Clear Coating Gas Tank

[natemoen]

Harbour Freight sell wet and dry sand paper. Do NOT use it. The grit numbers are not right and grit comes right off the paper. Get good stuff. 3M is good

+1!!!!! It really does not last long, and if the grit numbers are off they are off to the low side and the paper is finer than it states. At least the stuff I had was that way.

[BillyRok]

Lots of good tips and ideas, it appears we've used slightly different routes to end up at the same place.

You may find this interesting. I used aircraft stripper to remove the paint from the tank, some came off easy and some took more effort. There were dried paint chips all over the floor so I picked some up where the primer, color, and clear came off in one piece and measured the thickness with dial calipers, between 9 and 10 mils. So I did a little search to see how that compares with today's paint jobs on cars. One article claimed .3-1.5 mils on the primer, .5-1.5 mils on the color, and 1.5-4.0 on the clear...so anywhere from 2.3-7.0 mils total meaning the paint on my 32 yr old bike is between 28% and 300% thicker than on a new car!

So back to my tank and side covers. I wrapped some 3M 320 grit around a foam sanding block and lightly sanded the tank and covers. The tank turned out OK but I managed to go through the color down to the primer on the covers in a couple small spots so I had to hit those again (I can hear Fred now, "Just put it together and ride the damn thing!") The rough texture to the tank is gone but it certainly looks "scratched" from the sanding. But if I pour a little water over the tank, when it's wet it looks great! I assume that is what happens when I clear coat it...the sanding marks get filled in, the color shines through, and polishing will make it smooth and glossy?

Temps only are in the mid 60's today and it's rainy so I decided to wait a couple of days to spray the clear. And since the side covers were 95% OK I think I'm just going to spray them also without any more sanding.

What do you think about clear coating the tank badges and the side cover inserts as I've repainted those as well? I'll be sure and put up some pictures when this is all done...if the paint job comes out nice, the pics will be close ups. If not so nice, I'll stand back a little farther!

[DGXSER]

I will pass on the information I got from a paint mfg here in town. For sanding your primer, only use paper as rough as your base can fill. In my case, the mfg stated no more than 600 grit, that is the deepest scratches it can fill. So check your materials, may want to wet sand with 600 before you apply base.

As to sanding through to the primer, I would think your fine with that, as long as you did not go through the primer.

I would clear the badges and inserts, but realize it will darken the color a little bit when you do it.

[scratcher09]

I realize this is an old thread but there is a lot of misinformation given here. So for the benifit of anyone looking for advise on paint I'll add my 2 cents. Don't underestimate the importance of prepping. If you cut corners, it'll affect the end results.

Thoroughly wash surface with mild detergent and dry. Wipe down with wax and grease remover (acetone works well and is cheaper). Wet sand surface with 600 grit. Wipe again with solvent and shoot primer.

Wet sand with 600-800. Wipe with solvent. Wipe with tack rag. Shoot base coat. Most brands need to flash about 10 minutes between coats. If imperfections need to be worked out before clearing, use 600-800.

Drying time before clearing depends on manufacturer but 24 hrs is usually safe. Some bases only need 4 hrs. Look on tech sheet if you don't know. (If you wait more that's 24 hrs you will need to scuff with 800.) Wipe with solvent. Wipe with tack rag. Shoot clear. Allow 10-15 minutes to flash between coats.

After curing 24 hrs you can cut and polish. Using a soft sanding block wet sand with 1000, then 1200, then 1500 (2000 and 2500 are optional and make buffing easier). Finish up by polishing. 3M products are great. There are cheaper products that also will give decent results. It is important to wait a minimum of one month before waxing.

The method I described above uses automotive urethanes. In my opinion, if you are going to take the time and effort to prep and paint, then rattle can is not an option because it is not durable. I want my paint jobs to look good today and in 5 or 10 years. And if you don't have the equipment to spray, they now have spray cans with 2K urethanes. Once you activate the 2K you have to use them. The DIYer can get professional results out of a spray can. They can be ordered through Eastwood or bought at NAPA or automotive paint supply shops.

[pahako]

I have used spraymax 2k clear gloss on 3 tanks with great results. It is not necessary to sand the color coat before applying the clear. You will however have to sand and buff the clear which can be done after 24 hours.

[natemoen]

I have used spraymax 2k clear gloss on 3 tanks with great results. It is not necessary to sand the color coat before applying the clear. You will however have to sand and buff the clear which can be done after 24 hours.

It does make a difference if you sand the color. May not always be noticable but you will get a smoother look in the end.

[scratcher09]

Color sanding the base coat is not necessary as long as the base coat has not cured more than 24 hrs. If it has cured more than 24 hrs, color sanding is recommended for proper adhesion. And I agree with natemoen that the end result is better when the base is color sanded.

[CaptonZap]

I realize this is an old thread but there is a lot of misinformation given here. So for the benifit of anyone looking for advise on paint I'll add my 2 cents. Don't underestimate the importance of prepping. If you cut corners, it'll affect the end results.

Thoroughly wash surface with mild detergent and dry. Wipe down with wax and grease remover (acetone works well and is cheaper). Wet sand surface with 600 grit. Wipe again with solvent and shoot primer.

A caution, if I may.
Your instructions will work if the tank is down to bare metal. If however, there is any trace of old paint/primer left on the surface, acetone is not a wise choice of wipe down solvent. It can soften/degrade some of the old paint.
Enamel reducer is the better choice, as it will not soften anything that is over a month old. And a twice repeated reducer wipe, with clean rags for the second wipe, will remove most traces of silicone residue from waxes, which, if left on the surface, cause fisheyes. Some of the oldtimers would mix some silicone in with the new paint, which kept the fisheyes from developing, but that is sort of like farting to cover the smell of the s**t in your pants.
And if there is old paint/primer left on the tank, a sealer is advised, before priming, to prevent bleed through of the top coats. The newer epoxy primers help in that regard, but cannot be relied upon in all circumstances. There are just to many old paint chemistries out there.
A professional job is not a one step process, which is why they cost more than the price of a few cans of shake and shoot.
CZ

[scratcher09]

I now use SEM wax and grease remover but I did use acetone for years and never had any ill effects. And in the '90's I saw it used in body shops. But CaptonZap is correct. You wouldn't want to take a risk that might mess up all your hard work so it's best to play it safe--with the solvent and with the sealer.