Topic: What paint for sanding lowspots?

[rhinoracer]

It's getting harder and harder to find lowspots in my gas tank by feeling with my fingers. Block sanding isn't helping much either, so I want to spray a coat of some glossy paint to find any low spots left to fill out.

What color, what type, any extra tips?

[Sam Green Racing]

Black, I'm just in the process of doing mine.

Sam.

[rhinoracer]

Why didn't I think of that! I never liked black paint 'cause it shows all of the flaws, which makes it perfect for the job.

Thanks Sam.

[Sam Green Racing]

That's it, I've just put 6 coats of black on my RS tank and flatted back after each 2 coats.
I noticed how many low spots there were on the tank as it was easy to see being black.
I don't think it was any different when it left the Honda factory, after all it's a race bike not a roadster or show bike.

Sam.

[jay72chevy1]

yeah a simple cheap lacquer black spray paint will do. When you spray your tank tho spot it up like a cow. Then go ahead and sand. Where it sand off is good or the high spots. Where the paint stays is the low spots. Another good thing to do is check for the sand scratching lines where yo see the lines  its good or a high spot where yo dont see sand scratch lines are your low spots. If you have any more questions i am happy to help. I am ASE certified in auto body work. GL

[rhinoracer]

Thanks GL, I do have some doubts about paint types compatibility.

Can I use any type of primer under the paint? The paint I have uses some type of catalyst and thins with a reducer, not thinner.

When you say black lacquer, do you mean real lacquer? Is it compatible with my paint or do I have to sand it off completely before painting?

[jay72chevy1]

yeah lacquer you can top coat over lacquer. Here is a good reminder about lacquer and enamels. Here it goes you can top coat lacquer with enamel, but yo cannot top coat over enamel with lacquer. Why? Because Lacquer solvents in the paint itself will disolve enamel reducer. So in other words what you thin out enamel is weaker than what you thin out lacquer with. Here is is some nomenclature - Usually thinning out enamel they call that reducer or basemaker if your using base coat clear coat, thinning out lacquer they call that thinner. Now Reducers come in 3 different drying speeds. 1) fast 2) medium 3) slow. Easy to remember on how to use them. You use the fast reducer for the coldest days and yo use the medium reducer for the perfect condition days and lastly you use the slow reducer for the hot days. I can tell you why if you care to.  I wanna try to make this short.   Did you strip off all paint to bare metal? The catylist paint is excellent primer. I would use an epoxy primer. kepp coming with your questions

[Sam Green Racing]

Jay, his tank is glass.

Sam.

[jay72chevy1]

ok that clears that up.  Epoxy primer mix ratio is usually  1:1. It takes a day to dry but unbeatable. Can wet sand or dry sand it. Better to wet sand.  400 p black sand paper. What is the primer name you have?

[rhinoracer]

Short answers are fine for my IQ. No I didn't strip it bare, just beadblasted about two coats of paint and primer and what I think was the original gold candy paint and stopped at the base primer coat.

Sam, how about some pics of your racer's tank? Is it done yet?

[rhinoracer]

I don't have the name of the primer, it's not automotive or commercial primer, it's very thick and needs a lot of thinning to apply with a paint gun. One of the base components is piroxiline or something like that.

Sam, I don't know what you mean by glass.

[jay72chevy1]

ok . Now something for me to work with here.  If you have scratches feather edge them out using 80 grit paper and then 180 grit, so it looks like a circle all around where the existing scratch used to be. Then use 180 grit  for over all the primer and then quick with 220. For the primer use epoxy primer. How long have you had the primer? There is  something called a shelf life of paint and it eventually goes bad just from sitting for long period of time.

[Sam Green Racing]

Rhino I hope to have it finished over the weekend, but  I can't post pics from my company computer anyway.

If you look at the pics of Chris's CR in my signature, I painted the whole bike with cellulose primer and acrylic top coat, all from rattle cans.

Sam.

[Sam Green Racing]

Sorry I missread your first post, you said gas tank not glass.

I've been working all night for 14 hours and am about to drop.

Sam

[rhinoracer]

I'll try and get the epoxy primer locally. The one I used was a little old but it's supposed to be that thick, instructions say thin wit 30-35% thinner. I use it for painting bare metal, sticks better than any other primer I've used - except for epoxy I guess which I haven't sprayed for the risk of ruining my gun.

Sam, I thought it was you racing in the pic. That's why I stopped racing, coudn't keep up with work. That and a lot of other reasons.

[Sam Green Racing]

That's me racing Chris's bike in my avatar. As builder of the bike and sponser, I demand a go every now and then.
Off home to bed now, I've had it. Have a good weekend.

Sam. 

[paulages]

they make a really thin black paint specifically for this purpose, called "guide coat."  it takes very very little, and a can lasts forever.

[BobbyR]

I have watched custom painters do this. They very lightly  mist some black rattle can black over the primer, the low spots reval themselves as you wet sand. They still have paint in them when everthung else does not.  Just a mist is all they use, looks like dots is all.