Got A Stupid Total Newb Sheetmetal Question

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Just joined the site and currently in the process of researching/educating myself on welding. I don't think I've ever seen a welder in person so I'm really starting from the beginning lol. I have a bit of a predicament on my hands with my truck. Just bought the stupid truck a few months ago, a used 2012 Sierra SLE Z71. I noticed some paint bubbling on the external portion of the wheel well. I thought it was a minor rust issue so I wire brushed the paint away and found pretty extensive rust damage, it went through both layers of the sheet metal. I'm planning on borrowing my brother's crappy Harbor Freight welder that he never uses to attempt a fix. I'll probably practice spot welds/tacking (sorry still trying to learn the terms) sheet metal that's the same gauge as the truck's body for about a month or so before attempting the fix. I'm also going to buy and study the book Welding: Principles and Applications 7th edition. It's $28 on Amazon so I figure that's a good buy to at least make me not as clueless as I am right now. Sorry, long *** post already. Too many details. Anyway, as a more experienced welder, would you recommend buying new sheet metal and trying to fabricate/bend to the correct shape? Or I was thinking I could, if I'm lucky, find a truck at one of the local junk yards with the same truck bed style and cut out the section from the rear wheel wells. I'll probably have to use a hacksaw to cut it out though lol. If you read all that, thanks for your patience. I'm hoping I don't completely screw up and come to hate welding. I've wanted to learn how to weld for a long time and this truck is forcing me to jump in now. Planning on buying either the Hobart 140 or 210 MVP in the near future if I come to like welding. ThanksP.S. the truck is my secondary vehicle so I rarely drive it. I'm in no real rush to fix it.
Reply:You might be able to buy partial panels for your truck that will already be formed on dies with the appropriate compound curves, and then weld them into place. That's what I did to replace some areas on my 2001 F-250. If you try to do it with sheet metal, and then form those compound curves yourself, you'll need to learn metal forming in addition to welding...and you might not get as nice of a finish, at least not without plastic or FRP filler. It'll be more expensive than doing it with raw sheet metal, but it'll also be faster and probably come out better. Just something to think about.Welcome to the forum.
Reply:So first, I wouldn't even think of trying to find a good use part at the J-Yard, you'll probably end up with one that's either been repaired or "just about" to rust thru

Maybe a place like LMC has a replacement wheel opening?Next, what kind of HF welder does your brother have? I mean, you don't want to Stick weld it and you're gonna have a hard time learning the basics of TIG for this. You'd want a MIG welder of some sort (and HF does have some that might fit the bill).Good Vid ->
Reply:Look on eBay for wheel arch repair panels. I would just bond them with panel adhesive. That's a large area that will warp badly even for an experienced person.
Reply:

Originally Posted by Kelvin

You might be able to buy partial panels for your truck that will already be formed on dies with the appropriate compound curves, and then weld them into place. That's what I did to replace some areas on my 2001 F-250. If you try to do it with sheet metal, and then form those compound curves yourself, you'll need to learn metal forming in addition to welding...and you might not get as nice of a finish, at least not without plastic or FRP filler. It'll be more expensive than doing it with raw sheet metal, but it'll also be faster and probably come out better. Just something to think about.Welcome to the forum.
Reply:

Originally Posted by M J D

Look on eBay for wheel arch repair panels. I would just bond them with panel adhesive. That's a large area that will warp badly even for an experienced person.
Reply:Here's a pic of what I'm dealing with:


Reply:Trim the other side to match and paint it... done

although you can't see both sides at once.. so... paint and done

Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power

) Hobart MIG
Reply:*Which* Harbor Freight welder matters.  I have the Titanium 125, which I like, and I think could do a good job of welding sheet metal (because it's an inverter).  As mentioned, MIG is the proper way to do it, though.  I also have one of the older cheap HF welders and I don't think I would use it for sheet metal.  I think I even tried once and gave up in frustration.  It doesn't have enough heat control; I think the lowest setting is still too high (causes burn-through).
Reply:

Originally Posted by SquirmyPug

Trim the other side to match and paint it... done

although you can't see both sides at once.. so... paint and done


Reply:

Originally Posted by Ambull01

lol that's true. I have to do the other side too I believe, I see the same bubbling through the paint. I tried to ask him what model he has several times but he just says it's a mig. So frustrating. I'm about to buy the Hobart 210 MVP anyway and start practicing with it. Tried to find a welding class/school near me but so far no luck. Guess it's going to be book reading, YouTube videos, and tinkering with it in the garage.
Reply:

. This is a 2002 Silverado I did about a year ago. I used screws to hold it in place. Panel adhesive with about 3/4" overlap.Miller xmt304,  Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.
Reply:

this is after paint and before doing the final black and flares on the truck. I'm not a body man but have done quite a few rust repairs over the years. Last truck I welded in wheel arch panels was a 86 Chevy  K-20. The metal is so thin on this " newer" stuff. Rockers and cab corners I welded, but that large surface over a wheel well arch is asking for major warpage. I understand the OPs desire to weld but that arch area isn't the place to learn. Good luck on your repairs.Miller xmt304,  Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.
Reply:Yep... pay attention to what MJD is telling you. If you want to play, play... but if you want your truck to look nice when you're done, that's the way to go. Check around locally and see if there are any night courses you could take in welding this winter... that would get you up and running a lot faster than trial and error via Youtubes. Even installing a complete box side is a big job for a newbie welder. If you do try welding, pay attention to your gas fillers. The learning curve there is very abrupt.Last edited by whtbaron; 8 Hours Ago at 07:51 PM.250 amp Miller DialArc AC/DC StickF-225 amp Forney AC Stick230 amp Sears AC StickLincoln 180C MIGVictor Medalist 350 O/ACut 50 PlasmaLes
Reply:My '99 Silverado 2500 came with plastic fender well covers,, they basically snap in place,,

Other than the stock ones, I think I have seen all sorts of aftermarket extensions,, that might be the no-weld/no-Bondo/no-paint method of wheel well repair??There is some guy on Amazon that has snap into place rocker covers, and cab corners,,


Reply:

Originally Posted by M J D

. This is a 2002 Silverado I did about a year ago. I used screws to hold it in place. Panel adhesive with about 3/4" overlap.
Reply:That bonding adhesive is strong shlt. Rough it up with 36 grit and clean well. Notice the radiused corner on the panel. Cutting that in my opinion is key to preventing cracks in the future. I forgot to add, when done with the repair, coat the backside. I ground the backside down but primed and painted right up to the overlap before applying the repair panel. Afterwards rubberized undercoating. After that is fully cured, fluid film or some type of oil to prevent corrosion. Not sure where your at but in Wisconsin road salt can start in October and run into May. I douse the underside with fluid film every fall to prevent future corrosion.
Reply:

Originally Posted by SweetMK

My '99 Silverado 2500 came with plastic fender well covers,, they basically snap in place,,Other than the stock ones, I think I have seen all sorts of aftermarket extensions,, that might be the no-weld/no-Bondo/no-paint method of wheel well repair??There is some guy on Amazon that has snap into place rocker covers, and cab corners,,


Reply:If it fits up good on the other layer the adhesive will work well. A lot of the multiple layer construction uses foam as an adhesive and sound deadening agent. In my opinion that shlt is the chief cause of that rust. I rip all of that crap out that I can reach. If the panel needs reinforcement, I bend a piece of sheet metal, bond it to the inaccessible side first. Then on the repair panel, grind back where it bonds and apply adhesive to the brace. My theory is, right wrong or otherwise, is if crap can get in, make sure it can come out. I'm not as familiar with the series after the " classic", but I would almost guarantee that the areas that are prone to rust have that foam shlt right there.
Reply:A couple tips I will give you, keep in mind I'm no body man, auto restoration expert, etc. Get your self a " long board" sander. Harbor freight one is decent. Buy good 3m tape for masking and masking paper, not newspaper. Harbor freight has adequate paper for cheap. Use fiberglass reinforced body filler for a first coat over the seams as it will prevent cracks. When sanding with the long board, once you hit metal, stop and knock that spot down and apply another coat of filler. If you see the slightest imperfection it will be magnified 10 fold with paint.
Reply:

Originally Posted by whtbaron

Yep... pay attention to what MJD is telling you. If you want to play, play... but if you want your truck to look nice when you're done, that's the way to go. Check around locally and see if there are any night courses you could take in welding this winter... that would get you up and running a lot faster than trial and error via Youtubes. Even installing a complete box side is a big job for a newbie welder. If you do try welding, pay attention to your gas fillers. The learning curve there is very abrupt.
Reply:About the only paint I would attempt to spot and blend on a panel that size, would be lacquer and I doubt you'll even find that know. Some basecoat/clearcoats might work out alright, but you'll still be shooting the entire panel in clear.  You'll be shooting both box sides before you're done.250 amp Miller DialArc AC/DC StickF-225 amp Forney AC Stick230 amp Sears AC StickLincoln 180C MIGVictor Medalist 350 O/ACut 50 PlasmaLes