What is best temp/time for cooking spray bomb?
 

I have just completed fabricating my 3" compressor feed pipe for the K27 (I dunno, when I look at it I do see beauty, but not so much because it has such a nice finish to it). It has a coat of gray primer with a gloss black top coat over it, but this time I want to go a step beyond where I have ever treaded before, regarding the use of canned spray paint. Purely in the interest of durability and chip/scratch resistance, I plan on baking it (in a toaster-oven). It will be baked for a minimum of 1 hour at 200 degrees (it is not hi-temp paint). But I am considering as much as 2 hours at 250 degrees. Any opinions on whether or not the paint could handle that without getting burnt? It's the real cheap (WM) stuff. I have, and could have used, better stuff, but I want to see how well this stuff will hold up if a baking process is added to it.

Doubt it will hold well at all, maybe you should have used a good heat resistant paint like VHT. Even though it is the feed pipe, that whole turbo still gets pretty darn hot, and it will most likely cook the paint off.

I could always throw a coat of some high-durability epoxy paint that I have on to it, but what I am really looking for are comments on the merits or possible drawbacks of baking your regular, run-of-the-mill paint. It isn't a high heat application or anything, where it is being used.

I do hope you're not going to use that oven for foodstuffs thereafter!

when we bake finishes on cars and such its not for durability its for production ! paint go throw 3 phases to cure . 1st its flash then dry then cure . a hardener or catalyst will give a finish durability . a none hi temp finish needs to bake at 160 to 180 degrees for 30 minutes . a none hardened finish gets softer as its baked and will stay soft untill it cools back down to its ambient temperature .

It's done, and it appears to have worked! If the paint gets tacky when heated up, you know that it's going to be harder than it was before, when it cools back down, as it will have released more of it's VOC's.

Of course my preferred method would be to use a hardening agent, rather than baking it, but I have not yet found a way to mix the hardner with the paint, when it comes in pre-pressurized cans. But, I do have an idea that maybe someone could commercialize on: Invent a hardening agent that comes in a pressurized can that is sprayed on over the paint, after the actual painting is completed.

you can junk the spray can paints and just use mixed colors from the auto body paint stores ( jobbers ) you then can get your self a preval spray set up for about 15 dollars . at that point you can mix paints and add in hardeners and spray your colors . check out prevaispraygun.com . you can wash out the cup and reuse them over and over . thay spray like a spray can or maybe just a little better ?

I do agree that spray bomb is absolutely no match, compared to hardened auto body pant. I have a quart of PPG Delstar DAR acrylic enamel (+ hardener & thinner) that I use for touch up purposes on my 951. And I use a gravity-feed gun to apply it. I do need to paint an entire fender soon though. But the can of hardener needs to be kept in the freezer with propane displacing the air (oxygen) inside of the can, so it keeps well after being previously opened.

The paint itself, which contains a mix of 8 different things for stone gray metallic, cost me $110. It contains: DMR490 (straight black), DMR436 (medium aluminum), DMR414 (blue), DMR451 (deep red), DMR476 (red), DMR499 (clear), DXR495 (catalyst), and DXR80. You also need to mix in 2 other things - DTR602 (thinner) and JH002 (hardener) - before you can shoot it. I can't afford to waste paint like that on things other than the body itself.

I AM curious as to what a "preval" spray setup is though. 15 bucks seems pretty reasonable.

one of the guys in my shop ordered one from our jobber about a year ago and i was what the hell is this . i tryed it and like it ! the thing works great for little parts and spotting in real small things . they spray better than a spray can and has more uses because you can use coatings that work better with a catalyst . an other plus is you can buy just the cans of propellant or extra jars .

Is there any advantage to that system, over using a small spray gun with compressed air as the propellant?

just quick and ez ! the guys in the body shop can just do real small spots there selfs so they don't have to send it over to the paint shop for them to do . for the home user . because most home users shut off there air compressors when there not being used . they would not have to drag out all there things ( hose , guns ) to spray just a little spot or part and then wate for the air to come up to pressure . then clean up . with the preval you can just mix up what you need and spray it . if its not a catalyst product you can leave it in the jar . then there is the cost . if you want a spray can they cost about 25 dollars to have a color put in a spray can for you . and you only get abour 3 oz of color . were you can get your self a pint of color for the same 25 dollars and just use the preval .so your getting a hell of alot more sprayable color per dollar .

I probably differ from your typical homeowner, in that I have 200psi (before regulation) available 24/7. The only time I throw the knife switch for the compressor into the off position, is if the property will be uninhabited for 2 or more days. But then I also throw the switch for the water heater and pump.

Couldn't you just use your $25 pint of "prevel" paint in a regular air powered spray gun? It's just hard for me to justify spending even more money, when I have already invested in a small gravity-fed gun for small jobs. One thing I can't argue about though, with reference to air-powered spraying, is that cleanup always sucks.

I have also entertained the thought of taking your 99 cent can of WM paint, bleeding off all of the propellent, opening the can and mixing in some "japan dry" or other cheap paint hardener, before dumping it into the spray gun.

the preval does not take the place of a tuch up gun ! it takes the place of a spray can ! in the case of my shop the body guys just find it real ez to use the preval because its more like a spray can . they put a little E-primer in them and over the course of the day its there when they need it . if you have a tuch up gun then use it ! because at that point there is no need to have to have spray cans made up ! again the preval takes the place of a spray can ! my point is people spend money puting coatings in spray cans when its less than half the cost to get a preval and a pint of paint .

I understand. I guess MY point is that it is the very high price of the automotive paint itself which I am trying to avoid, for small parts/jobs that don't require the kind of extreme durability that auto body paint has.

ok ! MOST spray can paints are enamel based products . because of this places that make up spray cans don't have to add a hardener to it because enamel based products will in time cure by them selfs . the down side to this is that with out a hardener in a enamel finish . the finish is not as durable as it would be with a hardener or cayalyst . there are 3 main types of enamels used ( there are other tipes too ) but for the most part only 3 widely used and they would be alkyd enamel , acrylic enamel and urethane enamel . most spray can paints are the lower grade alkyd enamels the reason for this is its has a faster dry time . i may have stated before that paints go throu 3 phases to cure . 1st is flash 2nd is dry 3rd is cure . with out a hardener enamel finishes all take about the same time to get to cure thats 3 to 7 days . you can tell when a finish is cured by taking your finger nail and pushing into the finish when it does not leave a mark from doing so then the finish is cured . now by adding a hardener to paints you are bonding the polymer links together in doing so giving the finish a much greater durability to the finish . i hope your still with me ??? ok now by using a tipe of a spray system that you can add in a catalyst or hardener to you are dubbeling the the life of the finish . that would be UV , wear , solvents , chipping and so on . you can't add a hardener to paints that are already in a spray can . and that is were the preval comes into play if you don't have a tuchup gun to use . also an other plus to the preval is for the guy that has the same paint that his car was refinished in and say has a door handle or other little part he wants to paint and does not have a compressure and gun to do it with . he or she can in most cases use a spray can tipe paint but now it comes down to the cost again . for 15 dollars they can get a preval and do it there selfs . they can just mix up a little primer ,sealer, color and clear and spray the things them selfs .

But even if using hardened paint (or not), adding that additional 4th stage of baking, following the curing, drying, and flashing stages, will get you a harder and more durable finsih, no matter what type of enamel you are spraying, right?

that is wrong !as i stated before baking only is for [roduction reasons ! it only takes it to the dry stage faster . it has nothing to do with bonding the links making for a more durable finish . think of it this way the catalyst (hardener ) bonds the links . with out the hardener you still have what is called a reversible product . that meens that if you take a rag soaked with thinner or other solvent it will resoften the coating reversing it back to a liquid state .

So you are saying that with chemically hardened paint or not, after a week or so, the durability of the same paint will be the same, and baking will make NO difference?

Now I'm curious about the non-autobody paints which many hardware stores are equipped to mix up for you in quart or gallon batches. IIRC, it is still WAY cheaper than auto paint.

Are they any better than spray can paint?

Can they be successfully used with hardening agents?

I once painted a (pretty ratty) plow truck that I sold, a fair number of years ago, using that sort of paint. It did NOT come with it's own special hardening agent to mix with it, so I used 2X the suggested amount of the generic "japan dry" hardening agent, that I bought from the same store. It ended up with a lot of orange peel on the surface. But it wasn't exactly a high-dollar vehicle (not really worth the cost of using auto body paint), so the buyer didn't really care. I would be curious to know what the truck looks like now.