Wednesday, October 26, 2016

Triumph Spitfire Chassis Restoration #10

Before I start, I'd just like to say thank you to everyone who has visited. 10,000+ visits since I started this blog! Cool.

Due to a rained out soccer game, I scored some bonus time at the garage on Saturday for a few hours. I also went over there on Monday. These two days allowed me to achieve another milestone; getting the frame painted with the first coat of POR-15. But first, you may remember that I was getting my butt kicked by the rear mounting bushings of the differential. Specifically, I couldn't get them fully inserted.

One side, other similar.

Of course, my favorite forum to my rescue, as usual. When the vice didn't work, they recommended using a bolt and washer arrangement to draw the bushing through the hole. I came up with something using Grade 8 hardware because I knew it would be under a lot of strain.

The washers are the gold colored parts. Largest washer on the left as the bracing point, tightening from the right to push the bushing in.

I went at this setup with an impact wrench and it drew the bushing in, but not far enough, until the impact wrench just stopped turning the bolt. Back to the forum and the recommendation was made to use a long bolt that would go through both bushings at the same time.

After a trip back to True Value for an 8" Grade 8 bolt and a similar setup as above, I was victorious. I still need to assemble the differential, but what turned out to be the hardest part, surprisingly, is done.

Victory. Forgot to take a pic with the long bolt installed. I'll try to remember to grab one next time I'm at garage.

As for the POR-15, a long time ago, I purchased a starter kit from Amazon. It comes with a half-pint, each, of the Cleaner Degreaser and Metal Prep, 4 oz of the paint, a 1" chip brush and 1" foam brush and a pair of latex gloves. Not bad for about $20. Since the cleaner is cut with water, the half-pint did the entire frame, but I used every bit of it. You will need to buy more paint and metal prep to do the whole frame.

I had cleaned up the frame as best I could and hit it with the Metal Prep on Saturday. After the adequate application time, like with the cleaner degreaser, it gets rinsed off. The spray bottle method just wasn't cutting it this time. That's when I figured out that one person can lift the frame and move it around pretty easily. I had been moving the frame the whole time, but one end was always resting on a sawhorse. I'm not sure how much it weighs in total, but I'm not that strong of a guy. It was a bit awkward, but I got it outside, rinsed and wiped off, and back inside to dry.

When I returned on Monday, I found the Metal Prep had left a chalky residue. This is the zinc phosphate that did not adhere completely. The instructions mention that this can be wiped off or directly painted over. I chose to wipe it off, but didn't waste too much time doing it.

The residue. Not sure if this is before or after wiping it down. Like I said, I didn't spend too much time on it.

After wiping down the frame, I blew it down with some compressed air to ensure any remaining gross debris was gone. I situated the frame upside down, the front resting on the radiator supports and the back on the emergency brake cable guides. This gave me the smallest foot print of unpainted metal to minimize what I had to go back and get.

Weapons of choice. 

Then it was on to application. The paint goes on thin (directions call for a 1mm to 2mm coat) and flows very well. I started with using a foam brush, but over time, it started to fall apart and tear, mostly because of the roughness of the frame. After I used up the 4oz can, I switched over to the chip brush and completed the rest of the frame with no problems. Therefore, I recommend a bristle-based brush vice a foam one. While the 1" brush was the perfect size for getting into the tight spots, it was small for the straight runs. Being the only regular brush I had, however, I went with it. 

This was how far I got with the the 4oz can. All four sides of the frame and the bonnet supports are painted.

I got on the ground and painted the underside (top, actually) of the frame. Here I found some of the paint had run down the sides and flowed across the bottom, almost defying gravity, vice dripping onto the tarp. I moved in sections down the frame, painting about 3 to 4 feet at a time on all sides. The very front and very back were the two most tedious spots, but it was essentially brainless. I got the frame fully coated in about 3 hours. This was longer than I expected, but I am very happy with the result.

Stuff dries very shiny and smooth. It flowed out any bristle marks that I may have left as it dried.

I didn't take a lot of time worrying about the residual factory paint that remained on the frame. I may have misunderstood the instructions, but I thought the Metal Prep would adequately etch it for a good adhesion. Unfortunately, this doesn't seem to be the case.

You can see the factory paint bleeding through.

POR-15 recommends at least two coats. The second coat is supposed to be applied while the first is still tacky to ensure adhesion. Depending on humidity levels (the stuff dries faster the more humid it is since it is water-activated), it takes between 4 and 5 hours to dry. In my case, the front of the frame was dry by the time I was done at the back. I didn't intend to put the second coat on that night, but it was a good data point for me.

If you don't get the second coat on in time, POR recommends (I emailed them) hitting it with 200-300 grit sandpaper to rough it up, wiping or washing it down to remove the dust and then applying the second coat. I hope when I do this I'll also roughen up the factory paint enough to get good coverage. My intention is to stop with two coats, but depending on how it goes, I may go for a third.

First coat down.

Like I said, I was happy with how the stuff went on. Of course, I cannot speak for it's effectiveness as a rust preventer yet. But, while the process was tedious, paint preparation is more important than application and I have no reason to believe that the effort will be in vain.


2 comments:

  1. Lookin good. Hope that second coat gives you the coverage you want, but if you have doubts, throw a third coat on....it will never be as convenient as it is now.

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    Replies
    1. I hear that. I've learned the "rush" lesson a few times and strive to actually learn it this time, too.

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