Thermostat help

[Dr Stan]

I just installed a 300 watt incandescent light bulb in an old refrigerator to use it as welding rod storage.  Is there a cheap/simple way to regulate the temperature to right around 250 F or 110 C?

[Pete O]

I'd be testing with different wattage light bulbs, you may well find you get in the temp range you want without any other mods.

[TomG]

You can get a PID temperature controller and a thermocouple for about $35 at lightobject.com, but Pete may have the cheapest solution.

Tom

[f350ca]

Do you need it that hot Stan? Just asking. You'd need welding gloves to handle the rods.

[Dr Stan]

(12-06-2019, 06:09 PM)Pete O Wrote: I'd be testing with different wattage light bulbs, you may well find you get in the temp range you want without any other mods.

The only incandescent light bulb of sufficient wattage I could find was 300 watt.

[Dr Stan]

(12-06-2019, 09:18 PM)f350ca Wrote: Do you need it that hot Stan? Just asking. You'd need welding gloves to handle the rods.

You're right it probably only needs to be in the 90 to 100 degree range just to keep the moisture out.  For some reason I was thinking it needed to be at the boiling point of H2O.

[Highpower]

(12-06-2019, 09:18 PM)f350ca Wrote: Do you need it that hot Stan? Just asking. You'd need welding gloves to handle the rods.

I have a Keen rod oven (portable model) that is pre-set at the factory to 275° F and can be adjusted up to 300° F.
I also use it occasionally to de-hydrate several desiccant canisters I use around the house. While doing that one day I got lazy and decided to reach down into the oven to quickly pluck out one of the desiccant packs without a glove on and accidentally grazed one of the inner walls with the meaty part of the my palm of my hand. NEVER AGAIN, I can promise you that.  

Stan, my rod oven uses a very small bi-metallic switch for the thermostat. Could not be any simpler.

Maybe something like a clothes dryer thermostat would do the trick if all you would be running is a light bulb.
https://www.mouser.com/ProductDetail/Whi...6XfCYOA%3D

[Highpower]

(12-06-2019, 10:38 PM)Dr Stan Wrote:

(12-06-2019, 09:18 PM)f350ca Wrote: Do you need it that hot Stan? Just asking. You'd need welding gloves to handle the rods.

You're right it probably only needs to be in the 90 to 100 degree range just to keep the moisture out.  For some reason I was thinking it needed to be at the boiling point of H2O.

Quote:Welding electrodes are manufactured to have a specific range of moisture content. For example, low-hydrogen rods have a moisture content of approximately 0.1 – 0.4 percent. Cellulosic rods on the other hand have a moisture content of 4 to 6 percent. If these two types of electrodes are stored in the same oven, the lower moisture content low-hydrogen rods will absorb moisture from the higher moisture content cellulosic rods. It is important to note that cellulosic rods are not to be stored long term in a rod oven, and are only heated at low temperatures (100-120°F) if they have been exposed to humid air for an extended period of time.

I use my rod oven for 7018 rods (low-hydrogen) only.
Cellulose rods that have been sitting out for a long time just get chucked into a small toaster oven for awhile if needed.

[Vinny]

I made a curing oven for plastics (I think there's a pic of it in the plastics forum) using a 150 watt bulb and a PID controller. Works great! I probably got the PID controller on ebay, doubt I spent more than $20 for it and it holds the temp where I need it to within about 2 degrees - but that is also settable.