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welding the body

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  • welding the body

    know i've seen a write up somewhere on how to weld the body. this was something i have been planning on doing since the car feels less then great when taking corners. i'd like to stiffen it up a bit and was wondering where that write up was. i'm planning on welding the body before summer hits.


  • #2
    This was posted on Ziptied in a similar thread.

    In Japan you need to "double Spot" all unibody cars to pass inspection for most race classes. You are right about the prosses on the Apex car. They drill a hole in the TOP METAL only do not go all the way threw. Then spot weld it back. This is best done on a frame rack. Because of all of the spots that need to be welded you can actuly warp the car from the pull of the metal with each weld. When you spot the chasis you want to do all structual spots. This include the rocker pannels and the door jamb threw the roof line and a real good job includes the windshield and the side glass welds as well. For the front there is bolt on frame stiffeners for the iner fender area. one other point is while you weld cool each spot with a blow gun to keep the heat down on the metal. DO NOT USE WATER to do this you will fracture the weld and weaken the surounding metal. Another trick for a good job is to drill holes in the rocker panels under he sill plates and pour in some two part foam. I dont know what the value in english is for this. There is different stiffnesses for this product. We have put cars on wheel scales before and after, and let me tell you this is like a roll cage effect on the car without the weight. One more point on the spotwelds use a spot weld drill from a SPOTAL tool for the bit. They are a 8mm bit and it will cut the top clean and leave a nice surface for the bottom when it is welded.

    Put about 4 5/8" holes evenly spaced in the rocker pannels and yes when it expandes and dries sand the overflow off. Most good foams have a 50% expansion rate so you dont need to fill the rocker, a liter or so of mix should do one side. The spot weld drill bit can be purchesed where ever body shop supplies are sold if they dont know what a spotal tool is head for the door. When you spot the car do all the way around the door openings on the body side of the car. Pay attention to where the floor boards meet the rockers this is a good place to stiffen up the car. Also another good place is the trunk area. Sand or gring all the paint away with 80# grit to bare metal and lay down 3-4 coats of heavy fiberglass mat. Over the tire wells and down into the spair tire hole. This will stiffen up what you cannot spot weld in there.

    HINT when you spot weld always remove the seam sealer and paint from around the areas you will be working on . The chemicals in these products will mix with the welds and render them useless. I use a stripping wheel usaly made from SCOTCHBRITE, but there are other types you can use. Do all the surroundings with this first then drill the holes and weld them back in. For grinding I use a 1/2" air belt sander to grind them down there is less heat build up and the finnish is perfect. A 60# grit belt is best. also cool this down with air after each one.

    HINT DO NOT do these in sucsesion do them random like left door one right door one and so forth. OR bottom door then top door. If they are donne in sucsesion this will also warp the body and pull at the meatal.

    OK we have gone over the how pretty much. But lets recap. It is very important to stabalize the chasis when doing this I cannot stress this enough. A frame rack with pinch weld clamps is the only way. I have seen dumdasses do this and total there car before they even finnished. Also while doing this you can check for any bent components. Acid dipping is not needed If you want to fully restore, a good glass beed striping works fast and is cheepest. The glass beeds will not make any heat unlike sandblasting, this will keep the intact parts from warping. When we do this in my shop we charge 7k for a full front to back this is labor intensive. We totaly strip the car to just the bare chasis, all wiring components everything but the roof panel and the quarters are left. All seams are ground and prepped. Then every accesible point that we can drill the top metal is drilled and filled with a mig and mild steel wire. A spotwelder like they use when asempling is awsome but about 15k so we do this by hand. If you intend to drive and do this you can break down the areas. here are the areas and the procedures

    Area 1 Door jambs.

    Remove the doors and all the moldings and whether striping If you look closly there are spotwelds round markes they resemble a cigarett burn in the metal. You will want to drill and fill inbetween each one the entire diamiter of the door jamb on both sides. BE SURE TO COOL EACH WELD with a blow gun. DO NOT USE WATER YOU WILL FRACTURE THE WELD AND RENDER IT USELESS!!!!!

    Area 2 under hood and inner fenders front

    From the doors to the radiater support you need to do the same as the doors. If you pull the engine you will want to do the frame rails as well. Also do the strut towers and accross the firewall.

    Area 3 trunk and surrounding as well as window openings.

    Inside the trunk you will find the same spotwelds like the doors in the floor and around the rear wheel houses. Do all the ones that are accesseble.

    Area 4 Window openings

    You need to pull the glass if you cannot do this on your own have a mobile glass man remove it for you then when you have finnished and painted have him replace it for you. If he breaks it he will pay for it. Do the same as the doors hear as well.


    Use the strongest foam you can find, Stay away from the can crap it sucks. I use SOLAR 2 part its a 1to1 mix and has a 50% expansion rate, It dries like fast be prepared. Drill 4 5/8" holes in the rocker pannels under the sill plates and the length of the opening, evenly space your holes. Mix the foam and use a funnle to poor it into the rockers. it will take about 1 1/2 liters to do one, this is mixed and ready to poor. Let it expand and harden. After it is hard you can sand it flat and use plastic hole plugs to make it look nice.


    In the trunk you will want to lay at least 4 coats of fiberglass over the wheel wells and accross the floor down into the spair tire well, and into the areas between the floor and the quarter pannels. Remember to strip all the paint and sealer before you do this as well.

    POINT#### always remove any sealer and paint from any place you will be welding, so as not to contaminate your welds. After you have drilled and filled use a belt sander or a grinder with a 60# grit sanding disc. To prep for paint a 2 part surfacer can be sprayed or a 2 part epoxy sealer. You need to use somthing to treet the metal so it will not rust under the paint. I use an etch primer then a wet on wet system.

    If you are going to do the full blown race fram remember to have boxes and cups with lids to put all your hardware and parts in. Mark each one with whats inside. You can take before pics so you can remember how it came apart or draw little sketches, and mark what went were.

    lastly DONT BE A MORON

    Use safty glasses when sanding, grinding. A welding hood and gloves. And some type of dust mask. You dont want to breath any of this. If you are going to paint this yourself us the proper components and safty eqipment as well

    The more complete and profesinal you do the job the better your car will perform. It takes me about 30 to 45 days to totaly strip, fill drill and reasemble a S13- S15 this is long hours and intensive work but I garentee my work and ALL my customers a totaly satified. I can make a body strong enough to takle a H2 Hummer and still be light weight and rigid.


    If you need more direction let me know.

    I wanted to point out that seam welding is not required in D1 rules and that there are many D1 pros that donot do this. For instance Kumakubo has not seam welded his car as he likes to feel the course allitle more. What I meen is that if you car is totaly rigid like say a testarosa you donot feel all of the transitions in the course as you would with out the rigid setup. Remember that some body flex ads to traction, it is not only characturistic to the suspension.

    I wrap my paper weights in glitter.


    • #3
      tanks for the post

      Terrible idea putting those wheels on...


      • #4
        alright i finally got my passenger side door lined up so it closes right. i have to replace that rocker panel as well. i've got a 2+2 rocker panel i'll cut down and make fit.

        so tomarrow or wednesday i'm planning on welding all the seems underneith the front senders. i'll take some pictures. i ran my wire brush on my grinder over everything so its ready to be driven without front fenders.

        then when i pull the motor for my turbo conversion i'll weld the inner fender structures, inside the engine bay. then i'll slowly move my way to the back of the car through spring time as i build a rollcage.


        • #5
          i've got so many projects i'm working on for my car i'm going to be spinning soon. :twisted:


          • #6
            Awesome you are trying this stuff out.

            Terrible idea putting those wheels on...


            • #7
              I should have taken pics of my recent work on the k-car... cut out 2sqft from the driver's foot area and wheel well, then welded in new thicker metal, welding the tracing paper they used for the car was next to impossible so I just made a new border with angle-iron and welded new plate to that and the frame wherever I could catch it

              I did however manage to overheat the hood release cable so it sticks open now if I use it... requiring lots of grunting to get it back at the latch, still not a huge problem

              at the same time I noticed I was scrubbing the outside of my tire tread on driver's side only... so I also modified the strut to allow more negative camber, something I should have done long ago considering how I drive


              • #8
                i'll try to take pictures and document everything. it should ride nice after i get it all done.

                i'm going out to the parts car saturday and doing some chopping with my friends mr. sawzall and mr. generator . :wink:

                i'll be cutting out the passenger side.


                • #9
                  if the passenger a-pillar is any good can you cut it out for me, to be safe about 3" forward and below at the bottom and about 3/4 of the way to the roof

                  I don't plan to get to it immediately but I can throw you a few bucks plus shipping if it's mint. I can make a diagram of where to cut if you want


                  • #10
                    you know its a t-top.

                    i can probably cut it. i was going to pull the windshield. the whole car is going to hacked up.

                    anyway, back to the subject.

                    i welded the front engine bay areas. just the inner fender pieces, and around the shock towers. i'll take pictures later. i ran out of gas. so i'll have to finish up tomarrow. i stitch welded it every other inch.

                    when i drove it back home on the highway, i could already tell a difference. it used to feel like it was going to fall apart everytime i hit a bump. now it feels like a new car. it definatly helped. its to slippery out now to try taking corners fast, so that'll have to wait.

                    i have to replace the rocker panel on the passenger side still. and then i'll work my way from the rockers to the back of the car.

                    i've been thinking about doing this for some time. i wish i would have done it last summer. its great.


                    • #11
                      mine is a t-top 2+2


                      • #12
                        heres a few pictures of welding under the fenders and around the strut towers. there is still more to weld

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