Thoughts on baking the paint

Frequent question about finishing your stompbox: painting, etching, clearcoating, lettering, etc...

Thoughts on baking the paint

Postby super velcroboy » 22 Jan 2008, 23:34

People bake because they think it causes the paint to become more durable. I have my doubts. It seems to me like baking would only have 2 advantages. One is that only certain paint compounds will become harder with baking. Others don't, and without knowing which would benefit from baking, it's a big question mark. Second, baking cause the paint to dry faster. This is true. However in my experience, whenever i use the oven, i have run into more unpredictable problems like cracking, paint distortion and overflowing toward gravity. This is not even mentioning how smelling things can get and god knows what's that like for my health. It just gets ugly. Maybe it's me. So for me, the painting part has been about patience. I don't bake (outside). I just let it dry and respray for layers.

I'm positive baking helps for certain paint. Question for you is, which one? :?
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Postby MoreCowbell » 23 Jan 2008, 00:18

I agree 100%.

I don't bake, per se...what I do is use a 100watt spot light. It doesn't get hot enough to shrink the paint, but gets hot enough to A) speed the paint drying process, and B) heat the metal significantly, hot enough so that it may help certain paint compounds harden. However...I'm not necessarily sure that "heat" or baking" makes for a "harder finish"...for me, it just makes the finishing process quicker.

With the "heat lamp", I don't have nearly the fume issues, I can use the lamp normally (instead of dedicating a special toaster oven to painting), etc, etc...I see no real downfall to it. My lamp is a heavy duty one with a gooseneck, so it's easy to adjust "height wise", and I tend to keep the bulb 6-8 inches above the pedal I want to dry.
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Postby soulsonic » 23 Jan 2008, 04:54

I use a heat gun. I love it.
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Postby super velcroboy » 23 Jan 2008, 05:21

soulsonic wrote:I use a heat gun. I love it.


do you use it on all paint brands?
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Postby R.G. » 23 Jan 2008, 05:31

There is no substitute for actually knowing the details.
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Postby super velcroboy » 23 Jan 2008, 06:53

R.G. wrote:There is no substitute for actually knowing the details.


you know those paint cans don't come with detail instruction for baking and temperature settings :lol:
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Postby soulsonic » 23 Jan 2008, 07:58

I use Rustoleum "Professional High-Performance Enamel" over a coat of Rustoleum "Clean Metal Primer" which has been sanded. The top coat is Rustoleum "Lacquer Gloss". I wait until the paint has dried enough to carefully pick up, usually 20 minutes to half an hour, then, I just heat it up with a heat gun using a slow side to side motion for a few minutes. I keep it at least 12 inches away and I'm very careful not to let the piece get too hot. One advantage to doing it this way is that there are very few fumes and I can easily watch it to make sure it doesn't start to get ruined. I had used the Rustoleum "Crystal Clear Enamel" before as my top coat, but it doesn't seem to dry as hard as the lacquer.
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Postby R.G. » 23 Jan 2008, 17:38

super velcroboy wrote:
R.G. wrote:There is no substitute for actually knowing the details.


you know those paint cans don't come with detail instruction for baking and temperature settings :lol:

"Knowing" is much more difficult that "reading the can".

There are three major classes of paints; enamels, lacquers, and catalyzed paints, which are really forms of chemically hardening resins.

Enamels benefit most from baking. Mild baking of enamels can give you a clean, self leveling gloss surface that's had the solvents driven off almost entirely so they are as hard as they can get.

Lacquers and shellacs benefit least from baking. They don't depend on temperature for leveling and dry so fast that all baking does is get more of the solvent out faster.

Catalyzed paints benefit little if any from baking. Mild temperature elevation may speed up the hardening reaction.

In all cases, baking too hot in hopes of speeding it up really quickly will cause chemical changes in the paints that are not good, and may cause charring or browning.

EDIT:
By the way, consumer grade paints in spray cans from the home improvement store often contain major amounts of plasticizers that prevent them from ever getting really hard. You want hard paint? Go to the stores that sell auto paints to the auto body repair shops. Or even harder? Go to the shops that sell topside paints to the boat and marine industries.

Interlux "Brightsides" paint is an air-initiated self catalyzed paint that dries to a layer that's hard enough chip, but tough enough that you'll need a metal tool to make it do that. It can be brushed on and it self levels to a high gloss so it looks sprayed. It's only defect is its price: US$32 per quart/liter.
END EDIT

How do I know these things? I make a lot of mistakes. :lol:

In fact, I generally TRY to make mistakes, but I try to make them in a disciplined fashion. Before committing to a paint process, I'll get several blank boxes and abuse them by painting with whatever I'm wanting to use and then using/not using primer on the box, baking one, not baking one, low temps, high temps, etc. Once that messing around is done, I have a variable number of successes and failures in the batch. And I then know what works and what does not, in the conditions in my garage.

There seems to be an idea that one can do some new thing and get it right the first time. WALOHCS. Go ruin a few test pieces. Then you know. There's none of this "but the instructions said to ..."

As I say, education is ALWAYS expensive. Sometimes you pay for education with different things than money: time, test pieces, expendable supplies, etc.
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I highly recommend you read a copy of "The Sensuous Gadgeteer" if you can find one. It presents a really, really good view of how to think about building things of all kinds, including the view that the finished product is just the garbage left over from the work.
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Postby Bside2234 » 24 Jan 2008, 18:17

I use automotive paints (airbrushed on) and I bake them.

A friend of mine works at a auto paint shop and I gave him a whole bunch of cups with lids and he saves some of the leftover paint (only cool colors) for me. I spray them with the clear coat spray paint from the automotive parts store.

Since I switched to this method my pedals haven't really chipped much at all.

I just bake them in my toaster oven on the lowest setting for about 15-20 minutes.

Very smooth, clean results.

Make friends with your local auto paint shop! [smilie=a_goodjobson.gif]
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Postby cpnyc23 » 19 Feb 2008, 15:25

I've been using the heat lamp method and I find it too work well. It isn't intrusive into my life (i.e. stinky) and is pretty fast.

I think that the best possible thing for paint to bond to metal/primer is time. Painting, applying a bit of heat (heat gun, lamp or oven), and then leaving the thing alone for at 72 hours if not 5-7 days gives me the best results.

of course, that kills my sense of immediate gratification.... :wink:
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Re: Thoughts on baking the paint

Postby AlaskaBat » 19 Jan 2012, 16:03

Old topic, but here's some relevant info--enamel paint is what should be baked.
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Re: Thoughts on baking the paint

Postby rsuppa » 17 Aug 2012, 03:44

One thing I have not seen mentioned and works well for me is holding the spray can under the faucet with the water temperature adjusted to 80-85 degrees while gently agitating the can. This seems to make the paint "flow" better after it is sprayed onto the enclosure. The low temperature will not cause the can to rupture in case that worries you. I learned this technique from an article in Fine Scale Modeler magazine. :D
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Re: Thoughts on baking the paint

Postby gmf1313 » 28 Mar 2014, 20:50

I was looking here for some tips, but I guess I will be sharing my info instead. I restore antique fans and telephones. I start out with a regular fan blowing on the part for about a day, then I use and electric heater which blows warm air, which not only heats it but the moving air further helps evaporate the solvent in the mix. Lastly, if the parts or of the right size and shape, I will carefully support them on hooks or wires if they can't be placed on the rack, I will heat an oven to 150º and shut off the heat. Then I put the parts in and leave them for at least a day, turning the heating element on briefly every few hours. Depending on how dry there get during the previous steps I may do this only briefly or skip the step altogether, but I will use it if there are a number of coats. Ideally leaving it out in the sun works great in the summer
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