March 21, 2014 at 11:57 pm #20348ragstianParticipant
I have experimented a lot with different pens on the eggbot and want to share some of my experience.
After a lot of trial and error I sat down and really studied the “geometry” of the eggbot setup and how to get the best results. I now have a basic understanding on how to set the pen arm height, pen-arm “Y-position”, pen height in pen arm etc. When plotting the repeatability is now very good and I can plot the same figure twice with pen following the exact same track as it did the first time around. I Use this method for getting higher “saturation (deeper color) when using metallic paint ball point-pens. To get good repeatability i modified the original “presision coupler” as it was always slipping (even with very high spring pressure on the egg) the remedy was to replace the “abrasive paper” with a rubber washer carefully centered on the coupler, The rubber washer I used was a “standard” US garden hose gasket.
When it comes to creating the thinnest possible lines I have come to the conclusion that when using fibre-tip pens, no matter what tip size, the ink will “bleed” into the egg due to the porosity of the egg shell and create a course line.
I have obtained good results from using ball point tipped pens, in the plot below I used a Uni-ball Micro with 0.5mm tip.
To get proper pen pressure for this pen (the ball needs to “roll” on the surface of the egg to get the ink to flow) I have added a rubber band around the pen arm to “assist” the force from the stiff hinge.
As my artistic skills are very limited I “borrow” and convert images I find on the net as in the example below.
The original image in the example was “stolen” from a fantastic artist – Stoshi – see her blog page here: http://shoshiplatypus.blogspot.com
( I wish I had a fraction of the artistic skill displayed in her blog!! )
She called the image “La Bella”, a great work of art! I hand-traced the image in Inkscape to get a SVG file.
My eggbot version: https://www.dropbox.com/s/9osu5lpvmvquxpq/IndianFace.JPG
The “hand-drawn” look is due to the pen tip not moving smootly over the “rough” egg-shell. I am currently experimenting with different methods to “smooth” the egg-surface. Will report here when I get good results.
RagnarMarch 22, 2014 at 12:21 am #21801dnewmanParticipantNice results and interesting to read. Thanks for sharing this.Also, consider the type of egg you draw on. Chicken eggs have particularly poor sizing in this regard. And cleaning them first with water with a little vinegar makes it worse. I prefer duck eggs since they have stronger sizing. You can also apply coatings in advance to help with the sizing. Without any coatings, I’ve had very good success with duck eggs and technical pens with jewel tip nibs. The nice thing about such pens is you have a lot of control over the inks you choose to run, but with the smaller nibs you do have to be careful and sometimes even filter the inks first. (Also getting very hard to get jewel tipped nibs: the folks I know in Japan who make them for Koh-i-Noor only do so twice a year and there’s a waiting list.) Goose eggs, btw, have a rough surface. I stick to inexpensive pens on them as the surface can ruin them pretty quickly. Some of the nicer fiber tip technical pens have replaceable nibs, but I don’t like wasting them on goose eggs — I just use old Sharpies on them.March 22, 2014 at 1:16 am #21802ragstianParticipant
Interesting reading as well. I am learning something new every day using my eggbot!
The idea of applying a coating is interesting, I have used eggwhite on wood with very good results – this is a method used by lutherie’s (guitar-builders) – I will try the same on an egg.
Can you share some more info on the “jevel-tip” pens? I reckon making a thin fine hole in a jewel must be a difficult task! I have tried some of the japanese .Too brand coopic pens, Coopic Pens, I am still experimenting with these.
For an explanation on how to derive the correct pen arm height see this link; Eggbot Setup Guide. The post created very little interest (in fact no comments in 1.5 years!) Might be too technical or badly written!
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