Chapter I - Mostly Preparation and Body Work
We started by gathering up most of the big body and related parts to begin getting them ready. Here we have the entire body and all its related bits loaded on my trailer to be taken to the media blaster to remove all the old paint and surface rust. That's Dan's MGB visible in the third photo. Dick wisely decided to have it sand blasted rather than us trying to sand it all away. In hindsight, that was truly the right decision. The frame has been separated from the body for some time and actually seemed to be in pretty good condition. The paint was a little tired but none missing and no rust. I guess the body must have protected it pretty well from the fire. Anyway, it did not need to be stripped so we left it alone for now.
Well we got it back from the blaster in just a couple of days. It looks like we should have
told them to also remove all the filler material. All but the thinnest edges remain and the
metal is rusting a little under most of it. We have been D/A sanding all the removable parts
for a few days and still have more to do. So far the only significant rust we have found is
at the bottom on the cowl. There are structural supports inside that made two panels close
enough together to trap debris and moisture. We have panels ordered to replace them. We will
see how they fit; internet reviews have not been entirely good so far. In the worst case, I
will just patch in the rusty section. The left photo, upside down, shows the cowl as it was
returned from the blaster except the rivets have already been removed from the flange on
the bottom (top in photo). The rust is obvious. The right photo gives a better view of the
structural brace that probably caused the rust. The following photos show the brace after it
was removed and a couple of views of the resulting rust. We later removed the two side cowl
pieces from the firewall, they were riveted as well as spot welded. The top of the cowl is
actually the gas tank, which bolts on and had already been removed.
We are using epoxy primer from Southern Polyurethanes. This was recommended by my favorite paint supplier, LM Auto Color, as a supplier who specializes in restoration work more that production body shops. It is late August and early September and we have been hit by 90 plus degrees every day. We need to get the metal in primer as soon as possible so I called the manufacturer this morning to ask about advised maximum temperature and humidity. The answer was "No maximum, 100 degrees and raining is fine." I think I'm liking this company a lot.
Oops, it looks like I just found more major rust. The first photo is of the floor board and platform for the rear seat. Notice the significant rust in the floor section. I understand a bottle of muriatic acid was spilled in that area and this is the result. The second photo shows the same panel from the bottom. Several rust-through pin holes are visible just below the large "dimple" in the center. This is much too thin to weld from the bottom and access from the top for patching would be very difficult. Since this area is under the seat and not visible, I think some PC-7 epoxy is the ideal fix to eliminate any possibility of water intrusion. The third photo shows what we have sanded and ready for primer now. When spread out, or hopefully hung up, that is probably enough to fill our makeshift spray booth so probably time for primer soon now.
Well, we finally got all the pieces except for the main body and doors sanded and ready for primer. This did include some metal straightening and some welding. So here they are, all 20 pieces. Some hanging and some laying. Hanging parts this way is not necessarily ideal but it does allow for access to all sides during one session. The down-side is they want to move when hit by the air from the paint gun and they have a tendency to spin and touch one-another. Also, getting to the lower parts of some pieces, like those huge front fenders, can be quite challenging. All things considered, I would still probably do it the same way next time.
Another thing to really like about Southern Polyurethanes epoxy primer is it allows for up to 7 days to apply top coating before you have to sand and recoat it. We decided to go ahead and paint the back side of all the black parts to avoid having to sand later. There is still some finish body work on their outsides so that could not be painted yet. Here they are, not quite perfect but they are shiny. The undersides of the fenders show a little pitting, from rust I assume, that we elected to leave. The other pieces are pretty good.
We finally got the body sanded and all the old filler removed. Like the aprons, every bit of filler on the body also had at least minor rust under it. Also where the top was covered in fabric, there was significant rust pitting in the metal. I actually primed it a few days ahead so I could fill the pits. I was afraid they might actually telegraph through the new fabric even though it will have a cotton padding under it. Now, after the epoxy sets a day or two, I will have to reapply all the filler I took off. But this time it will not rust underneath. The only stuff left now is the doors, the wheels and several trim pieces, which are all at the sand blaster now. These photos show another feature of this particular epoxy. It has enough low gloss to readily reveal many of those little flaws that try to hide until you get the final paint on.
I waited a couple of days then applied filler to the most obvious flaws. The large ones had filler remaining after returning from the sand blaster so I knew where they were. The others were not so obvious until the epoxy primer brought them out.
After sanding and feathering all the filler, there were enough spots of bare metal that we decided another protective coat or two of epoxy was in order. No photos here as it looked the same as the earlier set.
The next step was deciding on what primer/surfacer to use. I have used the urethane high-build primers with good results in the past, specifically PPG K200. These are still available but current technology today is polyester high-build primer. This stuff is essentially sprayable bondo and can be built to two or three times the build of urethane or maybe even more. It is the DIYer's savior. I had two concerns though. Being polyester, it uses MEKP as its hardener, in a ratio of 2% or so. That is a couple of ounces for a gallon. It seems that it would be really easy to get it wrong mixing smaller amounts. The other is the pot life. Like bondo, it kicks off really quick. In most cases you have to get it out of the gun in half an hour. That is from the time you mix it until you clean the gun.
My paint vendor convinced me I could handle it. After I assured him we had no bare metal, he
recommended a product named
Slick
Sand by Evercoat, the company that owns the Bondo name, as the stuff most high-end
restoration shops use. I have to agree that it is really nice stuff. The gallon comes with 4
tubes of hardener, one tube per quart. The tubes are also marked off in quarters so it is
simple enough to mix 1/4 of a quart or 8 ounces at a time. We had the doors and hood (4
pieces) ready so I mixed 16 ounces and half a tube of hardener and started spraying. This was
enough to give almost 3 wet coats to everything, with Dick keeping an eye on his watch so I
didn't exceed the 30 minutes in the gun. It sanded easily with a long board and 220 grit paper.
We got flat surfaces very quickly. In short, I am sold on polyester as the way to final prep
for paint. I forgot to mention that the temperature of everything has to be above 70 degrees.
That includes the air, the gun, the paint and the stuff you will be painting. If it drops below
68 then it will not harden. And it must be kept there until it has fully hardened, at least
another few hours. Months later, after applying a lot more paint, I think I shot this a little
too dry. Wetter coats would likely have meant less sanding and paint sanded away.
So today, instead of swapping parts for the next batch of Slick Sand, dick wanted to build an adapter to mate the engine to our engine stand. See here for the full details.
So, back to the paint preparations. We sanded the Slick Sand applied a couple of weeks ago and
found that a lot of work was still needed. The sides of the body, where you saw all the bondo
above, were still pretty lumpy or at least wavy though nothing deep. This photo shows the left
side, the worst section. We filled the low spots with polyester glazing putty, essentially bondo
with a very finely ground filler material and thinned to almost the consistency of thick paint.
This allows it to be applied very thin and sand to a very smooth surface. The light color spots
are the filler, indicating low areas. The black is a light guide coat of paint to help find any
remaining problems. It looked pretty good so the next step was to apply a few more coats of the
Slick Sand then block sand one final time. These next photos are after that block sanding of
the same area. The two shot at a low angle are attempting to show the overall flatness after
sanding. I guess that doesn't work too well since the paint has almost no gloss at all. Well,
I think we will probably guide coat it one more time just to be sure.
That final guide coating and light block sanding left the body straight and ready for color. We
still can't get the single stage paint we hoped to use so that may wait a while. Meanwhile, it
was time to tackle that rusty cowl referenced above. We did order the replacement panels. They
looked pretty good and seemed to be shaped at least close to right. When we started test fitting,
however they were less than perfect. The first problem was the length from top to bottom. It was
a good 3/16 inch too long. The top has to align with the top of the firewall as the gas tank sits
on both. The bottom has to align where it meets the A post since it sits on the frame there. So,
corrections had to be made. The top is a complicated curve but the bottom is straight. I thought
it would be simple to just correct the bottom bend for the rivet flange. In order to get it all
aligned properly, we loosely reassembled the whole assembly and attached it to the body. Then,
trying to fit the new panels we decided they just did not fit nearly as well as the originals.
The final decision was to reuse the original panels and just replace the rusty sections with
matching sections cut from the replacements. This also has the advantage of all the rivet holes
already in the right places but a few former spot weld holes that have to be filled. the left
photo shows the original panel with the rusty section removed and the patch laying beside it.
The right one shows the patch panel in place, ready to be welded. There is a welt between the
cowl and the A post. The shop now has a MIG welder so I am currently teaching myself how to use
it before proceeding.
A couple of weeks later, I felt confident to reconstruct the panels as described above. I tacked
them together while properly positioned on the car then removed them to complete the welds. I did
the left one from the back side thinking I would save all that grinding. It bulged slightly
outward but a few taps with the hammer and dolly corrected that. Of course I still needed to
grind the welds. Therefore, I welded the right one from the front side and it bulged slightly
inward. Since there is an opposite curve in that area, a few taps with the hammer proved futile
in making it right. I had to do considerable shrinking to get the overall shape correct. That
turned out to be a big mistake and the resulting joint reflects the problems it created. I did
spend the time to clean it all up after this photo. Anyway, with that done we are now ready to
prime those cowls with epoxy and rivet them to the firewall. Then the entire body is ready for
top coating. Meanwhile Dan and Dick have been working on the brakes
and other mechanical features of the chassis.
With the cowl panel rust repair patches done, I put a good coat of epoxy then a little filler
to smooth out the weld seam then another coat of epoxy and here they are. We are now ready to
rivet them to the firewall and lower support bracket. After that we will do a heavy coat of
Slick Sand then sand and be ready for final top coating. Meanwhile, yet another problem has
presented itself. We tried riveting a couple of pieces of scrap metal with darn little success.
It seems that steel rivets are pretty tough and do not want to cooperate. Rather than mushroom
on the back side as intended, they are more likely to tip over and bend. This might work
acceptably in new construction where the holes are the correct size. In our case, though, the
holes are the result of previously drilling old rivets out. They are not necessarily the right
size, usually larger and even not round.
Our next attempt was to try aluminum rivets. That did not work too well either. Even with light pressure, the tool distorted or deformed the heads. Dick finally had an idea to save the day or maybe the project. By putting an appropriate size bolt in an electric drill and running it on the grinding wheel, he made what we decided to call "threaded rivets." We used these every place where rivets were used originally. The rounded heads are indistinguishable from rivets and the corresponding nuts are all hidden from view inside somewhere. No one will ever be the wiser.
Well, I finally got the cowl panels back together, fitted to the car and metal work done with a light coat of filler over my welds. Here they are, along with the mating gas tank being shot with the Slick Sand polyester primer. After a little sanding, the entire car will be ready for final painting. Now if we can just find the single stage paint we want to use.
After block sanding the above pieces, cowl sides, firewall and gas tank, we assembled them on
the body. This was necessary as the welt between them and the body is painted body color. I
actually like the look of the black welt but I do understand why it was done this way. The
whole thing is held together and attached to the body by 20 or more nuts and bolts, many of
which are difficult at best to reach. Assembling after paint would most likely result in some
scratched paint. That would have been unacceptable at the factory as well as in our shop. You
can see through the doors that the rear floor/seat platform has also been installed. The rest
of the floor is plywood which will be installed after painting as it is black. With all that
done, the entire body is now ready for finish paint, including the fenders, hood, doors and
all. There are still a few miscellaneous small parts, not part of the actual body, such as the
steering column and spare tire bracket.