# DIY Mayer Rod for Coating Carbon Tissues, Emulsions - Meyer, Metering, Wire-Wound Bar

Discussion in 'Alternative Processes' started by holmburgers, Jul 20, 2011.

1. ### holmburgersMember

Messages:
4,423
Joined:
Aug 13, 2009
Location:
Rochester NY
Shooter:
Multi Format
What got me thinking about making one of these tools was this video posted by Charles Berger on the UltraStable thread, showing Tod Gangler coating a color-carbon tissue in a most simplistic and perfect manner using a Mayer rod (Meyer, metering, bar, etc...). See 0:34

This was new to me, but these coating rods are elegantly simple in their functionality. A rod is wound with a wire, and the diameter of the wire is directly proportional to the coating thickness. A definite volume of a liquid emulsion is pushed into the valleys between the circular wires and as it passes, these liquid peaks spread out and make a very even coating.

For some eye candy, see here... http://www.rdspecialties.com/wirewoundrods.html

According to this informative web page, "Mathematical calculation indicates that the wet film coating thickness is 0.173 times the wire diameter."

The example in the video is a #200, laying down a wet film thickness of 18 mils. This means we need a 10-gauge wire.

The best source I came up with for an appropriate wire is Beadalon Artistic Wire for jewelers. Only the red & brown come in 10-gauge and with a non-tarnish coating.

Anyways, I went to Michael's and the best they had was some other brand in 12-gauge aluminum (hot pink no less!); but it was only \$2. I figured this would suffice for a prototype. Next stop was Home Depot for a 1/2" oak dowel rod (wood is probably not the best long term solution).

I drilled a little hole in one end, put the wire into it and then began to wind it up. This is of course the trickiest part; the wire is quite malleable, but can kink and get deformed quite easily, plus it requires some strength and dexterity to wind it it as tightly and closely as it needs to be. However, I think it can be done with some practice. The other end was secured with another small drill hole and all told, it looked pretty good. I'll try to post a picture soon.

I did a quick test with some sumi ink and got a respectable coating with only a few gaps due to imperfect winding of the wire.

In summary, I think this is an incredibly useful tool for the alternative printer and they shouldn't be particularly difficult to make once the particulars get worked out.

2. ### VaughnSubscriber

Messages:
5,339
Joined:
Dec 13, 2006
Location:
Humboldt Co.
Shooter:
8x10 Format
Neat! Not really applicable to my tissue making since I coat much thicker.

Vaughn

3. ### holmburgersMember

Messages:
4,423
Joined:
Aug 13, 2009
Location:
Rochester NY
Shooter:
Multi Format
Danke Schoen Vaughn!

I wondered about that actually. I think that anything over (well, under) 10-gauge would become unwieldy.

Messages:
4,423
Joined:
Aug 13, 2009
Location:
Rochester NY
Shooter:
Multi Format
5. ### VaughnSubscriber

Messages:
5,339
Joined:
Dec 13, 2006
Location:
Humboldt Co.
Shooter:
8x10 Format
Someone (Sandy, I think) worked it out for me at one point, but I forget. But I put 120ml of glop on 100 square inches, if that helps. The wet height on the tissue is impressive! LOL!

If the pigment load is high, no sense in pouring a thick tissue -- just a waste of glop and the added hassles of extra drying time, etc.

6. ### Photo EngineerSubscriber

Messages:
25,893
Joined:
Apr 19, 2005
Location:
Rochester, NY
Shooter:
Multi Format
That company is about 5 - 10 miles NE of George Eastman House. Mark has a few of them here IIRC, so those coming to the workshop in Oct. can try one out I guess.

PE

Messages:
1,033
Joined:
Jan 17, 2011
Location:
Maryland, US
Shooter:
Multi Format
8. ### Leigh BMember

Messages:
1,033
Joined:
Jan 17, 2011
Location:
Maryland, US
Shooter:
Multi Format
120ml on 100 in^2 = a coating thickness of 0.186mm = 7 mils (0.007 inches).

- Leigh

9. ### gmikolMember

Messages:
304
Joined:
Mar 2, 2009
Location:
Vancouver, W
Shooter:
35mm

120 ml = 120 cm^3 = 7.32 in^3 (120 / 2.54 / 2.54 / 2.54)
7.32 in^3 / 100 in^2 = 0.0732 in wet thickness.

--Greg

10. ### Leigh BMember

Messages:
1,033
Joined:
Jan 17, 2011
Location:
Maryland, US
Shooter:
Multi Format
Yep. I confused mm with cm. Sorry.

- Leigh

11. ### NeandermanMember

Messages:
575
Joined:
Mar 22, 2004
Location:
Ohio River V
Shooter:
Large Format
I have a lathe. Using the back gears I'd bet I could wind them pretty tight and consistently. I'd guess copper wire (easy to find in #10 size) would not be usable due to the ion exchange issue. Wood would make an okay core, but with a lot of use, the swelling/shrinking cycle would be problematic. I guess ideally you'd use 316 stainless for both the wire and the core.

Ed

12. ### Leigh BMember

Messages:
1,033
Joined:
Jan 17, 2011
Location:
Maryland, US
Shooter:
Multi Format
I think alloy 410 or 430 would be better options for this application.

A 1-pound (34-foot) spool of 0.105" (10 AWG) in 410 is \$18.47, while 430 is \$17.24 at McMaster-Carr www.mcmaster.com

Both are bendable (soft temper) and matte finish.

- Leigh

13. ### NeandermanMember

Messages:
575
Joined:
Mar 22, 2004
Location:
Ohio River V
Shooter:
Large Format
Leigh, thanks for that info!

15. ### wildbillbugmanMember

Messages:
819
Joined:
Apr 18, 2005
Location:
San Bernardi
Shooter:
8x10 Format
Check out the Carbon Transfer Group onYahoo Groups. We recently did a Group order for rods SD Specialties for . I useThemnow for coating subbing on glass and for coating silver-halide emulsions on glass.
Bill

16. ### PViaMember

Messages:
813
Joined:
Oct 3, 2006
Location:
Shooter:
Multi Format
What do the RD rods go for...?

17. ### vyshemirskyMember

Messages:
58
Joined:
Jun 1, 2010
Location:
Glasgow, UK
Shooter:
4x5 Format
Those rods are not expensive, actually. About \$40 for a 36" formed one. Wire wound must be even cheaper. Mine arrived yesterday and are a piece of art themselves. Thanks to Sandy for organising a group order.

18. ### mdmMember

Messages:
71
Joined:
Jun 11, 2009
Shooter:
35mm
There is a setup fee to pay which roughly doubles the cost, if you order only one rod. In my case, on the group order, not having to pay the set up fee paid for my shipping. I think the idea is that you use a high % gelatine with a RD200 to get a thicker tissue and a low % for thinner tissue or for sizing paper. I tried winding my own rod but was not happy with the result. Usually I pour 1.6mm deep with magnetic strips but extra thick tissue is a major hassle to dry, difficult to use and not necessary for reasonable relief anyway.

David

Last edited by a moderator: Jul 21, 2011
19. ### HologramMember

Messages:
135
Joined:
Oct 17, 2006
Shooter:
Medium Format
The good news actually is, you needn't run for one of those special Mayer bars. A simple threaded rod (something like this: http://www.allmetricsmallparts.com/products/hardwarerods.htm) might do the job at least as good...

20. ### Photo EngineerSubscriber

Messages:
25,893
Joined:
Apr 19, 2005
Location:
Rochester, NY
Shooter:
Multi Format
Stay away from mild steel, copper, aluminum and wood. Any non-magnetic stainless steel is probably ok.

PE

21. ### holmburgersMember

Messages:
4,423
Joined:
Aug 13, 2009
Location:
Rochester NY
Shooter:
Multi Format
Wow, thanks everyone for all the input.

Neanderman, a lathe would probably be perfect for winding one of these.

And I am surprised at the price of the RD bars; that's really not bad at all. One of the lab sized ones would probably suit my purposes; they can coat up to 12".

When I first saw that video I actually thought it was a simple threaded rod and I went to the hardware store to check it out. The problem however, is that these threaded rods are very coarse and have many imperfections which would likely lead to scratches. The wound-wire makes for a lot of smooth surface area and a way to tightly regulate the coating thickness.

22. ### holmburgersMember

Messages:
4,423
Joined:
Aug 13, 2009
Location:
Rochester NY
Shooter:
Multi Format
and so is Vaughn's tissue really 73 mils thick? Dang...

23. ### gmikolMember

Messages:
304
Joined:
Mar 2, 2009
Location:
Vancouver, W
Shooter:
35mm
Yep...but that's wet thickness. I use a recipe similar to Vaughn's (and the same coverage rate), and I just measured a dry tissue (at least as dry as it gets in the NW right now), and it's 8.5 mil dry thickness.

24. ### Photo EngineerSubscriber

Messages:
25,893
Joined:
Apr 19, 2005
Location:
Rochester, NY
Shooter:
Multi Format
Depending on solids content, wet / dry = about 10 / 1 in thickness. This is close enough for our purposes as long as you can repeat your work.

PE

25. ### holmburgersMember

Messages:
4,423
Joined:
Aug 13, 2009
Location:
Rochester NY
Shooter:
Multi Format
Greg, are you measuring with a pair of calipers? I don't know if my pair are accurate to thous (I like that word...)

So, for 8.0 mil dry thickness, based off of PE's formula, you would need a rod with 0000 gauge wire, 11.7mm diameter.

26. ### VaughnSubscriber

Messages:
5,339
Joined:
Dec 13, 2006
Location:
Humboldt Co.
Shooter:
8x10 Format
Which is why, for me, it is so easy just to pour the glop on the tissue support and help it a little with a finger to spread across the whole sheet. It is as easy and fast as in the video, if one includes the time to prepare and clean the rod.

mdm -- there is nothing reasonable about the relief I get...

Vaughn