need some advice on welding up holes?

[lasher78]

ok need some advice on welding up holes in floor board? i have a few holes on the inclined area of floor board on drivers side close to where the dimmer switch should go. one is prob rhe size of a nickel. now i used to weld on railroad cars for a living so its not the welding i am questiining, its how to weld the hole up without the weld falling thru. when we had a large hole on a rail car to fill we had a copper block to place behide area and just started layin beads down, filled the gap and removed block. but i sont have a copper block so what would i use to place behind holes to hold the weld bead from falling out? any suggestions will be greatly appreciated. thanks in advance
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[oem4me]

Aluminum will work too. Or fill most of the hole with an unplated washer. Just stitch it in and grind it smooth.

[lasher78]

Originally Posted by oem4me

Aluminum will work too. Or fill most of the hole with an unplated washer. Just stitch it in and grind it smooth.

nice idea about a washer, now what do u mean unplated?
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[64shortbox]

How about this copper welding spoon from Harbor Freight for $9.99

http://www.harborfreight.com/catalog...=welding+spoon

[lasher78]

Originally Posted by 64shortbox

How about this copper welding spoon from Harbor Freight for $9.99

http://www.harborfreight.com/catalog...=welding+spoon

that would be a great little tool to have would be perfect for what i want, if i dont get more ideas on how to do this with something i might already have i will deff be looking for one of these.
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[oem4me]

Originally Posted by lasher78

nice idea about a washer, now what do u mean unplated?

Sounds like a small enough job, but welding some plated or coated parts will create toxic smoke. You can always wipe any plating off with a grinder before welding if you can't find plain (naked) steel washers.

[franken]

Originally Posted by lasher78

nice idea about a washer, now what do u mean unplated?
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Washers are typically galvanized, which means zinc plated. Breathing the fumes is bad for you.

You can get copper pipe and beat it flat, or buy thin plate from the hardware store.

For a nickel size hole, you may want to use a washer as suggested, or make a patch with snips.

[donthekawguy]

Galvanized washers will probably kill you if you tried to use them. You might want to poke around with a screwdriver and see ho far the rot goes. Then you can cut out a small square of the rusted metal and make a small patch and weld that in. The rust isn't just the hole it might be bigger than you think.

[luvbowties]

Place a small piece of backing plate underneath and stitch across entire hole.
s

[mud.man.rj]

Good point made on checking the actual hole and around it, may be bigger and not as solid as you think and may burn right thu the thin metal around it, so check it good first and may have to just make a small patch. From all my welding it is better to make a patch and weld around it than try to keep pecking at a hole to big and fill it with weld, not a great weld.

[lasher78]

thanks for all suggestions. i will check for additional area to be patched( just in case ), not too worried about just filling in with weld, like i said before i welded on railroad cars for a living and we rountinly used this method with a copper block to fill in a gap that was almost 1" in hieght by placing copper block behind and then laying 5-6 overlaping beads( the weld is as strong as any other weld ) now granted the welds used at work are 440v and i will be useing a 110v but concept is the same as the metal i was welding on the railcar was 3/4"-1"thick and this metal is no more than 1/8" thick im thinking. i'll be making a trip to harbor frieght monday to pick up one of those welding spoons 64shortbox mentioned ( thanks by the way ). gonna pick up one of those needle scalers mentioned on another thread ad well as a media blaster while im there. hopefully this will really get me going on this project. gonna have to start a actual build thread to document the progress ( just as soon as i can come up with a clever name for the truck ) lol
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[64shortbox]

If you end up making patch panels large or small, Harbor Freight also have these neat little Butt Welding Clamps. A set of 8 for $7.99. I've used the spoon & the butt welding clamps many, many times over the years though I bought my stuff a long time ago and got mine from Eastwood and paid quite a bit more for them.

http://www.harborfreight.com/8-piece...mps-44751.html

[tincan1966]

Originally Posted by lasher78

thanks for all suggestions. i will check for additional area to be patched( just in case ), not too worried about just filling in with weld, like i said before i welded on railroad cars for a living and we rountinly used this method with a copper block to fill in a gap that was almost 1" in hieght by placing copper block behind and then laying 5-6 overlaping beads( the weld is as strong as any other weld ) now granted the welds used at work are 440v and i will be useing a 110v but concept is the same as the metal i was welding on the railcar was 3/4"-1"thick and this metal is no more than 1/8" thick im thinking. i'll be making a trip to harbor frieght monday to pick up one of those welding spoons 64shortbox mentioned ( thanks by the way ). gonna pick up one of those needle scalers mentioned on another thread ad well as a media blaster while im there. hopefully this will really get me going on this project. gonna have to start a actual build thread to document the progress ( just as soon as i can come up with a clever name for the truck ) lol
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You won't find any metal on these trucks even close to 1/8" thick except for the frame rails.
Most of the sheet metal is only 18 to 22 gauge. Making patch panels will most likely be your best approach.

[thunder71]

Take a piece of copper tubing and flatten it out for a backing plate...all my patch work is done with TIG welding
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[Snailed]

It's not a very good practice to make a patch out of just weld bead for several reasons.

After cleaning the area you should cut a patch bigger than the rust area, scribe it in and cut the hole so the patch fits tight with no gaps. Then you can weld it up with a small bead around the seam and no risk if it falling through.

[lasher78]

ok looked a little closer today i may have to make one small patch panel like 2" x2" rhe rest look like i will just fill in. so with that said once i have cleaned floor board either with using soda blaster or sand blaster or useing needle scaler all of witch i intend to buy tomro at HF, what should i put on the metal to keep it from rusting quickly. i am going to coat floor and back wall with bed liner material but i know i got to put somthing on first. someone mentioned por15 on another thread but i looked that stuff up and it is a multi step process, am i looking the right stuff up or is this what everone is using? or is there something else? maybe someone could post me a link to what they use? thanks in advance.
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[lasher78]

well went to HF today and got my welding spoon, butt clamps, but i for got to get a needle scaler cuase got to excited about getting a sandblaster and the little valve conversion to be able to also use baking soda. cant wait to try it out on some old wheels. anybody got suggestiins on what to ise after blasting the floor boards?
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[Snailed]

A needle scaler is not a very good tool for thin sheetmetal and not what it's intended for.

After blasting you want to sand the blasted area with 80 to 220 grit paper depending on how rough the blasted surface is. After sanding, you should get rid of all the dust and then degrease the area with a wax and oil remover or just thinner. Then you can use an etch primer. The primer needs to be top coated with a waterproof paint of some sort. I don't know how fancy you are making this but a good quality automotive spray can like Duplicolor might be good enough for floors. The bottom could be coated with an undercoating or your bed liner for better durability. There are a million variations on these steps but the basic idea is to have 100% clean, bare steel and cover it in something durable and waterproof so it doesn't oxidize again.

[Captainfab]

I have never sanded a sandblasted surface with sandpaper that is to be liquid painted. IMO that is counterproductive. Abrasive blasting mechanically etches the surface. The slight roughness from blasting allows the primer to get a very good bite on the surface. By the time you do any body work, filler and a few coats of primer surfacer, that slight roughness is burried. And on things like the floors, the surface finish is not as important, superior adhesion is.

With sandblasted parts, do not handle them with your bare hands. Always wear nitrile or latex gloves. Blow the dust away with compressed air, and spray 2+ coats of epoxy primer. On your floors, you can simply top coat with a quality paint in your choice of color.

[lasher78]

Originally Posted by Captainfab

I have never sanded a sandblasted surface with sandpaper that is to be liquid painted. IMO that is counterproductive. Abrasive blasting mechanically etches the surface. The slight roughness from blasting allows the primer to get a very good bite on the surface. By the time you do any body work, filler and a few coats of primer surfacer, that slight roughness is burried. And on things like the floors, the surface finish is not as important, superior adhesion is.

With sandblasted parts, do not handle them with your bare hands. Always wear nitrile or latex gloves. Blow the dust away with compressed air, and spray 2+ coats of epoxy primer. On your floors, you can simply top coat with a quality paint in your choice of color.

what kind of epoxy primer, or should i use this por15 i keep reading about on other threads. the top coat will be a brush on bedliner( prob a couple coats ) forsound deadener and help insulate then a little later some mating and rubber mate.
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[Snailed]

Originally Posted by Captainfab

I have never sanded a sandblasted surface with sandpaper that is to be liquid painted. IMO that is counterproductive. Abrasive blasting mechanically etches the surface. The slight roughness from blasting allows the primer to get a very good bite on the surface. By the time you do any body work, filler and a few coats of primer surfacer, that slight roughness is burried. And on things like the floors, the surface finish is not as important, superior adhesion is.

Yeah on a floor it doesn't really matter I guess. On exterior panels it does matter though. As all the layers of primers, sealers and paints cure they shrink and any texture will telegraph through the paint after a few months. No matter how flat you sand your clear, you can see it. This might better apply to $20k paint jobs, not backyard floor patches.

I agree epoxy primer would be a good choice if lasher has a gun and a mask. There's 100 ways to skin this cat...

[lasher78]

what kind of primer like a brand so i can look it up to see where i can get it local and what will the process be step by step after i have patched, welded, ground down and then blasted floors. tjanks
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[Captainfab]

I have to respectfully disagree

It has to do with the materials used and the process. And yes I have been around the process involved with $20K paint jobs. I'll leave it at that as this is irrelevant to the OP's question.

Originally Posted by Snailed

Yeah on a floor it doesn't really matter I guess. On exterior panels it does matter though. As all the layers of primers, sealers and paints cure they shrink and any texture will telegraph through the paint after a few months. No matter how flat you sand your clear, you can see it. This might better apply to $20k paint jobs, not backyard floor patches.

I agree epoxy primer would be a good choice if lasher has a gun and a mask. There's 100 ways to skin this cat...

[Captainfab]

There are many brands of epoxy primer, but you must have the proper personal protective equpiment to spray that type of primer. What brand to use will somewhat be dictated by your budget. After you patch your floors, clean and thoroughly blast them. If you are thorough with your blast job, all you will have to do, is blow away all the dust with compressed air, and spray your primer. Another word of caution. The dust from sandblasting can be extremely dangerous and even deadly. Especially with silica sand. Also the silica sand residue is not compatable with some epoxy primers.

Originally Posted by lasher78

what kind of primer like a brand so i can look it up to see where i can get it local and what will the process be step by step after i have patched, welded, ground down and then blasted floors. tjanks
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[1rudestude]

why not por15 it and call it a day , I have used this stuff with great results.