Yellow clear coat please help

[ng8264723]

I read this post and usuallty do it this way:
the cure time starts when the part has reached that temperature. It may take 30 mins to reach the temp, depending on the size of the part or density. You should get a IR thermometer and this way you can check the part temperature itself. You may need the part in the oven for 45 mins just to get a cure temp of 380 degrees for 10 mins. Heat up depends alot on the amount of "power" your oven has to emit BTU's into the oven chamber itself
I did it the way he mentioned. I then let it cure foir 15 minutes and it turned yellow. I'm now stripping it and will try again tomorow. Any advice?

[baz]

is your ir thermometer accurate ? is the part too close to the elements?

[o1dakota440]

in my past experiances yellow clear means that you cured at too high of a temp.

[ng8264723]

The temp was a little off maybe 20 degrees. Is that enough to yellow it?

[Harleydad]

The temp was a little off maybe 20 degrees. Is that enough to yellow it?

Yes it is.
What clear are you using and what are the cure instructions for the powder. You may also want to put an oven thermometer in your oven to be sure temp is close to what the oven is set at.

What powder did you clear over?

[ng8264723]

I used the caswell high gloss with a additive ti kill the gloss over bare alum

[baz]

in your first post you state (45 min. to reach temp plus 10 mon at 380 f )
if you are off 20 degree on top of that . then yes it is enough to cause the yellowing of the clear.
when i do clear coats i stay below 375 PMT at all times .

[ng8264723]

I will check but I think it said 390

[baz]

even if it says 390 on the can you should stay below 375 .
you should begin by making a few tests to see how accurate your readings are.
do like harley dad says and try to put a oven thermometer in there , take a few different readings in different places in the oven if its a larger oven .
if it s a smaller oven make sure your part is not too close to the elements

you did mention that you were working with polished aluminium .
ir guns do not give an accurate reading on shiny items. the ir rays bounce off the part

[FigureLLC]

i generally cure clears at 350 for an extended cycle. the only one i've had a problem with browning was an nic matte - i think - clear. caswell's seems to be fine at 400.