Topic: Engine Painting - Heat Cure

[Prospect]

I'm ready to paint my freshly media blasted k1 engine and have a quick question about the heat curing.  Paint is duplicolor 1615 Aluminium

I've read a lot of posts regarding this topic and most people don't use primer.  The media blasting did a great job of cleaning and providing a roughed surface for the paint to adhere. 

The can says to apply 3 coats within an hour and additional coats you have to wait 7 days for curing.  Dries to the touch in 1 hour.  Can be handled in 3 hours.  Heat cure at 300F for 2 hours.

So when is it best to heat cure?  Can you do it after it dries in 1 hour or 3 or do you have to wait 7 days?  I rather do it all in one day. 

[Bodi]

If you let the paint dry too much, overcoats will wrinkle if applied before the stuff is completely dry. So either overcoat within 3 hours or wait a week. I would wait a day before heat curing it, and ramp the heat up slowly: minimum oven temp (usually 200F) for an hour, then 250 for an hour, then 300 for two hours. Then turn off the oven and let it cool for a few hours without opening the door. That's with a home oven - and expect one hellacious stink and potentially a divorce if you have a spouse in the house.
I would check the real oven temperature with an oven thermometer before this job, many ovens are way off in calibration. You can either just figure out what temperature setting actually gives you 300F in the oven, or recalibrate the control. Electric ovens with knobs, you remove the knob and there's a hole through the shaft and a tiny long flat screwdriver can adjust the calibration control in there. Electronic control ovens usually have a calibration offset function but getting to it takes a button pushing combination you have to get from the service manual. Gas oven with a knob? No clue, sorry.

[ekpent]

If we took a poll I bet not to many guys have actually gone through the hassle of putting their engines in the oven etc. for heat curing,I may be wrong though. When the engine is finally started some gentle warm ups will help to cure the paint,just be careful with the gas etc. on that fresh stuff.

[Lars]

Not familiar with that brand of paint, but normally the cylinder, head and breather cover is painted with heatresistant paint, and put into an oven. Not necessary for the cases, as they do not get that warm.

[wingman1946]

I have done a couple by just letting it cure for a day or so then going for a ride. I have a hard time picturing somebody getting that much weight up inside an oven without smashing something. Or pulling something!

[Cain74]

Could you use a gas grill to heat the parts thus avoiding the stink in the kitchen?

[Freaky1]

Could you use a gas grill to heat the parts thus avoiding the stink in the kitchen?

I'm going to say no because heat control could be a problem along with getting an even heat throughout. Check Craigslist, many times people are giving away an old oven, that's how I got mine for free. Now I have an oven in my garage and a wife who is not afraid to leave me at home alone.

[Prospect]

Thanks for the info.

I painted the engine this morning.  It came out nice.  The aluminum surface isn't perfect because of 40 years of scratches and casting imperfections but it came out well.  I'm happy with it.  I did 4 light coats instead of 2 light and 1 medium.  I might wait a week and give it another coat.  It looks good from 2 feet away but if your really focus in closely you'll see some nicks etc.  I think that's expected for an engine. 

I can't use the oven in my house.  My wife would kill me and then ask questions.  I'll try a couple of test pieces in the grill.  I'm pretty confident the heat distribution is fairly uniform.  I have an extra temp gauge too.  I'll try it tomorrow as per Bodis suggestion. Pics to come.

[seanbarney41]

ummm, never tried before and I don't have a clue what your grill is like...but I would expect the presence of actual flames in the grill equals "good for your hot dog, bad for your engine paint"

[Prospect]

Here are the pics.

[wingman1946]

Looks good from here.

[chadayres10]

I just painted my engine as well. I went with a color called cast iron , its a darker silver with a hint of copper. I then painted the heads and side covers a wrinkled black and the valve cover the cast iron color. It turned out awesome ....the wrinkled look gives the pieces texture. Will post some pics. I did use the kitchen oven to cure it and the misses didnt kill me haha

Chad
cb750

[ekpent]

ummm, never tried before and I don't have a clue what your grill is like...but I would expect the presence of actual flames in the grill equals "good for your hot dog, bad for your engine paint"

I am with Sean on this one. Give your wife a couple of twenties and tell her to go for a looong shopping trip and then get cooking in the stove. Make Betty Crocker and Mr Honda proud 

[1974cb550k]

I painted the cases with the same high heat aluminum you used. I put 3 500 watt halogen lights around the block and let the paint dry. Been on for a whole season and hasnt started falling off yet. I think you'll be fine. Looks good BTW

[magconpres]

I used the same paint as well.  I think I used primer, but it was a while ago and I don't recall for sure.
Fortunately, my wife owns an art studio and has one of these

I can set the ramp up slope, max temp, hold time, and cool down slope. 

I can probably get two assembled engines in there if needed, but when I had the engine apart when I painted it.

[boatsdickson]

I would b curious about the results of a poll as EKEMPT mentioned. Not ever1 has the capacity to properly cure it, and his next sentence is my method. Given the amount of time the remainder of the motor build usually takes me, the paint has gained a good deal of strength. Your cases turned out great for a rattle can job and with caution you should get it remounted to the frame with minimal damage. Enjoy some riding as your ear is listening for possible rebuild mistakes, and before you know it youll have nicely cured cases. Good job & good luck with the rest of it.......Boats