Grinding Aluminum

[kb1ftx]

Our fire department just got a new boat from USCG surplus, but the radar tower was too tall to fit under the bridges between our lakes. I cut the tower off with my plasma, but there is still a short lip, about a half inch, that needs to be taken down. Any ideas about the best way to grind it down. I was thinking flap wheels? I dont usually do much aluminum grinding.

[boatbuilder]

36 grit sanding disc and some stick wax or wd 40.

[DSW]

They make specially designed alum grinding wheels designed not to load up and remove a lot of material.

http://keenabrasives.com/Type%2027%2...20Aluminum.htm


Sanding disks also work if used as above.

[weldinglifer]

If you plan to re-weld, I advise you not to grind. If it is a small area, use a file designed for aluminum, if it is several square inches a rotatry file (burr), if it is really large, than a powered plane with carbide inserts. Grinding aluminum and then welding can cause a lot of porosity.

[mrbacklash]

Just curious what kind of boat did y'all get a Safe? The 23' ones are a blast

[power]

I would use a aluminum bit in my die grinder if its just a small part that needs removed. If you have a lot to remove I would say use a 4inch wheel from cryo-vision it is based more on the design of a rotor style wood bit, these things are a widow maker be careful they remove alot of material in short order, but expensive. A flap wheel will tend to fill up on you but may work for your situation. Good luck Dale

[jakeru]

Aluminum-specific grinding wheel for a 4.5" angle grinder is what I'd use. They shed grains quickly enough, so as to not load up. Welding immediately after grinding with them also works great. No problems with contamination. Absolutely no post-grinding steps necessary before welding for great results.

You can weld right after using a flap wheel only if you take it slow enough so as to not get things so hot as to overheat the aluminum and "smear" the surface. There you no "speed limit" with the aluminum-specific grinding wheel (or at least, that speed limit is much higher), you can just go to town with them. They are fast.

[drivethruboy54]

stick wax on a resin fiber disc.

when the disc stops cutting just touch it with the wax again and its like brand new.

It welds just fine after without any cleanup.

[MikeGyver]

Btw those abrasive aluminum specific grinding wheels remove material FAST.

[Kelvin]

Originally Posted by power

I bet that would make you sit up and take notice if it got caught in your shirt!

[Doug247]

Where ever I have worked they have been too cheap to buy the aluminum specific grinding disks, but any of the disks good for stainless will work for aluminum.

[sjmj1966]

hit it with the plasma again

[power]

Originally Posted by Kelvin

I bet that would make you sit up and take notice if it got caught in your shirt!

Kelvin, Check out my post Got Lucky in the saftey forum had a wire wheel get away from me I would hate to see what this would do to flesh, thats why I call it a widow maker Man can it remove material!! Leathers and all ppe and operate it only at a bench for sure.

[MikeGyver]

Originally Posted by Doug247

Where ever I have worked they have been too cheap to buy the aluminum specific grinding disks, but any of the disks good for stainless will work for aluminum.

The aluminum only ones work much faster and I think they're basically the same price.

[Doug247]

Originally Posted by MikeGyver

The aluminum only ones work much faster and I think they're basically the same price.

I agree with you, I have used an aluminum only disk once, they do remove material faster. I guess i was giving my employer an excuse to why they wouldnt buy them for us lol

[Garauld]

I also use standard sanding discs; 60 grit works well. I also use a bit of beeswax on them to keep their cutting action effective. I guess most any wax will work. I tried WD40 once, but it was kinda messy. If you use a file, get some of those large sidewalk chalk crayons and load the file with it - it does a good job keeping the file clean.

[Rick V]

Originally Posted by Garauld

... If you use a file, get some of those large sidewalk chalk crayons and load the file with it - it does a good job keeping the file clean.

I'd not heard that before; thanks for the tip!

[Pangea]

Sawzall.

[fdcmiami]

and a wood cutting blade. 6 TPI.

[B_C]

Originally Posted by boatbuilder

36 grit sanding disc and some stick wax or wd 40.

+ that

[gatehead]

Originally Posted by B_C

+ that

x 3 , but I use bees wax it stays on the disc longer. I use the stick wax for all of my scotch-brite wheels, and saw blades.

[MikeGyver]

Why is everyone promoting a ferrous grindind wheel instead of just buying a aluminum wheel.

If you could find an aluminum cuttoff wheel that might be best. Lay a straight edge on the 'keep' side of the cut and trace against it with the cutoff wheel.

[LMironworks]

36 grit disc. I always use toilet ring wax. $2.00 for the whole ring. I just reuse the stick, it does get messing when refilling it.

[gatehead]

Originally Posted by MikeGyver

Why is everyone promoting a ferrous grindind wheel instead of just buying a aluminum wheel.

If you could find an aluminum cut-off wheel that might be best. Lay a straight edge on the 'keep' side of the cut and trace against it with the cutoff wheel.

Aluminum cut off discs work well, but all of the other types of non ferrous abrasives I have tried do not work nearly as well as a zirconia sanding disc and wax. They will last just as long as a grinding disc, and will leave a nice finish. I work in a shop that does 98% aluminum so my abrasive distributor is always is letting me try out the latest and greatest non ferrous stuff, but I always go back to the sanding discs and wax.

[BlueArc]

exactly how much grinding are we talking here? would a cut off wheel not be quicker for removing 1/2" of material?