If you will recall, I took my Cobra's gas tank to a local radiator shop
to have it boiled out and de-rusted to the extent possible. Thursday I
stopped by the shop during lunch to pick it up only to discover that it
had been painted with black water based radiator paint. The quality of
the paint job could be described, at best, as amateurish with rust spot
showing through in several places. When I complained about this, the
shop agreed to strip the tank and to have it ready for pick up the next
day.
Friday, I made another lunch hour trip to the shop. I had naively
assumed that the shop would chemically strip the tank. Instead they had
sand blasted it. In fact, the tank was still covered with fine dust.
They hadn't even bothered to clean it. I could see several places where
the sand had cut deeply into soldered areas. Considering the dust, they
couldn't possibly have leak checked the tank again after blasting it.
The other thing that bothered me was that all of the protective coating
on the tank was gone. Since I had expressed a concern about this when I
had originally dropped the tank off, I brought this to the attention of
Steve, the shop manager. His response was, "Oh, I told you that might
happen." Of course, he had said no such thing. Steve had other
suggestions about what they could do to "to do it right", but at this
point I decided to pay up and get the hell out of there with my tank
before it was damaged beyond repair. I felt more like I was ransoming
my tank than paying for service on it.
Over the weekend I had plenty of time to look the tank over and to get
even more depressed. Not only was there dust all over the outside, but
there was even more INSIDE. I could hear it rolling around when I
tipped it back and forth. Besides the dust, the outside was pretty much
a mess. I suspect the acid bath it was soaked in contained muriatic
acid because rust seems to be forming on the outside at an alarming
rate. Nearly gravel size sand must have been used during the blasting
because most of the surface was badly pitted. Fortunately it's made of
rather heavy gauge steel so I don't think any significant weakening
resulted. I'm more concerned about the condition of some of the
soldered joints. I tried resoldering some mounting brackets on the
sides of the tank which looked particularly bad. These brackets are
rivited on and solder sealed against leaks. The sand blasting had
stripped off most of the solder and what was left was cracked at the
joints. My first attempt wasn't too good. After buying a smaller tip
for my propane torch I was able to improve things slightly
(aesthetically, anyway) but I'm not pleased with the results. It still
looks pretty awful. I might take it to an another shop just to have all
the solder joints checked and the tank cleaned and leak checked. On the
hand, I'm a bit paranoid and may just give it another try myself. Is it
legitimate to leak test a gas tank with water?
The other thing I attempted to do while I was soldering was to see if I
could tin the tank's surface to make it look more original. That didn't
turn out too well either. Fortunately I had the foresight to pick a
surface that won't be visible when tank is installed to practice on.
Looks like I'll be doing some painting.
As already mentioned, the inside of the tank was pretty dirty. I
decided to try the nuts-and-bolts trick to knock loose as much crud and
scale as possible. I started by getting as much of the sand out as
possible first. I was able to empty out quite a bit. Next I tossed
about 100 nuts of various shapes and sizes into the tank. I decide
against using bolts because I thought they would be more likely to get
jammed between the tank walls and the interior baffles. I counted the
number I threw in (thanks for the suggestion Daren), but I'm afraid the
execution was a bit sloppy. While rattling them around I manage to
spill a few out on a couple of occasions. Of course they went flying so
I wasn't able to see how many were lost. No matter. I'm reasonable
sure I got them all out. If any are still lodged anywhere, I don't
think they're likely to come loose. I did a lot of jiggling and wapping
with a rubber hammer to insure nothing loose still remained inside.
I would guess two to three table spoons of crud came out with the nuts.
This consisted mostly of sand, though there was some reddish looking
scale too. There's still some rust inside the tank, particularly on the
bottom, but it looks a lot better than when I took the tank out of the
car. I'm reconsidering the use a sealer. Now that the protective
coating has been etched off, I'm not as concerned about the sealer not
adhering to the tank's surface. I can't decide whether to go with the
three part sealer kit Moss sells or the kind sold for aviation use. I'd
appreciate hearing from anyone who has done this on their own.
Disgusted is too mild a word to describe how I feel at the moment. I
had not planned on spending a lot of time working on this tank. I
thought I would get it back from the shop nearly ready to install. I
have plenty of other things that need taking care of and don't really
have the time to screw around with yet another project. Depressing as
hell. Last night I dreamed about gas tanks and earthquakes.
Roland
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