Cutting Aluminum

[whee]

I’ve tried several different methods of cutting aluminum during our build but never found any that I really liked.

Snips leave a rough edge that takes a ton of clean up and make long cuts difficult.

Power shears waste a bunch of material and still leave an edge that has to be cleaned up. Get too aggressive with them and they warp the piece your trying to make.

An A&P recommended an air grinder. It took forever and I hate all the noise air tools make, especially my compressor. But the cut edge take very little cleaning so this was my preferred method.

Tonight I was working at home but most of the tools have been moved to the airport. I scrounged around and put a 4” cut-off wheel on a HF 4.5” angle grinder. It was awesome! Made sort work of all the cutting and the edges need very little finishing. This will be my go to method from now on. Too bad I’m almost done😏

[svyolo]

Angle grinders are an amazingly useful tool. Equipped with 36 grit discs, the yacht repair industry used to call them a TMD. Tool of Mass Destruction. I have never hurt myself with one, and had gotten a bit cavalier with their use. Cutting up the wing crates, I learned the "easy way" that they can be pretty dangerous. I say easy way because I didn't hurt myself. But they can be pretty hazardous.

I haven't tried cutting aluminum sheet but it doesn't surprise me that it works well. I have been using a Rockwell saw recommended by SWpilot. Works great. It is basically a sabre saw mounted in a small table.

I am also not a huge fan of air tools. They are awesome for a huge commercial shop, but really noisy for a home shop. My psychotically loud Makita compressor died an early death, and I was not sad. I replaced it with a very quite compressor from California Air tools, but I still prefer electric tools.

[svyolo]

Cutting aluminum is actually pretty easy. A table saw with the right blade does a really good job. I don't mind cutting small parts out with shears, and sanding to a line on a belt or disc sander. But bigger parts it becomes pretty cumbersome.

[Aero_tango]

If you want straight cut, nice edges, no deformation, use a straight edge and an Olfa knife. Make sure your straight edge is clamped down. I used this method when I built my Rv and BH, and it works like a charm.
i found a video that explains it. Few strokes with the knife and then bend progressively at the cut line. The guy in the video use a brake, but it’s not required.

mike

[rv8bldr]

I use my angle grinder with a cutoff disc for almost everything (except sandwiches :-) I get the super thin discs from Canadian Tire (something like a Candian combination of PEP Boys/Harbor Freight/WalMart) whenever they go on sale. The 3/64" discs are perfect for cutting everything from 4130 to aluminum.

[davzLSA]

I think the angle grinder with the cut off wheel would make the sammies a little gritty?

[Chris In Milwaukee]

If you want straight cut, nice edges, no deformation, use a straight edge and an Olfa knife. Make sure your straight edge is clamped down. I used this method when I built my Rv and BH, and it works like a charm.
i found a video that explains it. Few strokes with the knife and then bend progressively at the cut line. The guy in the video use a brake, but it’s not required.

mike

I’ve wondered about those. They appear to be popular in the Zenith circles on 6061. I wondered how it would work on 2024.

[Aero_tango]

not a problem on 2024....

[Rollie]

For straight cuts, a shear does a great job, if you can find one to use. I did all mine by hand and had to do a lot of edge clean up. Then when I was pretty much done my local shop got a nice 4 foot shear. I used it for all the little trim parts like flap and aileron hinge pocket covers and along with leaving nice clean edges it is also easy and quick. I decided I won't build another airplane without a shear in my shop.

Also Kitplanes just did an article showing the use of a dremel multitool, the one that just vibrates a blade, not the rotary tool, for use on inside cuts. Works way better than hand shears as it doesn't bend the metal while cutting.

[interstate al]

I agree with Rollie, a shear is hard to beat. I have a 30" stomp shear in my shop as well as a bench mount rotary circle shear that is great for curves etc. Many heating and air shops have shears, brakes and rollers collecting dust in the corner and can be picked up for a song.

[whee]

Thanks for sharing your methods guys!

You can’t beat a shear for straight cuts. We found a shop that would let us use theirs but it was pretty inconvenient. I’ve never used or even seen a rotary shear in person but yeah, that would be awesome for curved cuts.

Small parts and curves cuts is what I was thinking when I made this post. Last night I was cutting out an oversized airfoil shape so every line is curved. Took me ten minutes to cut the entire thing out and finish the edge.

[robcaldwell]

I like using the Olfa knife along a straight edge. Those cuts are great.

I also use a Mini Rotary Shear that I bought from Eastwood. It takes a little "tuning" to get it set up right, but cuts nicely.

https://www.eastwood.com/mini-rotary-shear.html

p20642.jpg

[schu]

I have the eastwood open throat shear, it works okay....

[svyolo]

That rotary shear looks pretty slick. I guess if I was scratch building I would want more sheet metal tools. I will get buy with what I have for the kit.

[S Lathrop]

I have had a Black & Decker pneumatic metal cutting shear for decades. It was rated for 18 gauge mild steel. But I have never used it on steel and it was perfect for the aluminum cuts that I could not do on a stomp shear. I don't think B&D makes that tool any longer but the Amazon's Choice is an Ingersoll-Rand 78025A Heavy Duty 20 Gauge shear. Same tool. I would not tackle a sheet metal project without one. Setup a guide like you would for a hand saw and cut away. Fast, easy, accurate. Their are electric shears that work the same way. And it will cut curves and straights. And with practice you can cut square corners.

[fairchild]

I have been using one of these to cut my slightly oversize blanks out of the sheet. It has the advantage of leaving ZERO warp in the edge
of the sheet--- so its not all curled up like shears give. Once you start the cut-- its just like cutting turkey with the electric carving knife.
I couldnt be easier. The blade is only 1/4 inch wide so you can slip it between two sharpie marks only 1/4 inc apart. That helps you lay out
your parts on the sheet with maximum useage of the material. I usually cut my parts out about 1/2 inch over- then trim them on the band saw
down to about 1/8 to 1/16 over--- and then the router brings it down to the cutting template.

One of these--- its called a pneumatic body saw. All the auto parts have them.

[svyolo]

I was in Grizzly's HQ store (1 mile from my shop) and came across what is called a "Track Saw". Basically a circular saw mounted on a track that is 2, 4, 8, or 10 feet long. No slide a tool across the work piece, or sliding the work piece across a tool. Super easy long, straight cuts. I would bet it would work brilliant for long cuts on AL sheet. Other companies make them as well.

I might have to have me one of those.