Why is it that you can not use spray can primer on your car panels and than paint. I was told that the spray can primer will mess up the outcome of your paint?
Professional painters would probably have good reasons why you should not do it, but I have done it a couple of tmes with no ill effects. You need to sand the primer prior to applying the topcoat though.
Most spray can primers are not epoxy type, which over time will breath moisture. I would not use it on body panels, maybe small bolt on parts.
It's going to depend on the primer. If the primer is compatible with the paint then it will work. Many paint jobs have been done with spray can primer. On the other hand, profesional grade products are better than amature grade ones. Profesional grade products are not typically found in spray cans.
The're mostly garbage. A few quality uncatalyzed products are available, such as self etch, and UV cured materials. These are sold at automotive paint supply stores and are expensive. The crap you get at Home Depot is just that...CRAP Now you going to get many replies telling you how great this stuff works. I guess some people have very low standards. If your car or truck isn't worth decent materials, then take it to Macco, and motor on..............Someday it will be worth enough for someone with some pride to strip off the crap do it right.
I guess it depends on the type and brand,,I always buy a 6 pack of the etching primer spray cans on hand,,basically the same thing in the gallon can. HRP
This is what I was lead to believe. There are high end primers available in cans from the auto paint shops and they are compatable with quality paints, but they "breathe" and are not sealers. So I am guessing that they are for primer touch up, over a primer/sealer. True?
The resin types in spray cans are the least quality you can get for the most part. I have used them successfully and unsuccessfully, sometimes on the same car. Don't even think about comparing any of the spray cans to any 2 component epoxy or urethane quality resins. The issue is this. You are taking a quality surface (hopefully), applying your choice of primer and then your choice of topcoat. If you have a good surface and a good topcoat, the ONLY thing holding them together is the integrity of the primer. In real simple terms, it is sort of like applying masking tape or custom striping to a dirty car. It might stick for awhile... If you are doing a super cheapo paint job then it doesn't really matter that much (We used spray can primer on a $500 paint job on my son's daily.) But if you are going to the effort of doing even a decent quality paint job, it is just not worth the hassle. Also, if you decide to do a better paint job later down the road, you will be stripping EVERYTHING off to start over with a good surface. All good things cost... sooner or later.
I tried to paint some electric guitar bodies in the 80's with martin senor laquer paints(spray bomb) and seemed like the never got as hard as quality body shop laquers. Always left a mark after setting on the guitar stand too long. Its hard to believe that the spray bombs are an equal to professional shop use paints. My body shop here had a epoxy primer, in a can, and the activator pin was on the bottom. You pressed this pin in, and it released the hardner already in the can. Once activated, you had a limited shelf life. THey had HUGE amounts of trouble with them, and quite selling them. If you were build a home, would you pour concrete footings/foundation, or stack rock with mud/clay for mortor? Get the foundation good, and build from there.
Ive used "sandable" spray bomb primer on a bunch of small projects: minibikes , overcoated with laquer based and alkyd enamel, and a truck topper, overcoated with acrylic urethane with absolutely no problems at all.
I don't know if your issue is with spray cans or primer...but...if you really want to use spray cans, your local auto paint store will put any primer you desire in a spray can. Anything you can get mixed in a quart or a gallon, they can put into aerosols. You're going to pay more than K-Mart for it, but then you get what you want. I wouldn't put krylon all over a bare metal body then expect a great paint job. But for doing small patches it's fine. On the other hand, to be fair, I've custom painted motorcycles with rattle cans including primer and have gotten mega bucks for the job. But then, I do good work too. I've always thought that you can solicit advice all day long but until you actually do it, you wont learn anything about it. So, bottom line is, go for it and get some valuable learning experience. Worse case scenario is you will have to strip it and do it again.
Good information here. Also be aware that a "coat" of primer from a rattle can is about 10% as much paint as a coat from an automotive gun, couple that with the fact that unless you're dealing with an epoxy primer or some other 2K stuff that is designed to be non porous, the base metal is not very well protected from moisture at all. Another big disadvantage to any 1k rattle can product and some 2K stuff to some degree is the fact that the solvent to solids ratio is lousy. It takes a lot of thinner to get that paint out of that small hole at low pressure. Consequently, if you don't let that stuff dry for days before you top coat it, it's still gassing off and shrinking and that's going to telegraph through to your top coats. So, in a nutshell, if you use the stuff, put plenty on, let it dry for days longer than you think it needs to and dry block it no matter what's going over it because those little spray can tips are crap for creating a uniform film thickness unless you're an exceptionally good gun handler and keep the surface dry, that means no moisture and low humidity conditions or you will be well on your way paint problems before the job is even finished.
In the case of the outstanding quality and popular PPG DP series epoxy primer; the older stuff protected parts from moisture very well. When it was revised/"improved" a number of years ago to make it more environmentally friendly it lost quite a bit of its moisture resistance. The solvents used in spray can paint are super volatile. When paint is drained from a spray can(not the safest thing to do) it actually boils until some of the solvents evaporate! Although that aids spraying and helps avoid runs, it's another reason why spray can paint cannot be applied well to large surfaces.
1GREAT40, Has the right answer,spray can primer is usually applied too thin. It may look alright but ,way to thin to properly sand. It's also hard to apply to large surfaces evenly. I have used it on a lot of small stuff with great outcomes many times by letting the primer to dry well then top coating with a good non primer top coat. .....................Jack
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