Im doing another tremclad roll on paint job to one of my cars. The last one came out very respectable, but had a hammered-texture-look to it up close, although it was very smooth to the touch. I believe we came to the conclusion here on moparts that it was poor wet sanding on my part, so I want to try and do better this time.

Im using a 3m firm rubber sanding block, and have already sanded once with 220 after the initial coat, now 2 coats later im using 400 grit. The car is very curvy and I feel like my sanding block is to rigid, so it cuts down the ledges very fast and un-even. Should I be using a block thats more flexible and contours to the curves of the car? How hard should I be pressing?

Try a wooden ruler. Bout 6-7 inches long (broke off yard stick) flexable enuff

For color-sanding paint, use one of the soft rubber-ish pads about 1/4" or so thick that are sold for that purpose. You shouldn't press too hard - let the sandpaper do the work - keeping the surface wet, and use the palm of your hand instead of your fingers.
Water with a few drops of dish soap makes for a nice & fairly slippery ingredient.
400-grit scratches are rather hard to polish out; even 1,000-grit requires some fairly aggressive compound.
Not sure about the bodywork under your paint, but the shinier you get the paint, the easier it is to see the flaws (waves, dimples, etc) in bodywork.

The little ~2"x3"x1/4" sanding blocks work pretty well, they're very much just for wet sanding.

Don't skip paper steps, start at ~800 or whatever you feel you need and incrementally go up in numerical grit. 800, 1000, 1200, 1500, etc. Don't go 800, 1200, 2000...in my opinion. It just seems to take longer and the result isn't as good.

I usually have a towel near by to dry the area before I move on so that I can verify it's uniform and there isn't any orange peel. It's nearly impossible to tell when it's when and you are at a very high grit #.

As mentioned, do not push very hard when wet sanding, and keep it wet!



I use Durablocks for my general sanding, they work well on uneven surfaces and you can get a variety of them to fit your needs. They require sticky paper.

stay away from sharp edges. the paint will not be very thick at these places. you would hate to burn through the paint and have to start over

What I've been told and found myself is that you need to start at a fairly coarse paper, then work with progressively finer grits.
What happens when you use too fine a paper to start is that the paper will not cut the high spots down enough, and can even 'follow' the ups and downs, resulting in the condition you have described (slick, but bumpy).
Use a firmer pad than when doing bodywork. Plenty of water, change the paper when it's smoother than new.
Instead of a towel, try a squeegee. They sell them at paint stores. Work a small area at a time and when it feels like it's smooth, rinse and scrape off the water to check for shiny low spots. Don't stop until they are all gone. Go over the whole car this way. Then move to the next grit. By this point, you should have developed a feel for when the paper has leveled the paint.

I remember reading about that tremclad roll on paint job process decades ago that can rival a 5K job. Never got around to doing it & the $350 Maaco job garnered nothing but praise/attention/comments whenever I took it out (65 dart).

The best results I've ever had with wet sanding, and have only been able to achieve this on M/C tanks and fenders, was using Mothers Carnauba Wax instead of water. 400 grit, 600, and finally 1000 grit. I have never attempted this on a car but have done some Bikes this way and all have turned out beautifully.
Practice on something small- a valve cover has plenty of contours- ideal for the learning curve