scraping brass

[rich pierce]

I made a sideplate of old scrap brass (door kickplate) and it needed cleaning up, so I used a regular cabinet scraper I normally use for wood, burnished to have that wire edge.  It worked really well, leaving almost microscopic chatter marks.  Anybody use a lubricant or have other tips? Also it was difficult for me to get a perfectly level surface as it was cutting more on the sides than in the middle.  Maybe the scraper was bowing or something.  Your best practices with a scraper on brass?

[Habu]

So far I haven't had much luck with cabinet scrapers, I'm getting the same results as you.  The "high in the center" effect seems to be from the flex of the scraper.  I tried some different sizes (I sharpen saws occasionally, so there is always material available), but the best one I've found so far is a file with the teeth ground off.  I don't try to raise and turn  a burr, just scrape with the sharp square corners.  It works OK. 

[Eric Kettenburg]

I just use my flat wood chisels like scrapers and then resharpen them.  You have to constantly change your angle of approach.  Still get some marks but I don't have a problem with that!  You can mash some of it down with a flat triangular burnishing rod.

[Tim Crosby]

Also it was difficult for me to get a perfectly level surface as it was cutting more on the sides than in the middle.  

 If you hold it with both hands with your thumbs almost in the middle and bow it slightly it will cut in the middle. Put some color on the piece, magic marker, and scrape it, then you can see what you are taking off.
 I find that a square edge, stone the flats and edge, is better on brass as sometimes the burr wil have a tooth like edge and it really shows up on brass or horn.

Tim C.

[David Rase]

I have scraped brass with pretty much the same results as the rest of you.  I really like stoning brass.  A good stone and lots of oil to keep it from loading up works really well for me to keep those edges sharp.  
DMR

[Jerry V Lape]

David,  what "stones/grit" do you prefer for brass? 

[David Rase]

David,  what "stones/grit" do you prefer for brass? 

Jerry,  I never went out and bought any special stones for brass.  I just used some of my medium and fine Norton India stones. 
DMR   

[B Shipman]

As an aside, what I've done in the past when trying to finish brass without using paper is to file very fine (the great danger is to clog and scratch a gouge) and then burnish  out the fine marks. The spots that resist burnishing  a re fine filed again and reburnished. Finish with an abrasive like tripoli on fine felt on a hard backer. I' did a small display at Dixons a few years ago and compared with pieces finished with filing and paper and you cou;d not tell the difference.

[Tim Crosby]

and then burnish  out the fine marks.

 What did you use as a burnisher?

Thanks, Tim C.

[Acer Saccharum]

Artist supply stores which have printmaking supplies will have burnishers. They come in different shapes. Some are bent, some straight. But they are all hardened steel, and highly polished, and have wooden handles.

You can make one out of an old file or shank of a drill, but they must be HARD and highly polished.

Acer

http://www.dickblick.com/products/steel-burnisher-with-wooden-handle/

[Tim Crosby]

 Thanks Acer. I thought maybe it was something more exotic like, antler, a hard wood, a glass bottle or another piece of brass.

Tim C.

[Pete G.]

I like using a scaper to clean up castings instead of all that seemingly endless filing. Works great for curved surfaces, but I would imagine it could be difficult to keep a flat surface flat, just like filing is difficult to keep truly flat. If you will change the angle of the stroke slightly every few passes and keep the pressure light you will minimize the chatter.

[Ryan McNabb]

I experimented with scraping brass on several rifles, but now only use it on sand cast buttpieces.  There seems to be no good way to file the curve of a buttpiece easily, but scraping does a good job of leveling it out and hogging off waste.  I don't use cabinet scrapers for brass - they're too flimsy.  I bought an inexpensive pair of stainless steel scissors, took the screw out thus making two tools each of which has two scraper blades - one very sharp for wood, the other much coarser (but still sharp) for brass.  Works a treat.  I typically use cabinet scrapers on the stock only.  I don't do this all the time, but sometimes it just seems to work great when nothing else will.  I hate, hate, hate filing buttpieces.