Idea for polishing fins faster

October 1st, 2009 at 11:08am Under metal finishing

Let me start off by saying I’ve never polished any large fins. Only some fins on a valve cover that where easy. So pretty much I’d like someone who has done a decent amount of heads and cylinders to lmk me know what you think. Who knows, maybe everybody is already doing this. My idea is to have about 4-5 razor buffs on one shaft at a time, but with spacers in between. Lets say between each razor you put a washer, about the thickness of a fin. It would pretty much be a fork type buffing wheel, so you could buff 5 fins at one time. Obviously it’s going to grab and will want to knock it out of your hands. Probably a low rpm buffer would be best. LMK what you think.

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Newbie (somewhat) buffing question =)

October 1st, 2009 at 11:08am Under metal finishing

Hello everyone! I thought I would stop in and ask a couple of questions since you all have been so helpful before! (Thank you!)

I’m having a little trouble up buffing an item that I’ve made out of copper. I’ve done all of the sanding and early buffing stages and am right at the upper end of the buffing spectrum. I’m not a total buffing newb . . I’ve had a lot of success with smaller items. But this is really the first item that I’m buffing that is quite a bit larger than the buffing contact surface so it’s much harder to get a uniform surface.

I am trying to get the ultra small scratches out caused by the the last level of buffing I did which was with a green bar that I DID NOT get at Caswell. It’s a green bar composed of superfine Chromium Oxide. It is a step beyond Tripoli. And I’m trying to figure out where to go next to get the fine scratches out.

I just want to add ahead of time, that while I’m learning buffing, I am quite familiar with the process of sanding– so, the scratches you see in the pictures below ARE NOT scratches left by sanding. They are completely left by the buffing compound I last used and I know that FOR SURE.

SECOND QUESTION — In the below picture, I circled some of the small black specks that I get with some buffing compounds. Now I’ve heard talk about them in many places but I want to know what exactly they mean. I’ve read that it means you don’t have enough compound on your wheel and I’ve read that it means you have too much compound on your wheel. I think I’ve read a few other things to. So, how exactly do I determine the reason that I’m getting the black specks of compound?


**Just a note: I am well aware that in this photo there are scratches going in different directions. They are ALL scratches from the same buffing compound and NOT from previous levels of buffing/sanding. I’ve been experimenting with various wheels/directions/pressures to get rid of the scratches

As always, THANK YOU SO MUCH for the help; it’s always so very appreciated!

Thanks everyone!

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Question about your Extra Long Shaft Adapters..

September 26th, 2009 at 10:53pm Under metal finishing

I have this 1hp baldor motor..
http://www.motoragents.com/pdf/Baldor/VL1309.pdf

And would like to use it for buffing chrome parts. The shaft is keyed and 5/8 diameter.

Is the Extra Long Shaft Adapters the part I want and which thread? L hand?

Is a 8" diameter buffing wheel suggested for the 3450 rpm?

Thanks!

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Need Help with tight spaces.

September 26th, 2009 at 10:53pm Under metal finishing

I kinda have any idea on where to start but I wanted to see what other ideas were out there for getting into these tight spaces. The piece is and about 8" x 6". Thanks for any input.


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Help in Vibratory Polishing of Bearing Steel

September 25th, 2009 at 10:45am Under metal finishing

Hi Guys,

This is my first post to this forum and hence please bear with me if I have broken some rules

I am from India and we manufacture some components from bearing steel. After machining they are heat treated and as a result their hardness is around HRC 62-65.

Later the components are polished in Vibratory & Centrifugal Machines. Abrasive ceramic media (Grey) is used for deburring and while for very silky finish we use non abrasive type ceramic media (white).

Initially we put the components in vibratory machine filled with abrasive ceramic media and mild solution of oxalic acid to clean the oil and salts of heat treatment. After 30 mins we wash out oxalic acid and then mild solution of caustic soda is added and the machine runs for another 90 mins. Then we again wash out the solution and add another shot of caustic soda and run the machine for 90 mins.

After this the components are put into centrifugal machine where we use non abrasive type media and a mildly thick greenish liquid to get very silky finish. The machine is run for about 1 hour.

Now the problem:

Though the finish we receive is pretty good and acceptable the luster is dull and hence we need to manually buff the rings as hard chrome is the next process. I have noted that many companies in India as well as world over produce same components with better finish without buffing their components.

Where do I need to make alterations?

Please help.

Thanks for reading the long post.

Prasham

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Aluminum polishing trouble, what am I doing wrong?

September 25th, 2009 at 10:45am Under metal finishing

I have an tube I am trying to polish. It started off as a mill finish 8 foot length of 6061 AL, and my goal from square one has been to polish it to a finish that will not leave ANY black residue on hands or clothing that touches it.

I started with 220 grit, and I sanded the whole thing lengthwise, then moved up a grit to 300, and went 90 degrees to the original grain, and kept repeating this process up to 500 grit, each time making sure the last sanding marks were completely covered up.

After that I switched to polish, a creme polish made by Blue Magic called "Metal polish cream". I just spend 90 minutes with a power buffer (9" harbor freight) after an hour of hand and it still does the same damn thing, even if I clean the surface with gasoline, anything that touches it with any pressure turns black.

How do I get the #*$& thing to stop doing this?

Thanks in advance for any help guys….

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thin #8 stainless sheet?

September 25th, 2009 at 10:45am Under metal finishing

I need a source for 24 ga. #8 SS, quantity 50 sq. ft or less. This is the mirror finish stuff. My usual suppliers have nothing thinner than .030" (22 ga.) in the #8 finish. The object is to polish only the joints and seams of my product without having to remove scratches from thin unsupported sections.

I do see this product mentioned on Asian manufacturers’ web sites, so I know it exists. Any ideas?

thanks
John

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Need help with polishing motor / angle grinder

September 25th, 2009 at 10:45am Under metal finishing

I’ve been trying to do a large scale job and need a little help. By the way, I’m a total newb at this. I’m attempting to polish the surface of one of those OLD OLD C-band satellite dishes. It’s probably 10 feet across. I was lucky enough to come across one made of stainless steel (probably 304??).

I started with some 8" wheels on a 7.5" Central Machinery angle grinder from Harbor Freight. I didn’t want to drop a load on a grinder if it wasn’t gonna work. First grinder quit working within 10-30 seconds. Not good. I got it replaced and the grinder seemed to work fine, but kept popping the breaker when I put a load on it. After a lot of very aggravating trouble shooting, I fixed that problem with a shorter, heavier gauge extension cord, and a rewired, dedicated 30 amp outlet. Success!!!, I was just starting to get a good shine on in a small area, when the angle grinder burnt out both brushes and quit working. I replaced the brushes and gave the grinder to a friend. Kinda tells you something when a new grinder comes with replacement brushes, huh?

Anyway.

What now??? I need a motor that can handle the heavy load without melting down in my hands. Would a name brand, (dewalt or milwaukee) grinder hold up to the strain, or would I be wasting more money? Should I be looking at some other type of motor? I could really use some guidance here!

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Tumbling grotty parts

September 22nd, 2009 at 10:40am Under metal finishing

Any of you who have tumblers ever use them to clean parts, as well as debur or polish them? I’m worried about contaminating the media.

I routinely have small parts that have plastic + adhesive residues on them that are so stubborn that I have to use a wire wheel to get them off, which ruins my finish without more heavy .

Could I prep the parts (cut, machine etc) them, leaving the residues on, and when it’s time for debur and polish, use a tumbler to do all that? With the right media of course.

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cast brass surface conditioning

September 22nd, 2009 at 10:38am Under metal finishing

Hello all, new guy here with a couple of questions. I do sand casting of brass and and have a few issues with the surface quality, especially the brass. The surface is ‘pitted’ (the interior is solid) after casting. I’ve tried about every trick I know of to remove all the variables like loose sand, parting dust, trapped gas etc. Is there a process I need to go through to remove or mask the surface pits such as shot peening or glass beading before buffing/? I can get a mirror finish otherwise but the pits show. They are small like pin pricks shot gunned across the surface.

How would I get a satin finish instead of a high gloss.

And last, how do you remove the buffer residue from tight detail spaces? Is there a chemical or procedure?

Thanks!

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