Welding cracks in sheet metal

[sandybeach]

The sheet metal floorboard of my truck has developed stress cracks where the seat bolts through the floor. The truck is a '95 and has more than 200 K miles.

I think the best procedure would be to repair the cracks by welding them. However, I'm open to suggestions on a better way to solve the problem.

While I have done stick welding for decades, I've never used a wire feed (flux core) welder before. Since Santa brought me a wire-feeder, it seems like a good starter project. Still, I plan to practice with some scrap steel before attacking the truck.

Assuming that this approach is a good one, I need some tips, tricks, and traps.

The gas tank is 50"+ away from the damage; there are no fuel lines in the vicinity. Also, both of the truck's frames are between the damaged area and the fuel line.

Even given that distance from the fuel tank and lines, is this idea still too dangerous?

It's 16 ga steel. I've wire-brushed down to bare metal. I've also stop-drilled the cracks to keep them from getting worse. What diameter flux-core wire should I use? I have the .030 wire that came with the welder.

It's hard - or impossible - to apply a ground clamp to the floorboard. 2 possibilities:

1. clamp to a nearby steel part that is factory spot-welded to the floor
2. tightly install a bolt in a hole that's a few inches away, and clamp to the bolt

Would it be better to ignore the cracks and bolt (or weld) a 16 ga (or larger) patch over the damaged area and bolt the seat through the patch?

Or both repair the cracks and apply patch (bolted or welded).

Or ??? I'm open to other ideas.

 

[Shield Arc]

I take it as your wire feeder is not a Mig machine? Flux core is not the best method. .023 Mig would be my first choice. But it can be done with flux core. Make tacks every inch or so, make your welds from one tack to the other, let cool and move to another area. Do not be afraid to walk away and let things cool down!

Put a short piece of flatbar in your ground clamp, and tack the flatbar real close to the weld zone. Just to be safe first disconnect your battery!

 

[BIG DOOLEY]

The sheet metal floorboard of my truck has developed stress cracks where the seat bolts through the floor. The truck is a '95 and has more than 200 K miles.

I think the best procedure would be to repair the cracks by welding them. However, I'm open to suggestions on a better way to solve the problem.

While I have done stick welding for decades, I've never used a wire feed (flux core) welder before. Since Santa brought me a wire-feeder, it seems like a good starter project. Still, I plan to practice with some scrap steel before attacking the truck.

Assuming that this approach is a good one, I need some tips, tricks, and traps.

The gas tank is 50"+ away from the damage; there are no fuel lines in the vicinity. Also, both of the truck's frames are between the damaged area and the fuel line.

Even given that distance from the fuel tank and lines, is this idea still too dangerous?

It's 16 ga steel. I've wire-brushed down to bare metal. I've also stop-drilled the cracks to keep them from getting worse. What diameter flux-core wire should I use? I have the .030 wire that came with the welder.

It's hard - or impossible - to apply a ground clamp to the floorboard. 2 possibilities:

1. clamp to a nearby steel part that is factory spot-welded to the floor
2. tightly install a bolt in a hole that's a few inches away, and clamp to the bolt

Would it be better to ignore the cracks and bolt (or weld) a 16 ga (or larger) patch over the damaged area and bolt the seat through the patch?

Or both repair the cracks and apply patch (bolted or welded).

Or ??? I'm open to other ideas.

I would weld a patch due to metal fatigue and strengthen the areas.
Word of caution.
These photo's are what welding on a vechicle's floor inside a building unsafely can look like.
In my neighborhood 2010?
It's hard to stop a train also to put out a pickup truck on fire

 

[RoyJackson]

Definitely stop drill the cracks first...otherwise, they can propagate further as they are being welded.
That said, I would consider patching (Use rivets) before a weld repair.

 

[k0ua]

I can tell you what I saw many years ago. One of our company vans had cracks like that in front of and around the seat. The repair man took and oxy/ace torch and welded them shut with of all things for a filler rod, coat hangers. The cracks did not re-open. the man seemed very skilled.

James K0UA

 

[Shield Arc]

I remember when all we were ever given was tie wire and coat hangers for oxygen & acetylene welding. :laughing:

 

[sandybeach]

"... welded them shut with of all things for a filler rod, coat hangers."

Is there any other kind of filler rod? :thumbsup: I keep a couple of bronze sticks on hand, but outside of that, I rummage through the closets when I need to gas weld. But today's plastic hangers don't work too well. I might have to go shoplifting at a dry-cleaner's place .... if I could find one.

In this case, I'm leery of torch welding. It's too confined a space.

 

[sandybeach]

My Mrs. is a metalsmith. After 30+ years using propane (like she learned in college) she discovered oxy-ac. She got a couple of gas tanks. For the small jobs she does, those tanks last a long time. First time both of the tanks went dry, she put the tanks in her SUV to take to the parts store (it's a very small town with no welding supply store).

Normally I trust her judgment and don't question her actions. This time I had a fit! I described the horror films they show in welding class - the ones that show what happens when acetylene explodes in a confined space. So she put the caps from my tanks on hers, stood the tanks up & lashed them in place in the open bed of the pickup, and drove off - safely.

In pre-electric light days (and even later in houses off the grid), some houses had acetylene lights. To make it even more dangerous, some of those houses (maybe all) generated their own acetylene. Also, way back when .... car headlights ran off self-generated acetylene. And then there were the miner's helmets that had headlamps that ran off gas created by dropping water on to Calcium Chloride rocks.

I break out in a cold sweat just thinking about those "good old days." Do a Google search on "acetylene explosions."

 

[4shorts]

Using steel coat hangers for filler rod material has been done for much longer than I can remember But a little warning to those who do it these days. Steel coat hangers have a shellac on them to prevent corrosion. Sand off that shellac before using them as a filler rod because the fumes can make you very very Ill.
Just say'in :confused3:

 

[k0ua]

Using steel coat hangers for filler rod material has been done for much longer than I can remember But a little warning to those who do it these days. Steel coat hangers have a shellac on them to prevent corrosion. Sand off that shellac before using them as a filler rod because the fumes can make you very very Ill.
Just say'in :confused3:

I will just stick with the RG-45 filler rod. It is not terribly expensive.