Technical What Gauge Sheet Metal?

I need to make a transmission tunnel. I'm going to try and form it by bending it over whatever I can find that's the right diameter, gas bottle, propane tank, tree, anything. I've never done much of any sheet metal work, what gauge do you suggest I go with.

 

20 is probably plenty thick, as it's a curved piece. 22 would probably work, too, and would be easier to form.

I'm sure several guys will suggest that 18 is the thinnest you should ever use on a floor

 

I made mine from 18 gauge

 

20 would probably be OK if you brace it in a few places or bead roll some grooves. I buy a sheet of 18 cold rolled about once a year and cut pieces from it when I need patch material or tunnel stock. It is a good all around thickness.

 

Being a good all around thickness, means that it's too thick for some things, and too thin for others....right?

 

Think about your welding abilities, if you're going to weld it. Thinner the steel, easier to burn through

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I made my last tunnel from 18 G but the truth is that the squirrel is correct 20 gauge will be easier to work with and likely gaining strength from the curve will work just fine.

 

Thanks for the input, I think I'll go with 20 GA. A little while back I bought a drop piece of 16 GA. I've used it for various stuff but realized it would be a bit difficult to bend for the trans tunnel. I'll likely use what I have left of the 16 GA for the floor section, then use 20 GA for the formed section.

You can see in the pic below of where I'm at...and where I want to go, except I was going to make mine removable.

 

You might find the original floor is 19 gauge. Or maybe not.

 

Many early Ford's used 19 gauge which is .0437 thick. 20 Ga. is .0375 and 18 Ga. is .050. Not too many places stock 19 Ga. anymore. If you can find the 19 Ga., I would use it.

 

18 would be good for the flat places on the floor, 20 is fine for the curved areas.

 

Use 18 gauge and bend it around a 5 gallon bucket. You can use a couple of ratchet straps to snuggly and evenly wrap it around the bucket...

 

No shit, I gave up looking for 19 ga. I must have called twenty places and the only place I could find was somewhere down South 3000 miles away from Washington. If I had to buy a whole sheet, I would go with the 18 ga. but if you could find a remnant from a sheet metal shop, 20 ga. would work fine. A bead roller makes 20 ga. pretty strong.

 

I like the workability of 18 gauge and it is usually a bit thinner than it is supposed to be making it somewhat close to 19 gauge. I like that it holds its shape well without denting easily like 20 gauge does. I have shaped 18 gauge over my knee to make trans tunnels before.

 

Another vote for 18, but 20 will work great for the curves as the bend adds strength.
This day and age, 19 gage is a bastard size- even gages are most prevalent.

 

I tend to overbuild everything, so we use 18 ga on floors.


Don

 

I agree with Don, if you use 20g and don't like it later are you going to redo it in 18 or live with it. I think you will like the end result of the project using 18g.

Pat

 

if you're in new england yarde metals is the source for 19ga. I buy it all the time from them

 

If you are in the NYC area, Rapid Steel in Long Island City has 19 Ga. 4'x8' sheets or they will shear it to your size.

 

I just finished my tranny tunnel and front pans. All made to be removed. I will be installing nutserts on the perimeter and along the tunnel edge. I used 18 gauge for the tunnel and 16 gauge for the pans. 16 gauge is a little heavy I know but I wanted them to be really solid. I have an English wheel which is what I used to form the tunnel.

 

If you need tight corners, or multiple bends in a short distance, 20 g is a lot nicer to work with, and its easier to trim with tin snips. On a trans tunnel, 20 g is plenty thick enough.
If you have to cut the sheet metal with tin snips, 18 g will give you some sore hands by the time you cut the length you need to do a trans tunnel, and those tin snips better be in good shape.

I've made my living replacing rusted out floor boards. 20 g sheet metal is a good thickness if there are a lot of bends or curves, and you have to form it by hand or use simple hand tools. On wide open spaces, 18 g has much more support, but its more difficult to work with if you don't have a plasma cutter, or some other electric cutting devise to cut it with, and an English wheel or lots of experience to bend it. Gene

 

I bought one of these from Harbor freight and it says its good to 14 ga. I've never used it on anything thicker than 18 ga. but was surprised at how well it worked. Cost less than $40 with a discount coupon. I don't know how it would hold up in a production shop but I used mine about once a month and have no complaints so far.

 

16 gage.

 

Hot tip for sheet metal cutters. If you loosen the screws and rotate the head 90 degrees you won't have to deal with the cord (or hose) snagging on the edge of the sheet metal.