Zed Primed Again

I get that this is becoming almost comical in how cyclical the priming on Zed (1979 280ZX) has been. Today's post is another "Priming the 280ZX" posting. As much as I would like to say it is the last, I know there is one more primer shooting day coming, when the body kit arrives.

I did this work around another heat wave here in the Pacific NorthWest with temps pushing 40*C (104*F) at the peak. I spread out the final prep work over the full day Saturday and shot the primer Sunday morning. All of the other final sanding was after work in the heat of the day the week prior, causing me to literally pour sweat. Anyway, off we go.

Why More Primer

First, the obvious question... why more primer? For starters, this shoot was black 2k primer intended as the final coat of pre-paint. Hi-build primer can absolutely be your last coat of primer. In the reading I have done, many people have had great success with shooting their base/color coat(s) on top of the hi-build. I decided that I wanted a harder shell underneath the base than the hi-build provided. Also, the primer immediately under the paint is what is exposed when you get a rock chip. I think the light grey would show more than the black. Consider too, the color of your primer has a subtle impact on the color of your base coat, unless you put extra coats of color on to cover that. I felt that the black undertone beneath the gun-metal grey would darken the grey. Last, through the final rounds of Bondo, I sanded through to bare metal in a few spots. Those, at least, needed priming.

Preparation is Key

If you have read any of the posts about my efforts on Zed, this section is probably moot. Still, it is worth underscoring the importance of getting the panels as flat and straight as you can before you start spraying. Why? Because the paint is a very thin film of color laying on top of whatever your body shape is underneath. So, if it is lumpy, bumpy, or even deep scratched, it will show through. I performed many rounds of Bondo application and sanding, each time getting a little better at it, and each time getting the panels that little bit nicer. My final process has proven effective: mix a small batch (250ml / a US cup or so), applying slightly too much Bondo to the imperfection area on one pass (and don't touch it once it's applied), sand with less coarse paper (150 grit) for shaping and 400 for smoothing, and last, circle issues for further repair with chalk. This worked for me, and would probably work for others. The higher grit number means you use more paper and it takes longer to get the shape. I hand-block rather than use a DA orbital sander, which is additionally slower. I found this to be a fair price to avoid over-sanding.

Once sanded and smooth, the dust needs to be removed. Pigpen, my shop vacuum, is relatively effective at removing dust. The dust is so fine and Pigpen is so old that dust finds its way around the filter, creating a small cloud of dust around the canister (hence his new name of Pigpen, from Peanuts). I followed the vacuum with blowing compressed air on the panels (after the dust cloud passes) and then I set up for shooting. Since this shoot included the insides of the hood, tailgate and doors, there was considerably more prep than the last few cycles. I repaired the masking at this point as well.

For this spray session, I also prepared the hinges. I started with spray cleansers, but found they were not efficient with the 40 years of grease embedded in the hinge works. So, I grabbed a bucket, tossed in a dishwasher detergent pod and dropped the parts on top. I filled the bucket with a garden hose and then moved the parts around with a pry bar. I let the parts sit for an hour or so, agitating the bucket or moving the parts with the prybar periodically. I drained the dark grey wash water and rinsed the parts with the hose. All of the grease was completely gone.

Set Up

With the panels off the car, I need a wide area to shoot everything. I use a second carport space, laying a big blue tarp down as a floor. This keeps the dust away and protects the driveway. Onto the tarp, I arrange the panels to I can easily move from one to the other without drooping my air hose onto wet paint nor creating a weird maze to navigate while trying to spray. Once arranged, I blew off the panels again with compressed air and then cleaned the panels with oil/grease cleaner (Oil Eater). I do one last check, by holding the air hose and walking the area, making sure I can get to everything.

I have gotten relatively quick at getting the gun ready now. The 2k primer is a 4:1 mix. So, for a 20oz ($20US<) Harbor Freight purple gun that means 16oz:4oz of paint to reducer. I pulled a clean pickle jar out of my glass recycling to use as a mix jar. With a measuring cup and water from the kitchen, I marked a 16oz line and a 20oz line on the jar. My process was to pour in 16oz of primer to the first line and then add reducer to the upper line. A quick mix, and pour into the gun and I was ready to go. Doing it this way gave the air compressor time to catch up to me.

The Shoot

I checked my spray fan against some of the masked off glass, as well as the underside of the hood (it was flipped upside down so I could shoot that side first). With a decent fan, I started shooting around the radiator support first. I figured if there were any mishaps, better they happen in an area that will be almost completely hidden from view later. There were no real issues. I had a few "tiger stripes" where the gun would sporadically not produce a paint fan... resulting in what looks like a tiger stripe. I believe this could be attributed to either too much air pressure or a crappy gun. I will recalibrate for the next shoot. Overall, though, the primer laid down very well. Once all of the undersides were done, I sprayed out the rest of that batch and flipped the doors, hood and tailgate over. Then, I shot them. One thing I did this time was take advantage of the 1/2 squeeze on the trigger to blow air: If you press the trigger halfway, compressed air comes out, but the opening isn't big enough to pull paint. So, I was able to quick-blow the panel immediately before spraying. This trick will be more useful with the color, but it was good to practice it.

After I was done, and the primer all dry, I looked back over the spots where there were significant Bondo sections (again, not thick, just a wide area) and they look very good. Even the middle of the hood, where all eyes will be most of the time, the center ridgeline is exactly centered and looks just as I intended.

The pictures on the right show the before and after of the passenger rear quarter panel. I think they show how careful work can produce some pretty great results. I really like the satin glow. It shows the body contours very well, allowing me to look for remaining imperfections fairly easily when compared to the hi-build which sat flat. Everything looks pretty amazing to me, and I do not intend to pursue any additional rounds of Bondo on these panels nor the main shell. That is a huge milestone.

Next Step Musings

I am still waiting for the arrival of the body kit that I ordered in June. This is not a supply chain issue, really, it is about a manufacturer getting their business back operational after a CoViD shut down. I understand that my kit has been produced and is in transit. Depending on timing, I may 400-grit sand what I just shot and then plan for base coating the areas which are going to be either under the kit or under other body panels (like, maybe paint the front supports for the fenders, for example). I know I want to do those on a different day than the rest of the body, but I don't know how far ahead I want to get without the body kit in-hand. I understand that these kits are really one-size-fits-none-perfectly. So, there will probably be some shaping at least. Regardless, these kits need to be minimally surface sanded to remove the gel coat for paint to adhere. Last, I have read some advice about leaving newly formed fiberglass panels in the sun for a week so they get nice and warm help to complete their off-gassing / curing. Apparently, they will behave better over the long term if this is done. I recognize it sounds a little odd, but this came from someone who does these body kits all the time, so I'll trust it. If the kit arrives soon, I should still have time to finish the prep and paint before the weather turns... assuming the weather stays warm/dry until the middle of October like it usually does/used to. If necessary, I will switch it up and paint everything I can, leaving the body kit for next year.

Anyway, that's it for today. Thanks, as always, for following along--

Zed Body Progress

With the weather shifting warm to cold to warm again, Zed (the 1979 280ZX) work has been a little bit on-again / off-again. With the weather returning to hot for what looks like the Summer, I shifted efforts back to Zed from the other projects (you've seen the posts)... well, until this past weekend when everything came to a complete stop due to the record-setting high temps (over 45*C / 113*F). Today's post focuses on Zed's body work again, solving for the missing rear bumper and getting after some priming. Again.

Bumpity Bump

A lingering question for Zed was how to solve for the rear bumper. The original was a rusted out mess, and donorZed was about as bad. I was considering how to construct something one-off custom, but decided that an off-the-shelf fiberglass kit was a better looking, and fastest-to-implement approach. Rather than just do the rear, I got a full kit, so the front-to-back is consistent. Of course, this will delay the paint a little bit, as I have more body panels to solve for. Plus there is the added delay introduced by shipping. Ultimately, Zed will look better, so it's worth it. The kit I ordered looks like the one pictured on the side here, without the big wing on the back. That's not my style, but everyone gets an opinion. Later, I will add louvers to the rear window since that window lets in a ton of heat in the summertime if left uncovered.

In order for the rear fiberglass to mount, I needed the rear bumper bar that sits inside the big rubber ugly. I reconnected with the local Z parts-hoarding-guy to whom we sold donorZed and bought a rear bumper bar, and mounts... for about 1/2 what we sold the entire donorZed to him for. Funny how this all works. Perhaps, in retrospect, I might have saved the original rubber bumper support bar and mounts. Anyway, next was clearing the rust off the bumper mounts, and getting them ready for action. I used multiple passes with Naval Jelly followed by a coat of Eastwood Rust Encapsulator and then a coat of rattle can primer. I will shoot these with the hinges and other tiny bits that we want the color of the finished body.

Following that, I removed the front bumper support (4 16mm bolts each side) and the bumper from the supports (4 14mm nuts each side). Next, I wanted to remove the rubber ugly wrapped around the bar so we were ready for when the fiberglass kit arrives. The Phillips screws that hold the ugly cover on, however, were rust-locked in place. Multiple passes with the Kroil didn't allow them to budge. So, I had to grind them off. It is interesting how much rust was on the bumpers and how little the rest of the car had. Those front bumper mounts had virtually no surface rust on them while the bumper itself had been impacted. These mounts will also get the color spray with the other bits I mentioned above.

Prime Time

Last, I finished enough of the Bondo cycle to feel that I could lay another round of hi-build primer. The Bondo-cycle took an awfully long time, and I got far too into it. I imagine I still missed a bunch of things and it still will not look as good as a real pro paint job, but at some point you just have to stop dicking with it and go. Otherwise, you will never get to enjoy the fruit of your labor. It's just labor. I am enjoying the heck out of bodywork though, which I kind of surprising. My first round of high-build primer was both too light and mostly sanded off so if you are concerned that there will be this huge stack of paint layers, rest assured, that is not happening. I did have to wait for the weather to get warm and dry enough, though.

Once the weather turned warm again, I acted like the primer had not happened before: restoring the masking, vacuuming and blowing air, cleaning the snot out of it, etc. so it was ready to get primed. Then, I laid the body panels out under the car-port cover again and repeated the multi-passes of primer, just like I did last Fall (See Zed Prime), with a few differences. My set-up this time did not include the in-line line drier nor extra pressure regulator. I had not gotten another disposable line-drier, and without it, I could not attach the regulator. So, I set up my pressure with test fan blows on one of the fenders instead. Total Roadkill. I figured I could reduce the moisture if I kept the air compressor tank warm, so I moved it into the sun. Since the air around here is super-dry right now (humidity below 30%), there isn't much moisture in the air to get compressed into the air line anyway. This may sound sketch, but the primer landed fine.

As to shooting, I did a light first coat to give subsequent coats something to adhere to, while also avoiding runs or sags. The sunlight was so bright, it was hard to really see the fan, since the color of the primer was the same as the target panel most of the time. Similar to the 1st shoot, I did not meaningfully stop between coats 1 and 2: fill the cup, shoot the cup, repeat. Why? Because, by the time I got all the way to the end of the light coat, the place where I had started had sat for longer than the minimal flash-dry period, and it was warm enough to dry fairly quickly. The surfaces were tacky when I went around for my heavy pass, which, I felt, was just right.

The 2mm tipped gun got clogged about halfway through my 2nd coat. As I attempted to unclog it, I lost about half of a shooting-cup (or about an actual imperial cup) of paint: it turned to Jello. I think I mis-measured the concentration of hardener. Could it have been from the lack of an air-drier? I dunno. Undaunted, I grabbed another gun which had not been drilled out to 2mm; it was a 1.8mm tip. I did not clean it first, I just blew a few seconds of primer through it and got back to the job. Yes, that was lazy and yes it could have allowed for some shipping oil/crud into the primer. I considered all this and used the first little bit of shooting to second-coat the nose section that will be mostly hidden from view (under fenders, radiator support, eg). More Roadkill; maybe that show is a bad influence on me. Anyway, I finished the pieces I had not gotten with a 2nd coat after I shot some hidden areas. I found that the 1.8 tip flowed better, gave a smoother finish and had a more predictable fan than the 2mm drilled tip. So, I take from that either (a) I drilled the tip wrong or (b) my 21gal compressor, pressure set up, gun and material were all better suited as a unit to the 1.8mm tip. I'm not sure how you drill wrong, so I think the difference is really tied to my compressor, and it's ability to keep up with the air-pressure demand of the 2mm tip. Regardless, I will be shooting this high-build with the 1.8 tip on a very warm / hot day from now on.

Reviewing the Prime

None of these changes, including the especially Roadkill-inspired ones, appear to have made much of a negative impact on the primed surface. Quite the contrary, actually. I started setting up the first gun at 10 and finished spraying by 2. I took an hour to clean up work area and the second gun (first gun went into the garbage) as I let the panels sit for the rest of the afternoon. Late the following afternoon, after the panels had sat in unseasonably warm temps (30*C+ or 85*F+) most of the day, I did some test sanding on the mostly-hidden areas with some 320 grit paper. The primer powdered smooth very quickly. If this is any indication, then this priming session was much better than the first. Perhaps this high-build poly-primer is more temperature sensitive than the Eastwood folks indicated on their site: warmer drier days are much better. The first time around (when it got into the lower 50's*F/11*C overnight after shooting), there was meaningful stippling on the surface. This time, when the overnight temps barely got below 70*F, the surface is much less dimpled. And, it sands smooth much more easily; like, a few passes with 320 and it's smooth. Last Fall, I tried pre-warming the panels inside my garage but that had no effect: the shell which sat outside the whole time had the same little dots peppering the surface. I think the real difference was the long warm days both the day of and after shooting.

Learnings

My big take-aways from the shooting the hi-build poly-primer from Eastwood: use a 1.8 tip and an in-line drier on a warm-to-hot day when the overnight temp will not fall below 18*C or 65*F for best results. Do a quick-coat first for the next heavier coat(s) to adhere to. Last, it is a good idea to have an extra gun as an emergency fall back in case you mess up the hardener concentration and jack up your gun in the middle of your spray-sesh.

Go Forward

Next, I will be sanding the rest of the body panels. Then, once it arrives, I will be handling the body kit. At some point, there will be paint, but I may shoot a urethane primer/sealer first (once Eastwood has it in stock and ships it to me). And, of course, the body kit will probably need some tweaks and then priming. I sincerely hope I can get it all done before the weather prevents it. While the Fall rainy season is a distance away, we cannot guess whether we will be revisited by toxic smoke again, scrapping late-Summer plans. For that matter, we are having triple-digit heat waves (40*C+) that are keeping me penned inside as effectively as the smoke did last summer. 

I expect that if I have to wait too long for the body kit, I will set up and shoot the parts that will not be impacted (like the underside of the hood, the hinges, the bumper mounts, etc) so I can make some headway and save myself some shooting time later while also getting a better feel for the equipment and material. Some of this stuff may not be terribly post-able, but I will try to at least put a little message here about the work.

Thanks, as always, for following along-