My 3'x3'x6' Oven project.

[Kyrasis6]

Well guys I've had a lot of requests for powdercoating parts which where far to large to fit into a kitchen oven so it's time for me to build one. After getting some measurements of many of the parts requested I figure an oven measuring the common 3'x3'x6' ID will do most rear ends, bike frames, suspension parts, etc...

Construction will be the usual Metal stud framing with sheet metal siding. I'll build it in panels so that if I need to move it or transport it later and am in a pinch I can disassemble the oven to move it. To help with warm up times I'll be using a thinner sheet metal on the ID so there is less mass that needs heating. I've decided not to use some of the alternative wall materials mentioned in the past because of the long heat up times they cause. The oven will incorporate an externally mounted convection fan with internal ducting, lights, timer, circuit breaker, and an amp meter. Temp controller will be a 1/16 PID using K type thermocouple and SSR output. I already have some controller boxes sitting around I acquired from a previous job and will either be using one of the computer CPU heatsinks or amplifier heat sinks I have to take care of the heat.

I haven't quite decided on the door type yet. I'll probably make it two door so that it requires less space to open. In the top will be a roll out rack supported by two industrial rollers (like for keyboards but bigger). I think they have a 200-300 lb capacity for each and are all stainless steel construction so they'll handle the oven and anything I hang in there just fine.

I would like to have 9,000 watts but will probably end up running 6,000 for the mean time since I'm renting a house and probably won't have my own place with a garage for another year. More than likely I'll build the oven with two 3,000 watt elements with everything in place to add a third one later.

Below is the list of components with links I'm planning on so far:

Temp Controller:
http://auberins.com/index.php?main_p...&products_id=3

Solid State Relay:
http://auberins.com/index.php?main_p...products_id=29

Thermocouple:
http://auberins.com/index.php?main_p...&products_id=2

Convection Fan:
http://www.surpluscenter.com/item.as...tname=electric

Timer:
http://www.surpluscenter.com/item.as...tname=electric

Caster Wheels:
http://www.surpluscenter.com/item.as...catname=wheels

What do you guys think?

[ed_denu]

My only concern would be that 6000 watts for a 54 cu ft oven might be on the light side. Heat up time will probably be close to an hour to 400F.

[baz]

i also have the same concern i have about the same dimensions with 11000 watts , my heat up time is between 23 to 26 minutes but when doing parts with heavy steel plates it takes much longer to get them to temp

[CarWiz]

Skip that fan for recirculation. It's ok for a vent fan but won't take extended heat cycles because the housing isn't completely closed and the fan drive is made of rubber. I tried these and have since pulled the one I had as a recirc.

The PID comes with a TC so unless you need the extra length of the one you posted, you can skip it too.

The timer? Well, unless you're going to use it to make coffee I see no need for this type in an oven. It turns on at a specified time of day so I'm confused about why you included it.

Add a heat sink to your list!

[Kyrasis6]

and will either be using one of the computer CPU heatsinks or amplifier heat sinks I have to take care of the heat.

Heat sinks won't be a problem I have them big and small, nor will be a circulation fan, or fans to put in the controller box.

Does Auberins sell all their temp controllers with a TC? Only thing that I saw was that it was configured to use a K type out of the box.

Does anyone have other recommendations for a recirculation fan? Basically I want something I can mount to the side of the wall but still be able to run the duct work inside the oven.

Since wiring a dedicated circuit for the oven in the house I'll be renting may not be possable I might try making a slide in divider plate to basically cut the size of the oven in half when doing smaller parts.

[baz]

Originally Posted by CarWiz

Skip that fan for recirculation. It's ok for a vent fan but won't take extended heat cycles because the housing isn't completely closed and the fan drive is made of rubber. I tried these and have since pulled the one I had as a recirc.

The PID comes with a TC so unless you need the extra length of the one you posted, you can skip it too.

The timer? Well, unless you're going to use it to make coffee I see no need for this type in an oven. It turns on at a specified time of day so I'm confused about why you included it.

Add a heat sink to your list!

sorry carwiz but when you order from auberins. the probe is not included with the PID ,

but i agree about the timer , its useless for this application

the thermocouple on that list has a 1/2 inch threaded probe at the end
i think it would be better to use a 3 or 6 inch probe , i bought the 6ft cable with 6 inch probe

[Kyrasis6]

Oh, forgot to mention, the timer was to have a clock close by and would be wired into a buzzer since I'm a very forgetful person.

What would be the benefit of the larger probe? I was thinking smaller would be better since it would react faster to sudden heat changes and would be less likely to get in the way of something in the oven.

[CarWiz]

Originally Posted by baz

sorry carwiz but when you order from auberins. the probe is not included with the PID ,...

Ok, I guess I misunderstood this info from the website to mean it came with sensor. I got mine off ebay and they came with the TC.

Shipping configuration:
Input sensor: K type thermocouple (Max working range 32-2300 °F).
Display Unit: Fahrenheit (°F)
Display resolution: 1 degree.
Alarm 1: Deviation low
Alarm 2: Deviation high

As far as having an alarm clock, if you're away from the oven, what good is it? You'd be better off getting a timer that will shut down the system after the cycle is over. That's what mine does. The control system can also be set to open a vent (or not), to start a purge fan (or not), to restart with a new time or the same time (or not) and to sound an alarm (or not).

But, everybody works in a different process environment so I guess it may work if you think that's what you need.

Originally Posted by Kyrasis6

Since wiring a dedicated circuit for the oven in the house I'll be renting may not be possable I might try making a slide in divider plate to basically cut the size of the oven in half when doing smaller parts.

You might consider using multiple SSRs as well. You could "turn-off" the heaters (SSRs) that aren't being used. A simple switch on the control side will accomplish this. You can use as many SSRs as the PID current (usually 40ma) will allow without extra relays. Mine uses four SSRs to control area heating.

By making a divider panel that will adjust to the size of your work, you can control the size of the oven as well as which heaters will be used. No sense burning 9000w if you're baking a tin cup. Your only problem will be how to move or locate the TC if you're not using multiples. (Not hard if one end or area is always in use.)

[baz]

Originally Posted by CarWiz

Ok, I guess I misunderstood this info from the website to mean it came with sensor. I got mine off ebay and they came with the TC.

Shipping configuration:
Input sensor: K type thermocouple (Max working range 32-2300 °F).
Display Unit: Fahrenheit (°F)
Display resolution: 1 degree.
Alarm 1: Deviation low
Alarm 2: Deviation high

As far as having an alarm clock, if you're away from the oven, what good is it? You'd be better off getting a timer that will shut down the system after the cycle is over. That's what mine does. The control system can also be set to open a vent (or not), to start a purge fan (or not), to restart with a new time or the same time (or not) and to sound an alarm (or not).

But, everybody works in a different process environment so I guess it may work if you think that's what you need.



You might consider using multiple SSRs as well. You could "turn-off" the heaters (SSRs) that aren't being used. A simple switch on the control side will accomplish this. You can use as many SSRs as the PID current (usually 40ma) will allow without extra relays. Mine uses four SSRs to control area heating.

By making a divider panel that will adjust to the size of your work, you can control the size of the oven as well as which heaters will be used. No sense burning 9000w if you're baking a tin cup. Your only problem will be how to move or locate the TC if you're not using multiples. (Not hard if one end or area is always in use.)

i also made that mistake . i thought it meant that it was included but it jut said that it was CONFIGURED TO USE a k type thermocouple.

[baz]

Originally Posted by Kyrasis6

Oh, forgot to mention, the timer was to have a clock close by and would be wired into a buzzer since I'm a very forgetful person.

What would be the benefit of the larger probe? I was thinking smaller would be better since it would react faster to sudden heat changes and would be less likely to get in the way of something in the oven.

i just thought it was easier to make the installation with the narrow long one by having a tube through the oven walls and slip in the probe . but it is your choice