Experiments With Flex

[Frank C]

1 hour ago, InesF said:

Yes! 🧜‍♀️

The 12V Dremel should not harm me when submerged in the bath tube. However, I had a hard time to position myself correctly and the diving goggles changed my vision for the right distance so that I accidentally ground my fingernails instead of the nib ....👎

😉

I'm glad you used the 12V Dremel. When I tried the same thing with my 115V wall plug model, the Ground Fault Circuit Interrupter kept turning the power off. Finally, I had to run an extension cord to the garage and straight into my circuit breakers. The power stayed on, but now all the hair on my head is curly.

[Frank C]

Question for @InesF: I have a Montblanc Calligraphy 149 pen. It has a flexible nib. As such, it was designed to separate the tines when sufficient pressure is applied. It seems to me that inks with higher surface tension would be better in this pen to avoid railroading. Is that true? Are there any other criteria I should also look for?

[InesF]

Hi @Frank C, you're welcome!

Air humidity, paper and special pen construction details aside, surface tension is the most influencing ink property for getting or avoiding railroading - the lower the surface tension, the more the tines can spread.

Never having dismantled a MB calligraphy nib unit, I can only guess, it is nothing fancy special.

 

It is common knowledge, that ink will flow like crazy when the tines are spread. To help getting still a sharp (non-fuzzy) line, calligraphy inks (those, declared as such) have increased viscosity.

However, the second most important and often overlooked thing is an impurity (such as fingerprints, residual silicone grease, particles from textiles or paper or mould, surface corrosion, etc..) at any of those nib and feed surfaces which are in contact with the ink. The presence of such disturbances can also cause unexpected railroading, mostly paired with unsteady ink flow.

 

When reading your 115V experiment report, I guess, you may like to do the one or other practical experiment. 😉

You may remember from the ink wetness thread, that ink with increased viscosity (up to 1.2 mPa*s) has no reduced or otherwise restricted flow in a normally constructed fountain pen. So you may try to take a small sample of an ink which works well in your MB and add ca. 1 to 1.5% Gum Arabic (dissolve it fully - no particles left!). You write one page with the original and one with the thickened ink and compare lubrication, tendency to railroading and line appearance after drying.

In case you worry about the Gum Arabic, you should rinse the pen after use.

 

As my precious as well as my budget pens all can handle ink with viscosity up to 1.3 mPa*s (30% above normal), I'm confident the MB will do so as well.

 

Looking forward to read about your observations!

[duckbillclinton]

On 8/15/2021 at 1:41 AM, MarioR81 said:

Ok, I took a leap on my kakuno F. It's one of my most reliable nibs so really didn't want to mess it up. Increased the cut on the slit and a little "bite" on the sides. I had to run a couple passes of very fine sand paper on the slit near the tip. It improved the line variation with same pressure but I was expecting a little more. But maybe it's too much to ask for this type of steel nib.

OK, I did a quick mod with my Caliarts Ego (nib is fully compatible with Pilot steel nib serieses).  I cut the middle slit with a really hardcore approach, just using a dremel with a 0.15mm thick cutting disk, with my fingers to hold onto the nib, LOL.  The slit cut turned out to be OK, I could cut it deeper down to allow tines opening up more with less pressure, but at the end I decide to make the mod to be a semi flex (3-4x width variation), and it can be a daily user for taking notes during my self study.  I suggest you may take a similar nib template (flex mod) like mine if you don't have access to a wide selection of dremel attachment and accessories.  All you need to do, is just deepen and widen your existing "bites" on the side to allow tines opening a bit more, but this will also increase local stress on the "bite" spots, so 2 additional wider bites must also added to evenly distribute the stress caused by nib bending (up), they can also make the tines open up more.  Just do it gradually, and you will get good results like mine.  If you want moderate flex (5-8x width variation), the slit must be cut further down to reach the <F> marking.

 

My semi flex here, normal writing stroke width is about 0.32mm, flex writing is about 1.3mm.  You need to ensure your newly cut slit don't have any burs or spikes, or else you will affect ink film during flex writing, making the film much easier to burst and retract.  Don't make any cut or holes wider than your current cut, or else your feed won't be able to create an sufficient ink film during cold start (meaning, just removing the cap and start writing without turning the converter piston to force more ink to the nib).

 

[MarioR81]

@duckbillclinton thanks. I think my disc is about 0.15mm. It's the regular one, the one I used to cut the slit. The safest best is probably then follow your suggestions to cut on the sides and if I want more flex (which I probably will not, don't want to modify the feed etc)? 
New cuts on marked in red.

[duckbillclinton]

24 minutes ago, MarioR81 said:

@duckbillclinton thanks. I think my disc is about 0.15mm. It's the regular one, the one I used to cut the slit. The safest best is probably then follow your suggestions to cut on the sides and if I want more flex (which I probably will not, don't want to modify the feed etc)? 
New cuts on marked in red.

I will give you hints once you reach the point of ink supply problem.  Right now, let's get the flex done right first.

[MarioR81]

@duckbillclinton something like this? Made the side cuts and also increased the slit a little bit but I regret. It went a little to the side and I don't think it will make much difference anyway...

 

[duckbillclinton]

47 minutes ago, MarioR81 said:

@duckbillclinton something like this? Made the side cuts and also increased the slit a little bit but I regret. It went a little to the side and I don't think it will make much difference anyway...

 

Looking good.  Try it on to see if tines can now open to the width you intended.  Gradually deepen and widen the 2nd set of "bites", it should start to make your nib feel softer when flex write.  The 1st set of "bites" close to the tip don't need any more grinding.

 

Don't rush, slowly do the side grinding and testing.

[MarioR81]

Funny thing is that the ink flow increased to the point that I don't think it's a japanese fine anymore, it's almost like a western fine. The line variation is a little bigger but I still have to press hard enough, but the good news is that the feed can keep up even after several strokes. I'll get photo samples later on.

[DiveDr]

Flex is one of the characteristics that separated fountain pens from other writing instruments and gave them tremendous character. It is a shame that modern manufacturers do not pursue more functional options than the ones that are commercially available. The offerings from Noodlers are Indian bodies similar to FPR, a bit more quality control on the finish but you have to fiddle with the feeds and tines to get them working.  Ahab and Konrad which is not cheap were dry non starters out of the box, hours to get them to write consistently and they are both scratchy.  FPR flex nibs have been a disaster for me, can't get one of the 5 I have with the ebonite flex feed units working at all.  Kanwrite, also from India makes a good flex nib, have one Heritage with a broad flex nib and it's a wet noodle, had to decrease flow on it as too wet out of the box but good flex and very smooth.

 

Kanwrite does not appear to be offering the fine, medium, broad options on their #6 nib pens and medium flex is the widest available on the Desire.  If anyone knows where to source some Kanwrite #6 flex medium and broad nibs please PM me!

 

Will continue to fiddle and tinker.  Hey there duckbillclinton, can you tell us what tools and method you used for option 1 in your post?

 

Happy Saturday to all!

[duckbillclinton]

On 8/22/2021 at 12:56 AM, DiveDr said:

Will continue to fiddle and tinker.  Hey there duckbillclinton, can you tell us what tools and method you used for option 1 in your post?

 

Option 1?

 

Which post of mine are you referring to?

 

[Frank C]

On 8/19/2021 at 12:07 AM, InesF said:

Hi @Frank C, you're welcome!

Air humidity, paper and special pen construction details aside, surface tension is the most influencing ink property for getting or avoiding railroading - the lower the surface tension, the more the tines can spread.

Never having dismantled a MB calligraphy nib unit, I can only guess, it is nothing fancy special.

 

It is common knowledge, that ink will flow like crazy when the tines are spread. To help getting still a sharp (non-fuzzy) line, calligraphy inks (those, declared as such) have increased viscosity.

However, the second most important and often overlooked thing is an impurity (such as fingerprints, residual silicone grease, particles from textiles or paper or mould, surface corrosion, etc..) at any of those nib and feed surfaces which are in contact with the ink. The presence of such disturbances can also cause unexpected railroading, mostly paired with unsteady ink flow.

 

When reading your 115V experiment report, I guess, you may like to do the one or other practical experiment. 😉

You may remember from the ink wetness thread, that ink with increased viscosity (up to 1.2 mPa*s) has no reduced or otherwise restricted flow in a normally constructed fountain pen. So you may try to take a small sample of an ink which works well in your MB and add ca. 1 to 1.5% Gum Arabic (dissolve it fully - no particles left!). You write one page with the original and one with the thickened ink and compare lubrication, tendency to railroading and line appearance after drying.

In case you worry about the Gum Arabic, you should rinse the pen after use.

 

As my precious as well as my budget pens all can handle ink with viscosity up to 1.3 mPa*s (30% above normal), I'm confident the MB will do so as well.

 

Looking forward to read about your observations!

I know that gum arabic is often used to thicken ink. I have never tried it myself. My minor at university was chemistry, so I'm always willing to try an experiment—with proper safety precautions, of course. I will keep you informed of my progress. 

[duckbillclinton]

On 8/22/2021 at 5:57 AM, Frank C said:

I know that gum arabic is often used to thicken ink. I have never tried it myself. My minor at university was chemistry, so I'm always willing to try an experiment—with proper safety precautions, of course. I will keep you informed of my progress. 

Montblanc 149 calligraphy nib can only do very limited flex, by default, Montblanc test all their pens with their own ink.  So, for flex writing, if you want something easy out of the box, just get Montblanc ink.

 

Adding Gum Arabic will increase ink's viscosity, making it thicker, slowing down the flow, reduced flow speed means less shock on the ink film when doing flex write, ink is a bit dampened also slow down capillary retraction on the feed.  Like Ines stated, reduced surface tension is what allowed ink film/ bubble to form from the first place, and hence enabling flex writing.  So, to further reduce surface tension and increase the ease of forming ink film, for every 50ml of ink, you can add one small drop of dish soap (liquid type), remember, just one small drop.  For making the ink film "last longer", add about 5 drops of glycerin, that should make the film stable and have lesser chance of bursting.  All of these tricks are actually nothing new, but are classic recipes for soap bubbles being played by kids.  For us fountain pen fans, flex nib writing is another sort of soap bubble playing.

[duckbillclinton]

On 8/21/2021 at 6:57 PM, MarioR81 said:

Funny thing is that the ink flow increased to the point that I don't think it's a japanese fine anymore, it's almost like a western fine. The line variation is a little bigger but I still have to press hard enough, but the good news is that the feed can keep up even after several strokes. I'll get photo samples later on.

Sudden increased ink flow implies you have spring your nib, the tip (iridium point) is spreading too wide.  You need to do some small amount of bending to restore it, and high magnification glass is required.  Don't press down too hard when you try to open the tines when you flex write in the future, steel nib can only take certain amount of bending/ stress.

 

If you really want more flex, your current middle slit cut is still not deep enough, the cut need to strike through the entire <F> sign (I didn't state it clear enough from my previous post).  The reason for this is not just longer slit makes tines open more, rather, in addition, Pilot's nib geometry and feed design are unique, the construct is quite flat at the front portion near the tip, and the rear portion has a lot of curvature.  Like I previously discussed with Ines, curvature of the nib plays a vital role on how wide the width and angle the tines can spread.  So, your current slit cut is mainly sitting on the flatter part of the nib, the area around where <F> sign is at, is where the nib has it's max curvature which is same as the feed's radius.  Originally from your first post, I thought you only need semi flex, but since you mentioned you use dip nib pens almost daily, and your current Pilot mod is still not flex enough, I suspect you want something like a moderate flex or super flex.  For smaller streel nib like Pilot, this is stretching the limit, and you will need better tools, the cutting disk you have, like you mentioned, if it were a standard one, then it's unlikely to be an 0.15mm thickness disk(regular ones are likely to be 0.4mm or 0.6mm in thickness), because mine was specially ordered online.  In addition, the 2nd set of side grinds, they are still not deep and wide enough.  Compare to mine, you can see my 2nd set grinds to the center slit's distance is just a bit more than the 1st set, and they are almost at the same level.  Yours, on the contrary, is still too far away from the center slit.  You also need to widen the 2nd set grinds to further down to the rear portion of the nib.  With these tuning, you should get more flex, but like I said, Pilot nib is smaller in size, so don't ask for too much.

[DiveDr]

On 8/22/2021 at 2:03 AM, duckbillclinton said:

Montblanc 149 calligraphy nib can only do very limited flex, by default, Montblanc test all their pens with their own ink.  So, for flex writing, if you want something easy out of the box, just get Montblanc ink.

 

Adding Gum Arabic will increase ink's viscosity, making it thicker, slowing down the flow, reduced flow speed means less shock on the ink film when doing flex write, ink is a bit dampened also slow down capillary retraction on the feed.  Like Ines stated, reduced surface tension is what allowed ink film/ bubble to form from the first place, and hence enabling flex writing.  So, to further reduce surface tension and increase the ease of forming ink film, for every 50ml of ink, you can add one small drop of dish soap (liquid type), remember, just one small drop.  For making the ink film "last longer", add about 5 drops of glycerin, that should make the film stable and have lesser chance of bursting.  All of these tricks are actually nothing new, but are classic recipes for soap bubbles being played by kids.  For us fountain pen fans, flex nib writing is another sort of soap bubble playing.

Kodak Photoflow works a lot better than detergent.

[duckbillclinton]

30 minutes ago, DiveDr said:

Kodak Photoflow works a lot better than detergent

 

For real ???

 

[DiveDr]

Yes, it does, great surfactant and clear, no color, not expensive. I use it quite a bit when making inks very good results.

[duckbillclinton]

59 minutes ago, DiveDr said:

Yes, it does, great surfactant and clear, no color, not expensive. I use it quite a bit when making inks very good results.

 

Ok, just ordered 1 bottle.  LOL.  By the way, what option 1 tools were you asking from the previous post?  You mean cutting the middle slit?

[Pen Engineer]

On 8/18/2021 at 12:01 AM, InesF said:

Yes! 🧜‍♀️

The 12V Dremel should not harm me when submerged in the bath tube. However, I had a hard time to position myself correctly and the diving goggles changed my vision for the right distance so that I accidentally ground my fingernails instead of the nib ....👎

😉

Lucky you have a big tub.  May suggest one of those transparent boxes with rubber gloves sticking inside?

For prevention of cutting fingernails I recommend thimbles.  

Hope that helps, always trying 

 

(thanks for the good laugh (don't tell anyone))

[bunnspecial]

On 8/23/2021 at 11:03 PM, duckbillclinton said:

 

Ok, just ordered 1 bottle.  LOL.  By the way, what option 1 tools were you asking from the previous post?  You mean cutting the middle slit?

 

Photoflo is quite literally a very concentrated solution of nothing but Triton X-100, a non-ionic surfactant, in deionized water. It's likely the best consumer source of pure surfactant available, and is not expensive.

 

BTW, use it sparingly.  As a darkroom chemical, it's used as a final rinse aid on film-basically it's the last liquid the film touches before it dries, and basically lets water flow neatly off the film rather than beading up and leaving water spots. It's used VERY sparingly for this, however-1:200 is a typical dilution(meaning I put about 3/4 oz. in a 1 gallon bottle when making it). Too much actually can spot the film even worse.

 

When adding it to inks, a tiny amount goes a long way. When working with say a 5mL sample vial of an ink, I will typically add Photoflo in 5-10µL increments. If you don't have a micropipette or an easy way to reliably dispense such small volumes, I'd suggest making at least a 1:10 or so solution.