Thoughts on Cerakoting a mountain bike frame

[thughes]

Gentle loops are OK, a sharp bend is the kiss of death.

[Cgrutt]

Did you need to adjust temp reading with your sensor or was it pretty close out of the box?

[thughes]

Regarding your mounting of the thermocouple, I think you are going to find out that you need to get it off the electrical box cover and let it "stick out in the breeze" so to speak. The controller regulates temp by using an algorithm that takes into consideration how fast the temperature of the thermocouple changes, how fast the heaters will heat the space, and the lag time between turning on the heat and the temp of the thermocouple increasing as well as how fast things cool off when it cuts the heat. In other words: "A proportional–integral–derivative controller (PID controller) is a control loop feedback mechanism (controller) commonly used in industrial control systems. A PID controller continuously calculates an error value as the difference between a measured process variable and a desired setpoint."

That being said, the electrical box cover may act as a heat sink which will buffer the temp swings of your thermocouple and cause the controller to not react as quickly as necessary. Dig?

[thughes]

Did you need to adjust temp reading with your sensor or was it pretty close out of the box?

I had to tweak it a degree or two but it was pretty much spot on out-of-the-box. My PID has a "learning" mode which made life waaaayyy easier for the initial set up too, just ran it through a few production cycles and it figured out all the settings (P, I, D) without me having to screw with it. Configuring the P, I, and D parameters manually is a muthafugger.

[Cgrutt]

Thanks. Mine has the learning mode too. I'll take it off the cover and see if it helps but if I'm not mistaken, I believe the casing with the threads is meant to be screwed into some sort of metal. The TC itself free floats within the housing. I heated it up to 150 with map gas torch and the oven thermometer was changing as fast as the PID controller. Measured temps were within a couple of degrees of each other too. I really don't care if the temperature is a few degrees off, I just want it to control the heating elements and keep it temperature constant at whatever it is set at (+/- a couple of degrees is fine).

[thughes]

Sounds like you got it nailed.

[Cgrutt]

Yeah, but this is after compensating for difference in the measured temp out of box. I still want to see if I can get the setting closer to actual without having to compensate for any difference that I may have caused the way I installed it LOL.

[thughes]

Sounds like "close enough" is fine for your oven, I'm used to the brewing world where a 2 degree temp difference can be the difference between a good brew or wasting 6 hours and having to dump out $30 worth of ingredients. Paint is probably much more forgiving than amylase enzymes.

[camper4lyfe]

If it's safe to do so, you could put the TC in boiling water. That'll be your most consistent temp (212*), as even oven thermos can be wrong

[Cgrutt]

Not sure if the probe is submersible or not but that's a great suggestion. I ended up shortening the wires and error improved by about 30 degrees celsius. Still needs compensation but its a lot better. I took probe off of the metal electric box cover and measured temp changed by a small amount but nothing significant.

[camper4lyfe]

Not sure if the probe is submersible or not but that's a great suggestion. I ended up shortening the wires and error improved by about 30 degrees celsius. Still needs compensation but its a lot better. I took probe off of the metal electric box cover and measured temp changed by a small amount but nothing significant.

It's a trick used by smokers to make sure their BBQ thermometers are accurate.

[Cgrutt]

Got back on it again...



Doors were a pain to build but came out pretty good.



Took about 1/2 hour to bring it up to temp but it got there. Cycles for about 10 minutes off/on once at temp. Temperature maintained +/- 1.5 degrees (Celsius). I needed to bypass the thermostat within the hot plates to keep them running until it got up to temp.



Still needs a little calibration but it's pretty close to where I need it at 250 degrees (Fahrenheit)

[masterswimmer]

Like'n it CG

[Calculon]

Nice job CG. That's dedication. Now I know who to call to sweat the cosmoline out of any milsurp purchases.