temperature woes

[dix17]

Hi folks,

Iv'e just had my 6x6x4' three pase 415v oven supply connected. It's controlled by an ERO electronic LMS pid with a Eurotherm 92 over temp monitor keeping guard each fed by their own unkown thermocouple. I've been experimenting with my laser gun temp an am soooooooooo confused EG I pre heated oven then placed part in oven left it a while then zapped it with gun then immediately removed part from oven by braving the devil like enferno stylee heat (dont try this at home kids eyeballs melt real quick real good ) and zapped part with lazer and found it was way lower when measured in ambient shop 64.4 f/18c so back in the devil box I go, but now armed with googles and rehang part then zap it with gun and it reads 374 f (interpon recomendation) so what I fiqure from my fool hardy test was even though the part (a chain sprocket) was in the oven and reading 374 it can be sumised that only the surface is at that temp but the overall to the core of the item is lower so does that matter? do you guy's just start the timmer from the point from when your lazer reads the required temp even though the part may not be full cooked to the bone?

[SCOTTRODS]

Hi folks,Iv'e just had my 6x6x4' three pase 415v oven supply connected. It's controlled by an ERO electronic LMS pid with a Eurotherm 92 over temp monitor keeping guard each fed by their own unkown thermocouple. I've been experimenting with my laser gun temp an am soooooooooo confused EG I pre heated oven then placed part in oven left it a while then zapped it with gun then immediately removed part from oven by braving the devil like enferno stylee heat (dont try this at home kids eyeballs melt real quick real good ) and zapped part with lazer and found it was way lower when measured in ambient shop 64.4 f/18c so back in the devil box I go, but now armed with googles and rehang part then zap it with gun and it reads 374 f (interpon recomendation) so what I fiqure from my fool hardy test was even though the part (a chain sprocket) was in the oven and reading 374 it can be sumised that only the surface is at that temp but the overall to the core of the item is lower so does that matter? do you guy's just start the timmer from the point from when your lazer reads the required temp even though the part may not be full cooked to the bone?

sounds odd.... I do find that thinner metals do cool rather quickly in ambient air, but to the point of dropping below 100 degrees from 374? Not typical. It is very possible that you shot past the part and got a reading from the oven, or that the part metal is pretty shiny, and gives an erroneous reading at the wrong angle..... But a drop that huge in less than 15 minutes or so, shouldn't be hap'nin'.

If you are just trying ot get an idea how long it will take to get the part to temp, on a sprocket (if you're already at oven temp) shouldn't take very long,.... say 5 to 7 minutes. Keeping in mind this is a normal sized driven sprocket for say a dirt bike or ATV.

Those devil-like infernos are something to get used to. Due to the masive difference in the inner temps and outer temps, it seems much hotter in the winter months than in the summer..... You'll get used to it and you'll get to a point where you're mentally ready for the fire....

[dix17]

sounds odd.... I do find that thinner metals do cool rather quickly in ambient air, but to the point of dropping below 100 degrees from 374? Not typical. It is very possible that you shot past the part and got a reading from the oven, or that the part metal is pretty shiny, and gives an erroneous reading at the wrong angle..... But a drop that huge in less than 15 minutes or so, shouldn't be hap'nin'.

If you are just trying ot get an idea how long it will take to get the part to temp, on a sprocket (if you're already at oven temp) shouldn't take very long,.... say 5 to 7 minutes. Keeping in mind this is a normal sized driven sprocket for say a dirt bike or ATV.

Those devil-like infernos are something to get used to. Due to the masive difference in the inner temps and outer temps, it seems much hotter in the winter months than in the summer..... You'll get used to it and you'll get to a point where you're mentally ready for the fire....

Thanks for the speedy post bro, Im just a newbie and just trying to understand about how to take readings. Eg say I need to powder a handlebar and a set of wheels the same color the handle bar I guess will get to temp quicket than the more dense wheels so do I just start the timer from the time the different parts are all at the same curing temp?

[SCOTTRODS]

Thanks for the speedy post bro, Im just a newbie and just trying to understand about how to take readings. Eg say I need to powder a handlebar and a set of wheels the same color the handle bar I guess will get to temp quicket than the more dense wheels so do I just start the timer from the time the different parts are all at the same curing temp?

If you have an array of parts with hugely differing mass, it might pay off to cure them seperately. To get each part to PMT (Part Metal Temperature) you may have to overcure some things beyond their safest and best "over-cure" times.

If you are shooting sheetmetal and castings, definitely cure them seperately.

The idea is to get each part up to the curing temp and then start the timer for the proper cure time.... Maybe a little longer on darker colors.

The one thing you mention is two different parts, the same color... to match. If you want two parts of different substrate to match, they must have a base or a primer coat. They need to start (on the intended color coat) as close to the same color as possible. Sometimes this means that you must start off with a black or white base then cure, then coat with the color you desire them to be,... and after curing each coat seperately, you want a protective clear over them, shoot a clear and cure also. This concept is VERY important with Candy Colors/topcoats. Not so much with opaques,... but it can be on some.

Unless using an epoxy, or zinc rich primer, cure completely before applying susequent coats. If using one of the primers mentioned, follow the directions of the primer. Some require you only cure them til they flow out, then remove them and cool to room temp,.... then apply final coat (color coat) and cure completely at the color coats cure cycle.

Nothing wrong with askin'. Curing seems to be an art form lately.... I'm certainly still learning myself.