baking to cure paint

[Boedie]

Hi painters out there, can anyone give me an idea of temps and time to bake a liquid paint job to speed up cure time? And is it effective? Thanks for all input.

[velocolour]

It depends what paint you're using and how quickly you are trying to cure it.
Heat definitely helps.
I've always used mid to low temp. paints and was taught to crank up the heat.
After some investigation once I went off on my own I found out over baking at too high a temperature can make the paint more brittle.
I currently give at least a half hour to flash before adding heat. If it is too hot to touch than it is too hot for the paint.
For most paint jobs once they are done I put them in my warming box with quite low heat on and off for a couple of days.
To speed up a clear coat for sanding the next morning I will put it in over night still at a fairly low temp and then let it sit at room temp for at least an hour before working on it.
If work has to be done sooner than that a bit of kicker in the colour or clear means it can be sanded or masked the same day.
Most paints will have info on the can for curing and heating times at specific temperatures. You can also call your supplier or the manufacturer if you you want more specific details.
noah

[Boedie]

Thanks Noah. The guy painting for me doesn't bake, so I was thinking I could make an oven to help speed up cure times in order to ship it out quicker. After all, it's getting pretty hot around these parts lately.

[Rody]

Boedie,

If your painter has not worked with a hot box before, your finished products are not the medium to learn on. Flash curing has a whole realm of potential pitfalls, from crazing to brittleness.

Although I do use a hot box, I have over 15 years experience dialing it in for differing types of pigments and clears with LOTS of mistakes learned along the way. That said, if given the time, allowing the paint to cure at room temp will almost always give better flow out, durability, and clearity.

You've taken great care in crafting your frame...the customer can wait an extra day or two to receive the culmination of your best efforts.

cheers,

rody

[Dave Anderson]

Boedie,

I am not sure how you plan to make this work....are you planning on building a box and giving it to your painter so he has it in his shop? or are you planning on transporting an uncured frame to your shop? I assume the former. The latter would be a no go from my perspective.

I have an oven and force dry various paint products all of the time. It certainly makes me more efficient, but you know, everyone is different. Most of the products out there that can be force dried include related specs on their Tech Sheets. For example, the clear that I use calls for 15 minutes of flash, followed by 20 min at 140 deg F. I generally let it go 45 min to an hour, and then can do whatever I want with it...tape, sand, buff, put it into service whatever. I have not noticed any affect on durability. Every product is different, though, and so you should check with your paint rep. As with nearly all paint products, though, it does still take several days for the paint to fully cure for maximum durability, even when force dried, and so I always tell my customer not to clamp it in a repair stand or a car rack or whatever for a couple of weeks, etc.

Dave

[Dave Anderson]

......

[dbohemian]

Everybody here is right on so far. Increasing the temperature speeds the rate of reaction just as it does for most other chemical processes. Too much heat can cause paint to cross link too fast, shrinking and causing problems as has been mentioned before.

My problem? It's fargin hot as hell here right now (Tucson AZ). Forced curing is happening all the time, what I am trying to do is slow things down.. :)

[Scheisserad61]

Many years ago I worked for a guy who used to put the uncured frames inside his car for a few hours on a sunny day. Until he built his own hot box it was his low-budget version of baked Imron.

I seem to recall that he jokingly claimed that the Isocyanates helped prolong that nice "new-car smell".

[Boedie]

Hey thanks for the replies. It sounds like I am better to let the paint cure on its own. I usually pick up the frame a few days after it is painted and hang it in my shop by the head tube to not damage the paint. I have had plenty of experience dealing with uncured paint...like the first frame I ever made. So I'll be patient. Good things come to those who wait- or so I'm told. Hope everyone is having a great summer!
Boedie

[Tom Kellogg]

I can only speak from the perspective of Imron BC/BS. Standard "old" Imron, once it is flashed off for maybe 15 minutes can be cooked at up to about 190. If you do that, it is 98% cured in about an hour. Low VOC clear Imron 6000 (what we use) MUST be cooked. After a 20 min. flash, you can take it right up to 190. An hour is good enough for sanding and three hours is a 99% cure. If you don't cook Imron 6000, it takes well over a week for a decent cure.