Originally Posted by MARTINSR
Feeling it STILL is number one to make something straight, the guide coat is, well......a "guide". It is without a doubt the king for finding pin holes and scratches.
absolutely. We have a Trans Am at the shop and it's white and it's full of small dings. They are so small that I use an old production method in which I determine if it's original paint, and it is, then I use my da to feather ding areas out and like a block it tells you where the lows are at. So I'm doing these dings and since you're knocking a lot out during one filler application you're not gonna re-remind yourself with a quick hand feel before you apply filler to know how thick you need to spread the filler. Hand feel is crucial in those situations cause your filler won't cover all the dings even though guide coat didn't detect it. You have to find them by hand feel.
On compound curves it's more important than a guide coat if you ask me. A perfect example is a 55 chevy fender in the front where it rolls to the top from the outside. I have on multiple occasions and from different techs dealt with areas where I felt someone dug into that area and you'll have flat spots. Guide coat won't tell you a thing about it. Our guru is the raddest but he uses one 11" durablock for literally everything. The last thing he dug into was that area I mentioned and the compound curve on the roof near the sail panel. Guide coat didn't tell me nothing about that either. In a nutshell, hand feeling something is most important for compound curves, hoods, and decklids. The thing that sucks about compound curves is that if you do a good job blocking it out and it gets passed onto someone else you kind of have to be concerned on whether or not they know how to deal with compound curves, cause most guys suck at them, but good thing is compound curves hide a lot. Every time a car with compound curves gets passed to someone else and I know I did a good job on it I'm concerned. It's like that feeling you get when you take a stretch out of the roof but it's still loose cause you'd rather live with it a tad loose than to keep on it and open up a can of worms. So you're just hoping the next guy doesn't block on it too hard. The last car we did I handed them a show winner and the painter sanded the clear and re-cleared but put a burthole on each quarter chasing nibs. I was pretty pissed to see that after all that work and to know it went next door to the head honcho like that. My point is, if you're a painter learn bodywork and that won't be an issue. If you're a body man learn paint and your prep will get better. So that leads me to say from experience that if you give a painter/painter's helper that doesn't do bodywork a car to block he won't use his hand much, and if you allow a body man that doesn't paint to prep you better hope it's not silver.
As far as guide coat goes, get the cheapest flat black enamel can you can get. The only drawback is that it's a tad more tacky than a can of SEM and the can won't last very long but it's worth it. Another method is to get a black primer and thin it/reduce it down and dust some on after you prime. It works REALLY well and doesn't clog and gives you lots of droplets to use. I like the powder for troubled areas where I just guide coated and sanded adjacent panels and don't want spray on it, or trouble areas in general. If you have a quarter wheel crown that's giving you trouble you can keep applying over and over with ease. love that about the powder. Other than that, I love the spray and it's a lot cheaper. If you're doing one car you can get the powder and be left with too much in the end to justify the cost of purchase.