[unit44justin]

Well since I am definately a beginner (I would like to some day take some kind of auto painting classes) what do you guys mean by letting the paint flash for 20 minutes?

By adding clear coat with in a 24 hour period allow the end result to shine better than if you waited longer? Maybe thats where I went wrong with my tail.

[steves]

If you wait too long to clear, the base paint starts to cure, and the clear won't adhear properly.

"Flash" is the time it takes the paint to go from wet, to not wet. Usually about 20-40 minutes depending on the paint and mix.

[1990gsx 600]

so if the flash is twenty minutes than you clear it at 10? i was always told to sand the base too but that wasnt on this forum it was by my grnad dad maybe a i misunderstood him.

[Mojoe]

If you wait too long to clear, the base paint starts to cure, and the clear won't adhear properly.

"Flash" is the time it takes the paint to go from wet, to not wet. Usually about 20-40 minutes depending on the paint and mix.

well actually, I have sprayed the base on bike parts over a period of time, and have on more than one occasion applied the clear weeks after the fact....sometimes even months, and never had an issue.

Flash is when the chemicals like reducer have all evaporated out of the base coat. essentially, it means when it is dry.

[tmk7c9]

so if the flash is twenty minutes than you clear it at 10? i was always told to sand the base too but that wasnt on this forum it was by my grnad dad maybe a i misunderstood him.

First off, you should follow whatever directions are on the paint that you buy, not some forum advice. There are lots of knowledgable people here, but every type/brand of paint is different, and needs to be applied differently. Do whatever the directions tell you to do. Paint manufactuers deal with paint for a living (duh) and noone knows how to apply their product better than they do.

However, if the flash time is 20 minutes, you would typically want to spray clear after that. Ex, flash time is 20 minutes, wait 40, and then clear. Note that these times may be different depending on how thick of a coat you put on.

Your granddad may have been right, and he may have made some great paint jobs by sanding the base coat. However, he also may have experimented a great deal to get it right, he might have just gotten lucky, and it most definately was a different type of paint than what we're using now (paint has changed a lot because of environmental concerns). For you to do it would definately be a taking a chance, and I doubt it would come out as well as if you had just followed the directions on the can.

[teddy]

meh, took me too long...everyone else covered it...

[steves]

well actually, I have sprayed the base on bike parts over a period of time, and have on more than one occasion applied the clear weeks after the fact....sometimes even months, and never had an issue.

Flash is when the chemicals like reducer have all evaporated out of the base coat. essentially, it means when it is dry.

I don't doubt that for a second. But I would stress people just follow the directions that came with the paint system

[sonosam]

I have never done a base coat - clear coat paint job.

Now with that disclaimer out of the way, I will take the advice in this thread for when I do end up painting the bike as well as the advice of the people in the store that sells the paint and the directions on the paint itself.

To Mojoe about the rough surface promoting a bonding reaction, you are correct. It is basic chemistry. More surface area = quicker/better reaction.

Other than that I have nothing useful to add to this thread. Sorry.

Marc

[Mojoe]

I don't doubt that for a second. But I would stress people just follow the directions that came with the paint system

well steve, the thing is that when the paint manufacturer (on rattle cans) say to clear within 24 hours...well I truly believe that much of that is more of a suggestion than anything, for the simple fact that leaving it too long creates the risk of damaging or contaminating the base coat.

base coat is basically like primer, in the way it cures. it dries very fast. and if you let it set say 20 hours....well, in 40 hours there is absolutely no difference. it has cure the moment the last of the reducer has evaporated out of it.

take the custom painters for example.....the ones who do striping, airbrushing and other fancy stuff. just as often it is all done over the base coat. this is done for a reason...such as if you screw it up, all you have to do is shoot another coat of base over it and start over, as opposed to sanding it all off the clear coat. It just makes a niccer job when it is all under the clear. and these guys don't get all that extensive work done in 40 minutes....and often not in 24 hours.

in a nutshell, there really is no problem waiting weeks even to clear base coat, providing you stick your parts in a plastic bag, or make sure nothing gets on it.

[Astro4x4]

We used the term colour sanding back in the 80's but where shooting single stage paints so you were sanding the colour when you cut and polished.

[Mojoe]

We used the term colour sanding back in the 80's but where shooting single stage paints so you were sanding the colour when you cut and polished.

well we used to sand single stage paint back then as well. metal flake was the fad for a while, and the only way to apply metal flake was to mix it with clear and shoot over regular enamel. we just called it sanding, though...and not color sanding. those jobs never looked all that great seeing as the clear back then was very prone to yellowing.

[bob393]

OK....I am going to say this one last time. YOU DO NOT WET SAND YOUR BASE COAT BEFORE APPLYING THE CLEAR!!! http://www.easypaintyourcar.com/CarP...tcarpaint.html

I believe you

[aegis]

Good advice mojoe, i ruined what was a great paint job with lots of depth by following the advice of a friend that said you were supposed to wet sand before putting on the clear, went from a three dimensional wonder to a mushy looking blehhhh by the time the clear was done. NEVER AGAIN sand basecoat!!!!!

[Krusher]

I painted my son's first pocket bikw and when I sprayed the clear on it in a few places the paint wrinkled a little. May have been a difference in the paint and clear I used (not the same brand) but after it had dried and cured for quite some time I wet sanded then buffed it out and it smoothed right up and shined like new. It even looked deeper than before I done it. I've never sanded before clearing. You can make even cheap rattle can paint look good with proper prepping and care.

[slowgsxf600]

It depends on WHERE you paint it. If I am in a clean booth I shouldn't have to sand anything. But if I'm in a barn, most likely I'll have to sand some bigger dirt chunks/hair/bugs out and dust back over it. 800 to 1000 grit should be fine for this unless you are using waterbourne paint. Adhesion shouldn't be a problem if flash times are correct per paint manufacter. After everythings cured just sand the nibs out out of the clear if you want to keep the peel, or sand everything for a smooth finish.