Aluminum tube - "Au Naturel" ?

OK Gang;
I need more informed information.
I now have my 7” OD Aluminum (Aluminium) tube, 40” long ready for establishing my 6” f 6 Newtonian telescope. I had made an aluminum tube rolled and welded (.08”) and with folded over ends (3/8”).
I’ve got the seams ground down and filed, and am ready to ‘finish’ the tube!
I did get info for the interior – cleaned, primed and sprayed with ‘ultra flat black krylon’.
No disagreement, no problem. (Flocked paper would be better – not for me!)
But now, I am getting conflicting info on the exterior!
I thought of getting it painted in an auto-body shop, with a paint that they were using for whatever was going through - white, if I could get it cheap!
But, at ‘Starfest’ last weekend, in Ontario, I was advised to just buff up the exterior of the tube, by several people.
They said that it would “Dew less” and “Not get as hot” in the sun.
Also, apparently, after the oxide forms, it will be clean to handle, and not give off any ‘dirty’ marks when I am moving, twisting, working with it!
There are a lot of recommendations to use a “Scotch Brite” pad to scrub up the aluminum, to leave a random swirled pattern as the final buffing.
So, what are the opinions of the ATM people on this group?
My personal though is to ‘Try It’! There’s nothing to lose. I could have it painted later!
Thanks,
Mike Pupeza 6” f6 – most expensive homemade 6f6 in Canada!

I can tell you that with an airplace bare aluminum is a real pain to keep up. I don't think the black oxides will ever stop getting on you hands and clothing.
I would paint it so that it is protected. Also the white will work to keep it cooler in the sun. As for dew, I think that dew will always form on a metal surface, painted or not, and it is something you just have to deal with is all. A cork inner lining will help with this, but you have chosen to just paint it.
My $.02 worth, but I have painted all my aluminum flat black on my Dobs.
Floyd

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Mike,

You can alodine your tube yourself, cheap, with chemicals available at your local auto paint supply store; the resulting finish is a smooth, warm grey which is nicely paintable.

Alodine is a conversion phosphate process which creates a smooth oxide finish which is highly weather and wear resistant. Do a search, there are several suppliers for the chemicals, and it's an easy process.

James Adams

Mike,
If you want to keep it 'Au Naturel' (short of getting it silver anodized) I can recommend a clear-coat after sanding or buffing to desired level. A fully oxidized tube is a dull gray and still seems to get you dirty when wet with dew.
Attached is a photo of a 7" tube that was sanded with a 220 grit sponge and clear coated with Blair Matte Clear spray (available in most art supply stores). It has maintained it's lustre and does not fingerprint or mar like bare aluminum.

Also pictured is a 5" reverse insulated alum. tube. The interior is flocked and the exterior has a layer of cork covered with a Mahogany veneer. It is comfortable to use in cold weather. The bare alum.(regardless of color) gets really cold in winter (I dare ya to touch your tongue to it). I've had ice form on the clear coated tube AFTER bringing it in the house on cold winter nights. If you observe a lot on those cold Canadian winter nights you might consider insulating the exterior, as discussed in the "cooler than ambient" thread.
My 1/50th a buck, Bob

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Don't under estimate the work required to polish the tube. It probably 10 times the work painting is. As for not getting hot. Find your local airport and look for some planes with polished aluminum trim. Now flop your favorite focus fingers down on it. When you get over screaming and speaking rudely, think white paint. Hard to beat for a lot of reasons.