Budget Shortbed: welding, grinding, rust oh my

[KevinK7]

Like others have noted, excellent excellent work. I've restored a few Camaros and have been following car forums for years (more recently the trucks), and some people's skills (and determination!) never cease to amaze me.
Kudos again for the talent, but as well for taking time for photos to share with us all.
Keep up the great work

[70LonghornCST]

You make it look so easy! Excellent thread!

[Onry69CST]

Thank you everyone! Your motivating me as well, I've got about 70 hrs into the drivers side and the finish is in sight. It's hard to update more than a few times a week from burning the midnight oil.

I will try to put together a few posts on my welding and finishing methods, they are changing all the time.

The rocker, kick panel, cab support, and floor is in and needs finish work now. I tried raising the A pillar area up a 1/16th inch back to initial measurements, but it came back down after welding. Maybe I should have over compensated some.

[Onry69CST]

I had a tough time welding the cab support bracket back the way its done from the factory, so I welded it on top and bottom.

It's funny, I allways feel like I'm missing steps, trying to sum up hours of work with a few pictures. But cutting, sanding, and pounding things around - is really all the filler I'm not mentioning, and all I can remember!

[Onry69CST]

Here's a little bit on my welding process. In order to feel like I'm making this worthwhile I have to get detailed, so please excuse my long winded posts.

First off I just switched my welder over to start MIG welding this project. MIG (metal inert gas) is actually slang for GMAW (gas metal arc welding). I used flux core arc welding at home before that, for the last 15 years. Flux core is great because you don't need gas, the flux inside the wire melts/vaporizes and protects the molten metal for the atmosphere. It's also very forgiving on dirty metal, and can increase your penetration for thicker materials. But flux core creates a lot of spatter which translates to more weld finishing. There are parts of welding the floor in which I would of rather had flux core, but for the most part I'm much happier to be mig welding this.

My set up is 30 year old retail Lincoln 120 volt machine, with 0.025 solid core wire, 80/20 Argon CO2 mix. I transition between settings for 16ga and 14ga.

[Onry69CST]

Here's an example of what I would do on a typical panel.
-maintain a gap of roughly the material thickness
-if I'm worried about the gap closing (it will) I'll add shims to prevent it.
-tack strategically between shims or in the center of long spans
-start with a few small, hot tacks a few inches apart , moving around from side to side to spread the heat out.
-split the difference between tacks until you end up with about a half inch between tacks
-at this point I'll run a bead if possible to connect each tack, while still alternating around the panel. If I'm burning through while running a bead, I'll do several short tacks, not allowing the last tack to cool at all, to span the half inch.

Sheetmetal is tough. You must be constantly be on the edge of burning through your material to get proper penetration, but do it in very localized areas at a time to prevent warpage. I started using my half inch bead method so that I could put enough heat into that spot so I have a chance at penetrating the tacks at the start and finish of the weld. When wire welding like this, the start of the weld will have almost no penetration, and weld will build up in the start very fast preventing any further penetration. To counteract this, I'll often start my weld in front of the half inch span, on top of the tack. By the time i weld over the first tack this creates enough heat to allow penetration next to it. It ends up looking like a nastly weld on top though, not much you can do about that.

Essentially each tack is a heatsink, sucking your welding heat away, creating a cold weld
with little penetration around it.

[Onry69CST]

Process

[Onry69CST]

I was happy with this, then I looked at the backside and realized I wasn't paying much attention to melting the tacks in. So heres a perfect example of what I described. If you look close you can see the lack of penetration on either side of each tack.

Then I checked the underneath of my floorpan and was relieved to see I was paying attention when it counted.

[Onry69CST]

To finish the welds I use a grinding wheel on die grinder to take off a bulk of the material, then a sanding disk on an angled die grinder to take it flush. But sometimes to have to get out every unthinkable tool in odd locations.

[flashed]

From what a lot of my Chevelle friends in Northern Ohio tell me you guys dont have the best cars and trucks to start with so you learn to fix damn near anything . One friend up there uses me to find him better projects down here from time to time .

[Chevys4life]

Thanks for the great write-up with detailed pictures on your welding process. I purchased a Idealarc SP-150 Lincoln welder with my buddy a couple years back. He has been using it to do the welding that I needed for my other projects. I want to learn how to weld myself now since I have a truck that needs plenty of it. Do you know anything about the welder that I have mentioned above?

[HO455]

Excellent write up. I wish I could have had it years ago when I first tried to put cab corners on my AD. After years of steel fabrication I went round and round trying to get the welder set up to make make nice welds on sheet metal. Grrr! I knew enough to do tack welds to keep things from warping but that was about it. Your write up would have saved me lots of time.
Have you done any work with Silcone Bronze MIG wire? A friend demonstrated to me how they were using it on new car repairs. It looked pretty interested, but like everything, I'm sure there are drawbacks you only learn by doing

[Onry69CST]

Yeah most vehicles rot out in twenty years here with the snow and salt. The ironic part is this truck is from S Carolina originally.

Chevys4Life - I don't know much about that one, but I looked at the manual and it looks like a good old school machine. It probably has mostly copper internals and is transformer based so it should be around a while. For most MIG welders, the gremlins are in the mechanically moving components like the wire feeder or gun itself. The wire feeder is the mechanism that spins the drive rolls, that pushes the wire through the gun. It has to be adjusted with the proper spring tension to pinch the wire and force it down the gun liner. Not enough spring compression and you'll have intermittent feeding problems - which you will notice when the wire burns back to the tip when welding. The spool of wire is also held in place by a spring, and must be of proper tension as well. Not enough and the wire will unravel, and too much and the drive rolls won't be able to pull the wire off the spool. Of course the gun contact tip and drive rolls must match your wire diameter as well. It's all in the setup.

For starting out mig welding, try welding close and far away from your workpiece untill you get the smooth arc that you want and keep it there. The farther your gun tip is away while welding, the colder the weld will be, if you get too close it will get spattery and you'll ruin the contact tip. They call this CTWD, contact tip to work distance, and generally around a half inch is nice. But - you can use this phenomenon to your advantage welding sheet metal, if it's getting too hot at the end of a weld pull away just a bit to take some heat out.

Scientifically this is Ohms law at work. Voltage equals current times resistance. Since MIG welding is a CV (constant voltage) process, your amperage and resistance will vary to maintain your voltage setting. Since current times resistance allways has to be constant, when you increase one the other must drop. When you try to weld far away from your workpiece, you have raised the resistance and the amperage must drop, resulting in less heat.

[Onry69CST]

HO455 - I've seen the Silicone Bronze too and it is really awesome. I'd like to give it a try one of these days. The only thing about it is it's actually brazing, not welding. It's still plenty strong for non structural body panels though.

[Onry69CST]

I did end up getting the floorpan and B piller lower in over the last few days. The

The floorpan was just a ton of work to make fit and by far the hardest to make right. The rib had to be moved, I cut the dimple for the body bolt out to reshape it, deepen it, and move it, and the front left corner had to be totally reworked and pushed in a half inch down to meet the cab brace over an entire square foot. I probably have 15 hours in all that..but it all worked out.

I ended up hammering down the front left corner about half the distance out of the car. Then I tacked it in, leaving the area that still needed work free. After it was attached everywhere else firmly, I bolted it to the lower cab support and beat it down into shape. Sometimes it's alot easier to work it once its in

[Onry69CST]

The dimple was pretty pathetic looking, and only half as deep as it should be to recess the body bolt. I pounded it around and then used a hydraulic press to draw it deeper. I took it to the point I thought it might split and still needed more depth to contact the support plate. I found some washers and tig welded them to the bottom of it to make up the difference. The bolt head is flush with the floor now.

[Getter-Done]

Nice Work.
Thanks for the detailed explanations and pictures.
I am subbed.














.

[Chevys4life]

Originally Posted by Onry69CST

Yeah most vehicles rot out in twenty years here with the snow and salt. The ironic part is this truck is from S Carolina originally.

Chevys4Life - I don't know much about that one, but I looked at the manual and it looks like a good old school machine. It probably has mostly copper internals and is transformer based so it should be around a while. For most MIG welders, the gremlins are in the mechanically moving components like the wire feeder or gun itself. The wire feeder is the mechanism that spins the drive rolls, that pushes the wire through the gun. It has to be adjusted with the proper spring tension to pinch the wire and force it down the gun liner. Not enough spring compression and you'll have intermittent feeding problems - which you will notice when the wire burns back to the tip when welding. The spool of wire is also held in place by a spring, and must be of proper tension as well. Not enough and the wire will unravel, and too much and the drive rolls won't be able to pull the wire off the spool. Of course the gun contact tip and drive rolls must match your wire diameter as well. It's all in the setup.

For starting out mig welding, try welding close and far away from your workpiece untill you get the smooth arc that you want and keep it there. The farther your gun tip is away while welding, the colder the weld will be, if you get too close it will get spattery and you'll ruin the contact tip. They call this CTWD, contact tip to work distance, and generally around a half inch is nice. But - you can use this phenomenon to your advantage welding sheet metal, if it's getting too hot at the end of a weld pull away just a bit to take some heat out.

Scientifically this is Ohms law at work. Voltage equals current times resistance. Since MIG welding is a CV (constant voltage) process, your amperage and resistance will vary to maintain your voltage setting. Since current times resistance allways has to be constant, when you increase one the other must drop. When you try to weld far away from your workpiece, you have raised the resistance and the amperage must drop, resulting in less heat.

Thanks for the great information!!!

[Chevys4life]

Yes...........man you really do a nice job welding in those path panels. Great Work!!! And again thanks for the detailed explanations and photos.

[Onry69CST]

Thank you very much!

Everytime I think the next panel is going to be an easy fit, and I'm so wrong. If the panels were correct I think the job of each floor side would be cut down to around 40 hours, and I'll have a hundred for sure.

After trimming the B pillar lower it was apparent that 3 out of the 4 bends had to be moved. So I made a center bend my reference at the door opening edge, and unfolded the other 3 bends. I had to take material from the rocker flange when I rebent it, so it would meet the rocker, and this left the flange at only about a quarter inch. I welded another half inch peice on it to widen the flange. The other two bends I had to bring towards the door and ended up trimming off a half inch when I was done.

[Onry69CST]

The cab corner fit decent, but again I had to stretch the flange that meets the rocker to fit. Since it was a flange around a curve I had to cut it at the curve to unfold it and work it. It makes me wonder if the inner rock is too far in, but I was extremely careful about maintaining the original location, and all my measurements confirm this.

Now I'm ready for the outer rocker! I think I'll toss the door on before I weld it just to make sure its ok.

[7D2N]

Thanks for sharing the welding of patch panels. Awesome work.

[Chevys4life]

Thanks for sharing too. I now have an idea of how these panels go together after the floor is pan is cut for repair. This gives me a basis for a plan of attack on my cab when the time comes and have visual references to refer back to.

[clay68c10]

Nice work and documentation.
Definitely put a door on before you get too far fitting the outer rocker. You may find that the outer face of the rocker has a bow to it. Higher in the center and lower at the front and rear. That’s what I found with mine. You can see it in my build thread, along with the same fitment fits you went thru.

[72bowtiestepper]

Very nice work from someone that did most of the panel replacements that you did ( but not as neatly !) It takes a ton of time to get these old trucks back on the road after being rusted top to bottom, but looking at & driving them when finished makes all the work worthwhile. I used a Miller 115 volt MIG to do mine with .025 wire & argon CO2 mix gas. Doing the work yourself is VERY rewarding when the job comes out good !