“Basics of Basics
” Sectioning a body
By Brian Martin
In many ways sectioning a body is easier than a top chop. In every car made since the thirties the roof posts are slanted, chopping them is like shortening a cone in the middle. Most all bodies are still right angle with the bottom and are more like shortening a square box.
The first thing you have to remember is you don’t have to make this cut at the same height all the way around. In other words, unlike when you would section a cardboard box with one cut all then cut off a strip all the way around and reattach the two. On the car you will likely have cuts at many different heights, the firewall for instance may be cut all the way at the top a foot or more above where the doors shells are cut. For that matter, the skins on the doors may be cut a foot or more LOWER than the shells of the doors.
I found this to be the biggest trick when I sectioned an AD Chevy pickup (1948-1954) a few years ago. The first time I sectioned one of these trucks was about 25 years ago. I broke out the original “Little book” Rod and Custom from the fifties with the Rod and Custom “Dream Truck” being sectioned (at Valley Customs I believe). I followed their procedure and found that it was a tremendous amount of work. They may have been artist, but they were not very good planning out something like this, that is for sure. Maybe it was their first section too, all I know is they did it all wrong.
The next one I did was after many years in the collision repair industry so I had learned many “repair” procedures that really helped in custom work. I section parts on late model collision repair nearly every day. For instance it is common to install a trunk floor, frame rails, and a pair of quarter panels all of them requiring some sectioning to mate the new parts to the old at a strategic location for perfect fit and strength. That is the key, make the cut where it makes the most sense, not right in the middle like you are sectioning a cardboard box. Follow along and you’ll get a better idea of what I am talking about.
First things first, TOTALLY strip the car of parts. Your work will go much easier if all wireing, upholstery , glass, etc. is removed. Don’t laugh if this sounds obvious, I wouldn’t say it, if I hadn’t seen it with my own eyes.
Next, you want to do is find the widest part of the car. Put the frame on level jack stands, no sense starting off with the car leaning over. Next, take a large carpenters square and put it next to the car on the ground with one end pointing up. Mark the body all the way around (not a line, but just a 1/2” mark, here and there) at the widest point. Think about this, if you cut out a section at the widest point, it is more likely you lower the top to the bottom they will line up. If you were to cut it below this widest point, the top piece would be larger than the bottom piece and it would not mate up when lowered. Picture sectioning a ball, if you cut a two inch ring from the center, the two piece would mate perfect. If you cut your two inch ring from off center, one piece would be larger than the other and not mate.
Ok, this widest point is going to be the place where you cut the real critical points. Not all points are critical, many places on the car you can “cheat” very easily if they don’t line up perfect. But in the door jambs for instance, you want them to line up perfect, you can’t cheat a thing there. At least on the outside at the body skin, on the inside edge of the jambs you may need a little cheating by narrowing the inside of the jamb or something like that to make them mate perfect. The most important part is that they mate where the outside skin meets.
Ok, now is when the strategy comes to play. Look for any componants that can be removed all together and get them out of the way. A few examples would be the vertical supports behind the rear seat from the floor up to the package tray. Another would be the inner skin on the cowl sides behind the kickpanels. Some cars have a slanted support in the quarters behind the striker post maybe running from the bottom front of the wheel house up to the striker post top, at the bottom of the quarter window. Any supports running vertical or at an angle on the firewall. The supports going from the trunk floor up to the rear trunk like jamb are another one. There are two things you can do with these, remove them completely by drilling out the spot welds that hold them in, or at the very least cut out a good section of them at the point where you are going to be cutting the outer body or jamb area. If you are sectioning four inches out of this body, than remove eight or ten inches of this inner brace or structure to get it the heck out of your way. It is hard enough to line up all the points on the body that matter, having these in the way is just foolish. I like to completly remove them, drill out the spot welds, just like “unbolting” the part. If they bolted on you would remove them, right? I have found that you can remove these parts then “section” them after the body is sectioned and just plug weld them back in thru the holes where you drilled out the spot welds. Some of these parts don’t even need to be sectioned at all, you just trim off the top or the bottom and weld them back in, looks just like factory. You don’t want to rely on your upholstery to hide hacked up stuff , you want it to be beautiful when the body is bare.
Ok, now the marking for cuts. This is where the point of the cut being at different heights comes in. That mark you made at the widest point, it only matters where it is critical like at the outside point of the door jambs , that is really the only place it matters, all others can be cheated. The firewall for instance is where the Valley Customs guys really blew it. You don’t need to cut straight across the firewall for goodness sakes. On my AD I drilled out spot welds at the top where the firewall connects to the cowl top and then cut my section out of the firewall When the top of the body was lowered down to the bottom the cowl top came back down over the top edge of the firewall and was lap/plug welded back together, it looks just like it from the factory, no body filler even needed!
On the Shoebox Ford (49-51) for instance the firewall has vertical lines up the side to the cowl top. It has a lip folded out at right angle with the firewall face all the way up on each side and across the top (If I am wrong I’m sorry, I havn’t touched one in years, this is what I remember). On this firewall you could make your cut about one inch below the lip that folds out on the top. Then make your second cut at three inches (if you were sectioning four inches) down from that cut. When the body top is lowered down to the bottom the lip from the top can go behind the top of the firewall and you lap/plug weld it together thru 5/16” holes punched or drilled in the top edge of the firewall. If you ground the welds off and put a nice seam sealer in the seam tucked up at the corner of the lip it would be darn near invisible and look like the factory did it. Or of course you could completely weld it and smooth it off with body filler to make it perfectly invisible. Either way it would be MUCH easier than welding thru the middle and dealing with warpage and that whole mess.
So, on that cowl/firewall, you would cut the sides at the widest point, then when the cut comes meets with the firewall you drill out the spot welds up the side of the firewall to the lower cut you made in the firewall. The rest of the firewall would stand there uncut. After lowing the top of the body down, you would plug weld the holes where you drilled the spot welds out (remember you only drill ONE layer of metal) on the outside of the cowl sides, then across the top with plugs or a bead what ever you choose.
At the rear under the trunk lid it may be able to be done similar, I don’t remember much at all how a Shoebox is made back there. I think it goes down from the trunk jamb to a right angle lip behind the bumper, like the right angle lip at the top and sides of the firewall. If this is the case, you could do a similar procedure as I explained on the firewall. Again, it would leave you a little seam at the corner of the lip that you could just seam seal and no filler would be needed. I did the back of the cab on my AD this way, instead of cutting right across the middle of the cab like I did last time following Valley customs procedure I “Z” cut it from the widest point on the corner of the cab down to the bottom of the rear panel. I cut leaving one inch on the bottom of the panel still attached to the floor of the cab. Then punch holes (a Roper-Whitney punch is a VERY valuable tool and worth every dollar of the $175.00 or so it costs) about a half inch up from the bottom of the lip on the rear body panel after cutting my two and a half inch section out. The upper panel overlapped the lower panel on that inch lip left of the bottom and then it was lap/plug welded to the it. ZERO warpage, Zero filler, done deal.
On the quarter, that is pretty much gonna have to be spliced right down the center of the quarter at the widest point. I is “possible” I guess that on some cars you could make a vertical cut from the center point at the door jamb down to the bottom of quarter at the rocker and then run your cut along the rocker to the wheel well, go up vertically to above the wheel well then back to the rear of the wheel well then down to the bottom again. The skin would easily roll with the “new” shape as the top of the body is brought down. This may or may not be easier than just welding thru the center of the quarter at the widest point. I would think I would be easier to bring the cut down to the bottom or near the bottom. This weld could be lapped, as well. I lot of people get all heated up on the lap vs butt weld issue. I see it as a level of skill required need for either choice. If you feel you can butt weld down the center of the quarter than do it. Don’t assume because you are a “decent” welder that you can pull this off, it is a big leap from general welding to welding down the center of a large sheet of thin body panel like this, a BIG leap. Lap welding may be a much more common sense approach. Let’s face it, who the heck is going to finish off the back of the panel like the front, you WILL see a weld there if you look on the inside. If it is a butt weld or a lap weld, you will see it. A nicely done lap weld looks nice, not as nice as a perfect butt weld, but again, what is your level of skills? I have to tell you this, the average custom you see from the “big boys”, it is made entirely of “ok” welds covered with plastic body filler, period. I have seen MANY of these cars in person in the raw, don’t be fooled by the finished product, they are not very skillfully done. What ever you do, it will be as good as many of the famous cars you have seen over the years, you can trust me on that.
On the doors, this is one that I think definitely should be done by cutting the shell of the door at the widest point mark and leaving the skin intact. I did my truck this way and it was FAR superior to cutting thru the skin. I marked the shell for cutting, and again, you could even make two “Z” cuts on the door, one on the inside as well. You could mark the shell at the jamb at the widest point, then run a vertical cut down on the inside as it wraps around the edge of the jamb where the edge of the door panel would be. Leave the inside panel of the door complete with a lap weld at the bottom like I described the firewall. This would leave the inside intact so there is no chance of messing up where the window regulator mounts, along with the window channels (which by the way should be removed like the other braces I discribed and reinstalled later). Besides, it just makes for a cleaner job. But only by seeing the door would I make the decision of which way to go, cutting thru the center may be the bestest/fastest way. On the outside, you remove the bottom half of the door skin from the shell, section the shell then weld the skin back to the shell and cut off the bottom. Cut the lip of the skin that folds around the shell to hold it on with a die grinder and 1/32” cut off wheel. By the way, the 1/32” cut off wheel may wear faster than the thicker ones but it makes a much faster, finer cut in my opinion, it is all I use. And I use it on about 80% of cuts I do while sectioning parts in collision repairs. Just cut enough of it off so the shell will come off, you don’t want to cut the edge because that is much harder to rebuild. Most of the time the skin is much bigger than the shell, so you can cut the lip off leaving an eighth inch or more of the lip at the edge of the door. You could even VERY carefully cut the shell off thru the lip and the shells lip without going thru the outer skin and leave the little section of the shells lip under the lip of the door skin. After sectioning the shell you just tack weld the skin to the shell in that lip area where you cut. You can make a strip of metal and weld on a new lip that folds around the edge of the door to cover up all your work and it will look just like original.
On the bottom of the door, you can do one of two things, either carefully fold a new lip around the shell, or just cut it off with the bottom of the shell and weld it to the shell on the edge. Either way, you should be able to do a nice job where mininum filler is needed to finish it off.
One note, be sure you tack the door pieces together, and hang the door on the hinges before you completly weld it. And in fact, I would weld it very slowly, take your time. Make short welds, then go to another part then come back and weld another short weld. Welding all the welds none stop can really produce heat and twist things out of whack.
If the striker and latch end up in the middle of the widest point, you can “Z” cut around them so they stay right in the stock location.
On the radiator support just use your skills learned on the body. It is likely you can “cut off” the top of bottom of pieces just like the vertical supports from the floor to the package tray and not need to “section” them at all. The inner fenders are similar, just cut off the bottom.
The front feners are easier in that they don’t have the large flat areas of the quarter. So cutting right at the widest point up to the wheel well, then a vertical cut up then horizontally to the front of the wheel well then vertically down again to the finish it off around the front.
Remember, the vertical or “Z” cut is very useful. You can make a vertical cut up a panel to change the height of your cut. When the body comes down, the vertical cuts seam will most of the time stay nice and tight. Think of it as two boards standing vertically on the floor. Leave one on the floor while sliding the other against it up off the floor. You could nail them together at any point because they are always tight next to one another. Look at a “Z” vertical cut as the same way. The top of the “Z” is one horizontal cut, then the vertial part of the “Z” brings the cut down to another height. Of course on your “Z” cut the vertial cut is perfectly vertial not at an angle as it is on a typed “Z”.
Another tip is to make a template to use as a measuring device, not a ruler or tape. Take a piece of sheet metal or aluminum and cut it to the width you plan on sectioning out of the car. Mark it well at the side that is properly measured so you don’t use the wrong side or something. I also punch a hole in mine so I can hang it on the peg board. After doing a few jobs you get a collection.
Before you make a cut, find that center point on the car and look it over real well to determan if the amount you want to cut is the right amount for the project. Cutting only 3 & 3/4” may make the job a LOT easier than cutting four inches. Or cutting 4 & 1/4” may be easier than four, take a good look around the car with your measuring template and see if where you plan on cutting could be made easier if you changed this amount. On my truck I decided to go only two and a half inches total because it made such a big difference on the degree of difficulty of the job. Besides, I like the idea of a custom that makes you scratch your head not fully understanding what was done. Two and a half inches give me the lower hood line much like a Ford F-1 while not looking like it has been stomped on my a giant.
These are all just general guides for sectioning, read it many times to have a full understanding of what I am saying, then go out to the car find the places where it makes sense. Spend some time imagining how the metal is going to come down to meet the lower piece.
Take your time and have fun.
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