Measuring Ink Wetness With Surface Tension And Capillary Tubes

Here's a link to the tubes on Amazon, I couldn't see them anymore on Aliexpress
amzn.to/3K42GKu
Want to support my channel without it coming out of your pocket? Use some of the links below next time you're buying any thing on Amazon or other online retailers listed below. Thanks for all the support!
A great fountain pen:
amzn.to/3BCEHgs
Care for some ink?
amzn.to/3uzL9kv
VALENTINES SPECIAL for xTool Systems:
XOXO150: $150 off discount on Valentine's bundles below (18/01-14/02, PT):
xTool D1 Pro Cash-in Machine for Side-hustle:
www.xtool.com/...
xTool M1 Perfect Enclosed Machine for Side Hustle:
www.xtool.com/...
D1 Pro 20W Premium Gifting Kit:
www.xtool.com/...
M1 10W Household Gifting Kit:
www.xtool.com/...
Check out the xTool site for more details:
www.xtool.com/...
My Amazon Store - Work in Progress
www.amazon.ca/...
___________________________________________________________________________________
Check out the weekly sales at Goldspot Pens
goldspot.com/c...
___________________________________________________________________________________
For a 10% Discount from Osprey Pens use the info below: www.ospreypens.com
At checkout use the discount code: thedoodlebud
Or use the link below www.ospreypens...?aff=36
___________________________________________________________________________________
Canadian Online Retailer: www.blesket.com use code DOODLEBUD22 to save 10%
#doodlebud #fountainpen #engineering

[@MadUncleAndy]

You're blinding us with science! Well done!

[@Doodlebud]

Someone had to do it :)

[@villegas24]

I love when creators add experimental chapters into my favourite content

[@Doodlebud]

By my nature, I will always be experimenting! I have a playlist with some more engineering type stuff where I'm trying things out: kzbin.info/aero/PL6RAe6vPmtDiZnhH7NNjKORkwboOZUurR

[@amydebuitleir]

Honey is a very good example of why the timed "smear" test doesn't necessarily tell us how easily the ink will flow through the pen. Honey takes forever to dry, but it certainly isn't "wet"!

[@rahashi]

This is becoming my favourite YT channel. Only found you a few days ago and really enjoying the richness in angles to look at one of my favourite new subjects. This is a real goldmine!

[@danielklopp7007]

This video also explains why ebonite feeds behave differently than ABS feeds (i.e. ebonite and ABS have different surface energy)... ebonite tends to flow better than ABS (all other things being equal). This got me thinking about the surface energy of the nib; I'll have to do some research on the relative surface energy of various alloys of gold and various alloys of stainless steel (i.e. the most popular nib materials), to see what role these materials play in the wetness of a pen. One of the reasons I love the fountain pen hobby is the complexity of the interactions between ink, nib, feed, paper and atmospheric conditions (i.e. barometric pressure and humidity); any of which can change the writing experience.

[@brillcouncil4584]

It also indicates that there should be some easy ways to increase the flow of feeds without hacking away at them.

[@ArjanD78]

THIS is exactly why I follow your channel! Thank you very much for taking the time to think this through, do the research and for making this video. Big thumbs up! 👍🏻👍🏻👍🏻👍🏻👍🏻

[@markschumacher7408]

In many of your videos we see ink on your fingers. Now we know why. Great video.

[@johntoledo4438]

This is just outstanding. It explains why I've sometimes been confused with how some inks behaved where an ink was supposed to be wet or dry and it just didn't feel that way. Cool!

[@jondowee]

This is why your KZbin channel is exceptionally good.

[@Doodlebud]

Thanks

[@fossilimprint2954]

Now this is a great example of applied science. Thank you.

[@IAmTheSunBear]

Dude this video is amazing, i feel like it should be required viewing for anyone getting into inks and their individual properties. I wanna test all my inks this way

[@Doodlebud]

I have another simple test method people can do at home with stuff they already have. Hopefully I'll get a chance to make the video in the next few weeks

[@IAmTheSunBear]

@@Doodlebud oh I'm very excited for that, thank you so much for your work and diligence for the fountain pen community. Not enough people are looking at the nitty gritty of all this stuff that we just blindly accept or neglect and then make a purchase without understanding the reality behind the product

[@technoraptor7778]

This is so cool dude.....a fantastic way to test wetness!! I didn't even think of that. It gives even more identity to inks.

[@Johan-vk5yd]

0:40 Awesome! The adequate take on the matter of ”wetness”. Not to be confused with ”viscosity”which might happen.

[@zathrasnotzathras9435]

Whoever invents that number scale for wetness should do it in increments of Doodlebuds.

[@SalBC62]

I really enjoy this technical videos, but I am afraid that many of the fountain pen aficionados are not going to understand and like this discussions. Quite a great informative video. Thanks and congrats.

[@susanwymer6912]

Fascinating!!!!! Proves my thoughts on Pilot Iroshizuku inks and Writer’s blood. Would love to see you test a high surface tension ink before and after adding s bit of dish soap or Vaness White Lightening. Did the surface tension truly change? Great video!

[@gristlevonraben]

I would never have thought that these inks would be so different. Very fun to watch!

[@zacheryanderson7363]

I love your videos... They make my nerd brain happy 😁 thank you for taking the time to do this!

[@caseyjp1]

The DB comes through again. That clears up many questions I had about this very subject. Pushed this up to reddit.

[@klt479]

Excellent analysis. Like you basically said, while its not perfect, it's a great start / first run! Since you shared this we all are aware of the initial preliminary results. It's very clear how future tests can be used to further refine our understanding. I'm sure the initial discussion about surface tension, cohesive, and adhesive forces also has gone a long way to set up our understanding of certain ink characteristics! Thanks for posting this and make it a great day! Cheers!

[@coffeeguyd]

YES!!! I hope this will gain traction and inspire a bit of a paradigm shift in the standard of how reviews are conducted. I understand that most reviewers are amateur enthusiasts, not researchers and scientists, but it would be nice if there was an evolution towards more illustrative and reproducible objectivity such as this! Great job, DB! This is an awesome step in the right direction that many of us have been looking for (but didn't know how to do for ourselves, heh)! Can't wait to see if/how you progress this from here! 👍

[@osirisgolad]

Makes you wonder what metrics and methodologies the ink makers use, but they're all so secretive. Very enjoyable video.

[@petrisz]

Wow it’s both absolutely fascinating and totally useful. I like your unique take on fountain pen vlogging. Thanks dude 🙏

[@pnwesty7174]

Gee whiz........ I wonder why this is the most interesting FP channel on YT. And here I was thinking an advent calendar review was the pinnacle. The residues/coatings tell an interesting story as much as the "mobility" in the tube. Very interesting.

[@Doodlebud]

Thanks buddy. I want to play with this some more to we what I can come up with. Hopefully some others play around with this idea as well 💡

[@pointeplusplus]

I really like how you look at pens like an engineer (maybe you are an engineer? 😊). As an engineer, these are exactly the questions I’m asking myself when I’m wondering what someone means by a “wet ink” and these are the answers I was looking for!

[@Doodlebud]

I don't work as one anymore but did for 12yrs. Jsut gotta know how stuff works

[@InkquiringMinds]

Awesome video, DB!

[@Doodlebud]

Thanks buddy 👍

[@NicMcPhee]

Thanks for the really helpful description of surface tension! That was a cool test and seems like it could be a really informative approach moving forward. Love the science/engineering take on fountain pens and inks.

[@Fauxtonics]

A good way to measure the movement of the inks would be to hold your notebook vertically, place the camera so the sensor is parallel to the paper. Then place the tube with the ink onto the paper and measure the time it takes for the ink to travel from one dot to another.

[@cynthiaalvarado8610]

This just blew me away! What reviewers describe as being a “wet” ink meant that it just has greater surface tension that the ink stayed on the paper surface rather than absorb into the paper!! Also, I’m pretty sure KZbinr “An Ink Guy” has a lot of these measurements. Adam shares a Normal distribution and where an ink falls in viscosity within the distribution. You can only get that info by having a lot of measurements on lots of inks. I wouldn’t be surprised if he had more measures that he tracks for himself.

[@Doodlebud]

Well surface tension isn't the only thing at play. An ink like x feather can definitely skew results. Writers Blood has a low surface tension but takes a long time to dry. The smear test brings so many variables into things. A wet ink typically will naturally put more ink onto the page, and more ink means longer to dry. So surface tension plays a component. Viscosity definitely also play a role. With this "test" I'm not doing a direct measure of either so it's tricky to know what to make of it, buts it's a starting point

[@Wreneagle]

Wow! Always wanted to test surface tension. What a clever solution.

[@Doodlebud]

It's a start at least. Have to sit down again and do some more testing etc. But something people can play around with at home as well to learn more about their inks.

[@Johan-vk5yd]

18:33 I watched the video now. Congratulations! You did clear up the common confusion of internal adhesion versus surface tension! Thank you! I think X-feather works best in my vintage pens with ebonite feeds, and few extra fins but a wider channel.

[@MimiKandsomerandomnumbers]

Little bit of a trick I use: if my pen and ink combination are on the dry side, not enough flow to keep up with fast writing, I add just a hair of ox gall to reduce the surface tension. It's sold for watercolor, there are liquid, natural, synthetic and watercolor pans, mine is winson&newton, less than a drop and I get a wetter writing experience

[@odinson364]

Thanks for taking a more scientific approach to this! I had always thought that the "smear test" was pretty bad, and did not really tell us anything concrete.

[@ichirofakename]

I've got to believe it can tell us something about drying time. Though unfortunately I don't care about drying time.

[@Doodlebud]

The smear test isnt totally pointless as it does confirm for example, that Writers Blood is very wet. But knowing is ink A wetter than ink B can be trickier. Many variables at play, especially between users.

[@BGazzah]

Great to see a measured approach to all your testing, not just a "Oh look at the pretty colours" like a lot of pen/ink reviews... Based on your reviews Ive just ordered 2 gravitas pens (nothing to do with the fact Im in Ireland anyway :) )

[@Doodlebud]

Glad you like my approach. It's not for everyone, but I can't help but think like an engineer LOL. Guess it resonates with some folks who think like I do.

[@hogtownpens]

Loving this idea for testing - and great job on the explanation!

[@nitina8564]

Another fun and informative video.

[@archivist17]

Yes! This is what's been needed, and I'm glad you're thinking about how a standardised test would look. I'd been thinking of a fixed test angle, and a timer, but your idea of angle works well, so long as you can define what 'starting to move' actually looks like. I'd also be intrigued to know what ink mixing/diluting/concentrating will do to alter test outcomes 🤔

[@Doodlebud]

Yeah its still a bit tricky as some inks really wet the tube and when they do that the ink moves even quicker. Viscosity is also most likely playing a role in how freely it travels as well. Still not sure on the best approach but it does give a visual check so you can quickly and easily learn a few characteristics of an ink and compare it against another.

[@dsb1763]

I don’t think any manufacturer would do this comparison. I would suspect it would reveal the composition of the ink. All I know about inks are the main components are water and a dye/pigment. The milling of pigment I would say is the trades secret each manufacturer wants to protect, otherwise everyone would be making their own inks in the sink, just like how Noodler’s started.

[@KendallW]

Very cool. So many factors to think about. As usual, great video. I hope someone takes up the idea of doing a bunch of these tests. I absolutely love how well Writer's Blood flows, and knowing how inks compare would help me find others that behave similar.

[@nomadhawg]

Excellent video. Would love to see this test done on waterproof/permanent/indelible (I still don’t know if those all mean the same thing or not) inks, as well as inks at the same ends of the spectrum. Like which dry ink is the driest. Which wet ink is the wettest. Anyway, thanks for the info and the suggestion, as well as the explanation of how it all works together.

[@FrankDAgostino77]

Cool test! X-Feather is my go-to black, phenomenal on copy paper and pretty waterproof once dry.

[@elainenabors9832]

This is FANTASTIC!!!!! Thank you!!!!!!!!

[@Doodlebud]

Glad you like it 👍

[@theProf_01]

I like the approach you take. Great review of wetness for inks. I remember the review you did a few weeks ago of Private Reserve Infinity Inks. I bought some, and that ink is wet.

[@brillcouncil4584]

Very clever as a quick test, much appreciated!

[@wendyholiday2021]

One of my favorite videos Very helpful!!!

[@Marvin-yk4lp]

Another great engineering perspective video, the only one that would do something like this.

[@deita2191]

this is revolutionary

[@Schein1307]

Very cool liquid science. Some inks flow better than others...

[@santauxia]

DB, Amazing video. Very informative.

[@anguswhite8233]

As a leftie w small handwriting I want quite a dry ink: I like the ink to put down a nice fine line and not spread out! - for what it’s worth, Montblanc, Aurora and Pelikan seem to generally behave well whereas Pilot Iroshizuku and Monteverde inks seem quite a bit wetter!(but it’s not an exact science whatsoever!:(

[@mrcarterxxl]

This video did a great service, I’ve grown to loath Daimine Earl Grey, it will not flow through any of my pens properly. I’m only saving it for if I decide to invest in a dip pen

[@FlurinKoenz]

I never would buy an ink without getting the complete temperature dependent rheological analysis 😂. Very cool video!

[@philippebarillecavalier9275]

Some inks seem to behave like toffee when I move them around in a converter. It's so satisfying to see this range.

[@sonstatoazzurrodisci]

Always the best content. PS: "Man gets a lab technician degree to test wetness between two black inks"

[@kozygeorg]

Thank you very much for the very informative and intersting video. Would be very interesting comparing different inks in the same brand but different colors

[@paulherman5822]

Using iron gall inks regularly, wetness is a factor. I regularly have my late 1940s Waterman's Taperite inked with iron gall ink, as it's, like most vintage Waterman's, a VERY wet writer, so perfect for the dryness in the iron gall inks I have used. (Currently vintage from Dickson. 😁) Best type of ink I have found for the low quality paper used for checks/cheques. And my landlord is a Luddite that doesn't believe in debit/credit cards apparently. Check, cash, money order... Great idea for testing!

[@aardwolfssg]

There's another factor, evaporation rate which depends on ambient temperatures, atmospheric humidity, air flow (with air blowing, not blowing across), too many factors affecting ink drying....

[@scottbaker2451]

Fascinating stuff. Thanks!

[@seano51]

Great test and video.

[@thejumpingnomad2485]

That was really cool.

[@Calcprof]

Great. A good proof that viscosity is not wetness is some wet super sheeners (very viscous) vs. some very dry multi shaders (low viscosity)

[@Luma994]

Thank you for explaining the science, it helps me understand better. Go science! 😁

[@TimmerH]

Nice video - very thought provoking ! - I thought that surface tension was typically done by measuring the height of the ink that is pulled into the tube against gravity. Oh yeah, please add distilled water as a control. oh, and maybe your local tap water... :)

[@Doodlebud]

Yes the h value will be used to calculate the surface tension. But in the formula there is also the contact angle that needs to be measure with the tube & ink which requires special gear. I initially did some control tests with distilled water but even then I would a wide range of h values when dipping the tube. Thought the tubes were a bust after that until I started playing around and observing the behaviour of the inks within the tubes. So this won't get an actual measurement of the surface tension, you're able to observe the impact from changes in inks with respect to surface tension. Also, there is most likely some contribution from viscosity as well. So it's definitely not a direct accurate measurement of either property, it gives some info about overall ink behaviour. So would probably use distilled water as a control to see what angle or travel time it has and use that as a comparison with other inks. Would have to develop some sort of new metric to quantify the results

[@lpanades]

Super nice. I love putting gum into my inks. I love because it thicks the ink but raises its surface tension and the ink dries over the paper, slowly. Your test is an useful test. Another advange of gum is that it produces thinner lines. I write spencerian, real one, so the lines sre really fine. The problem is that they have a harder start. The gum stay sticky because I cook it before adding to my pens' ink. Here its called liquid gum and is produced from vegetal suggars.

[@ichirofakename]

Is it the same gum that is in watercolor paint?

[@lpanades]

@@ichirofakename Really I do not know nothing about watercolor; but, it is a kind of cheep option to gum arabic. I would prefere the original but the cheep option works too. This kind of glue, gum, is used in stamps.

[@lpanades]

It is opaque and white. After cooking a bit it turns transparent and like caramel. If you let it sit for two days it begin to gelificate and get pasty. If you cook more it stays darker and more dificultly gelificate. Something interesting. Some kind of cristalization seens occouring. At the ink, how it is much more diluted you will not see this.

[@slo_carry]

Very handy!!

[@TheDormousesDesk]

Absolutely fascinating. Thank you!

[@rsanderson100]

Good stuff. I love the engineering approach to these questions. Next experiment to think about - how could any of these properties - viscosity, surface tension, or surface energy - be correlated to the tendency of an ink to feather and/or bleed through a particular paper? Trying to predict feathering or bleed through for many different papers from an ink's properties alone probably wouldn't work - you'd also need information on the properties of the paper. But for comparing the feathering/bleed-through tendency of different inks on the same paper, could any of these properties be used to predict the relative performance of different inks?

[@jamesbenton8347]

Amazing!

[@kstutz230]

Fascinating!

[@bobanderson7313]

I wonder how long it'll be before ink companies put a DWR (Doodlebud Wetness Rating) on their labels.

[@melissam0ss]

🤓👏🏽 Awesomeness Great video !

[@strshooter7399]

Very Cool 🙂

[@Merlin012001]

You ought to try the ottoman rose and Shah's rose in this kind of test. They stay wet on some papers forever.

[@rsanderson100]

Noodler's red-black takes DAYS to dry on Tomoe River paper.

[@simonrobertson1985]

Love this video, always found ink testing to be very random with lots of reviews... we know some pens are dry pens and papers change things and they use different tools each ink review!!!

[@cerealnana]

This is brilliant! Thank you!

[@octopusgoodness1909]

The other thing that needs to be considered is humeactants in the inks. In some inks the carrier fluid evaporates far faster.

[@Doodlebud]

Yup, and depending hour the full chemistry of the ink works together will show different characteristics

[@MultiEbbot]

cool video I liked it a lot, interesting.

[@nataliagawior3910]

Next step would be tweaking the surface tension/wetness/viscosity. There's this one ink, FWP Blue cotton candy, it's a lovely pastel blue, but the writing experience is that of trying to write with a dry stick. It has poor flow even with a broad nib. I think it's drier than the Noodler (X-Feather), which does a great job at non-feathering on lower quality paper.

[@Doodlebud]

There are some additives you can put in your inks to change the properties. White Lightning is one that I know people use with drier flowing inks

[@amydebuitleir]

I see that capillary tubes come in two types; The ones with the red band (like you used) have sodium heparinate over the internal surface, and in medicine are used with for capillary blood. The ones with the blue band don't have the sodium heparinate, and in medicine are used with venous blood. I wonder if which one we use will affect the results.

[@amydebuitleir]

There's also tubes with ammonium heparin (green colour) and lithium heparin (orange colour).

[@amydebuitleir]

Just ordered both the plain (blue) and the sodiam heparinate (red) tubes. (Found 'em cheap at a local medical supply.) I will report back on whether it makes any practical difference which one you use for these tests.

[@Doodlebud]

Yeah I wonder which coating effects it more or if the tubes should be cleaner out in an ultrasonic cleaner first with some IPA (or whichever is appropriate) to remove the coating to begin with.

[@waynebosma6456]

@@Doodlebud Great video! I suspect that the coating will affect the hydrophilicity of the glass, and may change the properties of the ink somewhat if it dissolves. Uncoated glass might be the best way to achieve consistency.

[@Doodlebud]

They can be washed and reused. I have a bunch that I have used and washed out. I will clean them with IPA in my ultrasonic cleaner and then compare the same inks in brand new ones which are coated.

[@Iwoodlikethat]

If you wanted a more qualitative test you could put a known volume of ink on a watch glass and put the capillary tube in it, then measure how high up the tube it ink whets its way up the tube. The test you did though is a super cool visual test to show which is wetter.

[@Doodlebud]

I did that series of tests initially when I first got the tubes and there was significant variability doing it by measuring the height the ink went up. I was planning on calculating the surface tension of each ink but it just wasnt working at all. Even using water I got a wide range of values. So this is why I took this approach instead. Viscosity is also playing a factor in this as well so there's a bunch going on. But I think will some more thinking, refinement and standardization it might be quantifiable in some regard.

[@Equinox051256]

Great vid, as always. I'm assuming the shape of the nib (stub versus extra fine), as well as its composition, (Gold, versus Stainless Steel) would also come into play when determining the fluidity of a particular ink.

[@ichirofakename]

The next question (for me) is what to do about ink to change its behavior. White Lightning ink additive from Vanness works pretty good at making ink wetter. Is there not a product that would do the opposite, and make ink drier? I think maybe just adding water generally works, and you can add quite a bit without changing the color at all.

[@Doodlebud]

I've used gum arabic for my calligraphy inks but there's probably something that can be done for FP inks but I haven't ever looked into it. If you search around you can probably find someone who did. I tend not to mess around with my inks very much

[@j._t.]

White lightning acts as a surfactant, it reduces the surface tension and improves wettability. It’s the same reason why dish soap works. Inks are already formulated with surfactants since water has a fairly high surface tension, which is why adding water makes inks *feel* drier. IMO the only additives anyone needs are a surfactant and water-I don’t think it’s worth the trouble trying to change viscosity.

[@pensinfocus]

This is awesome. I was thinking of doing something like this, just to have as a point of comparison. I have some pens and inks that are wet to the point where I can't use them together: RO Fire & Ice in my Pelikan M1000 for example is a no go. Blobby and unusable.

[@ichirofakename]

I wish there was a place where info like this could be aggregated. I like info from experience like this.

[@ichirofakename]

1. Best video ever, thanks. I need to learn more about ink behavior. 2. I see and believe how much more viscous X-Feather is in your demo. The big problem for me is that I tested it against other inks and couldn't see any difference in behavior. Which makes me doubt the practical usefulness of measurements. Sorry. 3. It seems the actual color of the ink comes into play in ink behavior. Possibly it's just the size of the pigment or dye?

[@Doodlebud]

I haven't done much testing on paper yet to test the xfeather. Only done this stuff so far. I put some drops on a page and it did sit there for a very long time. I don't think colour plays a factor. The colour is just a function of which wavelengths the dye reflects/absorbs

[@FernandaSantAnaDeSouza]

Excelente test!! 👏🏻👏🏻👏🏻👏🏻

[@thrackmoorinvictus5948]

You could use a Dunuoy Ring Tensiometer to measure quite precisely.

[@Doodlebud]

Yup absolutely, that's what they're made for. However, I'm looking for a method that anyone can do with very simple and cheap gear instead of a piece of expensive lab equipment.

[@thrackmoorinvictus5948]

@@Doodlebud Ask at a local university chemistry department. They may do the tests for you or let you use one. I had a high school student who used one from a local university for a science fair project.

[@ironmic9244]

Very interesting. I don't know what else to say.

[@richtreinen991]

The glass capillary tube test illustrates the characteristics when liquids and solid are in contact. It clearly indicates how different inks behave in a glass capillary tube. Some coat and slip, some do it better and some not at all. Since you used a medical capillary, the glass is coated with another chemical. You will find that a non coated capillary would show different results. In a pen there are 3 fluid/solid interactions when ink flows through the feed, nib and onto the paper. Fluids can behave very differently when in contact with different solids. If all the solids in a pen had the same surface characteristics as your capillary tube, your observations would be useful. However the feed, nib and paper are not glass. This also explains why some inks work well in some pens on certain paper and do not work well if one part changes. As we all know, the difference in paper properties are the most dramatic. The difference in inks, feeds and nibs (when the nib is not messed up) are are much smaller.

[@clementmanuel1987]

Excellent test. Maybe the "Wetness Angle" as a measure of wetness.

[@paulfiorino7463]

Is there a standardized index, like Moh's scale, for ink flow? After I typed this question, I finished watching the video, and I think you are on you way to creating the Doodlebud Scale. "That ink is a 4.5 on the Doodlebud Scale."

[@Doodlebud]

There are standard measurements with units viscosity & surface tension. This was an attempt to see if there is a very simple DIY method for people to do at home

[@Toasty2006]

If AvE did fountain pens (sans colorful language😅). I enjoy these vids

[@Doodlebud]

There is PLENTY of colorful language, it just gets edited out..... My B roll would be pretty intense LOL!

[@SalBC62]

I wonder what is the minimum angle where the ink begins to move downards. Just like a solid object when it begins to move downward an incline.

[@SouthWind96]

As a vet tech, I use hematocrit tubes like these at work all the time to assess PCV (packed cell volume) when checking for or monitoring conditions like anemia or dehydration. I never thought of using them to assess the surface tension of inks, but that’s a novel idea! Quick question… those tubes appear to be treated with sodium-heparin. Would a coating like that on the inner surface of the glass affect the van der Waals or intermolecular forces enough to skew your results? Perhaps not all inks will flow the same if they aren’t equally polar solutions (e.g., two inks of identical viscosity and surface tension, but the one that’s more polar would coat the tube more easily due to ion-dipole interaction)?

[@Doodlebud]

The coating could impact how the ink works. The easiest way is just to wash them. I use my ultrasonic cleaner to do that. I've done the test with some costed & some cleaned and couldnt notice a diffence as of yet.

[@PickwickTurtle]

I am curious if the amount of coating is a good indicator of how difficult the clean out process might be

[@ILoveFountainPens]

What a great idea! Thanks for sharing. I'm struggling to find a truly wet ink for my MB 146 Calligraphy Flex as it often feels like I'm writing with a nail, which is a frustrating experience. This was very valuable. I think when other channels test wetness, it's more about how long it takes to dry on the paper and not how it behaves in the pen, which is far more valuable. Where did you get the tubes from? I'd like to try this out with my own inks. Can they be washed/rinsed with water and reused? Also, thanks for the sticker co. recommendation. I had some made of my own logo and I absolutely love them! They're much higher quality than I was anticipating.

[@Doodlebud]

I have a link in the description on Amazon. I bought mine on Aliexpress but I couldn't find them again. You can wash them out and reuse them. Keep in mind there is a inner coating on them. So if you use a new one and a washed one you might get different results as the coating may get the ink to act a little differently. So if you want to compare inks, use all tubes that havent been used or all ones that have and washed.

[@amydebuitleir]

I'm trying to think of a simple way that doesn't require direct comparison between a bunch of inks. A test that involves only one ink at a time, so I can easily test a new ink when I get it. A test that different people at different times in different places can perform, and hopefully get repeatable results. Maybe as an alternative to estimating the angle it takes to get the ink to move, we could get dip just the very tip of the tube in the ink, hold the tube upside down and vertical, and time how long it takes for the ink to reach the end of the tube. Seems like some of your inks would take less than a second, while other would take 10 seconds or more, so you'd have a good spread.

[@Doodlebud]

The drop test can work for sure, but on some of the inks it would already reach the end after a slight change in angle.

[@marcinb2083]

Someone wishes they could do the basic physics lab again and get to play with toys :)

[@spotsies]

I'm getting flashback from colloidal chemistry lab :D

[@jamesbrenza6811]

This is super helpful! So as I contend with some difficult pens (i.e., they dry out after sitting idle for 15 minutes with their cap on - and then have a seriously hard start), this may help answer which inks will work better with those pens. I do wonder about material selection for the feeds. FWIW, these are new'ish Monteverdes and Conklins. I sometimes feel like some wetter feeds are hydrophilic. Are some feeds hydrophobic (and allow the ink to fall right out of them and then hard start)? Maybe this approach will help determine if a lower viscosity, or ink that "coats" the sides of the capillary tube will help stay attached to the feed (or at least flow through the feed more quickly to reload it). Any thoughts on either solving the drying problem or this test approach?

[@Doodlebud]

Check out this video for nibs drying out kzbin.info/www/bejne/eGKne6ird910q7M

[@EdelAyGo]

Surface tension haven’t crossed my mind. Could It be possible to add a little bit of detergent when filling a FP so we can get Wetter inks?