“If you ain’t makin’ mistakes, you ain’t doin’ nothin’.” That’s what I’ve been told, anyway. Being told so helps a lot and as long as no one is injured, mistakes can end up laughable. That being the case, I prefer to laugh at myself first, before you can.
Now and then on the newsstand we do find detailed paint-related tech, which ordinarily spotlights the latest and greatest in waterborne-type technologies. Now suddenly it occurs to me that a look back at basic, solid-color, single-stage spot repair might still have its time and place as well. It certainly does here, down on the underside of our 1955 Chevy second-series build. The little truck’s frame is satin black powdercoat. Its hangy-down parts (springs, front axle, rearend, and so on) are glossy, black, single-stage urethane, and to this point we’d like to think we’ve saved our customer-friend some dough by using older materials we’ve had in stock. For our own particular purposes on our project’s underside, it’ll be just fine.
The spot repair to follow won’t be rocket surgery. This is stuff I learned as a kid at my first real body shop job, so long ago. Although you may recognize an up-to-date tool or two, consider this a small example of good ol’-fashioned spot repair.
The small surrounding area shows bare metal and body filler. Let’s spot that in.
Even though we’ll be spraying at low pressure in one small area, let’s mask this chassis like we care. Roll-out static-cling masking material is nothing new. As I recall it came along in the mid ’90s. Compared to what we had before, this is wonderful stuff.
The static-cling feature enables the plastic to stay put pretty well, but we have a droop where we’ll be working. These handy circular magnets were actually Harbor Freight coupon-clipper freebies. They’re surprisingly strong and here they’re pretty helpful.
This may not be very technical, but it certainly seems worth mentioning. Working busily below protruding framehorns has its hazards. Taping on a little padding doesn’t take that long, and it sure beats a trip to the emergency room.
By this time the chassis is well protected with masking firmly taped to the concrete floor. The area of axle housing to be spot repaired is trimmed out. There’ll be a little more masking done around that area soon, in step with proper prep.
We’ll need to do some color-sanding around the new fill hole. Inside the pump-sprayer is grease and wax remover, and this is a pretty standard first step for just about any spot job. Wiping this dry with clean disposable toweling should ensure a clean start.
If I could find a clean disposable mixin’ cup I might do this a little differently, but this’ll work. With a folded piece of 1,200-grit color-sanding paper, we’ll use grease and wax remover as our lubricant—this time.
Ordinarily this type of color-sanding would be done with water, or slightly soapy water. Here because we have exposed metal and filler, grease and wax remover is our lubricant of choice.
Foam masking tape has been around a while now, too. Before that we relied on a technique known as back-masking, but let’s not get into that. The soft, rounded foam tape is helpful for maintaining a dull edge should overspray go further than we expect.
Years ago now, I purchased this cute little Central Pneumatic 1.4 gravity-feed HVLP spraygun for a no-glory job. For $9.99, I figured I’d use it once and toss it. Long story short, it’s kind of grown on me. It hasn’t replaced other ‘guns, but I really do use it from time to time. Last time I checked, it was still $9.99 at Harbor Freight.
Here with the same setup we’ve just dialed in (low pressure, material restricted, pattern pinpointed), we’re triggerin’ the ‘gun while it’s held fairly still. Since the filler below has been sanded to 220-grit, this single-coat squirt of black epoxy primer will be sufficient. Now let’s allow some cure time. We’ll take a closer look at this in the morning.
Sure enough—shot at low pressure sans reduction—our epoxy-primed spot has a fuzzy outer edge. Metal and filler below are now protected, so we can safely sand the fuzz with water as the lubricant for the same semi-spent piece of 1,200-grit. Now that we’ve found ourselves a clean disposable mixin’ cup, we’ll make less mess, too.
Mainly for adhesion, our spot repair’s surrounding area is hand-buffed with a course compound and a folded section of Grant’s-brand microfiber cloth from Harbor Freight. Later if things go our way, we’ll be able to melt any spray fuzz with reducer. For this small spot job, additional blending solvent should not be needed.
So, once again, grease and wax remover is used before any spraying takes place. Some may notice that we’re not using a tack rag. Actually, we would if it were necessary. Here it’s just not.
Again with the same ‘gun setup we’ve used all along, here goes our first-coat color squirt of black single-stage urethane. Granted, we couldn’t ask for an easier color match. There’s really no need to expound blending technique here.
Here it’s a comfortably warm Montana day. With medium reducer our initial coverage coat is flashing quickly. Moving faster now, we unload the ‘gun as its catalyzed contents are poured back into the cup it was mixed in.
Now we add a glub of reducer. Then we’ll stir and strain as we reload the ‘gun for our final coat of color.
Providing we’re sure to overlap slightly beyond the previous coat’s outer edge, this coat’s thinner viscosity will help us melt a bit of spray fuzz.
The thin, final coat does leave a little fuzz of its own. To melt that we’ve unloaded the ‘gun again. This time we’re reloading with a glub of straight reducer.
Moving quickly as our final coat flashes, the pinpointed ‘gun is held at a slightly further distance as we circle around the spot. If our timing is right, this light fogging of reducer will pretty much melt what’s left of the stubborn fuzz ring.
Once again, the little purple pistol has earned its keep. If we really think about it, the $9.99 purchase price of this ‘gun adds up to less than the labor time required to properly clean it. Even so, let’s go on and give it a quickie.
So, let’s have ourselves a closer look at our little spot job. By the light of this Harbor Freight coupon-clipper freebie flashlight we see that the surrounding hand-buffed area is dull. We’ll get around to that.
First, this would be a good time to remove our foam masking tape. The fresh paint could use some time to cure before buffing and polishing. For this catalyzed urethane, overnight would do.
For a truly undetectable repair we’ll need to achieve a uniform gloss. To even things out let’s begin with a mild-side rubbing compound. With a foam cutting pad the cute little palm buffer speeds this process, but this job could be done manually as well.
After buffing we switch to a foam polishing pad for an application of foam polishing pad glaze.
With another clean section of microfiber cloth we’re finishing this job (for now) with a hand-application of a tried-and-true reseal glaze. We’ll allow another two or three weeks for fresh paint to fully cure before protecting our work with wax.
Now, let’s end this story where it all began. With the chassis sittin’ level on the concrete floor we can finally add gear lube to our freshened-up 8-inch Ford rearend.
“If you ain’t makin’ mistakes, you ain’t doin’ nothin’.” Now that we’ve made a big deal of a little mistake, let’s put a plug in it.