Ok, now I must stress the importance of good spot welds, trust me it will save you a lot of time later. Make the welds relitively close together for strength purposes. remember, this is a floor your welding
Ok, now that you have that new board in, you'll want to grind down your spot welds, just to make them smooth, but do not grind them down to the point where you completly remove them! After that you will want to get out the bondo, hardner, bondo board, severle good spatulas of various sizes, and you might also want something to mix with, although a spatula would work just as well. Again make sure the metal is clean and is a good surface for the bondo to stick too. Don't mix in too much hardner or you will have to work very fast to get the bondo on and smooth. When you start working the bondo keep concentrated and keep it as smooth as possible. remember to follow curves and when the bondo starts to harden, throw it out!! working with hard bondo will waste you time in the future and might possibly mess up your whole work!! It will take less time to mix a new batch than it would to fix your mess up later. Now that you have your bondo down, give it a little time to dry and harden, and start to sand. depending on th area, you might find that a block sander works best, or just some regular sanding pads and elbow grease suits you fine. HAND SAND ONLY!! some may disagree with this but in my opiniun taking your time to produce quality work is worth it. Take off to much bondo and again your in a mess. Contine the process of hand sanding and adding bondo until you get what you want. You want to barly be able to feel the difference in height where the bondo meets the metal. remember to leave enogh bondo for feathering in so you CAN"T feel the difference as I said above, and it leaves a much neater job. After you get all the bondoing out of the way, the rest should be relitivley smooth sailing. Put on several coats of primer, you might want sandable primer to make it easier for you, but again its up to you, and as you probably know there are different primer colors dependingon the finised color that you want to paint the floor with. If you were going to recarpet the floor an immiticulate job might not be needed, so it is good practice for you, but if not, you might take a little more time for each step. Again tough, if you cannot find replacement floor plans, you may want to buy some sheet metal, 14-16 gauge. The steps are basically the same, except that some bending with a hammer or cutting with some metal snips or an air cutter might be required depending on where you want to patch the floor at, and again, take your time, if there are a lot of curves, cut out little peices and spot weld them, don't try to make an elaborate curve or I predict it will end up kinda ugly
If you have never welded or Bondoed before you might consider taking it to a body shop, or, it is just the floor and it would be a perfect place to learn to repair and gain skills for a lifetime!!! I hope all this helped or at least gave you an idea of what to expect before you start that major repair job. Good luck and keep your PINTO rolling!
