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#2439981 - 01/24/18 10:18 AM panel making ? shrinker/stretcher
moparx Offline
Dreaming of implants

Registered: 09/03/03
Posts: 8632
Loc: north of coder
i just obtained a shrinker/stretcher to play with. i'm making outer rockers for my 33 humpback panel from 16ga. steel. the tool has specs for 20ga. stainless, 18ga. steel, and 16ga. aluminum. would it help if i heated the flange of the rockers before i used the tool to shrink it ? this does NOT need to come out perfect, just the basic curve to match the bottom of the truck. TIA.
beer

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#2440000 - 01/24/18 10:46 AM Re: panel making ? shrinker/stretcher [Re: moparx]
Old Ray Offline
member

Registered: 09/20/16
Posts: 99
Loc: British Columbia, Canada
My uneducated guess would be that it would not help, the heating would either disturb the original metal composition or have no effect after cooling. Maybe try a scrap piece and see the results?

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#2440134 - 01/24/18 02:17 PM Re: panel making ? shrinker/stretcher [Re: moparx]
68Cbarge Offline
master

Registered: 01/14/06
Posts: 3330
Loc: Canuckville
The laws of physics at play here..
Heating will expand (stretch) the metal,yet soft to bend.
Drawback is when it cools it will contract (or shrink) and will not be what you want when cooled.
Not doing any favours by heating it up.A risk of distorting the sheetmetal.Working the metal after it is heated/cooled can also harden it and tougher to work with.
Just more work than necessary,IMHO
With a good eye and elbow grease,test fit over and over and over till it is right.
Hope this helps.


Edited by 68Cbarge (01/24/18 02:20 PM)
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#2440193 - 01/24/18 04:34 PM Re: panel making ? shrinker/stretcher [Re: moparx]
earlymopar Offline
super stock

Registered: 01/30/03
Posts: 815
Loc: Oregon
Were the originals really 16 gauge? My 37 used a lot of 19 gauge (yes, 19 gauge) and some 18 gauge.

Do you have a profile shape you can show as to that you're trying to form? That would make it easier to comment on in terms of the tools to use.

- EM

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#2440212 - 01/24/18 05:26 PM Re: panel making ? shrinker/stretcher [Re: moparx]
poorboy Offline
master

Registered: 01/19/03
Posts: 6242
Loc: Freeport IL USA
Any time you work a tool at or above capacity, you run the risk of damaging to tool. Compared to the tool cost, the material is cheap.

Personally, I would be using 18G sheet metal for what you are making, but if your willing to take a chance on damaging the tool, try to bend the 16 gauge steel. Other then damage to the tool, damage or failure to bend the material is the worst that can happen.

I would also think that heating the steel can't be good for the shrinker/stretcher jaws. Again, your tool. Gene

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#2440460 - 01/25/18 08:13 AM Re: panel making ? shrinker/stretcher [Re: poorboy]
moparx Offline
Dreaming of implants

Registered: 09/03/03
Posts: 8632
Loc: north of coder
all of the comments made bring up thoughts i have had before i even acquired the tool. i'll take a pic or two later today or tomorrow showing what i want to accomplish. gene is absolutely right about possibly damaging the tool, but i think i'll try sneaking up on a piece of scrap just to see what happens. i'll pay special attention to the shrinker jaw teeth and the handle pivot area. the reason 16ga. is being used is i have some, and need the extra strength in the rocker area because the truck will be so low. the inner rocker will be welded with internal reinforcements, and was easy to fab because it was all straight shapes and 90* bends. if you guys can think of anything else, please comment.
beer

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#2440807 - 01/25/18 09:46 PM Re: panel making ? shrinker/stretcher [Re: moparx]
poorboy Offline
master

Registered: 01/19/03
Posts: 6242
Loc: Freeport IL USA
Moparx, I understand about wanting thicker metal in an area that may see more abuse, been there myself.

My 54 Dodge pickup sat pretty low, and I had running boards on it as well. I built the running boards, and they were mounted to the frame with 3 braces, 1/4" thick x 1 1/2" angle with an angle brace. I built the running boards with 16 gauge steel, formed with a 1/2" wide bottom lip, bent up 90 degrees for 2" then another 90 degree bend for the full width. The 1/2" flange sort of formed a "C" channel.

One time I went into a driveway that had a pretty big hump in it. Driving ever so slowly, about the center in the length of the driver side board scrapped the ground. I was going slow, and the running board was pretty thick steel with the channel, so I thought I would be OK. I was wrong.

That nice channel bowed up in the center before it bent in, and wrinkled to top surface of the running board for about a foot. Because it was 16 gauge, I couldn't straighten it out and finally ended up making a new running board. The new running board was made out of 18 gauge without the bottom lip. I bent it once and was able to straighten it back out.

Sometimes brute strength isn't what you want. That 16 gauge will fold up just as quickly as 18G or 20G under the weight of the truck, but will be a lot tougher to straighten. Gene


Attachments
Picture 036.jpg



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#2440926 - 01/26/18 08:45 AM Re: panel making ? shrinker/stretcher [Re: poorboy]
moparx Offline
Dreaming of implants

Registered: 09/03/03
Posts: 8632
Loc: north of coder
good point gene !
beer

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