noob sorta floor pan question

[hallboyone]

Hey ya'll,
So me and my brother are restoring a 1968 ford mustang coupe and the floor pans are completely gone. We are working on the passenger side first and have replaced the torque box and are know working on replacing the floor pan. My question is what is the best way to cut out a floor pan. We have been using a die grinder with cheapo blades but that takes forever and it is hard on the compressor. Any better ideas. Also any general tips on how to replace floor pans and rust repair would be great. Things that you wish you'd known before you started. Thanks.
hallboyone

 

[xtremek]

4"- 4 1/2" electric grinder for the big open areas? Plasma cutter? If you're cutting out a ton of structure, you may need to brace the body?

 

[hallboyone]

don't have a plasma cutter but would oxy acetylene work.

 

[astroracer]

Use a die grinder and cut off discs, just like you are doing. Get an electric one like xtremek suggested. A cutting torch will leave ragged edges and is almost impossible to get nice straight lines. The amount of cleanup you will be doing "after the cut" will negate any time you save.
Mark

 

[hallboyone]

Do cheap discs (i mean cheap) make a differences. Would spending a little extra make a difference.

 

[that-guy]

question is, are you replacing the pans with replacement steel panels, or patching it up? if your doing a "restoration" you should be replacing with new stamped floor pans, in which case you need to drill out the factory spot welds and drop the old pan as a whole, then fit up the new floor pan with little to no modification and spot/plug weld the new pan in

 

[hallboyone]

The mustang floor pans are one piece from the factory but it isn't all rusted and so we are just replacing the right and lift sections, not the center bump.

Complete floor pan, http://www.dallasmustang.com/root-c...or-pan-assembly-1965-1968-coupe-fastback.html

What we are using http://www.dallasmustang.com/root-c...-1964-1970-full-length-coupe-fastback-lh.html

 

[Kevin54]

You can use O/A, but your factory pans will have braces underneath that you will have to either replace, or save. You need to get a couple of spotweld cutters and drill the braces out. If you are only replacing what is bad, then you will need to do a LOT of trimming and measuring.

You can use a die grinder with cutoff wheels, you can use O/A, you can use a jigsaw, you can use plasma. It all depends on what you have on hand, or what you want to borrow or rent, or buy. When I did the floors on my '62 Impala, I used a cutting torch, spotweld cutter, and sheetmetal shears which were both electric and by hand.

BTW....post up some pics of your project. I know that since you mentioned it, inquiring minds want to see pics!!!!

 

[astroracer]

btw....post up some pics of your project. I know that since you mentioned it, inquiring minds want to see pics!!!!

ditto!!!

 

[MP&C]

The Mustang pans IIRC have a folded flange to the outer sides that spot weld to the inner rocker panels. If you have identified the piece to come out, I have found it easier to cut out the bulk of the panel and simply leave a strip of sheet metal where these spot welded flanges are. Then just drill/grind out spot welds and just roll up the strip with a pair of pliers. Much easier than fighting the larger panel.

 

[Barlow L]

Do cheap discs (i mean cheap) make a differences. Would spending a little extra make a difference.

Of course it makes a difference. However, I've found that the thinner sheet metal eats disc faster no matter the brand.

What works for me is to torch out the large sections first, so that my old decrepit *** can get in and drill spot-welds, or clean up edges with grinder.

 

[MP&C]

Do cheap discs (i mean cheap) make a differences. Would spending a little extra make a difference.

My experience has been that the cheap discs that you normally see at HF or swap meets do more to put a brown haze in the air than cutting steel. They just wear out too quick. I don't have time to change out junk discs all day long, so I've found that buying discs rated for stainless steel last much longer, minimize any brown haze, and all factors considered, end up costing me less in the long run. Rare is the case that the cheapest item actually is...

 

[hallboyone]

Here are some pics. Sorry for the mess. It's a tiny garage. So were do ya'll get your cut off discs?

 

[MP&C]

I normally get mine from the local welding supply, as they have the better selection to get the stainless rated discs.


Be sure to check around the fresh air inlets inside the cowl for rust, that's normally what leaks to cause the floor rust. Also, those hardtops are prone to drip rail rust behind that quarter window, you may want to check under that stainless to see if yours is still solid.

 

[hallboyone]

the air intakes are completely rusted though and so we bought a plastic replacement. So much rust, I really don't think that we knew what it was going to be like. Uhg!

 

[MP&C]

Sounds like you have a car from Maryland!

 

[hallboyone]

Not Maryland, kansas.

 

[hallboyone]

Still think he should have bought a Texas car. Not as much rust down here.

 

[Wes917]

I use thin cut off wheels also. You can use an air nibbler to if there aren't braces, or for the long runs to help speed up the process.

 

[Nor'Easter]

 

[k1rodeoboater]

I used a combo of an electric grinder with a cutoff wheel and an electric body saw. I used the grinder to hack out the majority then used the saw for the last bit of removal.

 

[Joe69]

+1

I use an air reciprocating saw similar to the one pictured above for patching sheetmetal. The blades last pretty long, make a thin cut, and you can lay the patch panel over the original, cut both at the same time, and have a perfect fit/joint.

In a pinch, you can break a hacksaw blade into pieces, and use them in the saw. It won't turn as sharp as the correct blades, but will work in a pinch.

Joe

 

[yaidunno]

Regarding the cut off wheels, 3M Green Corps are the longest lasting and least polluting wheels i've used.

 

[HMCFab9]

^^^ Yep, the 3M (for air tools / die grinders) cutoff wheels last the longest, but they are Expensive!

A cut off wheel in a 4" electric grinder works the best.

 

[FunkyfullWidth]

The discs are only as good as the grinder your using though. I've used good discs in cheap grinders and they end up as shrapnel. Now good discs in a good grinder, you're rockin.

I have one of those air reciprocating saws and have to say, they work extremely well on thinner sheet metal like body panels, but tend to bind up on thicker metals like 1/8"

 

[hallboyone]

All right, we will try the cut off wheel in grinder option and perhaps get some more expensive discs. Thanks.

 

[BigMike782]

These folks make top notch stuff if you cannot find the 3M,
http://www.walter.com/Walter/en-us/abrasives/cutting-wheels/angle-grinders-steel-stainless/toughcut

 

[arrowhead]

Just remember to protect your glass from the sparks. The sparks will actually leave pock marks in it.

I use a 4-1/2" angle grinder with cut off, grinding and flap wheels for just about everything.

If your good with a torch, you can burn off the one layer of sheetmetal where it's spot welded with out damaging the layer below it. Goes a lot faster than drilling out the spot welds. The trick is to almost lay the flame almost parallel across the piece your trying to remove and burn it off so the flame doesn't touch the good metal below it.

 

[hallboyone]

Where do you guys buy these (3m and Walter)? Online or do Home depot or someplace else carry them?

 

[xtremek]

.

BTW....post up some pics of your project. I know that since you mentioned it, inquiring minds want to see pics!!!!

What he said.

 

[hallboyone]

post #13. Little more info, 1968 ford mustang coupe with a stock 200 straight six and a three speed. Literally if you think of everything as base as you can this is the car that you get.

 

[BigMike782]

You should be able to be find Walter at a welding supply. A body supplier may have 3M.

 

[hallboyone]

Tried the angle grinder cut off with the more expensive, stainless steel, home depot discs ($2.77 each). Don't know how great they are compared to 3m but it is a hundred time faster than what we had been using. Thanks again.