Polishing a Set of Aluminum Wheels...Newbie Detailed Questions

[fcastro]

Hi all,

Very nice to have this site and the products offered by Caswell

Ok, I was wondering if I could get a little help with some questions. I have a set of aluminum wheels that I am going to strip and then polish. (wheels pictured here)


I am on a very tight budget and I am trying to leverage what I currently own hardware wise to make this project a reality. Caswell has a 50 dollar kit that includes 4" wheels and compound which is perfect!

Ok now here is what I currently have access to tool wise:

1. Dewalt 849 Rotary High-Speed Polisher - (1000-3000 RPM has a 5/8 spindle)
2. Rotozip - Its like a big dremel (15,000 TO 30,000 RPM, takes 1/4" shafts)
3. Dremel (5,000-30,000 RPM takes 1/8 1/32 shafts)
4. Electric Drill (2000 RPM takes 1/2 & 1/4 shafts)

So here is the dilema I am in right now. The buff wheel kit sold at Caswell is for 1/4" shafts. So I can use my drill and or my rotozip because they can handle that size. The Dremel can't handle 1/4 shafts there is no adapter from all the research I did. As far as the Dewalt well I don' think I can use that either (can't find any adapters).

From what I have been reading on here and in the buff guide my drill is too slow at 2000 RPM and my rotozip is too fast at 15,000 RPM. Anyone chime in on whether this is correct?

[Rasper]

Go to the Caswell main page. Under Buffing/Polishing supplies. Down at the bottom right of the list is something called a grinder/buffer adapter. It is made for 5/8 shaft buffing machines.

There are lots of felt polishing buffs for sale for dremels. Caswell has some with 1/8 inch shafts listed under felt bobs.

Richard

[fcastro]

Thanks for the reply Richard!

Great find on the 5/8 adapter I totally missed that. I have seen the dremel buffing pads but they are so small it would take ages I would think to finish off my four rims.

Anyone have any input on the whole what is too fast piece? Ideally I would love to use the rotozip just because it would be easier to move it around rather then move the rim around the polishing wheel (wheel is pretty heavy)

[chromo]

Well, speed is relevant to size and pressure to some extents.

Using say a 2000rpm drive, a 4" wheel has about half the surface speed as an 8" wheel and maybe third as a 12" wheel. 1 rpm is one full turn, so in feet per turn a larger wheel is moving faster than a smaller wheel on your part.

4" wheel X PI = 12.57" per rpm or about 1' per rpm. 2000' a minute at 2,000 rpm.
8" wheel X PI = 25.13" per rpm or about 2' per rpm
12" wheel X PI = 37.70" per rpm or about 3' per rpm

your drive motor must have enough torque to maintain speeds with your size wheel at the pressure you apply to the part. Press harder and you bog down the motor more.
So for a small light weight dremel tool with a low torque motor you need a small wheel and lighter pressure in order to keep up the RPMs, and if you bog down the motor with large wheels or hard pressure you'll burn it up.

That being said, 1/4" shafts for your rotor zip is not the problem, you need to figure out your RPM feet and Buffer wheel sizes for your rpm motor and torque. Any machine shop can turn a 5/8" bolt down to a 1/4" for you to fit your tool. Slap the buffer wheel on the bolt, tighten the nut, lock the 1/4" end into the rotozip.
In theory you can get basically any size shaft you need made then for about $5 maybe less at a decent machine shop. Be aware though, using a large wheel on a 1/4" shaft may bend the shaft easily or a little out of balance make it jump around wildly like a mexican jumping bean on steroids!
I turn stuff like this myself on my lathe all the time to adapt most any type part to any motor shaft I want.

[fcastro]

Thanks for the reply chromo. I wonder if I am understanding this clearly. Does my calculations make any sense?

I think I misread the buffing speed section then. I took the SFPM formula which is SFPM = 1/4 x diameter of wheel x RPM (revs of spindle per min).
(eg. 8" wheel @ 3600 RPM = 2 x 3600 = 7200SFPM)

For the rotozip I figured this:
1 x 4" = 15,000 SFPM <--- way over the recommended 3600-7500 SFPM.

Does this formula then generically apply to all buffing wheels then?
4" wheel X PI = 12.57" per rpm or about 1' per rpm. 2000' a minute at 2,000 rpm.
8" wheel X PI = 25.13" per rpm or about 2' per rpm 4000' a minute at 2,000 rpm.
12" wheel X PI = 37.70" per rpm or about 3' per rpm 6,000' a minute at 2,000 rpm.

Based on my math (which can't be accurate thinking about it now) If I were to use the rotozip with a 4" wheel I would be getting something like 15,000' a minute.

I think I am confused now, lol.

If I were to use my DeWalt Polisher with the adapter I would be inline with 3000 RPM if I used the 8" wheel.

I would probably avoid putting an 8" wheel on the rotozip just because I am pretty sure the shank would get bent especially if I have to apply pressure when polishing. Originally I also was under the impression that you really don't apply a lot of pressure on the wheel when polishing and it was more about just making contact.

[chromo]

Sorry I forgot a formula was here. What I meant was just you could adjust the surface speed on the part by size of the wheel staying at same rpms of the tool.
I was just giving examples, applies to anything round like a wheel.

If the outside of your car tire is 24" you move 24 X PI= 75.4" or 6.28' each time the wheel goes around 1 full turn.

Formula,
"SFPM = 1/4 x diameter of wheel x RPM (revs of spindle per min).
recommended 3600-7500 SFPM"

1/4 X 4" wheel = 1 X 15,000rpm = 15,000sfpm that's 2X to fast, so half that size wheel?
1/4 X 2" wheel = 0.5 X 15,000rpm = 7500sfpm so max is 2" wheel,
1" wheel would be half that and at 3750sfpm is near the low

So if I figured that right, the 15,000rpm rotozip needs about 1-2" wheel.
2" should work fine on a 1/4" shaft.

Not used it yet, but I was at a close out store and bought a nice buffing kit for a drill, has a 1/4" shaft, 2", 3", 4" cotton wheels and 4 little bars of compound (one each type).
I think Caswell sells something similar (but better quality) and they have the aluminum wheel kits also.

A 4" wheel on the polisher should run 3000sfpm on high speed, just under the recommended low of 3600sfpm so would probably work.

You do have to apply some pressure to make the compounds work and this will bog down a motor and the larger the wheel the more it will bog down. I don't know what your polisher is,
The online buffing book shows a 1/4hp motor should run a 8" wheel at 0.5" wide. There is a typo there, it shows 5" but it should be 0.5" I am sure

If you haven't read it yet, http://caswellplating.com/buffs/buffman.htm you should download it and read through it. Nice online book/manaul.

[jrow]

fcastro,

You guys are really trying to make this complicated, No?
The optimum for polishing wheels is a flexible shaft mounted to an electric motor. However there expensive. Get an inexpensive 3/8" electric drill motor, get yourself an assortment of buffs. If you have a compressor you can get a die grinder and use that. I wouldn't run anything bigger that 4" buffs on a 3/8" drill motor. Goblet and Facer buffs are ideal for doing rims. Measure the inside diameter of the area that you want to buff and get buffs that will fit into the opening, done deal. Use aircraft paint stripper to strip the wheels, then use some greaseless to clean up the aluminum, then buff! Put some duct tape around the chuck so you don't gouge the aluminum and go for it.

John

[mpierich]

Originally Posted by jrow

fcastro,

You guys are really trying to make this complicated, No?

LOL...Yes.

Originally Posted by jrow

The optimum for polishing wheels is a flexible shaft mounted to an electric motor. However there expensive. Get an inexpensive 3/8" electric drill motor, get yourself an assortment of buffs. If you have a compressor you can get a die grinder and use that. I wouldn't run anything bigger that 4" buffs on a 3/8" drill motor. Goblet and Facer buffs are ideal for doing rims. Measure the inside diameter of the area that you want to buff and get buffs that will fit into the opening, done deal. Use aircraft paint stripper to strip the wheels, then use some greaseless to clean up the aluminum, then buff! Put some duct tape around the chuck so you don't gouge the aluminum and go for it.

John

[mpierich]

Originally Posted by chromo

I turn stuff like this myself on my lathe all the time to adapt most any type part to any motor shaft I want.

For those of us without a lathe: I do this on a drill press - chuck the bolt in and use my die grinder or angle grinder on it. Prolly could do it in your drill and hit it with a file (or a coarse rock, for the cavemen in here, haha...)

[chromo]

"For those of us without a lathe:"

Ya, lots of ways to do many things if your creative in thinking.
I needed a large 1/4" round steel disk with mounting holes, I drilled the mounting holes after rough cutting the disk, then mounted the disk on a car hub, grinder under it, got a perfect disk

Must say I did not think of doing that myself, saw something similar on a forum and adapted the idea to what I needed.