Thread: A brayer (rubber roller) for spreading spotting blue

Great idea. We have a laser printer at work and we recycle the cartridges. Looks like some might not make it!

Simon

Sounds interesting, I have a crap roller that seems to do ok, but then I wouldnt know any better lol

Hi Ewan,
I'll p[ut my hand up for one when you get your hands on one. Then I can find out what I'm missing out on Thank you

Stuart

Originally Posted by Stustoys

Sounds interesting, I have a crap roller that seems to do ok, but then I wouldnt know any better lol

Hi Ewan,
I'll p[ut my hand up for one when you get your hands on one. Then I can find out what I'm missing out on Thank you

Stuart

No worries Stuart, Bruce (abratool) is getting the one i have, shouldn't be long till i need to replace another though, i'll let you know when i have it.

Thanks Ewan , no hurry I'm sure to be scraping for awhile yet lol besides I might take inspiration from your designs.

Stuart

Today, I got the idea to somehow guestimate the thickness of a layer of blue made with that brayer.
Granite plate was used. Means blue spread and "wiped off" through severals spottings and refreshes (without picking up new colour). So to say clean but saturated with blue.
Then I weighted the brayer in the clean state, picked up blue, and re-weighted it. It picked up 0.1 grams (well, resolution of my scale is 0.1 g; so some uncertainty).
Specific weight of the blue is a bit above 1 g / cm^3 (just sinks in water).
Then I spread the blue on the roller on my spotting area that is 90 by 15 cm.
So, the resulting thickness is 0.7 µm.

If I wipe over the granite with my finger, I almost don't pick up colour.

But this is extreme spotting! You won't get some readings if you haven't spent quite a few hours with the work trying to get it flat.

As a wild guess, I normally do have a layer of blue that is 5 times thicker.


Nick

Hi Nick,

I have a few problems with what you have done. Did you reweigh the roller after to see if all the blue was on the spotting area?
Also I think it assumes that your spotting area is not only flat(which it should be) but very smooth(which as you have said yourself granite isn't). So while you should be able to say that the blue is "no thicker" than 0.7 µm, it could be much thinner couldn't it? Though how much thinner when you say the pigment is ground to .001mm? I would expect most of the pigment would be much smaller than that but couldn't put a number on it.

Having said all that, as yet I haven't got any better ideas, Good work.

Stuart

Yes, I weighted before picking up blue, after picking up blue and after spreading blue.
As I said, the granite was not cleaned, but it already had blue in all the small pores. I've been using it for 4 days without cleaning it. Means, without using a solvent, just wiping it off.
I used Dykem, so I have no information how big their pigments are.
The number I got from Kremer was the average size of the pigments. Maybe they could be milled smaller upon request.

With the corse resolution of the scale, there's an uncertainty of about factor two. So it might also be 1.4 µm or 0.35 µm.
I'm quite at the sweet spot of the layer, because refreshing without picking up blue works only once, then the spotting on the work gets way too thin to make sense. So, refreshing with picking up blue, spotting, refreshing without new blue, spotting, GOTO 1. Rethinking this sequence, it would mean that the layer is half as thick as calculated.
Anyhow, it's just a ballpark of how thin the layer can be made.


Nick