Polishing A Kirby

[briguy]

Hey guys! I invested in a bench buffer with a stitched cotton and loose cotton buffing wheel. I am having trouble achieving a mirror shine. I keep having micro scratches left in the finish. I’ve sanded w/ 6 different grits of sandpaper and gotten deeper scratches out. I use black rouge on the stitched wheel and follow up with white rouge on the loose cotton wheel. I’ve also tried following up with Mother’s Mag and corn starch which helps, but still has micro scratches. I know I’ve seen other older models w/ beautiful mirror finishes. Maybe I’m expecting too much?

Any tips on what I may be doing incorrectly?

The small scratches are really bugging me.

 

[aaron158]

do u have any red rouge give that a try that's what kirby use to put in with there handie butter back in the day. tbh though it looks like u have done a good job on it already.

 

[briguy]

Red rouge

I do have red rouge. I’ve used that along the way as well.

 

[lesinutah]

Hmm

You lightly sand up to 2000 grit sandpaper wet sanding. This seems to get shine using green and white rouge.
I'd go up to 2000 wet sand. Wipe off metal then use green and white rouge. That should get the mirror image your looking for.
Les

 

[madman]

If I want a mirror shine, I sand up to 3000, which may not be necessary on aluminum. Then I have 3 stitched cotton wheels, I go black, red, then white. Then I use a loose cotton wheel with Mother's mag polish. THEN you need a good soft cloth to get all the crap off of it, and it should be fine. Probably overkill, in all honesty.

Also, there is some technique to polishing as well. Use a lot of pressure only for a first pass and assuming you haven't sanded it. Otherwise, use a gentle pressure under the wheel and keep it under the wheel for a long time, moving very slowly.

What's the final grade of sandpaper you're using? Cuz honestly, it looks like you're having an issue in the sanding phase, not so much the polishing phase. If I had to venture a guess, it looks like your final sandpaper was 1000 grit or less. If possible, go 1000, ~1500, 2000, 3000. Start with less if you stopped with less, obviously.

 

[rowdy141]

I'd suggest your stitched wheel might be too harsh? Or you're pressing too hard, instead of letting the wheel do the work.
It appears as though the stitched wheel itself may be scoring the soft aluminium?

Perhaps consider a hard FELT wheel? Softer than stitched Hemp(?) but firmer than a Cotton Mop. They're a solid, compacted felt, which is firm to work against, but gentle enough so it cannot mar soft metals such as Brass and Aluminium; even if you press a little too firmly.

I use varying grades of wet & dry paper to remove deep scratches and 'liver-spot' blemishes. Keep them wet.

Then Green Chromium-Oxide compound-bar with Felt wheel. Green will even polish hardened steel, by hand, on a leather strop.

Then use the Cotton Mop just to remove any waxy deposits and streaks. The mop won't do much for scratches. They have to be all-but-gone by that stage.

Then a final rub with Brasso/Autosol on a cloth. Not really necessary but I like to 'feel' the finish is smooth, get in and around awkward spaces, and remove any deposits left by the mop.

Some suggest a light coat of lacquer to preserve the shine and to prevent further oxidation, as you would with Brass Fan blades. I use Simoniz Car Wax with high Caranuba wax content.

 

[lesinutah]

Hmm

I have alot of different wheels and none seemed to hurt the finish. The felt wheel I used is more of a finish wheel. It just takes off excess polish. Felt I don't know about much about it but I'd guess it would be to clean up as well.
I bought the DeWalt brand and a harbor freight one, another off Amazon. The DeWalt lasted a while I still use them.
If it were anything I'd guess using to much cutting compound to polish.
He may be right but y opinion is stated above.
Les

 

[rowdy141]

Hi Les!
The Hemp/String wheel I have here (the only one I've seen) is really course. I'm going by BriGuy's photo and assuming all those fine in-line parallel scratches were the result of machining? I would have thought it unlikely that he was so accurate with hand-sanding in one precise direction?

Perhaps it's the Green Chromium Oxide compound that makes the difference? It could be the felt wheel is not a big factor, but the two do work together, and that's what we're looking for.

Apparently, Kirby use an enormously powerful industrial polisher. I don't know whether that's to speed-up productivity in their factory, or whether high torque is needed. I did discover that standard polishing machines such as the Handi-Butler, Dremel, Drill pad, and Floor Polisher were all useless at this, regardless of the compound or time spent. Finally, I opted for a purpose built Bench Polisher.

 

[lesinutah]

Hey

I have seen Kirby's 14" polisher in pics. I have a 9 inch that gets 6000 rpm.
I want sure on suggestion was my opinion. I do know my polisher the big moth effer I never use can polish almost anything. Some metal I believe you can't polish out. I think only way is sand deep into metal. I don't even know then.
I have never polished over 3 k rpms.
I don't have everything to ensure safety and not worth it.
You may be right on hemp I have never seen or used it.
Les

 

[madman]

Meh, my cotton wheels make the finish just fine. But like I said, there is a technique. I wonder how BriGuy sanded those parts? Like Rowdy says, it looks like machining. A belt sander? Maybe he just used a linear motion only. Not sure.

I'm still of the opinion that those scratches existed before he went to a polishing wheel. They look like sandpaper scratches.

 

[lesinutah]

Pic

The pic shows sanding scratches. You simply need to sand it until no scratches or blemishes like photo are left.
Les

 

[texaskirbyguy]

BriGuy,
What model of Kirby are you trying to polish?
I have seen those 'sanding' marks on a G6 I had done last year (the only G series I have ever owned) but never before seen them on the older non-G-series. I was going nuts trying to get those marks out but gave up thinking those later machines were just sanded more harshly at the factory.
The older machines I can get most of the sanding marks out (to the limitation of my equipment and patience).

 

[rivstg1]

texaskirbyguy

Rob,, you took the words right out of my head! I found the same issues with polishing the later G series vs the old Kirbys'

Kelton

 

[briguy]

Conclusion...

Thanks for all the input guys. I used multiple different wheels and rouges. I finally got it to a point that my OCD could accept. However it’s not perfect. The conclusion I have come to after talking to other collectors that have had issues polishing newer models & looking at photos online is that the metal of newer Kirby’s is not as good as the older models. That it doesn’t get that mirror shine like say a Tradition or Classic. This is a 2015 Avalir. And I just realized I posted this in vintage and it should have been the contemporary forum.

 

[lesinutah]

Metal

It's not that it's an inferior metal at all. They had metal poured into molds. They would heat it and let it cool down. They would then take off the mold and you can see some of mold casting lines on older models.
I don't know if I'm correct but I'm not far off guessing how they are made now. I think they use a CNC machine or a computer program the cuts the metal instead of using molds. The newer metal is stronger and different but it's not inferior. I can polish a newer Kirby alot easier than the old Kirby's. The g series is slot of flat surfaces. The older had vents curves and bumps every where. Trying to do an area would have vents curves and holes. The g series is straight lines and doing areas it's easier. It doesn't polish like old vacuums but the metal is different. I can polish a g series and any other model. I'm noticing on my 500 series the metal is porous and hard as heck to polish. The new metal gets like a chemical burn. I think certain products burn aluminum and you can't polish it. It's more sensitive metal but it's not inferior. It's how they are made different than before.
So older shine better newer are easier to polish but the shine is like a smoky shine instead of mirror shine.
Les

 

[briguy]

That all makes sense Les. I wasn’t aware of how the manufacturing process may have changed over the years. The way you describe the new “smoky” shine versus the older models mirror shine is a perfect description. I need to use my buffer on my Tradition and Heritage II. I just got so tired of hassling with this one I am taking a break. I’ll eventually tackle those.

 

[madman]

Les, I doubt they CNC a block of aluminum. That would be insanely expensive and time consuming. It would probably cost more than the retail price of the whole machine. They do that kind of thing for custom cylinder heads for race cars, each head is usually thousands of dollars each. *Maybe* they cast it in a mold like normal and THEN it's CNC'd to finish, as opposed to finishing by hand, maybe. Regardless, the method of manufacture should not affect the metal's ability to be polished.

But yeah you are probably right about the metallurgy, it's almost certainly not pure aluminum anymore, almost nothing is, these days. More likely an aluminum/magnesium alloy, which is very common.

 

[lesinutah]

Right

I know it's not CNC but its cut using a computer. Companies are all about quality and precision. No mold is going meet newest version of ISO 9000 quality standards. Companies live and die for highest quality rating. Precision computerized method is used. There is no more molds for metal.
If they cut piece of metal scraps simply collected reheated maybe treated and reused.
I may be wrong but with quality levels with defects of 5 per 1000 as a standard it's computer precision no other way to yield quality levels.
It's been a few years since I took quality management class but it's only improved since.
Les

 

[madman]

Well, yes to the quality standards, but there are still molds for casting aluminum. There's no other way to mass produce that kind of thing. The only difference now is that there's probably robots making the molds, like car manufacturers use. Either that, or the unfinished castings are made in China and shipped here to be finished.