Topic: Duplicolor engine paint... when to bake?

[Kickstart]

Sorry if this has already been posted, but I've read through almost every engine paint thread and I don't seem to recall when is the best time to bake the parts after painting them.

I finally decided to use the Duplicolor high temp engine paint (1615) for my 75 CB750F rebuild.
I put on three coats (well, actually four) within the hour (two really light coats, then two heavier coats), and now it's curing.

Do I wait 7 days before baking in the oven... or should I do the heat cure within the 7 day fully cured window?

Thanks

[kghost]

I generally bake it when it's dry.....next day usually.

I try and not go over 150 C.

[SONIC]

Yeah you want to do it before its fully cured, you're really just accelerating the cure.

[RSchaefer]

I did the same (CB750F, '75) but went with two light coats based on most folks thinking too much paint was a bad thing, holds in the heat.  I baked the parts I could fit in my oven right after spraying and am expecting the block to cure when I ride it.

[Kickstart]

Thanks guys... I'll be baking it in the oven around 24-48 hours after spraying then.

Sounds like the consensus (from other threads) is 200-250 degrees F for 20-30 minutes.

[kghost]

Realistically the paint will cure when the engine comes up to operating temp.

The reason I've always baked them is....it tends to make them more impervious to fuel when you haven't had the engine up to temp a couple times.

Nothing worse then your freshly painted engine bits getting ruined when you fiddling with the carbs....lol

[Kickstart]

Yeah, I have the engine completely apart in pieces... and I want the paint to be tough enough to handle the inevitable bumps, scrapes, spills, etc. during reassembly and mounting.
 
Thanks

[jamesbekman]

It sounds like a little too much of a precaution if you ask me.

[AbbyRider]

I use the Dupli-Color engine enamel quite a bit. I found baking at 300 for 2+ hours works the best. And I do it pretty much right away. Just make sure to let the parts cool before handling.

[davidtime]

Do you use a regular house oven or do you have one for parts specifically?

[bollingball]

Do you use a regular house oven or do you have one for parts specifically?

Simple you buy your wife a new oven they love that stuff. Then you say you know I might just keep the old one you never know we might be able to use it some day for something.  
Ken

[70CB750]

I use regular house oven.

[goldarrow]

i worked on my engine last summer.  painted pieces with high temp primer, then 2 coats of paint, and let them baked under the Sunny SoCal sun for what seems like forever while i was working on something else.  i had fuel leaks all over the place from carbs once, and wiped it off quick as i can and the paint seems to hold just fine.  500 miles now since the engine rebuilt, plenty of nicks from road debris though

[davidtime]

Do you use a regular house oven or do you have one for parts specifically?

Simple you buy your wife a new oven they love that stuff. Then you say you know I might just keep the old one you never know we might be able to use it some day for something.  
Ken

Haha yeah I rent at the moment but maybe I can tell the homeowners it isn't working good!

[davidtime]

i worked on my engine last summer.  painted pieces with high temp primer, then 2 coats of paint, and let them baked under the Sunny SoCal sun for what seems like forever while i was working on something else.  i had fuel leaks all over the place from carbs once, and wiped it off quick as i can and the paint seems to hold just fine.  500 miles now since the engine rebuilt, plenty of nicks from road debris though

I sure do miss that socal sun! Lived there most of my life and decided to move here to TN to start a business. Humidity makes it tough to get a good paint job. You have about a 2 hour window during the day in the summer.

[kghost]

Send your wife off for something.......

Get her a pedicure or a salon appointment......

Send her to the movies with her girlfriends......

Anything.....it's cheaper than buying an oven

[davidtime]

Anybody have a suggestion for frame paint? Got a new frame coming and I want to get it painted up before swapping everything. BTW my oven is not big enough for a frame! I wish

[jonboycox]

Painted my 400F engine with duplicolor engine paint, good color match until 2000 miles later, now it looks like a dog peed on it,especially the valve cover, as well as being scratched anywhere that I looked at it wrong. Latest rebuild (350 twin)is powdercoated for sure.

[Kickstart]

Do you use a regular house oven or do you have one for parts specifically?

I also used my main oven... same one used for cooking.

I waited 24 hours after spraying before backing... I was surprised how it hardly smelled at all.  I guess the majority of off-gassing happened in the first 24 hours.  I did have a small amount of oil I wiped on the valve seats, and I did notice an oil smell when I baked the head.

I baked everything at 225 degrees F for 30 minutes (I did the jugs for an hour).  Not sure if it would have smelled more had I set it to a higher temperature.

[Kickstart]

Painted my 400F engine with duplicolor engine paint, good color match until 2000 miles later, now it looks like a dog peed on it,especially the valve cover, as well as being scratched anywhere that I looked at it wrong. Latest rebuild (350 twin)is powdercoated for sure.

Yeah, I'm really worried about this.  But my build is hitting the year mark, and I'm getting to the point where I just need to start wrapping things up. 

I was going to try to find some local auto paint place to paint my engine... but I couldn't find anyone who had any real level of experience doing air cooled motorcycle engines.  The place that powder coated my frame messed up my brake calipers, so I didn't want to chance my cylinder and head to some powder coater (again, hard to find anyone with experience on air cooled motorcycle engines). 

Seems like most of the old-timers here just go with the Duplicolor engine paint, so I figured I'd do the same and save $400 that I would have spent on a professional to potentially mess-up my engine.

I think I read every post in the forums on engine painting, it seems about 50% say they're happy with using Duplicolor/VHT and the other 50% have had problems like you describe.  The former usually blame the latter's problems on prep, but I've read many posts where people describe how they went through all the correct prep steps and still had problems.  So, I know I'm taking a chance here. 

That said I did prep the heck out of my engine (I lost count of how many times I pressure washed the cases)... paint stripper, home grade soda blaster (but under powered), aircraft stripper, and went through a bunch of scotch pads, hit the corners and hard to reach areas with small rotary metal brush bits, sprayed the jugs and head with brake cleaner, and wiped all the parts down with lacquer thinner before painting.

The only part I wasn't able to get as clean as I wanted were the jugs.  I just couldn't get a good mechanical abrasive all the way in between the fins.  I did the best I could, but I suspect this will be the one weak spot of my paint job.

I'll try to remember to report back in a year on how well it's held up.

[AbbyRider]

Do you use a regular house oven or do you have one for parts specifically?

I have a separate oven in our basement, as we used to have a suite down there. I just open the back door to let it vent.

[AbbyRider]

In my experience, I've found that oven curing the paint at a fairly high temp is important for the durability around areas that do not get as hot when the engine is running. In particular, the underside around the oil pan and the whole back side is susceptible to chipping when the enamel hasn't had a chance to harden. I've tried the sun, and I've tried a small infrared heater, but nothing has worked as well (long-term) as the good 'ol kitchen oven.

[SONIC]

I have done duplicolor engine enamel
It sucked, even after baking it chipped and was not gas resistant. The first carb leak you have say goodbye to your pretty paint.
I have done POR 15 engine paint and it seemed better for a while, but i left the petcock on and came out to a ruined engine paint job.
I am using Eastwood 2 part urethane currently, and it seems to hold up well. I painted a cup and then put gas in it and a week didn't hurt the paint.

Even then though, for the cases I went powder this time around. And after many gas leaks it still looks as good as when it came out of the oven.
I wont do it any other way.

[jonboycox]

Kickstart.... If the success or the momentum of your build is on the line, use paint for sure. I complain about the paint on my 400 but I still love the bike to no end, no one else seems to notice but me. I have seen tons of build threads on this site and others done by some kick ass bike builders and they paint engines for sure. I am sure you engine will look great, you will just need to respect the fact that it is a rattle can job and try to take care of it. I have the luxury of working closely with a powdercoater on income related projects, so he does my bike stuff for a cut rate.... if I had to pay full price, I would be back to the rattle can too!