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Technician
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Discussion Starter · #1 ·
I received a '55 Chevy 2 door post on a rotisserie that needs the body and paint work completed. It was media blasted and primed with epoxy by the shop before me, and they covered both quarters with plastic filler. According the the owner of the vehicle, the car had never been wrecked. It could be that all the filler was one guy's way of making the body perfectly straight, but something has me concerned.

The body, which is a completely disassembled shell, is mounted to the rotisserie at 4 points, the body mounts under the cowl, and the body mounts under the rear seat area. I'm concerned that the lack of support at the rear body mounts may be causing some distortion of the quarter panels. honestly, I have not done a lot of body-off work, but one car I was indirectly involved with seemed to have a quarter distortion problem after the fact that could have been from improper body support. Is this a concern? Should I fab some extra rear mounts? If so, what would be a good way to equalize the weight distribution against rotisserie bars that have a lot of flex in them from the weight?

Thanks in advance for any help,

Jon
 

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Brian Martin,Freelance adviser
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Without seeing exactly what the braces look like it is very hard to know how much weight they could support. A 50 year old car IS going to have some work to do, even if it has "never been in an accident".

But one concern that I would have is what "media" was used to blast the body and if they warped it.

Brian
 

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Technician
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Discussion Starter · #3 ·
I might need to post some pics. There are two 1 1/2'' square tubes running lenthwise under the body with jigs that go between them and the body in four places.

What I think needs to be done is to simulate the loading the body would experience if it was sitting on the frame. Right now the back part of the body has no support whatsoever. I guess I'm not super concerned about the presence of body filler, I just don't want to get it all perfectly straight and have it change shape and be wavy once it's bolted to the frame.
 

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Brian Martin,Freelance adviser
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I have to tell you, I would be seriously concerned doing that body work without it being bolted to the frame. If you can't duplicate the frames support, you may be in trouble.

Brian
 

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Technician
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Discussion Starter · #5 ·
That's what I think, but apparently it's done all the time. I may just find a way to set this sucker on jackstands to equalize the pressure, do all the blocking and priming on the quarters, then remount it to roll into the booth.
 

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Technician
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Discussion Starter · #7 ·
The support bars are actually 2" square, but even so they are bending a lot. If is was up to me, I would do the bodywork with the body sitting on the frame, but since the frame is all painted and assembled they are afraid to let me have it, am I don't really want to accept responsibility for protecting it from overspray. So I still need to find out if panel distortion is a problem on these cars, and come up with a way to support the body properly.
 

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I think what I would do is finish whatever has to be done on the underside then, making sure that the doors were on, transfer the body to a good frame mock up (or the original masked off) that supports the entire assembly witout stress. If the rear of the car is not supported, it will flop around, especially if the doors and any internal structure isn't installed (i.e. removed for pro street tubs). A pair two inch square tubing rotisserie bars are pretty light - my preference would be a 3" I-beam section, and that probably should even be boxed to minimize deflection, plus full length. :rolleyes:

Dave
 

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I had a similar situation, 69 Camaro convertible, tub was on a rotissery for 11 years with one quarter removed, the back panel cut loosed and the other quarter partially installed. It was a bowed and sagging mess. I unloaded it off the rotissery and placed jack stands at all the subframe mounts and at the rear leaf spring mounts and started mocking up the body-fitting the panels. Aligned the doors to the cowl and rocker, quarters to all their locating points while adjusting support under the car as needed, aligned the decklid and rear panel, test fit the clip then welded it all together. Then loaded it back on the rotissery and now the underside is ready for paint.
Now your car is a welded assembly so I'm sure the distoration of being on the rotissery is much less but If I were you and want to be sure all is well I'd pull it off and support it under the body mount locations and do a trial assembly and also check if the quarters distort and door openings open or close. Better now than after the paint is on. Also might want to brace up that rotissery mount more for better support. Bob
 

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Technician
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Discussion Starter · #10 ·
It looks like all your advice agrees with what I am seeing on this vehicle. I was hoping to learn a trick from someone who has done a lot of body-off work. Maybe there is no shortcut. Right now I am looking at unloading or at least unbolting this body and finding a better way to support it with the load equalized over the six mounts instead of the four in use now.
 

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Crash, Before you take it off the rotissery you could do a simple test. Loosen the bolts that support the tub under the seat area jut a little then lift the rear of the body slowly under the rear mounts and watch the quarter panels for any flex. Lift it slowly untill the body just starts to come up off the seat area mount then lower the rear back down half the distance total and you should be fairly close to simulating how the car is while on the frame. Hope this makes sense. If the tub is fairly stout and in good shape we are only talking about lifting the rear about 1/4" max I would guess. Play around with it and I'm sure you'll see if there's any strain causing quarter panel deformation.
 

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Being that the tub wasn't taken apart you should be in good shape if you can get the right amount of support under those rear mounts. I'd still like to testfit the doors and decklid just to make sure there isn't going to be any problems. Sounds like you've got one heck of a project there-hopefully you're not going to get stuck with assembling the whole car unless this is a pay by the hour deal.

I seen a nice 70 GTO convertible get quarters installed while on a rotissery, beautiful job but after all was painted and assembled on the frame both NOS quarters buckled big time right behind the wheel openings. I seen a 55 chev body at the blasters this fall that was setup right, they had an old frame with 12" pieces of pipe used to space the body up off the frame at all mounts and the whole assembly was on the rotissery-very sturdy.
 

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Technician
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Discussion Starter · #13 ·
Thanks for taking the time and thought to reply, baddbob. I too have seen a similar heartbreaking problem occur on a '65 Chevelle, when all the floors were replaced, body off, after all the bodywork had already been finished on the quarters.

After looking more at the problem, I think I may be able to fab two load equalizing t-bars that will balance the weight evenly while still mounted to the rotisserie. Maybe between that and keeping open the possibility of putting a shim or two in the body mounts once it's assembled will keep me out of trouble.

Still thinking...
 

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Paintshop Dog
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In my opinion, the rotisury is for finishing the bottom. So, I suggest finishing the bottom, then wrapping the frame in ceran-wrap, alot of it, tight, allover. If you use your head, you can even wrap it right down to the back of the wheel-plates, if it's a rolling chassis. The stuff works great. Then, you can put duct-tape over the body-mounts, cut holes for the bolts, and put the car on its own frame. Do all the body-work, paint work, and buffing. Then pick it back up and rip off the plastic, the frame should be just fine. In my opinion that's the best place to make a car really staright and really make certain of the fit of all the panels. In my experience no two bodies or two frames are ever really quite the same. And, even if you made a perfect jig to put the body on, chances are the chassis is not "perfect" anyway.

:thumbup: Good Luck with it!
 

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Discussion Starter · #17 ·
Something else that I didn't mention causes concern on this type of vehicle.

Most models earlier than the '55 have bolt-on real fenders and tall upright quarters that are rolled at the top and welded to the pan at the bottom, making a structure that is not prone to sag much, expect topless versions which of course sag big time in the door opening, but this does not visibly distort the straightness of the sheetmetal, what I've seen on these cars is a hinging of the body where the rocker meets the quarter.

Cars starting in the late 50's(?) started to be made with a stiff outer wheelhouse that was welded to the quarter wheel opening lip, making more of a semi-unitized structure for improved stiffness and strength.

The '55 is a transitional design. It has the streamlined, welded rear fenders that are now one and the same with the quarter, a design that is now common to almost all modern cars. What GM did not see the need for yet was to tie in the wheelhouse structure to the wheel opening lip, so on these cars you see an outer wheelhouse that stops without touching the outer quarter at all, instead it has a rubber seal to keep mud out of the inside of the quarter.

This design difference is really what made the alarm bells go off in the first place. Clearly the body is not designed to have much strength without the frame in place, even more so than later models, and it's easy to see how sagging of the rear body could drastically change the shape of the quarters, especially around the unsupported wheel opening.

I know that putting the body on the frame would be the very best way to assure that the body is in it's intended position, but still I resist the idea of trying to keep the perfectly done frame protected through this long process. I'm going to keep thinking about it and sure welcome more suggestions.

Thanks for all the advice so far!
 

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Just finished a 67 vette that needed full bodywork and paint, but was on a freshly powdercoated and highly detailed chassis (chalk marks,tags,stickers,etc)was a bit nervous about keeping this thing clean from overspray and all the priming and blocking, but it can be done successfully with a little extra time and care in the masking process. Used alot of the norton blue sheeting, makes things a lot easier. If you have to do it this way it really is not as bad as you would think.
 

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Paintshop Dog
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:sweat: Now, now, don't be so timed. You can do this, the mere fact that you are so concerned about the frame, tells me that you can do the car on it without doing any damage. Not sure I would advise using paper (plastic coating or not). But, sounds like that can work too. It's really simple, just run down to the local Uhaul or wherever, get a roll of plastic and go off. Stack on layer after layer until you satisfy your concerns. Trust me it can certainly be done, and has been done. And hey, remember if I can do it anyone can :D! Well... ...anyway! Jus git er dun! 'cause ya can! :thumbup:
 

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I believe the idea with the saran wrap is a good idea.

If you have to paint it off the chassis, the only way, (I think) would work is to set it on the chassis and torque it down, then duplicate that height, thats what I did to make my jig, you don't have to go to the extremes like I did, but you could make something up.

When I block out my body it will be saran wrapped and torqued to the chassis, because I will be moving it to a modern paint shop.

The difference in the floor of the paint shop and mine, I won't take that chance.

Anyway, just wanted to throw my two cents in here.

Rob

"There are questions to be answered, and answers to be questioned"

Chassis, Body Jig, Trunk Pan Pics.
http://webpages.charter.net/2manitowoc

Paint booth, Ventilation, etc.
http://www.2manitowoc.com/paintroom.html
 
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