Prepping copper

[jdanforth]

I spent the whole day yesterday buffing copper in preparation for taking it to the silver plater.

What process do you use? Here’s what I do:
1. cut using sisal wheel and emery (black) compound
2. cut/polish using brown compound on stitched cotton wheel
3. cut/polish using white compound on stitched cotton wheel
4. polish using blue compound on unstitched muslin wheel
5. wipe off waxy buildup
6. hand rub using microfiber cloth

That gets the copper looking really good but I still have some *very* fine lines in the buffing direction that I’d like to get rid of. Any suggestions?

[Andy Stockton]

As a beginner I will look forward to any replies that are received to this thread. I also wondered if you would share info about your buffing machine? From pictures on your site it looks like you are using 12" wheels. That must take some fairly serious horsepower. What minimum do you recommend?

[jdanforth]

Andy_Stockton wrote:As a beginner I will look forward to any replies that are received to this thread. I also wondered if you would share info about your buffing machine? From pictures on your site it looks like you are using 12" wheels. That must take some fairly serious horsepower. What minimum do you recommend?

I have a Jet JSB-10L buffing machine that turns at 1725 RPM. I’ve mostly stopped using 12" wheels since even the industrial buffer I have doesn’t have enough HP to really keep ’em spinning under load. I switched to 6-8" wheels from Caswell Plating and those things are unstoppable! As far as horsepower, 1HP is sufficient in my opinion.

The reason that I like the Jet is that it has very long arbors. I can stack up two wheels on each side which is very useful for buffing copper. When I’m working on silver plates for daguerreotypes then I use one wheel per side so that I have lots of room to move without bumping into the motor housing.

[Jon Lewis]

A while back I was polishing bronze and I kept getting very fine lines in the buff direction. I was told that it was because the buffing wheels were dirty/dusty and needed raked. Now I’m not sure if dust is a problem where you are but EVERYTHING gets very dusty here and it’s a perpetual problem keeping the wheels clean. Now I don’t know all that much about buffing but perhaps there’s an even finer compound you can use to get rid of the last of your lines. Or you could give it a good buffing with a buffing paddle not used for silver. Do the fine lines come across once the copper has been plated?

[jdanforth]

The fine lines are not particularly noticeable especially when you view the dag properly.

I rake the wheels frequently.

edit: the blue compound is supposedly finer than red. I can only assume that my order of compounds isn’t sufficient to eek out all of the lines properly. Maybe a different wheel for more aggressive cutting is in order on the brown compound.

[Jon Lewis]

Just out of curiosity, you galvanize your plates at all? I’m not sure that’d do too much to the lines but it might do something.

[The Daguerreotypist]

Hi everyone. As a dinosaurus in making Dags I have buffed and polished hundreds and hundreds of plates. At first, do NOT use 1750 RPM! Your are not buffing. Only scraping copper. You’re buffing tool slams the plate and will produce lines!
Use around 600 RPM.It’s not getting hot and you are buffing. OK it will take a little bit longer but the result will improve extremly.

Use a handpolishing powder to finish it. This will take at least an hour for a plate 15cm x 20cm (sorry I’m from Europe and we use the metric system). This is appr. the size of a whole plate.

Be sure your copper plate will be plated with a substantial layer of pure silver. This is a soft metal. Polish this again by hand very gently. Make sure you polish on a 90 degree angle according to the image. In other words, if your plate has the long side at the top and the bottom (of course!) polish the plate for the bottom to the top.

[jdanforth]

Good advice, Daguerreotypist. I originally used 12-inch wheels to make the surface area per minute shorter and, therefore, do more of a buffing action. I still use this for polishing silver but not copper. I get good results with my method so it seems that there’s more than one way to skin a cat (as we say in the USA.).

[drdag]

I am/ was a silversmith so we did a bit of polishing in our time. I use a 5 to 6 inch wheel at 2400 with Tripoli this is brown and can be obtained from a jewelers suppliers. I use a cotton mop. It is important to keep it moving. This removes any scratches that are finer than say 1200 wet and dry paper. Deeper scratches I use a Water of Ayr stone, very wet. Once the tripoli is done, I use a finer cotton mop with rouge then another finer one that I keep really clean and dust free away from the polishing area.
You should be very near a mirror by then, I then finish by hand with some rouge on cotton velvet. The copper should not need any more abrasive than tripoli, if you are using emery and stitched sizals then you are putting more scratches in. If you are unsure go to a silversmith/jeweler and ask him to show you , I am sure they wont mind.

[drdag]

Following on from that, if you use the becquerel method (less invasive on the surface of the silver to mercury) the it is just a matter of the two rouge mops for 5 mins and the hand polishing to go again. I have had silver plated copper (50 microns) and have made 30 dags on one plate without going through.The rouge is hardly abrasive.

[jdanforth]

Thanks for the tips, Dr. Dag! I have a LOT more copper to prepare in the coming few days so I’ll try out some of your methods. I’ll use brown on a stitched wheel and try to slow it down somehow.

When polishing, do you cris-cross until the scratches disappear or do you just keep going in one direction?

[Andy Stockton]

As a beginner I am really hoping that the discussion continues on this thread. From what I have read and what I see here, there are probably as many approaches to preparing plates as there are daguerreotypists. Continued discussion will help those of us with less experience plan our approach – who knows, maybe even some "best practices" will eventually emerge.

I have two clarification questions at this point:

1) What is meant by the term "galvanizing"? I know what that is as an industrial process with zinc, but I doubt that is what is meant here.
2) When you say "rake the wheel" is that just roughing it up with a clean metal tool or is something more specific meant?

Thanks

[Jon Lewis]

I am going to preface this post saying that I haven’t actually prepared dag plates and I haven’t polished anything in quite a while. That said, I do have a basic understanding of the process but lack the actual experiences and nuances of the process.

To answer your fist question, Andy, I have run across the process of "galvanizing" several times as it pertains to the daguerreotype. First in Barger and White’s The Daguerreotype: Nineteenth Century and Modern Technology, pp. 44-45. Here it talks about the "American process" of preparing plates. Essentially the silver would be polished and then put in a galvanic battery and electroplated with a thin layer of silver. This is what they referred to as "galvanizing." The process is described in more detail in Humphrey’s American Handbook of the Daguerreotype, pp. 154-156. My understanding is that the galvanized surface is has a fresh layer of silver and which allows the sensitized daguerreotype a bit more speed and contrast (?). I believe that Robert Shlaer, Eric Mertins, and Mike Robinson use this method. The latter two are in this forum and will be able to give you a better answer than I have.

To answer your second question. A buff rake is used on a buffing wheel in order to free it of the buffing compound and bits of metal that it had acquired during use. This prevents scratches and a buildup of buffing compound. Here is a buff rake in use.

I’m hoping to start polishing my own plates within the next couple weeks and I’ll post my results here.

[drdag]

Couple of things , My motor is 2750 not 2400 as I previously mentioned, If you press the plate in harder then obviously it will have more of an action on the metal, if it is very gently applied, the lines start to disappear. (By the way I think a stitched mop is too agressive unless it has very deep marks). I was taught at art college by an eminant silversmith that the rouge actually ‘moves’ the very top surface of the metal, which is why it polishes. The rouge however hardly removes any silver hence the ability to use a plate time and time again if it is well plated.With regard to the galvanising or as we have come to understand re-plating I think that you are right, it is putting a brand new 99.99 pure silver coat on the plate, which I think was more important to the Victorians (sorry uk here) with the hand polishing methods, but less important to us with our mops. These whip the old image off in seconds. I think it would be folly to be galvanaizing (or plating) every time. As I said before if you go an visit a silversmith and ask them how to polish (telling them what you are up to ) I am sure that they will give you half an hour of their time.

[drdag]

Sorry back again, dont waste your money on a buffing rake, get any old bit of steel about 1/8th or so thick 1 to 2 inches wide and as long as you can comfortably hold, cut it with the roughest hacksaw that you have (a new file also works) then plunge the bit of metal rough end first (make sure it is below the centre line of the mop or you will be in ER having it removed from your navel) it needs to go in nearly at 90 degrees and hard, moving from side to side. You will immediately have threads and sneezy dust every where, do it for ten seconds or so. Then the mop is clean, apply a little tripoli or rouge. Never share mops between compounds and do it every time you polish. Even the dust that lands on an idle mop will scratch silver plates.

[jdanforth]

I have an announcement to make: ARRRRRRRRRGGGGGHHHHHHH

Thank you.

I spent the afternoon yesterday trying to polish copper and I decided to eschew the emery wheel and polish with tripoli and white. After I got off of the brown wheel I discovered tons of wormy gouges all over the plate! I *think* that the problem is that the wheel was just too hard, spinning too fast, or there were some errant strands that were whipping up on the plate.

So I’m in a real bind! I need to get these to the platers ASAP. I think that I’m going to start fresh with some nice clean wheels but all I have are two stitched denim wheels. D’ya think that I should scrap the stitched Muslin wheels and charge these denim ones up with brown and white? I might have to start all the way back on emery to get rid of these scratches! ARGH!

edit: and yes I have been raking the wheels. I raked them really heavily but still had problems.

[drdag]

I never use stitched wheels, they are just too hard if you have deep pits use 1200 or finer wet and dry paper (use wet) then the tripoli, I do not know what the white is, the white we used to use was for perspex( plexiglass over there) You do need to slow down to about 800-1200 for that. You need something like this for the tripoli http://www.hswalsh.com/Climax_Mop and a swansdown type mop for the rouge

[jdanforth]

I figured out what was happening last night. The wheels were just too old and had become saturated with metal particles despite my frequent raking. I have now changed my process. I’m using tripoli on a (clean!) stitched denim wheel followed by white on an unstitched muslin wheel followed finally by blue on another unstitched muslin wheel.

White is described by the manufacturer as "This compound will cut lightly, bringing most harder metals to a brilliant shine. Designed for polishing chrome and nickel plate, stainless steel and ordinary steels." I use it because it was strongly suggested as a post-tripoli cut and color step for copper. It works great!

So, in conclusion, make sure that your wheels are clean!!!!

[Race]

I polish my copper plates with slurry pumice stone using a palm sander ( felt in place of sand paper) for about 1 minute. It gets rid of all the mill marks and should have a matte finish to it. Then I send them to the platers. Does it make a difference if the copper had a mirror finish as opposed to a matte finish?

[jdanforth]

Race wrote:I polish my copper plates with slurry pumice stone using a palm sander ( felt in place of sand paper) for about 1 minute. It gets rid of all the mill marks and should have a matte finish to it. Then I send them to the platers. Does it make a difference if the copper had a mirror finish as opposed to a matte finish?

The silver is so thin that the silvered plates will only be as reflective as the copper beneath them.

The matte plates should still work but I guess the image will lack in contrast. I’ll have to defer to the more experienced guys on that one though.

---

I just dropped off some copper plates with a local copper/brass polishing guy. I thought that I’d give him a shot since I’m so swamped that I don’t have time to polish these plates. The copper guy suggested that I use quality flannel buffing wheels and that I treat the plates from Rembrandt Graphics with white, green, and red. They look pretty sweet but not perfect.

[Race]

I took my copper plates to Sheffield Platers to have them silvered. It cost $400 to silver (.0005) nine 1/6 plates! The price of silver is through the roof ! Does any pay this much to have them plated ???

[photolytic]

Half a mil (0.0005) of silver weighs less than half an ounce (0.417 oz) per square foot of surface.
You had just over half a square foot plated (0.5755 Sq ft).
That plater put less that a quarter oz (0.24oz) of silver on all nine plates,
It cost them $4 to $5 at the most.
They really took advantage of you.
Either your plater charged you a hanging fee of $40 per plate or he has a minimum charge of $400.
My plater only charges a fee of $30/12×18 sheet + a silver fee of $30/sheet for a 0.001 coating.

[Race]

I think it’s time to find another silver plater! I feel very "cash raped".

[jdanforth]

Sorry to hear that, Race. It sounds to me like they just have a minimum order. I use Surtronics in Raleigh, NC and they’re very fair. I’ve been working with Mike at Surtronics for a year or two now and they’re really getting the hang of what daguerreotype plates should look like.

All that Surtronics does is to silver-plate so you’ll still need to send them polished plates to start with.

edit: I just picked up one 8×10, four 4x5s, and one 3.5×9" and paid about $120 for a half mil.

[Race]

Wow… I just got my plates today in the mail. I spent $400 and my plates look as if a five year old silvered them Not only do they have deep scratches but silver dust clumps all over the place. What a mediocre plating company

[Author]

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