest to modify a stainless steel pot and lid to create a more easily contained volume. Then you could pipe gas in and exhaust it out. Doable probably

[Oven ManParticipant @ovenman]

As per discussions on another thread it looks to have a fake CE mark. Making furnaces that fully comply with EVERY regulation in order to CE mark them is a nightmare. The powers that be didn't consider this sort of equipment when they wrote the regulations.

Looks a nice bit kit and extemely good value for money considering it has a multi step programmer. You won't find a British made unit anywhere near that price – but it will be correctly CE marked.

Peter

[not done it yetParticipant @notdoneityet]

From your review:

Being 700W and small it will be reasonable on running costs as at most it will use 0.7kWh per hour of use and at roughly 12p/kWh that is roughly 8.5p / hour.

BG? Are you really sure of the unit cost of electricity? I just looked and didn’t see a rate below 17 1/2p/kWh🙂. Small point but important for readers of your review, to be confident of its validity.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Oven Man on 26/01/2021 20:35:07:

As per discussions on another thread it looks to have a fake CE mark. Making furnaces that fully comply with EVERY regulation in order to CE mark them is a nightmare. The powers that be didn't consider this sort of equipment when they wrote the regulations.

Looks a nice bit kit and extemely good value for money considering it has a multi step programmer. You won't find a British made unit anywhere near that price – but it will be correctly CE marked.

Peter

.

That would, if true, be very worrying … in view of the Certificate displayed on this site: **LINK**

https://www.prometheushobby.com/Kilns/Prometheus-Kilns-Pro1-PRG-p121c59.html

MichaelG.

[Nigel (egi)Participant @nigelegi]

Posted by not done it yet on 26/01/2021 20:50:22:

From your review:

Being 700W and small it will be reasonable on running costs as at most it will use 0.7kWh per hour of use and at roughly 12p/kWh that is roughly 8.5p / hour.

BG? Are you really sure of the unit cost of electricity? I just looked and didn’t see a rate below 17 1/2p/kWh🙂. Small point but important for readers of your review, to be confident of its validity.

ok, cost can be as low as 9p/kWh at night up to 20p/kWh on some tarifs. Thanks, I have corrected and given a range

[Dave SParticipant @daves59043]

I have a Paragon SC2 – Bought it for enamel dial making – Im still learning that.

It does however make an excellent heat treat oven.

I have not tried soldering in it (yet), but using Borax on parts for heat treating makes for hardly any scale.

Maybe straight Borax will work as a silver solder flux? I use it when I solder the dial feet onto the dial blanks before enamelling them.

Dave

[Colin HeseltineParticipant @colinheseltine48622]

I also have a Paragon SC2. Up to now have used it to bake high temperature paints and also to heat treat a couple of chilled castings. Also intend having a play with glass melting.
colin

[duncan webster 1Participant @duncanwebster1]

Tubal Cain book on heat treating recommends a bit of charcoal in the furnace to selectively take out the oxygen

[not done it yetParticipant @notdoneityet]

Colin,

You may find a lot of glass info on the ‘frit happens’ site. Forums are fairly dead but the info is still there.

[not done it yetParticipant @notdoneityet]

Posted by duncan webster on 28/01/2021 01:42:09:

Tubal Cain book on heat treating recommends a bit of charcoal in the furnace to selectively take out the oxygen

You’ve given me an idea – the exhaust from the oxycon will be devoid of oxygen…. Our kiln has a door in the door (for ‘garaging’ beads) so might give access for injecting inert gas…

[Nigel (egi)Participant @nigelegi]

Today I had a few more goes at silver soldering in the kiln and I managed to get one technique that has worked rather well. This is the longer article on silver soldering in a kiln, but here is an image of the final pieces:

Also, a bit disjointed, but I quickly pulled together a video

[Author]

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