Louvers

Tin snips?

I would take the cowling to a "coach maker". This is a subset of a motorhead. Coachmakers are the guys who make cars (car bodies in particular) from scratch. we just had a meeting at such a place in central Minnesota and the guy demonstrated making louvers, just like you want. The machine was all set up to do it and it takes about 20 seconds per louver and then about a minute to set up to the next one. go to

Pete Stanaitis

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Yep. If you are using aluminum of reasonable thickness the die can be a hardwood. I used oak. I carved a groove in the female half, not that accurately- I let the male portion be the forming section. For the male portion I used a piece of quarter-round oak trim. I cut the piece to length and rounded off the ends. I then cobbled up a little wood press thing. It worked fine. Hardest job was cutting the slots in the panel. The oak die will not punch through and make an opening- these need to be cut first. I did these cut lines with a chisel. This panel was from .025 aluminum. Only took a couple of hours to make the dies and press, had the whole strip of louvers done in a day.

About a quarter century ago I was in the siding biz. Some company was selling a punch to put vents in aluminum siding on the job. Tapco maybe. Try an old timer in the siding business, or a decent sheet metal shop might have a punch. Tom

Here's the gizmo. Now find a siding applicator that has one.

You also might find a punch like that at a body shop, for punching louvers in car hoods and tailgates, or truck body doors. And theirs will be made for heavier gauge steel or aluminum sheet, too. Siding is rather thin, you might snap that tool on heavier stock.

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Good call on the body shop. As for thickness of cowlings on flying machines, he's not building a 747. Siding is usually .027" thick. The cowling is probably .024" but would be a tougher alloy, 2024 maybe. I wouldn't hesitate to use that punchif I could find one. Tom.

Thanks for all the coments guys. The cowling material is .030, 2024 T3 and is pretty tough. The louvers need to be around 3 inches tall by, maybe, 2/3 wide. I`ve made large louvers years ago by simply cutting a rectangle slot with a radius in the corners of one side and making an insert the shape of the angled bump. left 3 tabs around it for riveting. It worked and looked OK. Might try that along with a couple of ideas you all have given me.

Thanks again