Interesting observation, to me anyhow ;)

[StealthTJ]

Dan and I were fitting up the tranny/engine skid yesterday.
I used a 3+' section of 12" wide x 3/8" thick 6061 T6 aluminum.
We had to cut it to fit, and pulled out the trusting 'ole plasma cutting, figuring that it would cut right through it like a hot knife through warm butter.
Well, it did cut through it, but it was a lot harder to cut than steel.
It also made a really neat fireworks display, reminding me of the phosphorus bombs that I've seen photos of.
It was spitting out white, really really white pieces, with neat smoke trails...

That 6061 T6 is interesting stuff.
I had tried bending a piece, a little while back, using the shop electrically operatated hydraulic press and an acetylene torch to heat it up.
I got it hot enough that I was a little worried about actually cutting it with the torch. It would bend in the press, but even pressing on it with everything the press had, it would return to it's originally (mostly) shape as soon as the pressure was removed.




Fred

[mrblaine]

Originally posted by StealthTJ
Dan and I were fitting up the tranny/engine skid yesterday.
I used a 3+' section of 12" wide x 3/8" thick 6061 T6 aluminum.
We had to cut it to fit, and pulled out the trusting 'ole plasma cutting, figuring that it would cut right through it like a hot knife through warm butter.
Well, it did cut through it, but it was a lot harder to cut than steel.
It also made a really neat fireworks display, reminding me of the phosphorus bombs that I've seen photos of.
It was spitting out white, really really white pieces, with neat smoke trails...

That 6061 T6 is interesting stuff.
I had tried bending a piece, a little while back, using the shop electrically operatated hydraulic press and an acetylene torch to heat it up.
I got it hot enough that I was a little worried about actually cutting it with the torch. It would bend in the press, but even pressing on it with everything the press had, it would return to it's originally (mostly) shape as soon as the pressure was removed.




Fred

To remove the temper of 6061 taken to T-6 do the following.

Take a cutting torch and light just the acetylene. Makes for a real smoky flame. Run the flame over the aluminum until you have a heavy coat of black soot on it. Dial in the Oxygen until you have a good cutting flame. Run that over the surface until you just burn all the soot off. Now go try it in the press.

btw- AL takes 3-4 times the energy to weld or cut because of it's tremendous heat dissipation qualities. You must have a very large plasma cutter to handle 3/8's AL. Probably equivalent to 3/4's steel.

[DanB98TJ]

Originally posted by mrblaine
btw- AL takes 3-4 times the energy to weld or cut because of it's tremendous heat dissipation qualities. You must have a very large plasma cutter to handle 3/8's AL. Probably equivalent to 3/4's steel.

Now I don't feel so bad about how crappy the cuts looked. It only took about a half dozen flap wheels to clean them up.

[Stu Olson]

An interesting thread. Although I had always been told that fabricating in aluminum was more expensive, I had assumed the increased cost was directly related to the materials. I was not aware of the time element involved (such as the cleanup that Dan mentioned) or the steps needed to simply bend the tempered material. At an hourly rate, I can see where it all begins to add up.

[mrblaine]

Originally posted by Stu Olson
An interesting thread. Although I had always been told that fabricating in aluminum was more expensive, I had assumed the increased cost was directly related to the materials. I was not aware of the time element involved (such as the cleanup that Dan mentioned) or the steps needed to simply bend the tempered material. At an hourly rate, I can see where it all begins to add up.

What I didn't tell them Stu was that I can make a cut that long in 3/8's with my Bosch jigsaw, a fine plywood blade and the only clean-up needed is to break the edges. All in less than 5 minutes.

It's a tad slow, but the cut is beautiful.

[DanB98TJ]

I'll remember that for when we build mine.

When we looked at the nice, clean edge that the supplier made on the aluminum I figured Fred's plasma cutter would do just as good of a job. I was more than a little surprised at how hard it was to make the cut.

[BlueJeeper]

If you cut it dry with a metal cutting blades you can fill in the gaps between the teeth with alloy from the cut as it melts then cools Its like a blade from the hood

[Allen]

A plasma is about the last thing I'd use to cut aluminum. Even if your machine was bigger, or big enough to handle the job, the edge leaves a lot to be desired. It just doesn't do the job on aluminum that it does on steel.

My first preference would be to shear it. Second, do what Blaine does, or use a band saw if it'll handle the piece. Or third, mill it.

Allen

[Matt Pascoe]

Like Rick said, I had I terrible time cutting 6061 T6 with a jigsaw. The material just kept filling in the teeth till it couldnt cut any longer. I tried several different high$$ blades and none worked well, but did the job.

Blaine, plywood blades huh... I'll have to give that a try.

Anyone try a circular saw w/ a carbide blade?

[Allen]

Originally posted by Matt Pascoe
Like Rick said, I had I terrible time cutting 6061 T6 with a jigsaw. The material just kept filling in the teeth till it couldnt cut any longer. I tried several different high$$ blades and none worked well, but did the job.

Blaine, plywood blades huh... I'll have to give that a try.

Anyone try a circular saw w/ a carbide blade?

Use some coolant.....

And variable speed would help tremendously.

You're getting the aluminum hot enough to semi liquify so to say. (Not the best analogy, but you know what I mean) Aluminum gums up very easily clogging blades, drill bits etc.

Allen

[papromike]

I have a nice 3-8's sheet sitting here at work.


Luckily we have a 6" automated band saw which should make short work of that


then I will put in the Brideport and have our machinest, chamfer the holes and edges..

hmm got me thinking....

[Allen]

What are you guys paying for aluminum?

The price has tripled in the last few months.

A 4x8 sheet of 1/4" 6061 runs us over $400.....

Allen

[mrblaine]

Originally posted by Rick Bernotas
If you cut it dry with a metal cutting blades you can fill in the gaps between the teeth with alloy from the cut as it melts then cools Its like a blade from the hood

They make a cutting fluid for aluminum. Specifically aluminum and you can dribble a few drops in front of that gummed up blade, start cutting and it will clean it quickly.

I use Aluma-Tap.

[Darrell C]

Originally posted by mrblaine
They make a cutting fluid for aluminum. Specifically aluminum and you can dribble a few drops in front of that gummed up blade, start cutting and it will clean it quickly.

I use Aluma-Tap.

That's good to know.

[Allen]

We use multiple cutting fluids for aluminum at work, and I've honestly never paid attention to the names.

I'll find out tomorrow and share the info.

Allen

[mrblaine]

Originally posted by Allen
We use multiple cutting fluids for aluminum at work, and I've honestly never paid attention to the names.

I'll find out tomorrow and share the info.

Allen

I'm sure there are many. I've seen them at the hardware/industrial supply I shop at. My point was not to use regular cutting fluid. Although, WD-40 does work to an extent.

[Allen]

Originally posted by mrblaine
I'm sure there are many. I've seen them at the hardware/industrial supply I shop at. My point was not to use regular cutting fluid. Although, WD-40 does work to an extent.

I know that. I just wanted to give some other lubes in case people can't find Tap Magic, or already have something else around that can be used. We use the Tap Magic stuff too.

Allen

[BlueJeeper]

Originally posted by mrblaine
They make a cutting fluid for aluminum. Specifically aluminum and you can dribble a few drops in front of that gummed up blade, start cutting and it will clean it quickly.

I use Aluma-Tap.

Now that's a good little tidbit. When I was making those dry cuts a while ago I was joshing around to see what would happen. Too bad the blade is long gone. Where does one get the aluminum specific fluid? I looked for something like that once upon a time but nothing for me locally, at least in the hardware stores.

[BlueJeeper]

Originally posted by Allen
What are you guys paying for aluminum?

The price has tripled in the last few months.

A 4x8 sheet of 1/4" 6061 runs us over $400.....

Allen

I hadn't paid much attention but it looks to be up about 30-40% since the last time I made a purchase. Of course I only ever buy in very small quantity.

[StealthTJ]

Originally posted by Allen
What are you guys paying for aluminum?

The price has tripled in the last few months.

A 4x8 sheet of 1/4" 6061 runs us over $400.....

Allen

I paid $55.00 for a 42" piece of 12" wide x 3/8" thick, 6061 T6, and that included what they charged me to cut it to that length.




Fred

[mrblaine]

Originally posted by StealthTJ
I paid $55.00 for a 42" piece of 12" wide x 3/8" thick, 6061 T6, and that included what they charged me to cut it to that length.




Fred

Not too bad Fred, you paid a little over 29 cents a cubic inch and Allen's cost 34.7 cents a cubic inch. I like your price better.