Alloy wheel polishing questions

[db_abz]

Hi guys, I'm a newbie!

I've got a set of polished alloys on my old BMW 540i.
They are off the E34 M5 if anyone's interested!

Anyway, after reading through the posts here and reading the handbook (excellent help!), I've got a few questions -

There doesn't seem to be much info on how much pressure or weight you need to put on a buff to get the best/easiest/fastest results, remembering these are alloy wheels.

How do you know if you've got too much/just enough/too little compound on a wheel.

How often do I need to reload the wheel?

I've got sisal wheels with greaseless 80/120/180/300 grit. (I don't use these often!)
I've got spiral wheels that I use grey and green compounds on
And loose wheels that I use blue compound on.

I'm in Scotland and it seems that we use a different colour coding to you guys - I think you use black/brown/white?

Appreciate any help you can give me, I'll try to attach a phot of my last attempt!

Dave

[pickleboy]

Originally Posted by db_abz

Hi guys, I'm a newbie! welcome to the forum

There doesn't seem to be much info on how much pressure or weight you need to put on a buff to get the best/easiest/fastest results, remembering these are alloy wheels. this is a learned technique, there is no definate answer to that question other than experience. i can only say that the metal should be hot to the touch when you are buffing. if not then press harder. also if you are not using enough pressure in the rougher grit bars you will be wasteing time and wheels.

How do you know if you've got too much/just enough/too little compound on a wheel. this also is a learned trick. when i load the wheel i will hold the bar against it for about 1-2 seconds depending on the wheel size and speed of the machine.

How often do I need to reload the wheel? when it stops cutting and starts to smear streaks on the part.

answers in your post in bold.

[db_abz]

Thanks for the reply pickleboy.

I guess it was too much to expect a reply along the lines of
"use 15 lbs of pressure"
"add 1/4 oz of compound to a 6" wheel"
"add more every 42 seconds" !!!!

Ah well, I'll keep practising then. I'm sure I'll find a routine that works for me.

When I did one of the wheels yesterday, I was using a 6" wheel on an electric drill with a max no load speed of 3200rpm. I used just enough pressure so that I could keep the speed up, seemed to work better than my last attempt where I used loads of pressure and speed really suffered.
Like you said, trial and error.

Guess I really need to buy a better drill so I can have speed AND pressure!

Dave

[Rasper]

Dave,

You will probably be more satisfied if you buy a polisher, rather than a drill. My experience with electric drills is: the ones with high speed have low torque; the ones with high torque have low speed.

Look on the Caswell Web Home page. Click on the tab "Buffing Polishing". Down at the bottom, on the right, under "Adaptors", click on "Grinder/Buffer Adaptor". It shows a great looking rig. The Caswell shaft extension for the polisher looks like a must have for me. I'm going to get one.

Note: You want something in the 3000 - 4000 rpm range, no faster, and definitely not a 10,000 rpm plus grinder.

Richard

[db_abz]

Thanks Richard.

I have a rotary polisher, 6 speeds, max 3000rpm. Unfortunately it has an M14 thread and not the 5/8" thread that you guys have.

Good idea though, I'll have a search in the UK to see if I can find an adapter.

Dave

[db_abz]

Not having much luck finding an M14 thread adapter but I did some checking on my drill setup.

It's got a 2 speed gearbox with variable speed control as well.
Max no load speed of 3000 rpm and it runs at 810W, which I reckon means that it's 1.08HP, should be OK?

I can also get quite cheaply, $70 or so, another drill of the same spec but with a bigger 1050W motor (1.4HP).

I hope my conversion is correct because it's cheered me up a bit!

Running 6" wheels should give me a SFPM of 4500, is there ever a case where you would cut or colour at less than maximum speed?

Dave