I need to make a hood, I used a pals sheet metal shop last night and ruined some metal in the slip roller, in the past I've used my hands to roll stuff but get creases when trying to roll over a long length, what's the trick, sure I've got gas bottles to help, so what's the process of doing it by hand, hood is 3' long, do I need to build a weird fixture? Posted using the Full Custom H.A.M.B. App!
What material are you using? If it's aluminum, you want to use, 3003 14 H. some of the other alloys just don't won't form very well.
I'm using 20g steel for the hood, the sides are alum, but of course I ran out Posted using the Full Custom H.A.M.B. App!
I always use .063 - 3003 H14 aluminum for hood tops and sides. Using some paper for a pattern, because it will conform better than cardboard and give you the true fit. Then using a slip roll to get some curve shape through the center. I then use a large dia pipe to form the rollover on the sides. The pipe I use stands vertical, rather than rolling it around on the floor. I finish the fit by clamping the bottom edges in a brake, and arch the metal by hand. Notice on the second and third pics, how much time it took to get it laid down. Good luck!
What Marty said above, but I'll add one thing - Aluminum has a grain to it that spans the length of the sheet. When you lay it out, you'll always get your best and smoothest rolls when the grain is 90 decrees to the roll. Unfortunately, if you were to have something louvered, louvers like the grain 90 degrees to the vent, so you have to compromise some where. As far as doing it from steel, good luck with that. Edit: Sorry man, my computer had a hissy fit when I ended the last sentence. I started to say "good luck", but if I were working with regular cold rolled stuff, I would get a piece of tubing or pipe about 3"-3 1/2" in diameter about 36" long, clamp it to a saw horse and just very carefully sneak up on the rolls you need.
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