Topic of Discussion TOD: Sheet Metal fab

[smashmetal]

Thanks for the kind words---OFN is a great forum as well.
1976 thru 80--- Iceland on EC 121's Super Connies---I was lucky to be one of the last reciep. crew chiefs. Everything else was jet aircraft with specialists for everything. Because these old birds were 52 and 53 models they needed extra care.LOL Iceland was nato at the time. The Air Force was phasing out the EC121's To the bone yards and bringing in the AWACS. There was along time in transission. during that time we had no specialists. The pigs had to fly so we did what ever it took. It seems to me like we had a master sgt. that was an airframe guy that would give some instruction once in awhile and sign it off. But Im not even sure about that anymore. Seem like a thousand years ago. I do remember sending the planes to Homestead where they would inspect further and make changes if required. But I will never forget the rivits, and frozen fingers. lol

Wowser, your an old dog thats been around the block. Lots changed since those days but it's always good to here a good story!
On with the tech.

 

[Metal Twister]

Wowser, your an old dog thats been around the block. Lots changed since those days but it's always good to here a good story!
On with the tech.

OLDER than dirt!!!

 

[redrock4x4]

Spot Weld

Hey all,

I recently welded in some patch panels on my cj using a mig and the alternating spot method. The patch panel fit was good and I thought I had pretty good penetration. However, when I smoothed off the welds with a grinder and flap disc, on close inspection I make out a tiny "crack" or outline of parts of the patch panel. I assume this means the penetration was not all that good and I need to do it again. If the weld penetrated correctly, the two pieces should be fused and I should not be able to tell the difference at the surface, correct?

Thanks in advance,
Brent

 

[Tacoma]

Sounds like it.

The latest Hot Rod has a cursory article on patch panels and bodywork...

 

[Metal Twister]

Hey all,

I recently welded in some patch panels on my cj using a mig and the alternating spot method. The patch panel fit was good and I thought I had pretty good penetration. However, when I smoothed off the welds with a grinder and flap disc, on close inspection I make out a tiny "crack" or outline of parts of the patch panel. I assume this means the penetration was not all that good and I need to do it again. If the weld penetrated correctly, the two pieces should be fused and I should not be able to tell the difference at the surface, correct?

Thanks in advance,
Brent

That is correct, Try turning the heat up a bit and holding the trigger just a little longer. It should work great with just a little practice.

 

[ProStreetZ28]

When I was a fabricator at Year One I stepped most of the patch panels and drilled the 3/16" holes in the surface metal (original panel) and filled them with weld. This way when you grind the weld back down it sitll has the thickness of the original panel. The I used the alternating spot method to fill the small crevous where the two panels meet. If the panel was going to visable from both sides I wouldn't step the patch panel, in that case I would make my patch panel slightly smaller them the hole so that there was a roughly 1/16" gap all the way around and did the spot method to fill the gap and weld the panel in place. For sheet metal work I would run an .024" wire in my welder so that I could keep the temperature down.

 

[Tacoma]

Wish you were still here!!!

 

[webyepn]

Just out of curriosity.. I may not be understanding all of you guys on how you are doing patch panels. But the way I was tought is a pair of sissors and a piece of cardboard. you cut it to fit into the hole then transfer it on to you sheet metal then you have a perfect match. You can also get contor with cardboard as well???

 

[YROC FAB.]

to get a true sparkfree spray transfer you need atleast 90% argon

 

[turbosniper1]

On the subject of sheet metal working and tools for working the metal, I am surprised that nobody has brought up the sheet metal break. It is one of those tools that you look at and you see people using and think to yourself, "if I had one of those, I could really make some great parts!" Well, it is not that difficult.. or expensive to just make your own break.

I had looked around at all of the breaks that were out there and came up with a design of my own. I used scrap metal that I had laying around in the scrap pile, a couple 2" door hinges from Home Depot ($2 each), and two 3/4" x 1 1/2" long bolts with wing nuts & washers (hardware store, about $3)..

1). Take an old CJ-7 front bumper and cut 3' out of the middle,
2). Cut 2 pieces of 3" x 1/4" Angle Iron, 3' long
- one of the pieces could be substituted for a piece of heavy plate, about 3' long, 4" tall, and a minimum of 1/4" thick but recommend 3/8".
3). Use solid stock, or small diameter-thick wall tubing to make the double handles
4) Weld and bolt everything together.... and Voila!!!! One heavy duty, Homemade Sheet Metal Brake! :greg:

Insert the sheet metal and tighten the wing nuts to lock it in place.....

Make the bend....

And here is the final product!!!

Not bad for a $10 Sheet Metal Brake!!!
I hope this gives you some ideas to go out to the shop and make your own tools!
- Matt

 

[TwistedRubi]

A quick easy way to bend light gauge sheet is to clamp your piece between two pieces of 3/16 or 1/4 in a vise and just fold it over by hand or with a body hammer. If it's too big to fit in a vise, you can clamp the pieces with vise grips. When it comes to welding, fit the pieces as tight as possible with no gap and tack weld in several places, the thinner the material the closer the tacks need to be, then grind the tacks down and weld all around. Turn down the heat and keep moving if you slow down or stop you'll burn through. Silicon bronze wire is great for light gauge material.