Floorboard questions

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I started cutting out the rusted areas of my 1971 Fiat 850 spider's floorboards, and have found so many bad areas that I'm just going to cut them all out and replace them with some 22 GA sheet metal I have.  I'm planning on making a 1/2", 90 degree bent lip with some 3/16" holes in it to attach to the sides, back, and frame rail, fill weld the holes and weld the edges.My main concern is rust prevention.  I plan on using POR-15 on the inside of the frame rails (not the edges I weld to) before I weld the sheet on top of it, and using basically coating the whole frame/floorboard area with it when I'm done.  But what about the 1" overlap area, and the tops of the frame rails I'm "spot welding" the floorboards to?  Should I try to weld the edges underneath the car?  Shove as much POR-15 into the edges as possible after it's done?  Coat it before I put the floorboard in and only leave the areas I'm filling with weld clean?  Drink a beer and not worry so much?And, yes, I know that "rust prevention" on an old Fiat is similar to "tooth decay prevention," something you have to do really often, and despite your best efforts, it will still need an occasional drill and fill.22 GA is a little thin for floorboards, but in this car one seat rail runs along a frame rail, and the other sits on one rail in the front, and a second in the back.  There is no way you could stand up on the floorboard or put any real weight on them, since everything from your knees down is underneath the dashboard.  The floorboard is mainly there to keep whatever is on the road out.What tool was used to get the beads in the middle of the floorboards as in the following pic?  I'm using this as my example of how to do it right:http://www.weldingweb.com/attachment...1&d=1154984798Thanks,PatrickLast edited by PatrickJ; 10-11-2006 at 09:52 PM.
Reply:Hey Patrick...First off, drink a beer and don't worry so much. If you have a lot of rust in the car then you'll need to find a way to neutralize it or it will continue to grow and be a pain to weld to. I usually get all of my rusty metal soda blasted. If you can't/don't want to get blasting done or there is a small enough area, you can use products like naval jelly and a good amount of grinding to get rid of it in the areas you will be welding on.If you are going to be coating the car in por-15, that should be the last of your rust worries. Por-15 actually stops rust from growing any further. I would rosette/spot weld as you said and stitch weld it alternately between the spots (like the pic of the floorboard that you posted, which I repaired ).22ga is very thin for floorboards but it sounds as if you have enough structure underneath to compensate. To put beads in panels, I use one of these from Mittler bros...I have the upgraded model to handle 16 ga steel and cost about $1400. There are much cheaper units for doing this type of work. You might want to check out Williams Low Buck Tools for a manual version....and thanks for using my work as an example.  - PaulLast edited by ZTFab; 10-11-2006 at 11:39 PM.http://all-a-cart.comWelding Cart Kits and accessories
Reply:Well, it looks like the bead roller is out, I can't afford the cheap one right now, and HF discontinued thier super cheap one.  Is there anything I could do with a metal brake to add a little strength?  Would making a v-shaped groove diagonally across the floor board help strengthen it, or should I just deal with it?Thanks, and you do some damn fine looking work.  I'll post pics of the floorboards for critique later (hopefully next week), as long as they keep water out, they'll be adequate, but I'm going to try to make them look as much like yours as I can.
Reply:If you have a sheet metal brake available, there are a few things that you can do to strengthen the panels.1. You can brake diagonally across the panel to form an "X". It only takes a couple of degrees on each bend. That will give it some rigidity but will also cause the panel to not sit exactly flat.2. Take some sheet metal and form some U-channels and spot weld those to the bottom of the panel (like a factory floor board brace) before you put the panel in the car. This will add a lot of strength and keep the panel flat.I would suggest #2 as it will add the most strength and keep the panel flat....and thanks for the compliments. - Paul Attached Imageshttp://all-a-cart.comWelding Cart Kits and accessories
Reply:Patrick,Paint everything you can up to the spots or edges that you are going to weld.  After welding, clean the weld areas with a wire wheel then slather on the paint to cover all areas.As a final seal use some brushable seam sealer.22 ga. may be fine for structural integrety but 20 ga. is just as easy to form and will be more forgiving when you are welding.If you can't buy or BORROW a bead roller then you could always do it manually with a blunt metal edge and hammer.  I use a 4"x4" board with a groove routered in it and a blunted brick chisel (4" wide 3/8" thick) and pound them in.  The flat sheet will want to warp but is easy to flatten after the bead is pounded in.  Heck, you won't see them so they don't have to look pretty just stiffen the panel.Below is a picture of a '86 Dodge truck floor pan I recently put in - only areas not painted were to be welded.Paul Wisner Attached Images
Reply:As far as you being primarily concerned with rust prevention, the product POR-15 seems to be fine. I would not try to weld through it after applying, instead weld up your pan and apply after to the entire thing. if there are gaps don't try to fill them with the POR, peen the edges flat to the existing body panel and tack weld where necessary. It doesn't have to be perfect, I assume there will be a carpet to go over the whole thing when you put the car back together.   Apply the POR as per manufacturer, let it cure. If you are concerned with the outward appearance to anyone laying under your car later on, apply a $7 can of rubberized undercoating and build it up in the areas of concern. You DO NOT have to weld the entire seam, you risk burning through every where you put heat, a headache in itself. Think Factory: strategic spotwelds hold 90% of any car together, not long beads.
Reply:Harbor freight still sells them, $99.00.http://www.harborfreight.com/cpi/cta...emnumber=34104 Most people "beef them up" , fairly easy, and they can be motorized or customized.  One of the best deals they have.
Reply:if you want to stop all that rusting ..check this site out..http://www.counteractrust.com/i put one in both my falcons and my F-350 plow truck..these are the real deal......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:ZapCan you tell us some more about the Counteract? I've heard of them, but never actually knew anyone that had one.Thanks Steve
Reply:Originally Posted by Cobra06Harbor freight still sells them, $99.00.http://www.harborfreight.com/cpi/cta...emnumber=34104 Most people "beef them up" , fairly easy, and they can be motorized or customized.  One of the best deals they have.
Reply:Patrick - I think you will have to buy that one online. I called the stores and asked if they could get it in and they told me online purchase only. Let us know otherwise. Thanks!John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:Patrick, the flange is what you would use to make a lap weld, it's a step die.The dies alone are worth the cost.Check out this tread on metalmeet about what one guy did with his HF roller, there's also a bunch of other threads there in regards to the roller:http://metalmeet.com/forum/showthread.php?t=6052If you don't want to buy the brake,  you could use a sheet metal hand brake, or use the roller with a large washer as the top die and a soft lower roller for a tipping die also good for putting in fender wire.David
Reply:Originally Posted by yhprumZapCan you tell us some more about the Counteract? I've heard of them, but never actually knew anyone that had one.Thanks Steve
Reply:Originally Posted by zapsterthey are quite simple to put in anything..for cars you get the counteract device and a "pad" you stick on the paint somewhere "shiney"there is one wire from the pos side of the battery..one for the neg side..and the one wire that attaches to the "pad"..thats it!the counteract device attaches anywhere out of the weather with velcro..the truck version is a little bigger and you get 4 "pads" ..one for each corner of the truck..installation takes about 1/2 hr and all you need is wire cutters/crimpers and something to heat the shrink wrap connectors...i love'em!...zap!
Reply:http://www.goestores.com/home.aspx?M...tingsystemsincHere's the link for their page where you can click on the type of vehicle, and it will give you pricing info.  If you buy from them, and you're buying more than one unit, call them, they give discount pricing if you buy multiple units.EdWhen the  drops the  stops!Check out my website at:  Tombstone 180 ACHandler 120Millermatic 210Powermax 380Harris & Victor torchesSawzallChop Saw
Reply:Originally Posted by Cobra06Zap, what do they cost?, I don't see any pricing info on their web-pageThanksDavid
Reply:Originally Posted by Cobra06Patrick, the flange is what you would use to make a lap weld, it's a step die.The dies alone are worth the cost.Check out this tread on metalmeet about what one guy did with his HF roller, there's also a bunch of other threads there in regards to the roller:http://metalmeet.com/forum/showthread.php?t=6052If you don't want to buy the brake,  you could use a sheet metal hand brake, or use the roller with a large washer as the top die and a soft lower roller for a tipping die also good for putting in fender wire.David