Curing Temp...

[try2kechup]

I am looking at building my own special size oven for powdering Kart frames...I have elements from 2 ovens I will be using...I will also be using the thermostats from the ovens as well...Just really need to know the best temp to cure the powder at and how long of curing time at a constant temp
One more thing...Should I mount the elements in the top or bottom of the oven for safety reasons...or would it matter(safety wise)...

:P Thanks, Carl

[DALE]

Most powders will cure fine at 350F ,the controls you are going to use will allow the temp to swing up and down at least 20 degrees,this is okay. Let the oven cycle on and off a few times to heat soak the metal and the swing will calm down some. Place the elements down low and make guards for them also think about a low speed fan to circulate air if oven is very tall. Remember heat rises! Place your temperature sensor or thermocouple at least half way up in the oven, 3/4 works better I have found. Be sure to mount it at least a half inch from side sheet metal or it wont' work right.

[try2kechup]

Thanks Dale...the info is appreciated...

Carl

[atijerino]

Now that we are on the curing temperature topic. I got a large convection over at a garage sale for $5.00, if wanted to use this oven for power coating is it better to turn convection off? or Do you think that need to reduce the curing time and temperature?

Thanks,

Antonio

[fredde]

Originally Posted by try2kechup

I am looking at building my own special size oven for powdering Kart frames...I have elements from 2 ovens I will be using...I will also be using the thermostats from the ovens as well...Just really need to know the best temp to cure the powder at and how long of curing time at a constant temp
One more thing...Should I mount the elements in the top or bottom of the oven for safety reasons...or would it matter(safety wise)...

:P Thanks, Carl

Just some brainstorming:

I would put the elements at the sides because if they mailfunctions in the future, the gasses would be consentrated at the top so its more fireproof (or the deposits)(if a element fails, you could have a spark that ignites the insulation) The thermostats should be located approx. 2/3 of the distance from the bottom and up.

If you are building a oven from scratch you should consider to weld all sides inside the oven so that the insulation is not exposed to the air inside the oven. Some powder coatings have wax substanses that under the hardening prosess evaporates into the air. Other powders may include bensil or benzoin that also evaporates into the air when hardening. What happens when the insulation over a few years is saturated with thees substanses is that it burns. So if an open flame/high temp or a spark suddenly enters your oven, it may actually burn. This is of course a minimal danger for us "home" users but has happened at several production sites. So better safe than sorry...

You should also consider to mount a fan that circulates the hot air in the oven, it gives you much more energi then. (just imagine you sitting in a bathhouse/sauna, when you blow at your skin it burns, this is almost the same principle) The convection helps also to even out the temperature in the top and bottom of the oven, so subjects that is hanging from top down to bottom is even cured. Just remember not to have a storm in it The powder may actually blow off, or the subjects you have paintet may blow together.

Hope you could use some of this info for something

[fredde]

Originally Posted by atijerino

Now that we are on the curing temperature topic. I got a large convection over at a garage sale for $5.00, if wanted to use this oven for power coating is it better to turn convection off? or Do you think that need to reduce the curing time and temperature?

Thanks,

Antonio

No its better to have it on. Your subjects will be heated a lot faster. But be aware that it must not be to high airspeeds in you oven, or else you will get trouble. Powder blowing off and subjects hittin each other.
You will also achieve a more even temperature top/bottom. Which leads to even curing of long objects.