Kiln questions and observations

I was at the space today trying to use the kiln in blacksmithing and found that it heats up very slowly. I’m not sure if this is intentional or not, I’ve not looked into the specific kiln.

I did start tracking the progress though based on the temperature readout. I started tracking it at 293 degrees and recorded about every 15min. I found over the course of 1.5 hours it reached 337 with every 15 min being a 6-8 degree increase. Seems like it was increasing linearly so I suspect that the insulation is working well and the slow rate is due to either the heating elements, controller board, or probably most likely would be a software thing.

I’ll try to take a look at it next weekend to get more details but if it’s not a software limit would we be able to leave the kiln on overnight to preheat for use the next day? The limit on the kiln is 2300 degrees. Starting at 70 (the initial reading today) it would take ~70 hours or ~3 days. To get to 1250 (slightly higher than aluminum melting point) it would take ~37 hours.

Another question is do we have tongs for holding crucibles? I didn’t see any one the rack


We don’t melt anything nor use crucibles. It is a blacksmithing shop The kiln is for heat treating and not for melting metals. Furthermore we don’t allow aluminum in the shop.

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At the risk of invoking

how is a new member supposed to know this? The committee page on the wiki does not say.

Thanks for letting me know about these rules. Admittedly I didn’t think to look for rules on aluminum or casting in blacksmithing, so I’m partially at fault for almost making that mistake. Although even if I did neither the wiki nor the confluence site mention anything.

I’m curious about the origin of these rules.
Why is aluminum not allowed? My only thought was it should not be used on the belt grinder so we don’t accidentally make thermite. Is there a problem with trying to forge it?

As for melting metals, why is that rule in place?

Editing to add:
I’ll volunteer to help update the rules and\or adding signage so that me almost violating the rules is the worst that happens.

I am still curious about the answer to the original question about leaving the kiln on overnight. I googled the temperatures heat treating steel. If 350f - 1350f sounds correct than it could take ~9 - ~40 hours for the kiln to heat up. That still seems like a long time.


Can you hammer forge aluminum?

Forging aluminum requires a significant amount of force to shape the material. You can use a forging press or hammer to apply the necessary pressure. The forging process typically involves three stages: upsetting, drawing out, and finishing.

I googled that because I know that welding aluminum is a bit crazy because of the way it heats. It’s a great conductor of heat. In welding, it’s tricky to know when it’s taking the weld, and when it’s about to fall into a molten lump. I was thinking that the same might be a problem with hand-forging aluminum.

I got the impression that he wanted to melt and cast aluminium. Note the mention of “melting point” and “crucibles.”

His second post confirms that with “casting.”

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Then there’s this

Bold added by me.

He probably posted that after reading this:

I still believe the original intent was to melt and cast aluminum.


As a new member, I find this to be the most intimidating part of the makerspace. The rules are gone over in the classes, but there doesn’t seem to be a consistent and easily accessible place to look up the rules for each piece of equipment. For example, in the blacksmithing class I remember there’s a rule against non-ferrous metals on the belt sander, but I don’t recall if that applies to the forge and/or saw in the blacksmith area, and I can’t find any rules online regarding this. I suspect as I learn how to use more of the equipment throughout the space, this will become even more frustrating.


That is something we need to work on.

<mumble>too much equipment and too few volunteers…</mumble>


I can see that as an issue. We are given so much information that it can be difficult to remember. A good cheat sheet or pre-equipment use may not be a bad idea. However it’s only good if someone reads it. We tend to have a problem with people not reading.

Best advice I can give to anyone is to get involved with the committee. This goes for any committee that you may have interest in. This not only helps you but also the space


Everyone wants to cast aluminum. No one wants to put in the volunteering efforts to make it a reality…,plus it’s dangerous so if we did do it we would have specific events for it.

Honestly aluminum work isn’t blacksmithing period. Aluminum is cheap and easy to machine, why cast it and not just machine it out of billet?

Often for casting aluminum the juice isn’t worth the squeeze. Your mileage will vary on the amount of dross. You will end up spending more $ on crucibles and energy to heat than you would if you just bought and machined billet


The ovens/kilns in blacksmithing are for annealing or heat treating steel not for casting or melting anything.
Blacksmithing is a steel/iron activity and all the tools in blacksmithing are intended to be used for blacksmithing. We don’t even like sawdust in the shop, although we allow it for the specific purpose of putting handles on blacksmithed items. You absolutely must clean up after yourself, too.

We are working on getting signage up, but truthfully a lot of shops have signage that just gets ignored.

Lastly, we had a smelting group once upon a time, but like @Mrholthaus says no one wants to put the work into managing, cleaning up and sponsoring the SIG so it just disbanded If we did have a smelting SIG It would have to do their smelting outside, and you’d have to provide your own smelting pot, crucibles, tongs etc. We just don’t have the equipment to do this right now.

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Back before SIG’s, we had a smelter for aluminum plus a crucible or two. That was part of Fired Arts, which has since split into Ceramics and Glassworking. When I was chair (of Fired Arts), I pawned the smelter off on Blacksmithing. At the time, they stashed it in the back of the Blacksmithing trailer. No idea if it still exists, or what.

Last time it was actually used was Before My Time, and I think Walter and a crew may have smelted some pewter.

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Paul @Hardsuit acquired the foundry & accoutrements, and taught several classes, including the on I attended back in 2015

Walter did a few pours, too

Since then, I think most of the stuff has been lost because others had no interest in maintaining or shepherding people through the process (it can be dangerous).

Walter also did some pewter, but I have no pics/proof.

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Well, to start with a definition: smelting is converting ore into the metal. Melting metal for casting is foundry work. My experience using a homemade foundry fired by propane used for aluminum recovered from soda cans and brass/bronze from melting household keys recovered for when I worked in a hardware store is linked here: Metal Central and I challenge anyone to machine from a billet of aluminum the lost wax and sand castings that I was doing in my backyard: found here:Cast Metal Goblets, Optics, etc.


I took a delft sand casting lesson
And we melted Pewter with a torch and poured on while in the jewelry section. This was pre Covid. Which metals are ok’ed for this procedure and can it be done in the metal shop? Or blacksmithing. Or where?
Thanks. Was thinking of melting silver?

@Mike1942f We met a gazillion years ago, you showed me your glass pot furnaces, I never got around to building one but have thought about it a few times. Your website has a ton of useful information!
-Randy Lisbona

@coloneldan - you have a rare volunteer here to update the rules online. You could be missing out on an opportunity.

I was watching this post to hopefully get more insight on the rules that exist. I’ve taken what I could from here and made a draft on the confluence to at least there is something written down.

I think it would be good to expand upon what I have and include reasons for the rules. I’ll try to show up to the next committee meeting although I don’t see one on the calendar.

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