Sheetmetal question

[Barnaby]

Hi all, I'm at the point where I'm going to be taking out the windows and covering the sides with sheet metal. I know 18 gauge is the way to go but my local metal shop had a great deal on some 16 gauge they had in the warehouse. Ironically the 16 gauge is less than half the price of the 18 gauge thanks to, well, you know why.

What shall I do? Go with the 16 gauge or pony up for the 18 gauge? My main concern is that the 16 gauge is going to be much harder to work with; everything from hoisting it to drilling holes is going to be a greater effort. additionally, I'm concerned that the 'stack' is going to be too thick where two sheets of 16 gauge overlap and still have to fit under the overhanging roof sheet metal.

Still, it's like a five hundred dollar difference...

Am I setting myself up for failure with the 16 gauge or will it be fine?

 

[Jolly Roger bus 223]

the thicker the better most older buses are built with 15-16 guage.

 

[ewo1]

Go with the 16 gauge for sure !!!

 

[ewo1]

Hi all, I'm at the point where I'm going to be taking out the windows and covering the sides with sheet metal. I know 18 gauge is the way to go but my local metal shop had a great deal on some 16 gauge they had in the warehouse. Ironically the 16 gauge is less than half the price of the 18 gauge thanks to, well, you know why.

What shall I do? Go with the 16 gauge or pony up for the 18 gauge? My main concern is that the 16 gauge is going to be much harder to work with; everything from hoisting it to drilling holes is going to be a greater effort. additionally, I'm concerned that the 'stack' is going to be too thick where two sheets of 16 gauge overlap and still have to fit under the overhanging roof sheet metal.

Still, it's like a five hundred dollar difference...

Am I setting myself up for failure with the 16 gauge or will it be fine?

look at my build thread around post #37.
I lifted ALL of my sheet metal and screwed them into place, all by myself! No helper!

9906 build thread

It is quite easy if you plan ahead.

 

[nikitis]

Make sure it's "Galvannealed" steel. Not to be confused with "Galvanized". They are two separate types of processes in their forming. Galvannealed is annealed metal for hardness which is what you want for strength and to help prevent warping, and the galvanized process helps with rust preventative. Your metal place may be giving you traditional steel or galvanized steel. Tell them you need Galvannealed. They may not know what that is as they don't usually get those requests any longer, but a good metal shop will know what it is and that's how you can tell if they know their business or not. I suspect you will be calling around to find "Galvannealed" steel.

16 Gauge is the default thickness of the bus naturally in older buses. People go with 18 gauge cause it's cheaper usually. 18 gauge will be lighter. There's a small but almost none possibility of warping with 18 gauge. It's usually safe though, Anything less will warp. 16 is solid but tougher to bend around the back corner so be ready to expect that part, that would be the only negative I'm aware of with 16 gauge, but you can still do it.

If 16 gauge is cheaper which is usually never the case, it is the better option overall for stability and rigidity of the bus.

I'm about to do my roof raise here soon. I've bought the steel already. 18 Gauge. The rest of the steel on my bus is 16 Gauge. 16 was not cheaper in my area. I looked everywhere for 16 and 18 gauge galvannealed steel.

 

[Barnaby]

Thanks y’all! Going to stick with the 16 gauge. I guess I was just really lucky they had these sheets lying around in the warehouse.

Looked at your build thread ewo 1, great primer on how to get those sheets up there. I’ll use a very similar setup with two or three lifting straps and one wrapping strap to keep the sheet close to the bus.

Nikitis, yep, it’s galvanneal, made sure to go with that. Thankfully there will be no bends in any of the sheets; they are mostly just rectangles except for the ones at the back that will have some angled sides to conform to the inward tilt there. I don’t know if my power shears will be able to handle the 16 gauge but I’m sure the angle grinder will

 

[Ozbozz57]

It was 16 gauge for me. The tinner had some he wanted to use up.

 

[hmoore]

I did the same job and used 16 gauge, because there was a big difference in price too. Yes, harder to drill and lift, but nothing critical - the main thing is to prepare the instrument in advance and not hurry. About «stack» - in places where the metal is really thicker, but I got everything under the roof, just had to carefully cut and fit. If saving is important, you can take 16 gauge, but with 18 it’s easier - it’s up to you.

 

[Barnaby]

Based on the replies here I went with the 16 gauge and it worked out fine. Yes it's heavy as all getup but 18 gauge isn't exactly styrofoam either.

Drilling holes in 16 gauge didn't turn out to be particularly hard. I just went slow, used cutting oil and worked my way up in bit sizes for the larger holes.

I used ewo 1's method of hoisting the plates up with ratcheting straps. Again, not a big deal and easily doable by a single person when using some planning and foresight. The center ratchet strap, which wraps around the entire bus, is important; without it at some point the sheet will do a not-so elegant somersault back to the ground.

The biggest challenge turned out to be opening up a gap at the top, where the roof sheets are, for the new sheets to slide under. On my bus it's all screws instead of rivets holding things together, for which I'm very grateful, but in this area there was also a large amount of epoxy.

Amazingly, Harbor Freight sells an air hammer for under twenty bucks (how do they do it?!?). It's probably not going to last a lifetime but it's actually a pretty solid little tool for what it's worth. With a chisel bit I made short work of separating the glued-together sheets.

The new sheets are held up temporarily with #12 nuts and bolts (much cheaper than clecos!). Things will be sealed with Sikaflex 221, and riveted together. I initially ordered 1/4 inch Avdel Avibulb rivets from Bay Fastening Supply for the job, but it turns out that the thicker mandrel of these rivets doesn't fit the 1/4 inch nozzle of my cheap air riveter. So I sent them back and ordered a different type from Grainger. I'm away for work for the next two weeks so I can't tell you yet if these rivets are any better. I sure hope so...

 

[nikitis]

Glad you got it done. You may can take a air hammer with a flat bit and see if you can straighten out the top lip some now that the sheet metal is mounted.

 

[TaliaDPerkins]

Make sure it's "Galvannealed" steel. Not to be confused with "Galvanized". They are two separate types of processes in their forming. Galvannealed is annealed metal for hardness which is what you want for strength and to help prevent warping, and the galvanized process helps with rust preventative. Your metal place may be giving you traditional steel or galvanized steel. Tell them you need Galvannealed. They may not know what that is as they don't usually get those requests any longer, but a good metal shop will know what it is and that's how you can tell if they know their business or not. I suspect you will be calling around to find "Galvannealed" steel.

16 Gauge is the default thickness of the bus naturally in older buses. People go with 18 gauge cause it's cheaper usually. 18 gauge will be lighter. There's a small but almost none possibility of warping with 18 gauge. It's usually safe though, Anything less will warp. 16 is solid but tougher to bend around the back corner so be ready to expect that part, that would be the only negative I'm aware of with 16 gauge, but you can still do it.

If 16 gauge is cheaper which is usually never the case, it is the better option overall for stability and rigidity of the bus.

I'm about to do my roof raise here soon. I've bought the steel already. 18 Gauge. The rest of the steel on my bus is 16 Gauge. 16 was not cheaper in my area. I looked everywhere for 16 and 18 gauge galvannealed steel.

How do you feel about hot dipped "Galvalume" steel sheet?

 

[ewo1]

How do you feel about hot dipped "Galvalume" steel sheet?

I used plain old cold roll.... wipe clean with mineral spirits then Opsho for sealing and etching.

 

[nikitis]

How do you feel about hot dipped "Galvalume" steel sheet?

It's an option. Not one usually chosen, but if you can buy it already like that you'll already have what EWO1 achieved with his basically.

EWO1's panels look rusted. Not caked rust but just a smooth covering of it all over it's entirety. He'll be able to paint right over it using two coats of paint. Shouldn't even need primer. Using Ospho puts the metal in a similar state as Galvalume and the metal while it looks rusted shouldn't rust further and never completely corrode. Which is the benefit. Galvannealed takes a really long time to rust, like 30 years before you even start seeing rust if my bus is to be a judge. I've only seen slight flash rust and VERY little at that. Galvannealed will corrode to nothing eventually, like in 60 years or even longer. So realistically I don't see much of a benefit of Galvalume which will never corrode but have a slightly rusted texture look, unless you just don't want to use primer and like the rough matte look.

 

[TaliaDPerkins]

It's an option. Not one is usually chosen,

Eh, it's the one the local steel house could supply. C'est le guerre.

 

[nikitis]

It can certainly work, just be warned about the texture though. If you are okay with that no reason it won't work for you. And you'll have panels that will never degrade fully.