[4]

Baked on Enamal Spray Paint

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

RandyM

H-M Supporter - Gold Member
Staff member
H-M Supporter - Gold Member ($25)
Joined
Apr 12, 2011
Messages
2,358
I just had an interesting experiment on a bracket I was making. Last weekend I painted it and left it to dry all week. Well, I went to mounting it and found that it was still very soft and sticky. The paint was enamal from a spray can (fresh can). After not wanting to wait any longer on "if" it would dry, I fired up the powder coating oven and baked it. Not ever trying this before I was unsure as to my results. I mean what temp and time do I use? I figured it didn't really matter as I was probably going to have to re-coat it anyway. So, after slowly turning the heat up to 200 degrees and baking it for about 3 hours I let it cool and removed it from the oven. The reason I baked it so long is that the paint stayed soft as long as it was hot, which I was not expecting. I then figured that it might harden up once it cooled down. Yup, that is exactly what happened. So, long story short, everything turned out perfectly and I was able to finish the project. Has anyone else experimented with baking paint? Please let me know how it turned out for you. I may do more of this in the future just to speed things up.
 

astjp2

Active User
Registered
Joined
Aug 23, 2013
Messages
949
I just had an interesting experiment on a bracket I was making. Last weekend I painted it and left it to dry all week. Well, I went to mounting it and found that it was still very soft and sticky. The paint was enamal from a spray can (fresh can). After not wanting to wait any longer on "if" it would dry, I fired up the powder coating oven and baked it. Not ever trying this before I was unsure as to my results. I mean what temp and time do I use? I figured it didn't really matter as I was probably going to have to re-coat it anyway. So, after slowly turning the heat up to 200 degrees and baking it for about 3 hours I let it cool and removed it from the oven. The reason I baked it so long is that the paint stayed soft as long as it was hot, which I was not expecting. I then figured that it might harden up once it cooled down. Yup, that is exactly what happened. So, long story short, everything turned out perfectly and I was able to finish the project. Has anyone else experimented with baking paint? Please let me know how it turned out for you. I may do more of this in the future just to speed things up.
My work bakes all of their painted parts at 140* for an hour or two depending on what the part is. We use epoxy, eurothane and water based paints. Tim
 

pjf134

Active User
Registered
Joined
Jan 26, 2011
Messages
617
Some body shops use curing heat lamps after a paint job and has been done for years. A old auto paint guy told me a long time ago to use cold water on a Enamal job after a day or two to harden the paint, but no hard stream or rough wiping. A uncle of mine back in the 60's worked as a painter in a shop that painted metal office stuff and baked it afterwards. I wonder if this would work on rustolium oil base paint? I will have to try this, thanks for reminding me of this.
Paul
 

RandyM

H-M Supporter - Gold Member
Staff member
H-M Supporter - Gold Member ($25)
Joined
Apr 12, 2011
Messages
2,358
Some body shops use curing heat lamps after a paint job and has been done for years. A old auto paint guy told me a long time ago to use cold water on a Enamal job after a day or two to harden the paint, but no hard stream or rough wiping. A uncle of mine back in the 60's worked as a painter in a shop that painted metal office stuff and baked it afterwards. I wonder if this would work on rustolium oil base paint? I will have to try this, thanks for reminding me of this.
Paul
So Paul, did you try the cold water trick? I am having a hard time understanding how it would actually work. Yeah, try it on Rust-Oleum and report back. My guess is, it will work pretty well. I had a hard time finding anything technical on the web. Looks like a lot of experimenters on other forums, but nothing from any of the manufactures on baking.
 

Ed T

Active User
Registered
Joined
Dec 10, 2012
Messages
85
I have had very good luck baking solvent based paint especially enamels which can take a long time to harden up. It is particularly useful on wrinkle enamel which, once you figure out how to make it wrinkle, still takes forever to get hard enough to handle. Enamels "dry" in two stages, the first is the evaporation of the solvents and the second is the polymerization of the oils in the paint. Generally, the solvent evaporation does not take too long depending on how much paint was applied, but the polymerization can take weeks or longer to complete. I remember reading that old auto enamels could take months before they were hard enough to wet sand or polish. Anyhow, baking accelerates the polymerization process and really helps to make the finish harder sooner. If the paint is applied too heavily and there are solvents trapped in the paint film, you do run the risk of boiling the solvent embedded in the paint which produces a mess. I generally let the parts get dry to the touch and then put them in a cold oven and turn it on. It's a lab oven with a convection fan and heats pretty slowly and there are not any exposed heating elements, so there is no radiant heating like you might get in an ordinary kitchen oven. Radiant heating is a potential problem since the part can get way hotter from the radiant heat than from the air temperature in the oven. I generally run the oven a 200-250F. I set the timer for 3-4 hours and just let it heat up and cool down on its own. I have also found that getting the paint harder helps a lot with the removal of masking. If the paint is not hard, it tends to come off with the masking tape which is really annoying.
You don't have to have an oven to bake the paint. I've used a cardboard box and an old, low wattage hair dryer on many occasions. You can also heat the parts other ways. I recently rebuilt an old lathe and some of the parts are just too big for my oven so, for example, I heated the pedestal base by arranging a heat gun to blow into it hich warmed the whole thing nicely and the paint was hard enough to proceed with the reassembly in less than a day. Needless to say, any of these alternatives require careful monitoring while in operation at least until you're sure the whole thing isn't going to catch fire or melt something.
Baking works for me. Your milage may vary
 
F

f350ca

Guest - Please Register!
Guest - Please Register!
I add automotive enamel hardener to any oil based paint such as Tremclad or Rustoleum. Dries in an hour or two and gives a harder and shinier finish.

Greg
 

rdhem2

Active User
Registered
Joined
Sep 11, 2012
Messages
327
Great information. I am about ready to try my first "REAL" paint job. A 1939 International Farmall "H". Never done more then rattle can before as I hate the mess and always get heavy handed because I am impatient with the whole procedure. My painter delivered his gun, said "About time you learn. Good project for it. Good luck", and left. What an attitude!
 

RandyM

H-M Supporter - Gold Member
Staff member
H-M Supporter - Gold Member ($25)
Joined
Apr 12, 2011
Messages
2,358
Now this is great stuff. Thanks guys.
 

astjp2

Active User
Registered
Joined
Aug 23, 2013
Messages
949
Epoxies are normally thermal setting, IE they cure with heat. Heat lamps put off UV, so it can degrade the shine, oven temps need to be warm but not baking hot (140ish) not 250....Tim
 

pjf134

Active User
Registered
Joined
Jan 26, 2011
Messages
617
Randy,
I have tried the cold water trick and it seems to work on some test pieces that I did years ago. I will have to try hardener with Rustolium to see how that does. I do agree with the lower heat for the regular paint and I think that powdercoat takes higher heat because you have to melt the powder to get the finish. I have also cranked up the heat a little to warm the metal a bit before painting and seems to stick better. I do need to paint a steel man door before winter and was thinking what to use that will dry quick so I can put it back on the same day and car paint is a little costly. I did use some paint a long time ago from a hardware store but don't remember the name and it dried real quick because it rained as soon as I was done spraying it and no water marks at all on it and it is still on my neighbors trailer since the mid 70's and still looks good.
Paul
 

frbutts

Active User
Registered
Joined
Dec 29, 2012
Messages
36
For years I have put all my paint projects out in a gentle rain after it is dry enough to not be sticky. It make the paint hard enough to handle after over night.
 

bstarling

Newbie
Registered
Joined
Jul 15, 2013
Messages
7
I used a heat gun on a shotgun barrel that I had painted with BBQ grill paint. It came out harder and tougher than woodpecker lips. Didn't bother to check the temperature of the barrel, but it was plenty warm.

Bill
 

yugami

Active User
Registered
Joined
Jan 11, 2012
Messages
75
How does one do this "cold water trick"? Just a little spray bottle or a a wet rag or what?
 
D

Deleted member 20190

Guest - Please Register!
Guest - Please Register!
Great information. I am about ready to try my first "REAL" paint job. A 1939 International Farmall "H". Never done more then rattle can before as I hate the mess and always get heavy handed because I am impatient with the whole procedure. My painter delivered his gun, said "About time you learn. Good project for it. Good luck", and left. What an attitude!
I don't mean to go off topic here, but do not let yourself be intimidated by your first paint job. My first one turned out just fine, and now I don't buy rattle cans anymore except for really small projects. One thing that I can recommend is to get your red paint from CaseIH and get some hardener too - it is a bit more expensive but you will not be disappointed. Most of the other 'look alike' paints just don't look the same, nor do they hold up as well. My first is shown here:

View attachment 60632

Oh, ignore the date on the photo - I replaced the batteries in the camera and forgot to reset the date on the camera! The tractor was painted in April of 2004 and the photo above was taken in August of that same year after all of the assembly was completed.

As for baking paint, I've been doing it for years. Small parts go in the kitchen oven at low temp for two or three hours, larger items get placed under heat lamps, usually surrounded by cardboard or similar to keep the heat in a bit better. I never tried the hair dryer trick, but don't see why it would not work. None of the parts on the Super C were baked though, I just used enamel hardener in the paint.
 

jgedde

Active User
H-M Supporter - Gold Member ($25)
Joined
Jun 23, 2011
Messages
787
As far as enamel paint and baking, it does make the paint cure faster. However, what you end up with is not baked enamel. The term baked enamel is used when talking about the baked ceramic (or porcelain) finish used on appliances and bathtubs.

As far as the water treatment goes, it does work... Enamel dries by solvent evaporation and cures by oxidation (or cross-linking if a hardener is used). Water speeds oxidation. Just like with iron and rust.

Heating the enamel helps dry the solvents and speeds the reaction time for curing. In some cases, if the humidity was too high when the paint was applied, or if it was applied too thickly, it may be weeks to get full cure. This is because the outer layer of paint is cured, but inside it's sealed off from the air. Solvents can't get out and oxygen can't get in. B

Baking can help with this sometimes by allowing the solvents inside to escape... Why? The vapor pressure of the solvents is increased at high temperatures and the outer layer softens and the solvents can get out.

Baking works well, but don't rush it. Heating the curing paint too soon can cause bubbling (solvent pop), loss of gloss, smoothness issues, etc.

John
 

Uncle Buck

Registered
Registered
Joined
Nov 10, 2011
Messages
0
I generally avoid Rust-o-leum paint except for the hammered finish line because it seems to be the only brand I have had consistent problems with it not drying. I prefer most any other brand due to this problem.
 
D

Deleted member 20190

Guest - Please Register!
Guest - Please Register!
Sorry about that. Some photos disappeared off of a bunch of posts a while back when they had to restore the forum due to the site being hacked. Here is the photo once again:

100_0269.JPG

Thanks for bringing it up!!

100_0269.JPG
 

donthack

Active User
Registered
Joined
Dec 24, 2011
Messages
75
e

Replaced our electric oven with gas, set aside the oven for powder coating in the garage. Before I ran the power line 2 years later a single mom needed is more that me. Do you get by hardening paint in your house oven? Now using gas I don't want to cook paint in case of off gasses.
 
D

Deleted member 20190

Guest - Please Register!
Guest - Please Register!
I don't think one would have to worry too much about gasses from the paint as they would burn off slowly as they are produced. I don't think that the paint could produce enough gas fast enough to reach the LEL of those vapors. Not only that, it wouldn't matter if you used an electric oven or a gas oven, if the temps are high enough to ignite the gasses, it doesn't matter what the heat source is.
 

The Liberal Arts Garage

Active User
H-M Supporter - Gold Member ($25)
Joined
Sep 4, 2013
Messages
494
As far as enamel paint and baking, it does make the paint cure faster. However, what you end up with is not baked enamel. The term baked enamel is used when talking about the baked ceramic (or porcelain) finish used on appliances and bathtubs.

As far as the water treatment goes, it does work... Enamel dries by solvent evaporation and cures by oxidation (or cross-linking if a hardener is used). Water speeds oxidation. Just like with iron and rust.

Heating the enamel helps dry the solvents and speeds the reaction time for curing. In some cases, if the humidity was too high when the paint was applied, or if it was applied too thickly, it may be weeks to get full cure. This is because the outer layer of paint is cured, but inside it's sealed off from the air. Solvents can't get out and oxygen can't get in. B

Baking can help with this sometimes by allowing the solvents inside to escape... Why? The vapor pressure of the solvents is increased at high temperatures and the outer layer softens and the solvents can get out.

Baking works well, but don't rush it. Heating the curing paint too soon can cause bubbling (solvent pop), loss of gloss, smoothness issues, etc.

John
As far as enamel paint and baking, it does make the paint cure faster. However, what you end up with is not baked enamel. The term baked enamel is used when talking about the baked ceramic (or porcelain) finish used on appliances and bathtubs.

As far as the water treatment goes, it does work... Enamel dries by solvent evaporation and cures by oxidation (or cross-linking if a hardener is used). Water speeds oxidation. Just like with iron and rust.

Heating the enamel helps dry the solvents and speeds the reaction time for curing. In some cases, if the humidity was too high when the paint was applied, or if it was applied too thickly, it may be weeks to get full cure. This is because the outer layer of paint is cured, but inside it's sealed off from the air. Solvents can't get out and oxygen can't get in. B

Baking can help with this sometimes by allowing the solvents inside to escape... Why? The vapor pressure of the solvents is increased at high temperatures and the outer layer softens and the solvents can get out.

Baking works well, but don't rush it. Heating the curing paint too soon can cause bubbling (solvent pop), loss of gloss, smoothness issues, etc.

John
 

Billh50

Active User
H-M Supporter - Gold Member ($25)
Joined
Jan 26, 2015
Messages
1,922
The old timers in the body shop when I was a kid used to soak the paint with a gentle flow out of a hose the next day. They would do that for about 15 minutes to 1/2 hr.
 

pontiac428

Mo-Max
H-M Supporter - Gold Member ($25)
Joined
Apr 23, 2018
Messages
620
I've gotten into the habit of curing rattle can paint with a heat gun after it flashes off. Best for enamels. I like engine enamel for durable things in the shop; it becomes a different finish after heat is applied.
 

macardoso

Brass
Registered
Joined
Mar 26, 2018
Messages
555
I have recently paint-n-baked a number of components using rustoleum spray paint. It gets quite hard after a few hours at 200*F max. I am pleased with it. Preheating your parts also helps. I don't think it is power coat or machine paint quality, but that is fine for what I do.
 

KMoffett

Active User
H-M Supporter - Gold Member ($25)
Joined
Jan 18, 2013
Messages
439
I sent a question to Rust-Oleum Product Support several years ago:
Are general spray paints improved in curing time or hardness by baking? I'm not referring to your High Temp consumer spray can paints. If so, what times and temperatures are recommended?

Their response:
Thank you for contacting Rust-Oleum Product Support. We appreciate your interest in Rust-Oleum coatings. For our aerosols, they fully cure in 7 days. "Baking" them high temperatures would not be recommended for paints other than the High Heat. I hope this information is helpful to you and wish you luck on your project.

I still find heat curing ( ~200°F) rattle can painted parts greatly improver the curing time and toughness.


Ken
 

markba633csi

Platinum
Registered
Joined
Apr 30, 2015
Messages
4,180
In good weather when the sun is out I've used RustOleum brush enamel and gotten good results. And it's inexpensive.
Couple hours in the sun and it dries hard. I like their spray primers too. I used to be a Krylon guy but I switched.
Mark
 

Asbestos

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Jan 26, 2019
Messages
15
I'll bet Rustoleum says that because people think baking means the oven in the kitchen at 350 about 15 minute after spraying. I've redone a fair amount of lantern founts and a bake in a large toaster oven under 200 works quite well, especially when the shop is cold. Quite anxious to try the water thing.
 

Belugawhaleman

Swarf
Registered
Joined
Sep 13, 2019
Messages
1
I've had great results with Duplicolor engine enamel. After the paint has dried, I bake in an oven at 250 degrees f. For two hours. The paint cures very hard and glossy.
 

randyjaco

Active User
H-M Supporter - Gold Member ($25)
Joined
Oct 5, 2010
Messages
855
Here in Texas, you just paint something and leave it out in the sun for the rest of the day. The following morning the paint is rock hard. Just don't try to paint something already hot in the sun.
Randy
 
[5] [7]
Top