best extra insulation under kiln between kiln and electronics

[coppercone2]

I have a kiln I am retrofitting with some PID control, the previous control is analog, manual setpoint + monitoring

I am a bit worried about putting a omega in there, is well vented but still. I have some room near the ceiling of the bottom electronics box.

Its two boxes on top of each other, top box is the kiln and bottom box was electromechanical control.

Is there any good clean materials in sheet form that might be possible to attach to the ceiling to reduce temperatures a little bit? I dunno how how it will get, there is basically a soft fiber brick lining the sheet metal, with the heater inside.

I know of kaowool, but that is messy. If there was like a aluminum bubble wrap but filled with kaowool that you can cut to the shape that you want, that would work.


I mean I think it will probobly work, it should not get that hot, and nothing is attached to the ceiling, but I definitely got the room to add 1cm of insulation.



Again, something to attach to the ceiling of the control box on which the kiln box sits to cool it a few degrees extra.

[Njk]

Attend a scrape yard nearby to find a big kitchen refrigerator. Use the condenser, it's typically a large flat metal panel with embedded pipeline. Of course, some plumbing will be required to get the tap water flowing through the pipeline all the time. But that'll result in real cooling effect

[coppercone2]

im not gonna put a water cooler inside of a fucking kiln

[themadhippy]

In days gone by we'd have shoved a sheet of asbestos in there,maybe  mineral board would work

[coppercone2]

Can you put high temp paint on that like a sealant to turn it into a stable chassis element?

I don't want flakes or fibers coming out of the thing, it needs to be like solid


Maybe like some sort of tile? Like glazed. I could drill it with a diamond hole saw for the 2 feed through

[Doctorandus_P]

I assume the oven itself is already isolated by itself so it does not loose much heat.

A secondary problem is that even when absolute heat loss is small, it can still accumulate into areas. To fix that, a small fan to blow some fresh air though your box helps.

If you can fit an aluminum sheet in between the kiln and the electronic box (with some natural ventilation around it) this also helps. Aluminum is not a good heat conductor, but it reflects a lot of IR and thus does not heat quickly, and the ventilation (or even better: a fan) keeps it, and everything below it cool.

Another option is to use fire blankets. Those are made from glass fiber and can also withstand a lot of heat, or even woven glass that is normally used with epoxy.

Kevlar would be another option It's stable to around 550 degrees centigrade. It's relatively expensive, but if it's just for the box you don't need much. (Or Teflon, carbon fiber). But still, a small fan to stop heat from accumulating over time is probably the best option. But I would add some fan monitoring and/or over temperature alarm in the box.

[themadhippy]

This is the sorta thing i was thinking about https://www.philipharris.co.uk/product/lab-equipment/labware/tripods,-burners-and-mats/bench-mats-230mm-x-230mm-pack-of-10/b8a55347

[coppercone2]

its a totally perforated box wit tons of little holes (like a net).


I don't think a fan will work properly in this situation? Or do you think it will help?


I was thinking that I can probobly put a aluminum sheet in there to act like a 'attic'.

If I put a aluminum plate like 0.5 inches from the ceiling will that cool the under side some, since its a mesh box?

[coppercone2]

I guess since its for a bench it might be OK.

would a metal plate spaced with the air holes around it or insulation be better?

maybe the plate would kinda get convection going around it when its hot and the gas would go away from the bottom of the enclosure?

Maybe I should carefully run it with my big variac after I get it reassembled and test it. I need to add a bit of fiber insulation to some gaps and then put ICT 100 in it, then I can do my first heat test.

I can put a thermocouple where the PID will be and another one attached to the metal plate under the firing chamber


and yeah, its like a full made kiln, just the bottom is some car blinker relay crap from 1960

[twospoons]

https://www.rockwool.com/north-america/products-and-applications/products/comfortboard-80/

Or something along those lines...

[coppercone2]

actually this is called a muffle furnace, its not a kiln like for pottery. like some little thing they would have in a semiconductor lab


I dunno how hot the bottom is. My hope is that it fairly acceptable. it does have a dial gauge in there with acrylic for the thermocouple, and its some kinda black plastic. maybe that means its moderate

[Doctorandus_P]

I don't think a fan will work properly in this situation? Or do you think it will help?

I don't know, I have not seen your gadget.
Having a totally perforated box may be good for ventilation, but it's not good for keeping dust and other stuff (molten metal splatters?) out.

Have you ever measured the temperature inside the box? Maybe it does not get too hot in the first place.

And al long as you stay close to the thing, you can even put some cardboard in between for some short tests to see how good that works. It's not going to be exposed to the inside temperature of the oven. Maybe you have some other metal such as a tin can lying around to do some tests. But I recommend you start with a thermometer inside the box to get a reference, so you can apply math to measure the difference when you make modifications.

And that ton of holes, is that a metric ton or a short ton, or maybe one of those other banana measurement tons?

[tatel]

Aerogel?

https://www.amazon.com/roVa-Guard-Aerogel-Insulation-Padding/dp/B07XJRZ5CJ/ref=sr_1_2

[coppercone2]

that looks very interesting. I saw that airoloy or something, but it is expensive.

i need to finish rebuilding and test the temperature lol. 30$ for the sheet seems acceptable

[johansen]

i doubt it will get so hot that fiberglass insulation won't work because it will melt.

perlite is one of the best insulators you can get cheaply, vermiculite is also really good.

a sheet of aluminum, an air gap, half inch of perlite trapped between two sheets of aluminum, followed by another air gap and your electronics is probably good enough, if not, add a fan to blow air through the air gap.

[coppercone2]

do they have something that can be cut into shape with fiber glass like bubble wrap so you have a way to cut it to a general size shape without breaching it and letting fiber glass out? Say a matrix of fiber glass cubes connected by foil so you can slice out a insulator to the nearest inch in dimensions. And holes for the wires

My main problem is that I don't want dust coming out of it. I suppose you could make some kinda pillow thing from some kind of foil to hold the fiber glass in place. I don't know what foil material that would be. Same for the vermiculite . I made that before, its really dusty. And it needs to be fired to set properly. I would need 2 grommets also in this case for the wires.


And it needs to be able to cure without a kiln, because I don't have a bigger kiln to fire it


The matting material I can cut and put in there and it does not need a real seal and I can punch holes in it. The pastes are tricky. I would probobly need a full on formed metal case (like hydroforming). Way too much work


If I could get a custom aluminum case that I can stuff with fiber glass, with holes for the wires (doughnut cut in half and hollowed out) I would do that. But that is 11/10 difficulty to make that



The most realistic fiberglass holder I could make would be to solder it out of copper or nickel silver with tin, sealing the fiberglass inside hermetically.

[coppercone2]

kaowool paper (thin) is actually pretty damn solid, I thought it would be snowing insulation. It seems possibly reasonable to wrap kaowool in some kind of soldered foil shell.

I wonder if soldered reynolds wrap would be good enough

[coppercone2]

well I got it working on the original switch. It just needs some better grounding, a fuse, and a grounded bottom cover (its one of those designs where you can reach in from the under side to touch live wires) and new rubber feet

probobly should not play with it until I do that. my heater replacement and new insulation seemed to install OK

[coppercone2]

its been curing the new inside coating at a balmy 550C for a few hours now. The lid is around 75 degrees C, enough to hurt yourself if you lean on it. They should have put another mesh over the kiln spaced at 1cm made out of aluminum to keep it safer, that would be a neat mod.

I don't want to probe the underside, i need to do that very carefully since screw terminals at line voltage are there, so I am gonna use a TEC to peep through the gauge slot. But the air temperature seems to be in the low 30's. I think so long nothing is hugging the ceiling, and it gets a little metal guard, the PID should be fine in there. I can position it lower then the middle, then it should get favorable temperature conditions at the cost of aesthetics if its offset a bit.

The hottest part is the door flange, which got slightly past 100 degrees after a few hours.

[coppercone2]

it still does not seem hot in there even when it was glowing at 999c

I think my next test will be to get a black plastic box, tape a thermocouple to it, and set it where the pID would be. Like a dummy. I am thinking maybe if the plate above it is hot, it will heat up from radiation. That would be the best test

I am pretty sure the air won't heat it up, but maybe thermal radiation could

i suspect the far future space warship might be built like this kiln, a thin stainless steel layer with meters of ablative armor for lasers

the true form of a borg cube?