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Discussion Starter · #1 ·
I am attempting to weld the passenger side toe pan in my 68 coupe. I have cut the old out and fitted the new. I am attempting to butt weld the two together and this is frustrating. I keep burning through the firewall and tunnel portion of the sheet metal. I have a weld pak HD from lincoln electric flux cored unit. Have the temperature switches on low and keep turning the speed lower and lower and now I have spattering welds and still burns. The pan looks horrible and I think I am going to cut it out, buy another and overlap the new and old by 1/4 inch. Any suggestions would be appreciated. I am currently using 0.35 wire. Thasnk in advance

eric
 

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Discussion Starter · #3 ·
Thanks for the reply. Does anyone know if 0.23 is available in gasless weldings (flux). Thanks
 

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You can try .030 FC. I am pretty sure no one offers any .023 FC. Too bad you can't gets some .023 and C25, you'd be set.
Grant
 

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I'm no pro but I have found a few good reads. This one may help with some of your problems.

http://www.millerwelds.com/education/articles/articles37.html

You will see that gas is recommended. It will also greatly reduce your splatter. It can be done with gasless but seems to be a little easier with the gas.

Good Luck
 

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Discussion Starter · #7 ·
I dropped the wire to 0.030 (smallest flux size at depot) and I cant even get the weld to hold ot the pan, jsut forms small beads and doesnt adhere to small pan. I went back to the 0.035 and bid the 2 second burst and that works nicely but cant do a continuous bead or it burns through. The burn is not a problem on the american racing toe boards. They are nice and heavy. The problem is on the original sheet metal of the car. Just pops a hole through. I think I am going to grind down what I have done and reassess the situation. thanks again

eric
 

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For 19 gauge sheet metal, which is typically found on Mustangs, you really should be using gas MIG systems with 0.025" wire. Anything larger or using flux-core will do exactly what you describe.

You have to use the right tool for the job.
 

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You could try placing a piece of copper behind the spot you're welding. It helps from burning through, and the weld won't stick to the copper. I keep a couple pieces of copper in my welding kit (2" wide by 3" flat bar & 1" long by 1" round bar).

But you'd do a lot better if you were using gas and smaller wire.

Good luck.
 

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You will never be able to run a continuous bead on sheet metal, especially with flux core. I'm using a 175 amp Lincoln mig (I can't remember what amperage the weld pak HD is, 140?). Anyway with mine set on B (second lowest of 5) on the amps and 3 (of 10) on the wire speed it welds the sheet metal perfect. This is with 0.023" wire and C-25 shielding gas, butt welding with about a 1/16" gap between panels. You MUST use the spot welding technique.

I consider myself a pretty good weldor with Mig and stick, and I have a heck of a time welding with flux core wire on 1/8" steel.
 

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Discussion Starter · #11 ·
Thanks for all the help guys. Going to try the copper idea provided by garner67 adn then just spot away. Its frustrating having had very good success with the front frame rail, aprons, and radiator support but now burning through the floors. I dont think the weldpak hd is upgradable to gas so I am going to have to bite the bullet and upgrade but thought I would try the copper.

Last question once I get the toe pan in are people butt welding the full floor pans or overlapping them?

I thought about overlapping them by an inch with aircraft fasteners I just bought from eastwood, then cutting the new floor and tunnel at the same time and tacking as I go making a butt weld. Maybe those with more experience have a different thought.

Eric
 

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I butt-welded floorpans in two '69 Machs. Your idea may very well work but that isn't how I approached it. I cut out all the rot, trimmed the replacement pan down some, placed pan over patch area, traced cut lines onto pan from underside. It will take a little more work than this but you get the idea. This gave me a near perfect fit(cut on the big side then trim down) that I had no problem butt-welding in. The proud on the weld was left in place for strength but, if ground down, the job would be 99% smooth and seamless. Looks much better when viewing from the underside or with carpet out.
Grant
 

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I have a Lincoln Weld Pak 100 HD and it is upgradeable to gas according to the manual I found online. (page 13)
"GAS CONNECTION (OPTIONAL)
When using the GMAW process, a K610-1 MIG conversion
kit and a cylinder of carbon dioxide (CO2) or argon-carbon
dioxide mixed shielding gas must be obtained. For more
information about the K610-1 MIG Conversion Kit for use
with the Weld-Pak 100HD, refer to the ACCESSORIES section"
Pm me if you need more info on the manual. I have it downloaded on my computer.
Course, I haven't tried to find this kit mentioned above yet. Hopefully it is still around. But I am sure something could be put together if it isn't.
hth,
Russ
 

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Discussion Starter · #14 ·
Hey Russ, thanks for the reply. I have a weldpak hd, dont know if that is different than the weldpak 100 hd, but I will call lincoln and ask them. I only have a high low switch and a 1/2 switch with a speed dial. I will post what I find out from lincoln.

Made some progress today with the 0.35 flux wire. (I know this is not the correct way but hear me out.)

The new pans I bought are from laurelmountain mustang and are the american racing 19 gauge pans. They are quite thick and tried today to burn through one with the welder and there was no signifincant burn through. So the problem is the existing metal that is thinner and the problem. What I have tried that seems to be working is I place the copper flush behind both pieces of metal. I then start the arc on the new 19 gauge pan cause when the arc starts is when I seem to get the most burn through. Then I move in a zigzag motion from the new to old pan. Seems if I just try to run down the middle the old sheet metal burns. The flux is messy but with a lot of grinding it may work. I will try to post a picture in the next 1=2 days.

eric
 

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I started out with Flux, and while it works, I would recommend the mig conversion or upgrade in the end. If you consider how much extra time it may take you to weld the welds, and then clean up from the flux mess, the expense isn't to bad. I was shocked at how easy it was to weld with gas on over flux.
 

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Discussion Starter · #16 ·
After the 300th attempt to fix holes I cut the pan out and through it across my garage. Will start over....this bites the big one.
 

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You really should be pulsing your welds instead of that zigzag technique (too much heat=blow through). Trying to weld a bead in thin sheet metal is going to result in blow through, especially with any wire larger than .023. Just hit the switch for a second and then do it again and again. Also, you should stagger your welds around the pan, eventually closing the gap until all the welds are joined to prevent warping. As stated by the majority, GO GAS!
 

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When you position the pan, you should quick tack it every 6 inches or so around the whole pan. Just a very quick, pop of the trigger should do it. If you do it every six inches around the pan, you will be able to come back and adjust between the tacks to ensure that you have good alignment, and then split the tacks in 1/2 with another round of tacks. You basically keep doing this until your tacks are 1/2 inch or less apart then it should just be tack, tack, tack to fill the gap. Skip two or three sets of tacks and do it again. You want to spread your heat around, or panel warpage will be a big problem. I work in 3 inch sections around the panel being welded in, and then come back and work the next set of tacks in 3 inch sections, and I have perfect welds when all is said and done. I guarantee you that 95% of your frustration is the fact that you have flux wire on your welder. Is there anyone local to you with a gas mig that could come over and show you the difference. It really and truthfully is night and day. You can still blow a hole out with gas, but it is far harder to do. If there is anyone local who can come show you a bit about welding, it will help alot. My neighbor is a structural steel welder, and he showed me how to do basic welding on larger metal. Sheet metal is so thin that you can't just lay a bead to it. Even trying to fill a hole, I find that it is more a series of tack welds. Anything else just makes the hole bigger.
 
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