Slightly off topic: working sheet aluminium easily - Page 1
Forum section: electronics / general

author: SingedFingers
author_rank: Frequent Contributor
timestamp: January 30, 2017, 11:12:46 am
content: I've built a few small enclosures with limited tooling recently out of 0.9mm sheet aluminium. These are four parts: two identical U shaped lids and bases and two identical U shaped front and rear panels. Four machine screws are used to screw the enclosure together (i epoxied the nuts to the inside of the case front and rear! The controls and connectors are screwed to the front and rear panels mounted to the board. Allows access to top and bottom of PCB then.I've got to build a larger one for the new frequency counter I have built and I'm looking at it and thinking it's a chore now.I'm limited to a vice with two bending bars (angle steel), a wood block for folds (hammer the feck out of it over the bending bars), some straight aviation shears for cutting the basic sheet, a nibbler, a hand drill, a flat file and a deburring tool.Is there anything I am missing to make my life easier? I'm limited to living room table workshop unfortunately at the moment. Internal folds totalling more than 180 degrees in total on a single piece are difficult if not impossible and accuracy is a big problem at the moment.Also how do you finish / paint bare aluminium nicely? I have considered plastic wrapping it because it looks easier.

author: elecman14
author_rank: Unknown
timestamp: January 30, 2017, 01:10:52 pm
content: You could look for a small metal bending break. I envision something like this mounted on a sheet of plywood clamped to the table:http://www.eastwood.com/18-mini-bender-brake.html<- I have no affiliation with this company it was just the first link that showed what I am thinking of.As far as paint. Clean the piece to make sure it does not have any oil or other contaminate. Then hit it with some 800 grit sand paper to rough it up. Take it outside and a couple light coats of spray paint should get you a nice finish.

author: kosine
author_rank: Regular Contributor
timestamp: January 30, 2017, 01:48:18 pm
content: Try this stuff instead:http://www.cutplasticsheeting.co.uk/dibond-aluminium-composite-sheet/You'll find it readily available and much easier to work with. (Cut, drill, score, fold and rivet.) it's also available in different colours so no need to paint it.

author: jpanhalt
author_rank: Super Contributor
timestamp: January 30, 2017, 02:25:29 pm
content: 1) Be sure to radius your bends, particularly if you use a hardened alloy. One can use bending bars/dies that are radiused, or you can bend a piece of scrap sandwiched between the bar/die with the piece you want to bend.2) "Rivnuts" (i.e., a pop-rivet threaded on inside) have become quite readily available by a variety of names. They allow nice threads without having to glue the nuts to the back side. Installation can be done with an ordinary pop-rivet gun.3) A flat file is needed, of course. For aluminum a "vixon" or other brand file has teeth that are designed for aluminum and other soft metals, like lead. It will give you a very nice shaving from an edge. Takes a little practice, but the result is worth it. A bastard file is not the same.4) Wide flange pliers sometimes called seaming pliers can help, but are not essential.John

author: SingedFingers
author_rank: Frequent Contributor
timestamp: January 30, 2017, 03:02:31 pm
content: Thanks everyone for the tips.My current "bending bars" are L section steel which have been radiused with a bastard file crudely. These are clamped in a vice with the piece, a hardwood wooden block nudged up to it and this is lumped until folded. I would love a better solution here but I haven't found anything that will clamp in a vice and to the table that is large enough but doesn't need permanent attachment to the workbench (the dining table!)Riveting is a good idea. Never thought of that!Will look for a vixen file - that looks like it's better than the flat bastard file I'm using at the moment which is quite ineffective.Thanks for the painting advice. Will try that on some offcuts and see where I get.