At times rust repair can be ultra simple; cut the old rust out, cut a square of fresh metal and weld it in. But those repairs aren’t usually as frequent as we’d like. Rust seems to like to creep into a curved area or into a body line that takes more care to repair. I recently decided to tackle a large rusty area of the rear portion of the floor on Project Pile House. This area was behind the seat and sat under the original gas tank. Over the years a rusty tank leaked and contaminated the metal underneath. What I was left with was swiss cheese. I wanted to replace this metal completely and make the repair relatively stock looking.
A big part of making a rust repair job go smoothly is to study the damaged area and really think through the repair process before just cutting right into the car and having to change direction afterwards. Above you can see what I was working with. The center section of the panel was rotted away completely and the surrounding areas were eaten away. I also had rust that had rusted away on the back lower outer cab sheet metal, what a mess! I decided to remove the entire width of the floor section that was damaged so I could repair the lower cab skin more easily. I started by using a pneumatic body saw to cut along the corners and the front edge of the damaged area; leaving the stepped bead in place. The majority of the back panel was separated from the metal, so I got off easy. Originally the back panel would have been spot welded to the flange on the floor and they would have had to been drilled out. Cutting the panel this way will leave a clean butt weld between the original floor and the new patch panel.
With the damaged area out we can really see what we’re working with. The metal is very bad in the center as we imagined, but I also noticed it was rotted evenly along almost the entire flange that would have been spot welded to the back of the cab. Another complication was because the part fits in the curve of the back of the cab; the flange and the stepped bead changed dimensions across the piece. I decided to take measurements off of the best side of the part and transfer them to a piece of cardboard to get the initial shape of the patch panel.
With overall shape of the panel laid out on the cardboard. I took a scribe and traced the outside shape of my pattern. I then used a set of dividers and transferred the width of the back flange into the new metal. The scribed line will eventually be my line where we turn the flange. I then removed the pattern and used a divider again to mark out the stepped bead line.
Finally I cut out the patch with the electric shears, leaving an 1/8th or less of the line and came back with the aviation snips to cut accurately right on my cut line. I then used a fresh sharpie to mark my bend and bead line.
Next I mounted the manual bead roller in the vice and set up the offset step dies to make the stepped bead in the panel for strength. I ran a few test pieces to get the size and depth of the bead pretty close to the original. With a helper I rolled the step into the panel.
I then switched the dies and inserted the soft lower wheel and the smallest radius upper die on the bead roller. This step you won’t be able to do in one pass no matter how fancy or expensive of a bead roller you have. You first must make a pass with moderate pressure between the dies and pull up lightly on the panel as it rolls through the rollers. This first pass creates a “track” for the wheel to run in and subsequent passes require less effort to keep the dies on the line. This means more focus can be put on the upward pressure used to tip the flange. Above you can see the panel after three passes. Depending on the shape of your panel it may fight you in the corners because it is trying to tip and there’s too much metal to move. This was the case in our situation. You can solve this by tuck shrinking the corners or putting relief cuts in the corners, removing the excess overlapped metal and welding the seams. The shape of our piece I couldn’t quite get a 90 degree flange on in the bead roller so I used a hammer and dolly to fold the edge over the last few degrees.
With the panel shaped I test fit it in the truck and it should fit well with some very minor adjustments. Before welding the panel in place I’ll clean the entire panel with fast etch. Other than making the pattern, the most tedious part was hammering the flange over the last few degrees. Hopefully anyone with a similar repair can get some ideas from how I did this one.
-Matt/EW
The best bet is to use an access hole in the backside or drilling a small hole and applying our Internal Frame Coating.
I love the info. good pictures very informative. Can always use info from other peoples projects. mines a 54 chevy truck . putting it on 74 blazer frame thank you
Good article. Hammer and dollying mig welds is tough the welds tend to be brittle and will break. Tig welds you can beat on all you like
What can be done when welding a small repair patch when ya can’t get to the back side of the weld to clean and prime ,paint? welding starts the rust process
Great point Jeff! More than one way to do a job and come out with the same results. Thanks for the great input!
very helpful, thanks for the tips.
I’m working on a 42 MB Jeep and this was great information, I’d would have loved to see it on a video.
Excellent… My, how body work has changed over the years… Thanks
Rock on guys !
Great write up and information. I might add you can also complete this type a fabrication with out a tipping/ bead roller, I have completed many. Make your pattern out of card stock, for the horizontal metal, transfer to metal as indicated in the article. At the rear edge, I have either rolled with a radius die or formed with hammer and radius edge dolly. Place the panel aside and repeat the same procedure for the vertical panel, including the radius edge. Now mate the two pieces together and weld it either with TIG or MIG. Use proper welding methods to limit distortion. Metal prep the panel and install with clecos, magnets, or other clamps for the final welding to the existing metal.
I have a few pictures of a complex patch that I completed on my sons Honda behind the front fender, wheel house , unfortunately, I do not know how to load photos here.
As with all metal work, I have found there are different methods to achieve the same results. Practice… and more practice.
Always nice to see practical applications and approaches. If anyone want to see a master metal former at work check out Lazze on Youtube. He has an excellent site that offers free videos on bead rollers, shrinker stretcher, English wheel. I have learned so much.
I have seen this method before and it can work if you have a form to hammer against, but you do have to take care not to overstretch the metal with the air chisel. I’d suggest practicing on a smaller piece of metal first.
Hi Graeme,
We offer those forming wheels for the bead roller on our website. They should fit all manual bead rollers with the 7/8″ mandrel like ours.
Hi Tom,
Sounds like a fun project! Those old Plymouth pickups are a rare breed! Feel free to share your progress with us as you go. Thanks for following along!
this was very interesting I’m in the process of some rust work on a 1963 1/2 Ford Galaxie 500 fastback. not much rust but in all the wrong places.
Matt,I’ve seen your video of the pilot house chop, way cool! I’m restoring a ’39 Plymouth pick up that’s pretty solid for 75 years old. I bought a donor cab for the roof, mine met a large tree. Braced both cabs and measured and checked for 2 days before cutting. All went well.I’m now replacing back,bottom of cab like you. I made my patch panel angle from the seat bracket from the donor cab. Recycing at its best. Thanks for sharing the nice work you do
This Tech Tip couldn’t have come at a better time. I have a same issue on the interior rear floor just below the rear truck door on my English Ford. A 1955 Ford Popular. This will work out great on the repair.
Thank you, Matt
Hi , I am so pleased i saw this demonstration on this type of repair. The tub on my F 100 has rusted in the same place ,every time i walk past it i stop and look at it to see if i can think of an idea to fix it . Where do you get those bending wheels from? Great idea.
Thanks for the Tips , Graeme
Just saw a YouTube video for flow forming metal using an air chisel. Along with Jeff’s suggestion of a wood form with a nice routed radius edge, the air chisel method looks as if it would flow the metal better. Your thoughts?
Jeff,
I feel your pain! I’m also restoring a ’69 Firebird and very well understand the issues of burn through. Finding a suitable place to weld to is always difficult, but I find I have a lot more luck if I sandblast where I’m going to weld to instead of grinding. Like you said, it thins the metal even more. Assuming you are using a MIG welder, one trick I’ve found, (told to me by my father, who is an awesome welder) is to use a piece of brass or copper on the back side of the weld. I believe Eastwood also sells a clamp set up with a copper piece to back up welds. It works very well, but the best thing is sandblasting or soda blasting to clean the metal instead of grinding. MIG welders don’t like to weld through rust! I hope this helps!
I have a MIG 110v unit loaded with .024 wire and run C-25 gas. The gas will weld hotter than plain CO-2 so with a little less amperage you can get away trying to fuse the thin stuff. It’s work well even with the Japanese thin high carbon tensile sheet metal they use. Go slow, spread out your tacks evenly and let everything cool before coming back to the area to weld again. Patience is the key and don’t put a lot of heat in any one area. Put new quarter panels on a ’66 Mustang and not an ounce of bondo was needed when done. Good luck!!
informative, good work, looked complicated but came out very well, TY
Hi Tony, The methods are the same, I usually either take a pattern off of the area I removed or take a pattern off of the hole that is left from removing the metal. Make sure you form the piece and test fit it a bunch of times for the best fit-up before welding.
The reason you see that is because The back of the cab was rotted out as well and I had cut that metal out. I am currently welding that piece in place first before I weld this floor patch in as I need to get in there to hammer and dolly the welds on the cab.
18 gauge steel which was a close match to the original floor in the truck.
Thanks JC! We’ll put that on our list of tech-pieces to shoot here in the future. Thanks for watching!
I like these Tech Tuesdays, there are lost to learn when you are doing a restoration and thee tips helps me out a lot. Thanks Again for these tips.
I have found on the complex curved pieces making a wooden die set to form the metal works well Even though metal workers dont like to rely on wood it easier to form . Just like a steel die set make a male and female form pin them together and put in your flat panel and form away you will have to cut relief cuts but they can be welded after Once you get profecient at tool and die you can even use your shop press Dont be discouraged if your pieces need work right out of the die some of the oem pieces require alot of hand work to be recognizable
Matt, it is always amazing and informative when share your metal working technique. Especially with the Eastwood bead roller and English wheel, of which I have. It would be great if you could do an instructional session on how to do fender flares as I am struggling to look like the ones on one of your bead roller adds.
What gauge of metal did you use?
I always get something out of these articles and videos, especially from Matthew.
Thanks, man!
I always enjoy and learn from this tips, keep up the great work.
Nice explanation of steps. In one of the last photos, the repair panel doesn’t seem to come to the rusty bottom of the rear cab sheet metal – which would probably be too thin to butt weld – but I wonder if that is because the replacement sheet metal isn’t tightly in place. Also, do you use galvanized sheet metal? Thanks!
Nice job, not much of a challenge with the right tool. Eastwood makes it look easy and it is.
Yep the key statement is to really think it through before cutting. A lot of us only see the extent of the repair at face value and then we really mess up when we encounter more work and time than we originally considered. Rot and rust varies due to the circumstances and every repair is different. Your presentations are very informative.
This is great! Thank you so much for the helpful insight and walkthrough
Some good idea’s keep up the good work. I would like to see an example of same type of application but on a curve.
thanks good job..
Nice work..would have been interested to see what you used as settings on your welder for this. Welding new to old rusty metal can be tricky..especially after grinding the rust off the old sections effectively thinning the metal even more. I’m restoring a ’69 Firebird and have done more than my share of panel and patch welding, and burn thru is always a worry.
Very helpful !
Excellent. I learned a lot about the correct way to approach a complicated repair and how to better use the sheet metal tools I have.
Any thoughts on a patch panel for small rusted out spots on a GMC conversion van rocker panel?
been at it for years but never tire of seeing how someone else does it and never stop learning. always able to pick up an idea or two, even if it wasn’t5 they way the author did it. maybe an idea for a jig?
i’m repairing a 1955 belair with rust also ,this is helpfull.
hi.. very informative. thanks ………..audie