SEJW - Cutting Aluminum

Ok... about a zillion years ago I worked in a specialty tool store. Amoung other things we carried a wide variety of products from a company called
Sait Abrasives. We carried metal cutting abrasive blades labeled specifically for aluminum and soft metals.
I am now wondering what would be the best thing for cutting aluminum sheet and plate that will contaminate the aluminum the least so that it does not impair welding. I'm sure I can cut it with the right blade in my bandsaw, or with a jigsaw, but I am not sure how much contimants will be left behind by those bimetal blades.
For longer cuts it would be nice to be able to chuck up a blade in a table saw or even in a circular saw using a saw guide. I have not seen abrasive blase specifically for aluminum in many years, anbd I know regular abrasive blades will gum up with aluminum when cutting. I also don't know how clean the cut is when I am done. I'm open for suggestions.
P.S. Yes I should have said foundry or casting rather than smelting. I should have known better. One of my buddies took a class in foundry at the local community college, and I considered taking the class, but owning and operating a contracting business makes it difficult to commit to it.
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You can easily cut aluminum on with a table or circ saw with a common carbide blade. Paraffin or machining grease is a big help, but is not absolutely necessary in most cases. But beware, and a good full face shield AND goggles are a must. Large chips come out like machine gun bullets.
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I just put the Aluminum sheet on my plasma table and cut once the design is done.
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
Maxwell wrote:

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Maxwell told it right.
Normal woodworking carbide works better than a carbide non-ferrous blade. A wax stick will reduce galling. Lots of chips - long sleeves / gloves / face shield. I've tried ATB blades, positive rake, negative rake. I cannot tell you I see a substantial benefit from any one type.
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Finish cut blade work better maybe? Finish cut usually means more teeth in a less agressive posture. I've got a variety of 7" & 10" carbide blades for my various wood working saws.
The work I have in mind needs to be fairly smooth and straight.
For the guy who suggested plasma. I've not seen it used on aluminum, but I've seen it used on steel. Yes it does a much better job than a torch, but its still not a great edge. Might be ok in the hands of an experienced master for some "scroll cut" work, but certainly would not be my first choice. Even for steel I prefer to use a chop saw with abrasive blade, grinder with diamond blade, or bimetal jig or band saw when I need a clean accurate edge (blade and method depending on the specific application of course), and of course a Dremel tool or die grinder for detail work.
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Bob La Londe
Fishing Arizona & The Colorado River
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The quality of the saw will affect you finish more than the type of carbide. A purpose built Al. saw gives a much better cut than a woodworking saw. They normally have a heavy cast iron base to absorb vibration, and good clamping. The better saws are fitted with brakes that prevent the blade from chattering.
Dom.
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I think I have had my best luck with rough cut blades. Seems the fine tooth blades require more horsepower, and both types chatter enough the results are about the same. If you want the appearance of a fine machine cut, a single pass with 36 grit on a disk grinder should do the trick. In either case, a light wipe with acetone should leave a weldable edge for anything short of x-ray quality work.
Plasma is nice, but in my experience still needs to be ground. I think depending on your circular saw and thickness of aluminum, plasma can also be a good bit slower on straight cuts as well.
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The difference is a shear cut on the blade or a burnt/melt cut with plasma. Al with a lot of chrome in it is best done by blade or shear. The Chrome melts and 'chills' out rapidly forming very hard and sharp AlCrOx - They make grindstones out of that IIRC... :-)
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
Maxwell wrote:

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Bob:
Basically any quality tooling that you would use for woodworking will work effectively to process aluminum. Plasma is cool, especially if you have a table, but I have somehow managed to run a successful business without having one on my floor. I do have a shear, brake, ironworker and an assortment of bandsaws (vertical, large and small horizontal)
From my experience having to pay/provide for the tools/consumeables I use daily in my custom metal fabrication shop, hands down the best blade and saw combo (also cost effective as well) is a Makita 7 1/4" circular saw and a Freud Diablo 40 tooth finishing blade. Some of the newer blades got a little thin and don't last as long as the older ones did. If you don't knock any teeth off them, they can be resharpened a few times as well. I usually get about a month and a half out of a blade before it needs a sharpening. I cut everything from 14 guage right up to 1 1/2 plate this way. Any material above about .375 I use a walter stick wax for lube and to keep the galling to a minimum.
As for contamination: my professional opinion is that it has to be clean, but not as sanitized as some people would like to lead you to believe. If you use wax while cutting, wipe down the edge with laquer thinner prior to fitup and just before welding, give a little brushing with a stainless brush. I generally don't use any wax if I'm cutting 1/4" and under. For the people that insist that AL has to be clean enough to perform surgery on or with before welding I say BUNK!! I have personally, just to see if I could do it, performed and passed certification testing WITHOUT brushing the plate before putting in the root, or between passes. I wouldn't recommend this but it can be done. If you are doing real world repairs to old aluminum (i.e. Salt impregnated boat hulls, oil soaked engine cases/parts, etc, etc) sometimes you have to be creative and make whatever you can work, no matter how against the rules it is.
Hope this helps some, Aluminum doesn't have to be as complicated as some people like to make it sound.
Drew
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