Paint at Home Part 3: Spraying Those Topcoats

Since you never miss an issue of GRM, we know you’ve already read the previous two installments of our “Paint at Home” series. If not, here is part 1, and here is part 2. The first showed us stripping our BMW’s paint and fixing its imperfections with hammers and body filler. The second covered the iterative process of priming and block sanding.

These two chapters represent about 100 hours of work leading up to about 4 hours of actual painting. And after that, we spent another 20 hours sanding and buffing the car to remove the dirt and imperfections left behind from our less-than-perfect garage-cum-spray booth. The resulting paint job may not win Pebble Beach, but it sure gets us big compliments everywhere else.

Now, watch as we take our E30 from gray primer to an eye-popping blue.


As in previous chapters, we haven’t gone into too much detail about paint and materials. That’s because local and regional regulations may affect availability or practices in your area. We advise working with a paint supplier for recommendations about mixing ratios, dry times, and other factors that are specific to the paint you’re using.

We can tell you we spent about $1000 on filler, abrasives and private-label primer, paint and clearcoat. This job can be done for less and it can be done for much more, but we’ve found that products from a decent, mid-tier brand deliver great, long-lasting results.

As for tools, we offer this bit of wisdom: You can achieve these results with Harbor Freight-level equipment and keep your investment in the $300 to $500 range. We’ve purchased some higher-end tools, but most of them were in used condition and cost about a third of their original price.


Before the actual painting can begin, the lower portions of the car need some extra protection. Start by spraying the wheel arches and underside of the front valance with rubberized undercoating. While most people buy this stuff in aerosol rattlers (around $8 to $12 apiece), we’ve found that it’s faster and less expensive to invest in a $30 sprayer and source the underrating in cans (typically $15 per quart).


Next, use the same gun to spray textured rockerpanel coating on the front of the valance and on the rocker panels themselves. This stuff lends excellent chip resistance to the lower areas of a car. Once applied, it looks like the OEM coating.


Our garage is always pretty clean, so we didn’t bother to hang plastic sheets as many home painters do. We did make sure the garage was spotless, though. Start by clearing out as much dust and debris as possible with a leaf blower-an electric one, since a gas blower might contaminate the surfaces of the car and countertops. Next, wipe down every surface and mop the floor several times.


Time to clean the car again. Wipe it down with a paper towel dabbed in pre-paint solvent, then dry off the solvent with another clean paper towel. We recommend going over the car this way about three times, making sure to clean the cracks and crevices thoroughly.


Spotless garage, spotless car, all ready for paint.


Once you’ve changed into clothes that won’t dangle in the paint-we usually wear a tight T-shirt and keep it tucked in-it’s time for the first real painting step: “edging” the car. Apply enough paint around the edges that you won’t have to worry about achieving full coverage in these areas during the main painting pass. A full-size sprayer will work here, but a touch-up gun is a bit more accurate and a lot less messy.


Sometimes it’s easier to remove some body parts and hit them with the touch-up gun.


Now comes the stressful work. When laying down paint, it’s important to follow a very deliberate progression around the car to avoid “dry spray” and other pitfalls of moving without forethought. In general, the strategy is to fully paint a panel before moving on to the next one. To avoid literally painting yourself into a corner, try rehearsing these sequences before hooking up the air or putting paint in the gun:

  • At the front of the car, paint one fender before going across the hood to the next one.

  • At the center of the car, paint across the roof before coating the doors to avoid accidentally touching them while they’re wet.

  • Spray the rear quarter panels and trunk lid in a similar sequence to the front: one fender, then the deck lid, and finally the other fender.

Throughout the process, be very careful to keep the air hose out of the way. In fact, we recommend having an assistant maneuver the hose and warn you if your clothing is dangling too close.


For this job we used a basecoat/clearcoat paint. The basecoat is less stressful to work with since it goes on fairly dry and is less likely to run. After about three or four coats, it flash-dries to a semigloss finish. While waiting for the paint to flash-dry, we like to clean our guns in preparation for the clearcoat.



Following a similar painting sequence, put down about five coats of clearcoat. It’s okay to go heavier on the clear, especially on the horizontal surfaces, since a lot of it will be sanded and buffed off.

Our car photographed wonderfully at this step, but if you were in the garage with us you would’ve seen the fair amount of dust that settled on the horizontal surfaces–that’s what happens when you paint in a garage and not a booth. Wet sanding and buffing will solve this problem. (Make sure your painting space is equipped to remove fumes; our garage has a sparkless box fan mounted in a window.)


We usually sand the clearcoat by hand, but for this project we decided to try one of the new air sanders made for wet sanding. This is a higher-end Hutchins sander that we bought at the local paint supply store for about $150.

While keeping the car’s surface wet with a rag and clean water, start sanding with 1500-grit paper made specifically for this kind of work; then move on to 2000-and finally 3000-grit. Doing this step by hand would have taken us 5 to 10 hours for the hood alone. With the air sander, the job was done in about 30 minutes. We’re sold!


After air sanding, the surface has a subtle gloss to it. It’s too risky to go near the edges with the air sander, though, so sand them by hand with gradually finer-grit paper: 1000, then 1500, and finally 2000.


Just as you sanded the car three times, buff it three times as well, each time with a finer polish and finer buffing pad. Working roughly a square foot at a time, apply a few drops of polish and buff until the gloss comes up and the polish residue disappears. There’s an art to buffing: You need to move slowly enough to get some heat into the paint, but not so slowly that you burn it. Best to practice on something less important than your new paint job.


Buffing the whole car may not be necessary. We skipped the vertical surfaces since they looked great and didn’t really gather any dust. We did sand and buff the hood, trunk, roof and body sides above the beltline.


Final result: The paint pops, proving that you really can achieve high-quality paint results at home. If the car is kept clean, waxed and out of the sun as much as possible, paint jobs like this can last 20 years or more.


Eclectic Motorworks


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View comments on the GRM forums
wae SuperDork
6/6/19 12:10 p.m.

Very pretty.

(the real reason for my post is that it is staying at the top of the Latest Topics page with a last post time of 0 minutes ago and I'm hoping that another post will put it back in its place :) )

CJ Reader
6/6/19 12:10 p.m.

In reply to Carl Heideman :

Edit: Issue fixed.  Move along.  Nothing to see here.

Jordan Rimpela
Jordan Rimpela Digital Editor
6/6/19 2:05 p.m.

Sometimes when I time things to post they'll hang for a hot second. It's a weird glitch we're looking into. 

BimmerMaven New Reader
6/11/19 9:39 a.m.

Nice job. Good tips. 

I worked part-time in a body shop during college, about 1200 hrs.  Enough that I've done nearly all of my own bodywork since then. 


One picture shows a common mistake... During cleaning the right rear quarter panel, all attention focused on gloved right hand, towel, solvent.... While ungloved oily-skinned left hand is making a nice palm print on the trunk lid. 


I would also consider hanging blankets or tarps around the car, as the overspray gets everywhere in your nice clean shop... Much less work to hang than to clean. 


Of course, if weather is good, consider spraying outside. 

stan_d SuperDork
6/12/19 8:18 a.m.

Plus on tarps. Still finding things with red over spray on . Blue and White colors didn't have the hang time of the red.

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