What's new
What's new

Buffing Tips?

i_r_machinist

Titanium
Joined
Apr 12, 2007
Location
Dublin Texas
I'm making some brass and aluminum s&p shakers and not getting good results on the buffing. The first one I polished up in the lathe with a 4" buffing wheel on my 4" right angle grinder, using that white compound. (Yes, I covered the ways.) It came out perfect, in about a minute. Did the 2nd one the same way, results not as good. Cleaned the buffing wheel and reloaded it. Not as good as the first one.
It's buffing, how hard can it be? Just hard enough to piss me off! Figure I'll just build a buffer with the two wheels on it.
So, I'm assuming I want to build around the biggest wheel I can get? I've seen buffers with 4 wheels on a shaft, should I just go for that? 3000 rpms? Wheel plys?
any pointers?
have fun
i_r_
 
Oh the hells of buffing, where to start?

First thing is I would most certainly get a designated buffer motor with long shafts and the right wheels. Buffing on the lathe is a pita and I find it takes 10x longer than using a buffer with the right compounds.

I polish parts a lot and what it comes down to is simple.
Initial surface finish. If you start with a grooved piece of aluminum and try to buff the groves out to a mirror with just the finish rouge you will be there all day. I am always trying to get things done as economically as possible and have found that a DA or orbital sander first works best. anything off the lathe I will hit with 320+ as it shouldn't need more than that. I then switch to a hard bar for aluminum (its red) or stainless (its grey) on a stiff but soft wheel. Once finished buffing the entire surface I move to the other side of the buffing motor which is set up with a large dia. soft wheel with much less plys (sewn rings which add the stiffness to the wheel) Here I use one rouge only, a hard white bar for finishing.

What it comes down to is pressure, process and the correct equipment i.e. wheels and rouges.
Before I discovered the secret of the DA I would use soft bars of different grit and slowly work up 80, 120, 220, hard bar, finish bar. Now I save a ton of time DAing 120,220,320, hard bar, finish bar. It goes so much faster and there is a lot less cleaning wheels and applying new rouge.

This is getting lengthy but there is a good bit of info learned through experience. I find if I'm not getting good results which just means black gunk is building up on the part the wheel is out of rouge, add more. If your bad results means its not polishing up to a mirror you need to go back get some 220, sand it and keep sanding until all deep scratches are removed. Sometimes its hard to tell if they are all out on a dull piece of aluminum but you will know as soon as you try to polish and the scratches appear.

As far as rpm goes 1750 is fine. Buffing motors are $ but you could get lucky, search CL thats where I found my Baldor...$25 I used the rest of the money I had planned on spending to buy wheels and rouge.

Baldor Buffers, Merit Abrasives, Specialty Buffs, Seymour Paints, Sand and Bead Blasters, Metal Working tools and more - Tarheelparts

This guy is very knowledgeable and will take time to answer any more questions you have.

Finally, last nights work. It still looks like I'm wearing eye liner, did I mention buffing makes a HELL of a MESS, wear a respirator!
 

Attachments

  • IMAG0795.jpg
    IMAG0795.jpg
    91.6 KB · Views: 599
  • IMAG0789.jpg
    IMAG0789.jpg
    93.5 KB · Views: 550
Okuma,
Could you explain "DA"?
thanks
i_r_

Sorry, cut that reply short. Had a customer.
Going old school on the bike. I like it!
 
Last edited:
Wife is retiring from her job, of the last 30 years, next Wednesday. She has already committed to being head of the "Finishing" department. (anyone know of a emoticon for evil laugh?)
Would you use the sander with the part spinning in the lathe?
i_r_
 
I guess you could do that, I just use the sander for things like that Sissy bar or gas tanks, etc the draw to the sander is that the pad is flexible and forgiving. For sanding while a part is in lathe just use fine emory cloth.
 
A local guy showed me his motor setup. He took a 4-ft wood lathe and made arbors for all his grinding, wire, and buffing wheels. Buffers could run 4 at a time. Nice setup, quick to change it out for the needs of a given project.

Now I wish I'd kept that old Atlas 10" parts lathe
 
I guess you could do that, I just use the sander for things like that Sissy bar or gas tanks, etc the draw to the sander is that the pad is flexible and forgiving. For sanding while a part is in lathe just use fine emory cloth.

I have been using emory with the part turning in the lathe. Down to 20 micron, then went to 6 micron diamond paste and newspaper. Parts look great until I hit them with the buffer, then the tiny imperfections show up. I think the red paste (lack of) is where I'm screwing up.

have fun
i_r_
 
Heat is the secret to making solid stick buffing compounds work! Generate the heat with high buffing wheel speeds and/or preheat work to 150 degrees F. Use 6 inch wheels on a 3600 rpm bench buffer or uses a high speed air buffer with 2 to 4 inch wheels. Large parts MUST be preheated to at least 150 degrees.

I spent countless hours trying to polish a 4 inch Dia. brass cannon without any results. I did an web search and found this site. https://www.swmetal.com/page/faq

Very good advise here. I heated the barrel with an electric blower heater while slowly revolving in a lathe. I used red Jewelers rouge on a 4 inch wheel on a high speed air buffer. Perfect results in a short period of time.

This is a very messy and dirty process. A good respirator and face shield are a must. Wheel strings and compound go everywhere. Cotton gloves are a must for holding a part up to a bench buffer. For safety, do not wear gloves when revolving work in a lathe.

Dave
 
Would you use the sander with the part spinning in the lathe?i_r_

I have a small Festool random orbit sander and found while polishing some hand wheels recently that the use of that tool to sand the wheels while they spun on the lathe saved a LOT of time. I do use a vacuum to pull the dust through the sanding pad and the sander which probably helps but I'm sure what helped the most is being able to have a very random scratch pattern on the metal and being able to take off material faster than I would by holding the paper by hand. Kept my hands cleaner too! I would guess that it halved my polishing time.

I was very surprised at how well I was able to polish cast iron!
 
Last edited:
Heating the part and using the red paste helped. Also buffed perpendicular to the scratches with my air grinder while the part was spinning in the lathe. This seems to justify a random orbital grinder. Still took about 30 minutes to get the finish I wanted. I bought a "Thor" two wheel grinder from a friend last night. Big heavy cast iron 3500 rpm grinder that should make a pretty good buffer. Would a clear coat of lacquer cover up some of these imperfections?
Buffing sucks.
i_r_
 
I have experimented with various clear coats including lacquer. All scratches and sanding marks are clearly visible through the clear coatings. A high gloss buffing is necessary if you want a good polished look after clear coat. Also, I have found that the brass will darken with age under all clear coats. Some faster than others.

If you are doing the buffing correctly; 220 grit marks will buff out with say 20 seconds of buffing per wheel application per spot. Remember to go slow so as to heat the work.

Dave
 
The only finish i know to hide small scratches in polished work is the chrome like plastic coatings.
 
Stradbash, if you're doing a lot like that on your lathe, you might try a variable-speed drill on a stand, away from the lathe. (Last time I did that, I had quite a bit of messy grit to clean up.) Your abrasive material may not shed very much, so it may not be a big issue...

Currently buried in the corner of my shop is "Buffzilla", a home-made hand-me-down from a gunsmith. It's a 3-motor, 6-jackshaft, 12-wheel affair completely decked out with buffing heads. He used it for metal polishing, and some wood finish buff-out. You can see where he built the 4-head device first, then added a 1/2" plate deck to the top to triple the number of available wheels. I need to investigate (somehow) what compound each was used for... or just replace them all. But I've got a little polishing to do this coming spring, so we'll see how it works then.

Chip
 
I do a lot of buffing unfortunately. It is a filthy job - especially with aluminum.

I'll briefly go through my method for you. There will be a number of pictures - so there will be a number of posts.

The key to buffing is preparation. I'll demo with a couple copper spinnings that I do and have pics for.

While still in the lathe, I'll sand down the surface with 320 grit sanding cloth. It comes on rolls 2" wide. I tear off what I need and then rip it into 1" wide strips. I do this with spinning lube on the item to eliminate grit and metal dust all over the lathe. After the sanding cloth, I go over everything with a scouring pad - usually red. Again this is done with lube to control dust and to produce a finer finish on the metal. If you sand aluminum dry, you will regret doing so.

Now sometimes the metal is ready to begin buffing after the above. More often than not I go to the next step... done outside.

Using 320 grit flap wheels on my buffer, I smooth out any spin lines that might still be evident. My main buffer is shown here as are the types of flap wheels used. These are used dry. A copper spinning after these processes is shown in the pics.

Continued in next post.
Jim
 

Attachments

  • finishing21Sm.jpg
    finishing21Sm.jpg
    20.7 KB · Views: 247
  • flapwheels09sm.jpg
    flapwheels09sm.jpg
    24.4 KB · Views: 283
  • Grizzly05sm.jpg
    Grizzly05sm.jpg
    15.3 KB · Views: 355
  • Cup2329.jpg
    Cup2329.jpg
    4.8 KB · Views: 244
  • compounds08sm.jpg
    compounds08sm.jpg
    20.6 KB · Views: 258
Last edited:
Once the surface is as shown, buffing may begin using compounds as shown here. For prebuffing I like to use emery on sisal wheels (not pictured). I gang mount three 8" sisal wheels on my buffer. The rpm is 3450. This gives a very nice prepolish to the metal and allows me to see any imperfections that might be there.

From there I go to a hard spiral stitched wheel like the yellow one shown. The white spiral sewn wheel is softer. The loose cotton wheel is for final buffing. I will often use the same buffing compound (blue Formax bar) with all of these cloth wheels. The finished examples of my polished metal spinnings were all done with the blue.

In addition to the wheels described, I will often utilize pleated cloth wheels. The different colors indicate hardness of the cloth. Color varies with manufacturer but you can tell by feel.

The items get very hot during the buffing process!
Jim
 

Attachments

  • spiralsewn03sm.jpg
    spiralsewn03sm.jpg
    25.7 KB · Views: 169
  • spiralsewn02sm.jpg
    spiralsewn02sm.jpg
    16.1 KB · Views: 158
  • loosewheel01sm.jpg
    loosewheel01sm.jpg
    16.4 KB · Views: 195
  • pleatedwheels12sm.jpg
    pleatedwheels12sm.jpg
    26.1 KB · Views: 179
  • pleatedwheel11sm.jpg
    pleatedwheel11sm.jpg
    25.7 KB · Views: 222
Here are completed copper and aluminum items. All were done using the blue Formax bar for buffing. Also shown is a half polished stainless steel ball.
Jim
 

Attachments

  • Cup2336.jpg
    Cup2336.jpg
    21.5 KB · Views: 208
  • Cup2341.jpg
    Cup2341.jpg
    16.1 KB · Views: 214
  • Shaker040sm.jpg
    Shaker040sm.jpg
    22.8 KB · Views: 223
  • BothCups045.jpg
    BothCups045.jpg
    14 KB · Views: 372
  • SmallHalfPolished396.jpg
    SmallHalfPolished396.jpg
    16.4 KB · Views: 209








 
Back
Top