Kiln / furnace question

[Nick martin]

Hi all,

As part of my quest to gradually buy equipment to allow me to cast using the lost wax process, I purchased a kiln / furnace today second hand.

It's still advertised on Benchpeg actually and I managed to buy it for considerably less than advertised. This and the fact the seller is only 30 mins from where I live meant I got a bargain.

It's practically unused which is great, but I've got a few questions that I'm hoping someone could answer.

Firstly it's not got a timer. It heats to 1600 degrees but there's nothing to regulate the temp, and it only has a digital temp readout. If I'm burning out a flask, could I simply let it heat to it's max, leave for an hour, then remove?
I know programmable kilns have a program where the heat ramps up, stabilizes, then ramps down but is it strictly necessary?

Secondly, can bolt-on timers be purchased and fitted by qualified electricians easily enough and if so are they expensive?

Finally do those of you on here who use kilns, use them exclusively in open air outside areas or are they safe enough to use on benchtops? I've made sturdy wooden benches in my workshop but I'm wary of placing it on as I don't yet know if the casing of these things become seriously hot or whether it's just the insulated internals?

Thanks folks,

Nick

[ps_bond]

Rather than a timer, a PID controller is fairly simple to add on - they usually use a thermocouple (K types lose their accuracy at the higher temperatures) and a solid-state relay to drive the heating coils.
Ramp & hold are important for burnout - the first stages drive off the remaining water, then subsequently the chemically bonded water in the investment. The investment makers have fairly detailed burnout instructions (although they vary depending on what you're burning out - RP resins for example).

My HT oven is on a normal formica-type bench, with the requisite space around it - but it has legs. Depending on the size of your furnace, it might be wise to sit it on asbestos-substitute mats.

I'm jealous - I bought a s/h furnace recently but it tops out at just over 1k C, which is fine for most precious metals but I was looking to melt copper in it...

[Nick martin]

Thanks Peter.

Some of your reply makes sense, some doesnt. Purely on my behalf that is!

PID controllers. Can these be fitted by the layman such as me or should it be an electrician? Also could you be so kind as to maybe provide a link for me to get a sense of what I'd need and to gauge prices etc?

Nick

[josef1]

Maybe look at an arduino there cheap enough on ebay to control a solid state relay, once you programmed it you could just switch it on and it would run you burn out schedule. You dont need to be an electrician just careful. I would be willing to help with setting it up if you like just PM me

Just did a quick search and found this https://www.wekadesign.com/blog/2013...ln-controller/

[Nick martin]

Cheers Josef.

The arduino option looks interesting although its way beyond my scope of expertise and I wouldnt feel comfortable putting one of those together and installing it on something as potentially dangerous as a kiln!

I'm very technically minded in a few areas, but where electronics are concerned not very much so.

I've since googled and found a local pottery supplies / kiln company and they provide controllers for about £200 fitted. Bearing in mind I paid less that £100 for my kiln, and the fact its a professional model with a large capacity, even with this added expense I still feel I'd have myself a bargain so I think this is the route I'm going to go down. The kiln is going to be utilised for lost wax casting, but will also come in useful for hardening argentium and enamelling work. Its also important I dont burn the house to the ground because that would be a touch inconvenient

Thanks fellas,

Nick

[josef1]

Lol I can see that that could become a bit inconvenient !! Glad you got a plan sorted and if you need any info on burnout etc let me know

[ShinyLauren]

Rather than a timer, a PID controller is fairly simple to add on - they usually use a thermocouple (K types lose their accuracy at the higher temperatures) and a solid-state relay to drive the heating coils.
Ramp & hold are important for burnout - the first stages drive off the remaining water, then subsequently the chemically bonded water in the investment. The investment makers have fairly detailed burnout instructions (although they vary depending on what you're burning out - RP resins for example).

My HT oven is on a normal formica-type bench, with the requisite space around it - but it has legs. Depending on the size of your furnace, it might be wise to sit it on asbestos-substitute mats.

I'm jealous - I bought a s/h furnace recently but it tops out at just over 1k C, which is fine for most precious metals but I was looking to melt copper in it...

Hi Peter, entirely off topic, but can you check your inbox please! Sent you some messages over the past couple of months but not had a response so don't know if you've received them?

Thanks

[ps_bond]

Argh - sorry Lauren - I've not been seeing the notifications, so hadn't looked. Shall do so imminently.
(And I need to look into what's happened with the notifications...)

[Nick martin]

Well well well, what a tool I am! No pun intended.

Called a guy up who's company I found locally and who's a kiln engineer to discuss adding a controller onto my unit.

Turns out that my small eurotherm temp indicator on the front is also a controller and there's three buttons that become functional if you press them a certain way. Thanks for all your help Peter / Josef and although I feel stupid I've saved £'s and a whole lot of frustration.

Now just need to find the manual online ha!

Nick

[ShinyLauren]

Argh - sorry Lauren - I've not been seeing the notifications, so hadn't looked. Shall do so imminently.
(And I need to look into what's happened with the notifications...)

Thanks lovely - I assumed you hadn't got them, as I often don't get notifications either!