I need to buy some galvanized sheetmetal, for the purpose of building a generator enclosure. The generator is 4x3x5 ft in size and is on a wooden platform. So my plan was to make a frame from 1 inch angle, and then bolt (not weld) sheetmatal to the frame. I want to use screws instead of welding sheetmetal because I want every panel to be removable.
That said, what sort of sheetmetal would be the most common one, I want to know a bit before I call steel suppliers.
On May 25, 2:33=A0am, Ignoramus24299 wrote: I want to use screws
If I were building the enclosure, I would use some OSB ( oriented strand board ) under the sheet metal to cut down on the noise transmission. It would also let you use thin sheet metal. I would use pop rivets instead of screws. I would not expect to remove the panel very often, but pop rivets can be easily removed by drilling them out. Screws are likely to rust a bit and be hard to remove.
I am not sure what thickness of sheet metal is most common. Your local HVAC shop will know that. But I expect somewhat thinner material will be cheaper than the most common thickness.
I like the steel roofing that HD and Lowes sell. They have both galvy corrugated and painted flat with ribs, which looks better. The screws to attach it have rubber washers that seal out water and allow thermal expansion. I let pressure treated wood air dry before framing with it and haven't had much trouble with corrosion.
For flat sheet you have your choice of thickness: 30 ga (.012" is just too thin. 28ga (.014") is used for residential duct work, gets fairly bouncy for panels over 24" minimum dimension. 26ga (.018") cuts nicely with a snips but is getting harder to bend with hand tools. 24 ga (.022") is sturdy stuff, I make small water trays from it. 22ga (.022") is small tool box and trays for steel parts. for your application I'd be looking at 24ga or 26 ga range with 28ga (a bit thin) and 22 ga (heavier than you need) as options.
Flat galvanized sheet usually comes in 4'x10' pieces. My local has a nice on-line calculator, their prices are for new, prime, quantity 1, cash and carry.
26 ga $40
24 ga $45
22 ga $55 That works out to around $1 to $ 1.35 per square foot
The other choice is the ribbed steel panels sold at the home stores. These are usually 29ga painted galvanized steel with 5 ribs. The steel is a higher carbon than the flat sheets, has a fair higher tensile strength. They come in 38" wide panels (36" coverage), 8',10',12' stock lengths (special order any length up to 40') Usual price at a pole barn supplier (NOT Home Despot!) is around $50 per hundred square feet.($.50 per square foot) They also have all sorts of 'J' edges, gaskets, trim, etc to make a super nice job. Not to mention LOTS of nice colors.
I buy 'cover sheets' of this material to cover my wood piles: When they make a shipment, the top and bottom sheets are some sort of seconds (blah paint color, etc). They keep the cover sheets, sell them out in a bargain area for $.50 a running foot ($.17 per square foot).
For outdoor use I'd recommend the pole barn sheet metal screws: hex head, galvanized, painted to match the color, self drilling tip (it has a nifty drill bit end!), and a rubber gasket under the head. Chuck up a hex driver in the drill bit, insert screw, press hard. Goes right through the sheet and anchors in the heavier stock below.
Someone mentioned using treated lumber for the frame. Not a good idea!! The new treated lumber is extremely corrosive to steel, goes right through the galvanized panels in a few years with regular humidity. If it gets wet it can rust out in a year or less.
If it was me, I'd head for your local Menards store, check out the pole barn display for ideas on how to make it look nice and keep it waterproof.
I don't know if looks are any part of this project, but I would use metal building sheets and have a cap made to match that lipped over the tops of the sheets, Metal building screws with washers are readily available. The sheets can remove easily, though I think I would rig it where it hinged back or picked up and off.
The use of two layers of _louvered_ sheet metal on the sides/ends [with the louvers in opposite "/ \" directions] will both reduce vibration AND, while providing adequate protected ventilation, reduce the sound level of the running generator motor.
If desirable, sheet metal screws can be installed to add additional dampening.
My dad bought a prefab galvanised water heater enclosure from some chain hardware store. It has some louvers, but needs more for compressor duty, he just removes the door when in use. It has no back wall, so it just attaches to the building.
I forgot to mention that I spray the corrugated panels with LPS3 first. Maybe that's why the ACQ treated wood doesn't corrode them. Without it rust spots appear in a year or two. The galvanized screws don't last long where the wood is damp so I punched washers out of an old inner tube and used stainless and ceramic-coated bugle-head decking screws. The stainless ones are soft enough that removing and reinstalling them a few times strips the head, even the square-drive ones.
Just buy a suitably sized cheap pre-fab garden shed and then focus your efforts at gluing some acoustical panels into the interior for sound control. The end result will likely look better, be done faster and be cheaper.