Tuesday, June 29, 2021

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-

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