Need help stripping/priming tank

I messed up with the paint and stripped the tank down to metal and primed/painted it again. After the paint dried, I wet sanded it with 800 grit and when the tank dried it was very dull. I cleaned the tank and hit it with a tack rag. I then clear coated the tank. How is the clear coat supposed to look ? It looks like it might have had a reaction to something, it looks like it is cracking. Is that how it is supposed to be before wet sanding it ? What grit should I wet sand the clear coat with ?

The clear coat should not be cracking, peeling or anything....it should look nice and glossy (unless you chose matt clear coat). After it's set up you can hit it with 1000 - 1500 - then 2000 wet and dry paper and then buffing out. If there is any cracking/peeling there is something in the paint that will come out at some stage and you have to get rid of it. Did you really clean off the bare metal tank well from the paint stripper? No fuel residue left in the tank which might produce vapor that messes paint up? Use something like PrepSol or similar to prepare the tank for paint....also try to use the same primer/paint/clear manufacturer to avoid some of the issues you mention. High humidity can also produce problems, dropping temperatures too, I like to paint in the early part of the day as the temperature is slowly rising.

When I paint metal I always start off with a coat of acid etch metal primer (I am surprised no-one mentioned that), then 3 coats of a sandable high build primer, three coats of paint and two of clear. Pay special attention to recoat times specified by the manufacturer and resist the temptation to caress the paint 'cause it looks so good....finger oil can mess with paint adhesion. Be careful what tack rag you use, make sure you talk to the people selling you the paint and get their recommendation, there could have been something in the rag you used that messed things up....I never use tack rags for this reason, I use a clean cotton rag moistened in the PrepSol I mentioned earlier. Good luck and post pics of the results

I resanded the rough spots out of the tank and repainted it. I then sanded it down with 800 grit wet sand paper and the tank turned from plank to almost grey, from the sand. Do I then clear coat the tank ? If so, should yhou see the greyish of the tank through the clear coat ? What do you use to get the paint/clear coat to shine ?

I take it that when you say plank you mean black? If so the greyish colour should be fine. Clean off the tank with water only thoroughly to remove all the sanding dust and sandpaper particles.. .dry it off with clean paper towel and let it air dry really well and inspect the colour coat for any imperfections. Don't use any tack rags or cleaning solutions. What clear are you going to be using? Again, try not to handle the tank with bare hands so you don't get any finger oil on it. Also post some pictures of each step you take, it really helps. Hit the tank with a few coats of the clear depending on the directions for use, pay attention the recoat times, try to spray the tank in the middle of the day and patience is very important. When the clear is nice and set you can lightly wet sand with 2000 grit wet and dry paper (use with lots of water) and then get some buffing compound from your local NAPA or similar auto store and they will show you any buffing wheels you can use, there are a few that are not expensive and can be mounted to power drills....then rub rub rub

Good luck man.