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Chop the top on my 1947 Ford Pickup

98K views 173 replies 16 participants last post by  mechanik 
#1 ·
Well, i am a little nervous since this is going to be the first time i have ever done this. I kind of wanted to keep the top the way it is, but everyone i show it to says i should chop the top. So, what i have done so far is; i measured off of the frame up to where i felt the rear window of the cab could be moved down without allot of changes. I then took a level and walked around the truck with the level and drew a line where i am going to make the cuts. I too measured down 4" inches since i am taking that much out of the cab. My lines are now all the way around the cab and doors. Here are the pics of my layout and i will be cutting the cab off with a sawzall.
I know before i make the cuts that i need to reinforce the cab, so i will be using heavy rebar and weld it to the inside of the cab.

Wish me luck.......oh, and i added a picture of the rims i am planning on running.
 

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#52 ·
Okay New Interiors, i cut the window about 3 1/2" above the top of the glass and then i flipped it and welded it back into place. From the look of it, i am thinking i have it pretty close to center again. Also, off of the 2nd picture here, would you cut the roof where i have the line or would you move it forward?
 

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#53 ·
hotwheels1 said:
Okay New Interiors, i cut the window about 3 1/2" above the top of the glass and then i flipped it and welded it back into place. From the look of it, i am thinking i have it pretty close to center again. Also, off of the 2nd picture here, would you cut the roof where i have the line or would you move it forward?


You want to move it forward.. Where you won't be close to the round on the roof..I would go where it is the straightest..Make's it easier to fix. ;)

Back glass looks a lot better.. :thumbup:
 
#55 ·
hotwheels1 said:
I gotcha, i will move it forward. Thanks a bunch for your help on this. I know i am going to make a few mistakes, but in the end i think i will have a fairly decent looking top.


A man that don't make mistakes,,Is a man that dose not do anything... :)


You are doing great.. The next one will be much easier.. ;)
 
#59 ·
Thanks deadbodyman, i really appreciate that.......Okay, i moved the line on my cab ahead 6" inches so that i am far away from the curve of the cab. Then i took 2 pieced of angle iron and welded them level off of the bottom inside of the cab up to the roof. I cut a 1/2" off of the angle iron and then i torched a couple pieces of flat metal with the curve of the current roof line. Hopefully this will allow me to set the 2 pieces back in place. It's pretty sturdy so i am comfortable that the 2 sections will go back together pretty easy.
 

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#65 ·
It is looking great, the "Props" you made to hold up the skin look like a great way to go.


If you don't have a perfect fit for the butt welds you can use a "Backing" behind the weld. After you have "massaged" your metal with relief cuts or pie cuts or what ever you need to make the pillars line up perfect, you then can take a piece of the pillar you cut off and dice it up to stick it inside of the bottom pillar. This photo (I grabbed it off the net, I don't have a personal example) gives you an idea of what I am talking about.



A "Butt weld with backing" is a standard weld done in collision repair. It is in fact required buy many manufacturers in splicing any piece of their cars. I has however been dropped by many because of corrosion issues but in your hot rod, this is hardly anything to think about.

Anyway, your fit doesn't have to be perfect, and in fact you WANT a gap using this welding method because you direct your weld to the underlying piece and "bring" the weld up onto the adjacent metal.

The backing should be all the way to the end of the weld (unlike the Model A in the photo). You can take your time and do this fitting,bend and match the piece until it fits like a glove (this is VERY easy to do) then "Plug weld" it in as on the photo.



A few plug welds will hold in place until you get your roof back on then you can weld the "Butt weld" (with backing :)). You still need to be careful, VERY careful not to weld to fast or you will end up with a warped mess. Going across that roof should take you ALL DAY! I am not joking, a little 1/4" weld on one side, go all the way to the other side of the roof for another then work on something else, a weld on a post or something to let that weld up on the roof cool NATURALLY. DO NOT COOL THE WELD with water or air or anything. Cooling SHRINKS the metal and cause all kinds of trouble. Just make very small welds and let them cool naturally while you are off doing something else. There is PLENTY to do on the truck right? You won't be bored waiting, right? I didn't think so. :D

Welding across that roof really has to be given a LOT of respect or you WILL end up with a warped mess with a LOT of filler. The metal is so thick it will hold it's self in place pretty good. If you make these small welds you and letting it cool you will be able to pull it off without a bunch of hammer and dolly work (though some will be needed of course) but if you weld it too fast or cool welds it will be VERY challenging.

So far, loooooooking gooooooood. :thumbup:

Brian
 
#67 ·
Windshield channel

Well i started some welding on the cab, but it is a little slower going then i had hoped. The windshield channel took me a while to figure out the angle to cut in the cab to bring the windshield lip outward. Here are some pics.
 

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#68 ·
First off I want to congratulate you on the progress . I apologize for my crytical eye . but I would have brought the bottom channel in instead of the top out . It looks like you've got an odd curve where they meet to me . I would have to redo it if it were mine , but I am a perfectionist . Not necessarily a good thing .
 
#69 ·
Bringing the bottom in instead wouldn't have done a thing, the cut was too high up into the curve of the window, that is all there is too it.

Hotwheels, I am thinking at this point your best bet is simply to "create" the inner post you need to make the shape of the window correct. You have a few different ways to go, one is being a skilled surgeon and dice up the post above and below the cut bringing the inner line in more to make a nice line.

I am thinking to be more realistic, you take a flat piece of metal and you weld it on the inside of the pinch weld bringing it in where you need it (1). You trim this piece so you have a perfect line/curve. You then make templates from poster board (my favorite for templates) and make a triangle shaped template (2) that fills the outer portion of the pillar from the middle of the cut on the pillar over and in to cover the "poor" line that is now there.

Excuse the poor drawing, hopefully you can see what I am saying.

Brian
 

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#70 ·
MARTINSR said:
It is looking great, the "Props" you made to hold up the skin look like a great way to go.


If you don't have a perfect fit for the butt welds you can use a "Backing" behind the weld. After you have "massaged" your metal with relief cuts or pie cuts or what ever you need to make the pillars line up perfect, you then can take a piece of the pillar you cut off and dice it up to stick it inside of the bottom pillar. This photo (I grabbed it off the net, I don't have a personal example) gives you an idea of what I am talking about.



A "Butt weld with backing" is a standard weld done in collision repair. It is in fact required buy many manufacturers in splicing any piece of their cars. I has however been dropped by many because of corrosion issues but in your hot rod, this is hardly anything to think about.

Anyway, your fit doesn't have to be perfect, and in fact you WANT a gap using this welding method because you direct your weld to the underlying piece and "bring" the weld up onto the adjacent metal.

The backing should be all the way to the end of the weld (unlike the Model A in the photo). You can take your time and do this fitting,bend and match the piece until it fits like a glove (this is VERY easy to do) then "Plug weld" it in as on the photo.



A few plug welds will hold in place until you get your roof back on then you can weld the "Butt weld" (with backing :)). You still need to be careful, VERY careful not to weld to fast or you will end up with a warped mess. Going across that roof should take you ALL DAY! I am not joking, a little 1/4" weld on one side, go all the way to the other side of the roof for another then work on something else, a weld on a post or something to let that weld up on the roof cool NATURALLY. DO NOT COOL THE WELD with water or air or anything. Cooling SHRINKS the metal and cause all kinds of trouble. Just make very small welds and let them cool naturally while you are off doing something else. There is PLENTY to do on the truck right? You won't be bored waiting, right? I didn't think so. :D

Welding across that roof really has to be given a LOT of respect or you WILL end up with a warped mess with a LOT of filler. The metal is so thick it will hold it's self in place pretty good. If you make these small welds you and letting it cool you will be able to pull it off without a bunch of hammer and dolly work (though some will be needed of course) but if you weld it too fast or cool welds it will be VERY challenging.

So far, loooooooking gooooooood. :thumbup:

Brian

We call that a backing strap where I'm from.. :D And they do work well.. :mwink: You really don't need to plug weld it.. Unless your working by yourself.. If you have someone to help hold it into place for you so you can tack it.. You don't have to plug it.. :nono: That's just a lot of added heat.. That you don't need.. :mwink: And What work's very good too is.. Take a wet rag..(Not dripping wet) And as you make a weld, Pass it along side the weld on both sides of the weld.. (don't cool the weld) Just the sides.. And it will help a lot.. And if you do it right,, You will not have any warped up metal... :mwink:
 
#71 ·
So at this point, you guys don't think that the rubber seal and the windshield being cut to that shape, that it will fit? New Interiors, i gotcha on the notch and filler piece. Just curious though if this will work the way it is. I put a rubber seal in place last night and it didn't look that obvious. I'll go out into the shop this morning and see if i can make the notch work.
 
#73 · (Edited)
I'm glad brian brought up the backing plate butt weld ....the plug welds are important for strength,I think of them as the whole job the actual butt weld would be more cosmetic then structural..it gets all it strength from the plug weld. a sleeve is much better than no sleeve and a plug welded sleeve is how I've always done it , for the strongest joint and easier job ....One other thing about using the plugs,Punch the holes and use some drill screws (through the plug hole) to fasten everything down and draw the two pieces of metal together tight for a better weld that that wont blow through ...(the tighter the backing plate is to the skin the better the weld will be...The backing plate also absorbs a lot of heat but I always use a wet rag or towel about two inches away from the weld on both sides to absorb even more heat .
As faras the front pillars go I would use an 1/8 ' rod to determine the radius and make a nice curve and re make a whole new edge and pinch weld. Its only metal , you can make it do anything you want.so anything you can think up can be done.I wouldnt sweat the front pillars right now save them for last so you can concentrate on only them...That long roof seam will be a chanenge once thats done you'll feel like superman..and attact the pillars with a new vigor.
On that long seam, insted of a backing plate and a filler piece,I would use one piece of steel,(more like a flanged backing plate) ora (filler) with flanged edges) with plug welds in the flange,Plugs welded from inside the cab and lots of drill screws (through the plug holes)to hold it all in place before and during welding.when you pull a scew out to do a plug weld the hole the screw made is filled with weld...
I hope we havent overloaded you with information ,just trying to let you know all your options
 
#74 · (Edited)
NEW INTERIORS said:
The lip isn't the problem.. It's the curve of the body its self.. Thats what you want right.. If the rubber covers it, It won't matter.. But if it don't,, Then it will show.. :)
Another way is to "glue" your glass in with an edge moulding ,they come in many different widths and not use the big fat seal at all. The way theyre done today
 
#75 ·
The "lip" or "pinch weld" needs to be brought out as well because if you bring out the body with the triangle shaped metal as in my drawing the lip is going to be covered up. A portion of it will be gone or near gone, that is why I said to bring the lip over. It is super, super easy, and it is an important part of the windshield mounting and sealing.

DBM, the plug welds are NOT for strength, it IS to only hold the metal in place prior to the welding of the seam.

This is a test coupon from a welding test on aluminum. It shows how a buttweld with backing works. You are welding TO the backing, that is where you want your wire to hit down into the backing. Then you bring the weld up onto the panels you are welding together. To past the ICAR or AWS (American Welding Society) you need to fully penetrate that backing. The backside of the backing needs to show melt thru the entire length of the weld.



I agree that they should be plug welded only because you are very right that it IS a form of reinforcement and if the butt weld is not up to par, the plug welds are adding a little more strength. But honestly, if the butt weld is done properly that plug weld is doing nothing but going along for the ride.

I personally spend a lot of time fitting that backing, it doesn't look like the one on the Model A photo I posted. Now, I have never used this method on a chop, I haven't done a chop or body section or anything like that since I learning about the butt weld with backing, plug weld, flange weld and all the other forms of joining two sheets of metal together. I may have "done" them, but I didn't "know" about them if that makes any sense.

I didn't start using them on a regular basis until ICAR (click here for ICAR) and manufacturer training. So I used them every single day in collision repair being they are the "standard of the industry" ways of "sectioning" panels.

And in those cases, I cut the backing from the old panel I just cut off to discard. The part you cut off the top to lower it of course is a perfect source for our backing! So why not cut an inch off this piece and use the whole darn thing for you backing, not just "patches" like on that Model A body.

You cut off an inch from the piece, trim the ends of course because you can't have it overlapping at the pinch weld (window lip), so you cut that portion off. But other than that or any other places where you need trim it. You leave the curves and body lines there, I mean, you HAVE THEM right there in front of you in that piece you cut off to lower the top! You don't have to make them, they are right there in front of you!

So, you take that one inch piece that fits perfectly (sometimes you need to reform it a little because it IS after all going on the inside of a curve and may need to be "shortened" by moving a bend to fit) along the entire weld. You butt weld it as in the photo above and end up with a perfectly strong joint. Where I agree is certainly with the plug welds. They are usually smaller (1/4" is plenty) and not as many as that test panel photo, that was for weld testing or practice or something, you don't need that many plug welds to hold that little strip in. But I DO plug weld it in because I want it perfectly placed and not moving around when I weld the seam. But that is just me and the way the "standard" is taught in the collision industry. There are MANY, MANY places where they are used in late model cars that are double panel like roof pillars and rockers where there is no way you can hold it, it MUST be plug welded.

But on something like this truck, sure if you wanted to you could clamp it in place when you weld your seam, in this case sure, if that is what you want to do and there is room, clamp it in. I personally still plug weld because it has became the norm for me.

Brian
 
#76 ·
deadbodyman said:
Another way is to "glue" your glass in with an edge moulding ,they come in many different widths and not use the big fat seal at all. The way theyre done today
Do you have any pictures of the glued in windshields? The one on this ford is a 2 piece windshield, that's why i felt the angle that i currently have in the pillar is still doable. I know too that i cut to high up into the curve, but it is a little late to recut. So i am going to make the best of this and like someone stated earlier, i will move onto other parts of the top fabrication and then move back to the windshield pillars....Since this is my first ever chop, i honestly think it isn't looking to bad and will not be perfect. With the tips i have just received on the backing plates and plug welds, i now know how i will line up the back of the cab for welding and the top of the roof. I just went and bought some little self tapping screws too, so i can pull the backing plate flush to the original metal and start my welding. Your guys help is greatly appreciated and with the knowledge i am gaining from this build, i think i may end up being a decent fabricator for these old cars.
 
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