Aluminum finishes

[El Guanche]

I need to know how to give a brushed finish to an aluminum pipe that came mill finish.

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Sandpaper.

[El Guanche]

It is a 6 inch dia by 10 foot pipe and it needs to be cosmetic flawless brushed finish. I was thinking of making a jig like a lathe to turn it around and moving the sand paper but it needs to look perfect. Is there any machine that can do the job better?

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That's a big piece of aluminum.
If you must have the grain running radially, then yes, your jig would be the ticket towards perfection. If you have a lathe and can chuck the tube up and extend it off the bend with proper support, I'd say go for it.
Sometimes you just gotta jump in and work it out.

I think you'll find that "perfect" quickly becomes a relative term.


Good luck, El Guanche, and I'd LOVE to see some pics of how you go about this.

[TS-Off-Road]

Scotch brite pads work the best for Aluminum.

[RWC]

I think your lathe fixture idea is a workable solution. We have put brushed finishes on small parts using lathes and abrasive cloth, paper, or scotchbrite, so it should work the same on a bigger scale. If you don't know someone with a long enough lathe bed you can just rig up somthing to turn the tube. If you don't have enough waste length to chuck up without scratching the material, you could make some inserts to fit inside the tube and have small enough spuds sticking out to chuck up or support on the tail end. You could use a belt wrapped around the tube driven by any motor if you don't have access to a lathe. Hopefully your customer will pay you enough to git er done.
Good luck,
Rube Goldberg

[El Guanche]

Thank you guys I found a weld seam grinder and pipe sander from Unitec that can do pipes up to 10"diameter. Here in Puerto Rico they sell it for $990.00 plus the sanding belts. It seems a little expensive for a hand tool but I'll look for one over the net.

El Guanche

[El Guanche]

Bought the machine and it works wonderfull. I started with #30 grit then #60 and finished with #120. It gets a little hot both the machine and the aluminum. It took me about 2 hours to do the whole thing. Ain't that amazing". Last time it took me more than 8 doing it by hand and it wasnt that uniform.

[Craig in Denver]

That sounds pretty cool. Any chance of pics; both the project and the tool you used?

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Wow. If it did all that you claim, I am both surprised and impressed. Congratulations. If the tool is what I'm thinking of, it is also used to finish handrails of smaller dimensions, correct?

[El Guanche]

This is the machine the picture is from the site http://www.csunitec.com/sand/pipe_sander.html

[Craig in Denver]

El Guanche:
Thanks for the pic. That thing costs $990? Does it have variable speeds or one speed fits all? Are the belts specific to alum? Did you turn the tube by hand or machine? Sorry, pics cause questions; like marriage causes divorce.

[El Guanche]

It is variable speed, I did it in segments rotating the pipe about 1/10 of the circumference at a time and it blended well with no banding, I moved the machine the whole lenght of the tube back and forth with each grit starting at 30 then 60 then 100 and left a nice radial pattern just like a factory made brushed finish. The belts I think are good for aluminum I welded afterwards with no problem at all.

[Craig in Denver]

Thanks for the follow-up.