Poor Adhesion

[garykelly]

I got poor adhesion on some air intake pipes. I used urethane and it went on nice I cured for about 15 minutes after flow, but its chipping off.

Would this be a good candidate for a primer ?

I use IR and its cold in my garage.....

[remotestartdepot]

Sounds like it was under cured. Did it get up to temp? My first parts I did were under cured and chipped very easily.

Kris

[garykelly]

I had good flow and then went for 15 minutes. It could be that I just cant maintain the heat good enough with a cold garage.

I talked to the guy and we are going to try it again when the temps come up...

Thanks

I use IR and its cold in my garage.....


using and ir in the cold is hard .. build a box around the part to help keep the heat in

[jtagger19]

did you measured the part temperature ??
the powder starts to melt at 250 and if it doesn't get higger it will melt normal but will not fully cure cuz it stayed at 250

[viper56]

garykelly,

Did you just wait for the powder to start flowing assuming that the part was up to temp, then cured for the allotted time? Or did you use a IR gun to check the part temperature, then started timing it?

Jim

[garykelly]

I watched the powder flow. I use an IR gun but my temps have never exceeded 300F even on warm days. I attributed this to curing with an IR lamp...

Other projects that I have done have been very durable this is my first oops....

It could be that while the powder had enough heat to flow, it didnt have enough cure, since I have no way of increasing temperature (other than fabricating a better encloser) is it possible to cure at lower temp for longer times ? The finish was beautiful, no beading, great gloss...