Need to build small heating element box(3X5)

[David burdick]

Hello everybody
I have a small project I'm trying to design.
It's a stainless steel heat box that will be 3"X 5" in size and 2" high the stainless wall thickness will be .06 the inside of this box must reach and hold. Temperature of 200 degrees quickly and hold For 10 minutes. It will be supplied by standard 120 volt household current vie power cord. It would be nice to be able to adjust temperature from 100 to 200 degrees.
any help with this design and where to get the parts would be appricated .

Iam Willing to pay a small fee for help designing this and knowing where to get all the parts at a good price.

I want to be able to build this project at as low a cost as possible but yet have a good working unit.
Thank you to all that respond
David Burdick

 

[Pommie]

Blow one of **broken link removed** through it.

For better suggestions you need to describe it's use better.

Mike.

 

[David burdick]

Ohh ok
Thru the top of the box will be six .250 holes inside theses holes will be .200 dia steel rods that will be slipped into the holes and heated to 175 degrees to remove dryed on wax.
Also there will be two holes that are .625 in dia which .562 steel rods will be inserted that are covered in dryed on wax. The wax needs to be heated so it drips off.
Hope that helps

 

[Pommie]

It sounds like a heat gun type device is probably the easiest way to achieve your objective.

Mike.

 

[David burdick]

Hi mike
Yes that is a cheap way to do this but I really need something that is more automatic I would like to use some kind of heating elements with insulators and electrical cord connected to a thermostat or temp controller.
This way I can drop in the rods turn it on and walk way to do other things. Come back to unit later and remove the clean rods.

 

[alec_t]

The wax needs to be heated so it drips off.

... and drips all over the heating elements? You'll obviously need some form of thermostatic control, but if that should fail you have a fire risk.

 

[David burdick]

Hi Alec
Thank you for responding to my post.Good point about the wax causing a possible fire. But I did think about that.
The amount of wax is small I will have a stainless steel tray in the middle of the 2 inch height of the box that will slide in and out as needed to catch the wax. I wanted to mount the heating coils on the side walls of the box under the slide out tray

 

[Diver300]

I would suggest one of these:-
https://uk.farnell.com/omron-indust...ontroller-temp-1-16-din-100-240vac/dp/1973877,

one of these:-https://uk.farnell.com/ist-innovati...007/sensor-pt100-600-deg-c-class-b/dp/1778045,

and some of these:- https://uk.farnell.com/multicomp/mc14667/resistor-1k-ohm-50w/dp/1306664

The sensor goes in the heated box, along with the resistors. I will leave it to you to work out how to fit them. I would also suggest that insulating the box where possible will improve the evenness of the heating, as well as safety and power consumption.

Each of those resistors will dissipate around 15 W on 120 V. All the resistors are wired in parallel, and connected through the relay output of the controller. The relay in the temperature controller is rated high enough to run around 25 resistors like that. The resistors are rated at 50 W each, and are only being run at 15 W, because of the high temperature.

The temperature sensor is connected to the controller, and you need 120 V onto the controller to power it. You should then be able to tell it to auto-tune the control, which will take it half an hour or so, and then you set the temperature and let it run.

Those units will remember the set temperature so you can turn it off by unplugging, and turn it on by just plugging in. You can see from the display when it is up to temperature.

 

[alec_t]

Is that 200C or 200F? Whatever, personally I'd use a wall-wart to power the project at, say, 12V for safety and ease of control. Mains voltage + steel box would worry me.
You might have difficulty finding mains cord and cheap (i.e. plastic rather than ceramic) cord clamps, insulators etc to withstand the temperature, so it would be better IMO to have all the control electronics external to the box. As for heating 'coils', have you considered using standard high wattage resistors?