Floorboard patches... ideas & techniques?

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What are your favorite tricks? I know there are several ways to skin this cat. My holes are in the middle of the floor & will be impossible for me to clamp... Do you guys clamp (using those panel clamps from H.F.) & butt weld?Do you screw down the patches & weld up the holes afterwards? I'll be using my MM 175 with C25 and .024 wire... Floors are 18 GA. Let's hear your ideas!
Reply:pop rivit it or do a tack, tack, tack senario.  You might try using a magnet or two as well to help hold it.  Im no expert on this by a long shot.  Just shot the first Idea that popped in my head.  Good Luck.Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.
Reply:I do a fare amount of autobody repairs and will try to help here for whats its worth. The way you do this type of repair depends greatly on what quality you are looking for. If its an old car you are fixing up just to drive than you may want to take the simple route. In this type of repair I would cut out the bad rusted area first than clean up the good metal with a grinder preferable with a flap disk or using a die grinder and sanding disks. Watch for direction of disk when sanding the edges. always grind towards the edge. I would cut the patch slightly bigger than the hole, place the patch in place and tack weld it every inch or two all the way around holding the patch in place with a piece of wood when tacking each spot. If all looks good, weld it all the way around in short welds moving to different spots so you don't over heat the metal to much causing wrapage. I do not use pop rivets and only use removeable rivets when do custom body mods.  If its a car that you are restoring to reasonable shape where you want to grind the welds down to hide the repair than you will need to do a butt weld. For this I use a very simple technique. Again the same prep but the patch is cut the fit the hole perfectly. Now here is the simple trick, I tack weld a small pieces of metal on the patch to use as handles while welding in the patch. after the patch is welded in place I brake or grind off the handles. For show quality you may want to do a easy weld to the back side. Now just grind the welds down and you are ready for resurfacing.the art to body repair is making a prefect match the the piece cut out  before welding it in place. This maybe easy to achieve or may require special tools. Sometimes it is much better just to buy a replacement panel.I don't have any pictures of good body repairs that I have done. I had a few one time but lost them when my computer hard drive died. The last floor repair I did was on a 1970 GTO judge which came our beautiful. The only pictures I found were of a very quick job I did to an old tempo for my brothers winter beater. The first pic is of the floor before the patch and the second is with the patch tack welded in place. It is a very quick job so don't be to critical. I used the HF sheet metal roller to add some ribs to the steel for strength.Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:Nice work!! I have nothing to add to the orig question......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapsterNice work!! I have nothing to add to the orig question......zap!
Reply:The easy way.Take a piece of steel bigger than the hole.  Set it on top.  Cut the steel and old panel bigger than the hole with a plasma cutter.  Weld the new piece in the old hole.  (Its a perfect fit)Works for me!DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:J Little Said it really well.I would just like to add that on restoration projects, I have replaced whole sections much larger than the rust damage. I've bought whole or partial floor pans. Then cut out the section with the damage large enough to be able to have my seams located in good hiding places. (Like half way up the side of the drive shaft tunnel, or half way up the inner rocker panel) Then I just cut out the section of the floor pan or partial floor pan that I need.What's really great is if I can make my weld at a factory seam.By doing these things, even thought I try to make my welds undetectable, I also put them where someone can't see them. Just in case my work isn't perfect.I've had some cars judged by some real priks at car shows. I'll bet Zap knows what I'm taking about with the Falcons. (last show, had points taken away for using the wrong interior trim screws on a kick pannel, and you damn near need a magnifying glass to tell the difference between the right ones and the wrong ones!) Oh.....I hope Zap's not a car show judge.Patrick
Reply:I'm picking up a D-100 Dodge tomorrow that I will be putting some floor pans into. I'll have to take some pics as I do it.Patriot Performance AutoLincoln Power Mig 255CLincoln AC-225 StickVictor Journeyman O/AQuincy QT-5 Compressor
Reply:Jamlit's job looks very nice. My question on this is what type of stuff do you all use to keep the rust from coming back? I have seen many great looking repairs that didnt last long because the rust came back. I guess a better way to state my question would be how long should a proper floor panel repair last?
Reply:Originally Posted by RIVERRATJamlit's job looks very nice. My question on this is what type of stuff do you all use to keep the rust from coming back? I have seen many great looking repairs that didn't last long because the rust came back. I guess a better way to state my question would be how long should a proper floor panel repair last?
Reply:Oh.....I hope Zap's not a car show judge.
Reply:Using POR-15 is a major help at keeping rust away. It dries and is as hard as ceramic when done. Makes a nice smooth finish. It is kind of pricey but well worth it. It sticks to everything and is hard to clean off, so good preparation is necessary - of yourself and the car.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:OK. The floor boards are done. I went the route of butt welding the joints, so I cut out the patch first, then used that as a template to cut the floor. Here is what I learned. 1. I'm not nearly as good at MIG welding as I thought  2. Butt welding 16 GA patches to 18 GA floors is not as easy as it looks (see lesson #1).  I kept blowing through. Next time, I'll use the correct GA sheet metal for the patches. 3. I am now pretty good at welding up holes from blowing-through. 4. Clamping butt welds would be a good idea... metal likes to warp & curl    Next time, I'll overlap the pieces & use sheet metal screws to clamp everything together. Then, I'll remove the screws & plug weld the holes. 5. Welding toe boards under the dash requires the human body to contort in ways that you will feel for several days afterwards! All in all, the floors are solid now & the welds are strong. A little grinding, a little primer, a little seam-sealer, a little paint, and all should be good. Thanks for all the advice!Last edited by Mouse; 03-12-2007 at 08:57 AM.
Reply:You can say number 5 again, welcome to the wonderful world of working on cars. It's a love/hate relationship...but at least the don't leave you and take your money. John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Please be kind - I'm a beginner...Here is one of the damaged areas I repaired. This is the cage nut that holds the body to the front subframe. Previous ownver cut the floor to get to it because the nut was spinning. I ended up welding the cage down (not shown).Here is the "cleaned up" hole cut to fit the patch. Notice how the floor support nicely held each end (patting myself on the back):Here is the final product. You can see where I was having trouble with blowing through.
Reply:You're new at this right? You did well. It gets easier with practice.Craftsman 230a Buzz-box,  Lincoln 140T & 180T, Century K2789, PUROX W202 O/A14" cheapo chop saw that cuts straight and square!A toolbox of the cheapest Chinese tools money can buy"Real" tools all old reliable Husky/Craftsman/Proto stuff
Reply:Yep - good job.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Jamlit, thanx for your reply. Also, I did not know that about zixk oxide primers
Reply:Hey Mouse, you did pretty good if you are new to mig welding sheet metal.  Mig welding sheet metal is an art all to its own and requires different disciplines compared to heavyer metal. doing the butt weld type of patch was the right thing to do as I see it. The floor you were working on looked in very good condition and if I don't miss my mark you cut the hole to get at the body bolt that most likely was seized. I will try to pass on some ideas for you to try. Keep doing the butt weld patch but only tack it every inch all the way around, Tack weld on some scrape metal to use as handles on the patch. Now set your welder for sheet metal amp and wire speed and only weld 1/4 inch or less at a time. I have even had a cold wet cloth that I layed on the weld to cool it as soon as I pulled the gun away. One of the big problems I see people run into is they keep welding on the same spot, even with the start stop method The problem is that even waiting a few seconds before you weld again their is still heat their and it grow as you weld. If you only weld very short pieces at a time and move around your patch so as to not weld the same spot all the time you will find that the blow through will decrease allot and wrap age will be allot less. Some times you will find that you may need to tack weld beside tack weld or what I call the sevier start and stop method to complete a welding job. I hope this helps and I will try to post a pic or two of good sheet metal welds for reference.Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:Thanks, guys! I feel a little better now. I am a little intimidated to post pics of my work on this site. But, I really do want to learn & improve my skills, so I'm willing to swallow my pride! Originally Posted by jamlitI hope this helps and I will try to post a pic or two of good sheet metal welds for reference.
Reply:Will be working on my shop tomorrow on some sheet metal, I will see if I can get some pictures for you.As to what else to do, just practice. when you start getting the hang of it you will see all the has been talked about here. I guess their is one more thing I might add. Make sure to protect your eyes but use the lightest shade you can so you can see better. I use a #7-9 filter when doing sheet metal.Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:OK, I spent a few minutes on some sheet matal welding. I didn't spend allot of time but did some decent examples. Its not the best in the world but will do. Its time consumeing for perfect butt welds so practice is a must.I used 18 guage sheet metal. Here are a set of pictures showing the step by step process I did.First step, cleaning and alignmentsecond step, tack weld in position\Third step, welding in short beadsForth step. welds completed and wire brushedFifth step, weld partly ground to a smooth surfaceMiller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:Here are a some more pictures. Here is a new piece welded togetherHere is the back side of the same pieceA picture of the previous weld example with the second example And last the work areaMiller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:Good instruction J - a few great examples!John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Originally Posted by MicroZoneGood instruction J - a few great examples!+2! and probably a whole lot more noobies out here lurking that found this tremendously helpful - ed.
Reply:Originally Posted by edl+2! and probably a whole lot more noobies out here lurking that found this tremendously helpful - ed.
Reply:great thread. I also have rust repairs on a 51 chevy truck. I have a tig welder and a mig welder and am considering tiging the sheetmeta. Which is the best Mig with many tacks or tig with many tacks? Also how do you prevent the little holes in the spot welds shown on the pics.. I have a snap on mig with a spot weld timer but it seems like the colder i run it the more of these little holes i have.. Thanks Terry
Reply:Great tutorial Jamlit! Once again showing why I can't get enought of this place. Great peeps taking time out for us newbies. Latest Toys Miller 180 Mig and Elite Mask!!Wright Welder 225ACShop OutFitters 20/20 Bending SystemHypertherm 380 Plasma30 Years of Sparking (Electrical & Welding)
Reply:J Little Said it really well.I would just like to add that on restoration projects, I have replaced whole sections much larger than the rust damage. I've bought whole or partial floor pans. Then cut out the section with the damage large enough to be able to have my seams located in good hiding places. (Like half way up the side of the drive shaft tunnel, or half way up the inner rocker panel) Then I just cut out the section of the floor pan or partial floor pan that I need.Myself, I like to use flangeing pliers after you cut all the bad metal out, to creat a shelf on all four sides of the hole. Cut the patch to fit, set it into the pocket you've made and then start with your tack welding. You can hold the patch in place with your off hand as you go around. When the welding is done, smooth the weld down with a grinder or pearl wheel and the joint is almost invisible.