04-08-2015, 05:34 PM
#1
User Info
First, I asked Ravi for permission to post this here rather than in the Artisans Corner, as I thought it might be of general interest. Establishing context will require some discussion of Dark Holler’s First-batch offering of brushes made in collaboration with Lee Sabini; however, it should be obvious that the purpose is not promotional.

Among the 74 first-batch brushes that came back to us from Lee in mid-January were a dozen or so that had what my son and I considered to be significant issues. Those included unsightly glue showing above the socket rim and/or highly prominent glue bumps.

At least several bushes sold in the M&F Group Buy on B&B exhibited the glue issue to some extent. Hardly anyone complained. Nonetheless, I ended up acquiring three of them. One was offered to me by a friend in KC who badly needed to raise cash to replace a laptop that had failed while he was in the middle of writing his dissertation. (Of the Group Buy Chiefs I’ve come to possess, that one is probably my favorite in terms of feel and performance.) Another was purchased by a friend on the B&B BST. He was displeased when he discovered the imperfection upon the brush’s delivery and asked if I might help him obtain some consideration from Lee. Long story short, I ended up buying that brush to remove it from circulation.

To the best of my knowledge, neither of those brushes possessed any defect that would compromise the quality or longevity of its service. The third brush, however, had a more serious problem. Its knot appeared to the owner to be slowly but inexorably emerging from the handle socket. I swapped another Chief for it, and pried the knot out within about an hour of its delivery. Lee had speculated the cause might be an air bubble trapped under the knot, and indeed there appeared be a pocket there.

A few weeks ago, grantmm, a friend and respected member here inquired whether I might have any Chiefs left from the Dark Holler First-Batch. My reply, in part, stated: There are some BM Chiefs with knots that were set higher than what I'd call normal, although Lee might disagree. I decided to hold them back. No problem as far as I can tell, but I'd expect them to be stiffer/scrubbier due to effectively shortened loft, which some would like, but I would not.

Grant was persistent, so I offered to send him one those brushes to try, but I refused to accept payment before he could experience it himself and decide whether he liked it. As it turned out, he did. And that’s great. I think there a risk, however, that some of the discussion about that brush with reference to its “higher loft” could generate misunderstanding.

This is one of those cases where a picture can be worth a thousand words. Cody and I carefully examined the rest of brushes we’d held back, and selected the one with both the highest glue bump and most glue showing. Although I’m sure many here would have been very pleased to own and use that brush, we would not have been willing to offer it for sale, and it had a higher purpose to serve anyhow.

The first photo below shows the brush from four angles. The glue ring above the socket entirely surrounds the knot, which is highly reminiscent of the one I previously extracted (so finding air pockets wasn’t a surprise). It was hard to measure exactly, but the glue ring is approximately 1.25 mm high for the most part.

The second photo is of the entire brush, which stands about 111.65 mm high, with the handle contributing 59.4 mm, which implies a loft of 52.25 mm. Before we cut the brush in half, I inserted a wood toothpick straight down from the crown of the knot until it stopped, and then marked the toothpick at the top of the crown. Measuring from the bottom of the toothpick to the mark indicated insertion depth of 41.5 mm, leaving a difference of 10.75 mm presumably attributive to a glue bump .

The third photo largely speaks for itself. Amazingly, 10.75 mm was also the exact measurement we obtained with calipers spanning from the rim of the socket up to the highest level of impermeable glue at the center of the knot. That’s the way it was supposed to work, but I expected some difference.

What that obviously means is that although this particular brush had apparent loft of over 52 mm, its effective loft was less than 42 mm. I washed it and used it a couple times before we bisected it. The brush lathered like a champ and performed well enough otherwise, but it was scrubbier than I prefer, and more to the point here, scrubbier than I’d expect from a Blonde Badger knot lofted at 52 mm.

And that’s really the issue. I don’t think there’s anything wrong with a highly set knot or prominent glue bump, per se (although this one clearly had some glue-associated pathology beneath the surface). But consistency in relation to expectations is an issue. Enuf said by me on that subject here. This is about brush anatomy, not marketing. The important things are to figure out what you like, understand what contributes to and/or corresponds with those attributes/qualities/effects, and know how to identify them more or less objectively when describing or selecting a brush.

FWIW, here are links to a couple other threads that discuss glue bumps: first and second.

[Image: Paladin-Chief-360_zpsqzilsqdl.jpg]
[Image: Paladin-ChiefBisected-2-Dimensions_zpsiraysapa.jpg]
[Image: Paladin-Chief-Bisected-2-Dimensions_zpsk35oegzn.jpg]

3 961
Reply
 04-08-2015, 05:48 PM
#2
  • Agravic
  • Super Moderator
  • Pennsylvania, USA
User Info
Fascinating, Ken .. thank you for sharing these insights.

102 18,552
Reply
 04-08-2015, 06:08 PM
#3
User Info
Great information. Thanks Ken


Sent from my iPhone using Tapatalk

61 3,072
Reply
 04-08-2015, 06:10 PM
#4
  • refles
  • Senior Member
  • New York
User Info
Great appreciation Ken for the knowledge and experience you share with us!

35 1,329
Reply
 04-08-2015, 06:39 PM
#5
User Info
(04-08-2015, 06:10 PM)refles Wrote: Great appreciation Ken for the knowledge and experience you share with us!

Thanks, but I have greater respect for what I don't know about knots than what I do.

They remain a mystery to me in many respects. Almost all of the important respects.

IMHO, badger-hair knots defy reduction to simple declaratory pronouncements.

And I like it that way.

3 961
Reply
 04-08-2015, 06:52 PM
#6
User Info
(04-08-2015, 06:39 PM)Chiefbroom Wrote:
(04-08-2015, 06:10 PM)refles Wrote: Great appreciation Ken for the knowledge and experience you share with us!

Thanks, but I have greater respect for what I don't know about knots than what I do.

They remain a mystery to me in many respects. Almost all of the important respects.

IMHO, badger-hair knots defy reduction to simple declaratory pronouncements.

And I like it that way.
Very interesting info and graphics, Ken. Thanks for sharing!

26 232
Reply
 04-08-2015, 08:20 PM
#7
  • refles
  • Senior Member
  • New York
User Info
(04-08-2015, 06:39 PM)Chiefbroom Wrote:
(04-08-2015, 06:10 PM)refles Wrote: Great appreciation Ken for the knowledge and experience you share with us!

Thanks, but I have greater respect for what I don't know about knots than what I do.

They remain a mystery to me in many respects. Almost all of the important respects.

IMHO, badger-hair knots defy reduction to simple declaratory pronouncements.

And I like it that way.

I can understand and it's not given lightly, I've come to appreciate and value the self derived conclusions regarding brushes you've been so kind to put down in writing for us here and in B&B. It's an incredible read on topics we've maybe accepted or never dwelled that deep into but definitely have not put down to 'paper', as it were. This is a pretty serious hobby that has practical application for us and I find it a informative and wonderful read overall.

Plus the illustration of the cross section of one of your brushes does also add legitimacy in a way most only come to the conclusion from hearing others views and experiences and experiencing it for themselves to formulate their own conclusions.. Not to mention it's downright cool to cut something in half so cleanly! Smile


Sent from my iPad using Tapatalk

35 1,329
Reply
 04-08-2015, 08:35 PM
#8
User Info
Very informative insights, Ken and thank you for sharing the information and for sacrificing such a lovely brush for our viewing pleasure!  Biggrin

82 21,056
Reply
 04-08-2015, 10:14 PM
#9
User Info
What a great post Ken.

Extremely insightful. Something I've always wanted to see.

7 1,182
Reply
 04-08-2015, 10:52 PM
#10
User Info
Fascinating stuff, Ken!
This is brush science in the making!

0 655
Reply
 04-09-2015, 01:45 AM
#11
User Info
Very interesting indeed.
Like you said, the real issue is not the presence of glue bump, but the inconsistency of it (and sometimes, other parameters as well).

2 5,545
Reply
 04-09-2015, 05:22 AM
#12
User Info
(04-09-2015, 01:45 AM)oversaturn Wrote: Like you said, the real issue is not the presence of glue bump, but the inconsistency of it (and sometimes, other parameters as well).

And oftentimes there is inconsistency on top of inconsistency.

One thing that can lend to confusion in the reporting and discussion of glue bumps is inconsistency in methods of measurement.

I touched on that subject in this post (scroll down to just below the photo of four knots taken from above).

Here's a shot that shows two bumps being compared by pressing across and down with thumbs. A problem with this approach is there's no good way to measure and subtract out height contributed by the hair, and knots with different diameters and densities will add to variance.

[Image: Glue-bumps-1_zpsz48tsbe3.jpg]

3 961
Reply
 04-09-2015, 07:18 AM
#13
  • TheMonk
  • Super Moderator
  • Porto, Portugal
User Info
Very thorough work, Ken. This is exactly the type of in depth analysis we need from shaving brush manufactures, but that they almost always fail to deliver - a shame really, as this is extremely useful work, and will not only help to evolve the industry, but it will also allow to correct potential errors. Again, fantastic work, and please do keep at it.

26 4,895
Reply
 04-09-2015, 07:31 AM
#14
  • bullgoose
  • The Enabler
  • Redondo Beach, California, U.S.A
User Info
Great post Ken! Very interesting.

46 18,074
Reply
 04-09-2015, 09:03 AM
#15
User Info
Great information Ken,

Your attention to detail and commitment to provide the best possible product to the consumer shows your passion and heartfelt dedication to your venture.  I dare say the callaboration that you and Lee have going will stand the test of time and be hard pressed to be shadowed..!!

Fantastic job Ken

Tappan

17 1,297
Reply
 04-09-2015, 11:57 AM
#16
  • bosseb
  • Ex-Lurker
  • Stockholm, Sweden
User Info
(04-08-2015, 06:39 PM)Chiefbroom Wrote:
(04-08-2015, 06:10 PM)refles Wrote: Great appreciation Ken for the knowledge and experience you share with us!

Thanks, but I have greater respect for what I don't know about knots than what I do.

They remain a mystery to me in many respects. Almost all of the important respects.

IMHO, badger-hair knots defy reduction to simple declaratory pronouncements.

And I like it that way.

Ken, thanks for this. I thought I was the only one...  Rolleyes 

[Image: attachment.php?attachmentid=562155&d=1428224073]

0 5
Reply
 04-09-2015, 12:53 PM
#17
User Info
A great and informative post Ken.  Thank you for the time and effort to put this together.

I can understand that a buyer might the happy with the performance of a brush despite a glue bump lowering the effective loft.  However, I think that virtually any buyer will be unhappy with the appearance of a glue line just above the rim of the handle, as illustrated in the first picture of the same brush from four different sides.  You clearly made the right choice withholding these brushes from distribution.  The issue then becomes, how these brushes with the glue lines even got to you.  The glue line is clearly visible even upon a cursory inspection of the brushes.  This raises two possibilities.  Were the brushes not inspected prior to being sent to you?  Or were they inspected and sent to you anyway, with knowledge of the clear cosmetic defect?  Both possibilities are troubling.

The way you are doing business is to be commended Ken. 

48 5,709
Reply
 04-10-2015, 03:34 AM
#18
User Info
Let me add my thanks for this as well, Ken.

TheLegalRazor raised an excellent point about quality and the steps that should be taken to ensure it. This is not intended as a criticism because I applaud the way you handled this situation. I wanted to emphasize this point however because you correctly remarked that there are many variables (and, by extension, nuances) that contribute to brush manufacture.

My point is that the more we understand about those variables, and their effects on brush performance, the better we are able to assess quality both as consumers and as makers. To that end, I applaud your willingness to section that brush. When I turned bowls, we would periodically cut a piece in half on the bandsaw to learn what made it good or, more often, why it somehow missed the mark. Seeing a piece in cross section taught us a lot and made us better in the process.

It's great to see this kind of passion for quality. Well done!

2 583
Reply
 04-10-2015, 07:20 AM
#19
User Info
(04-09-2015, 12:53 PM)TheLegalRazor Wrote: ....I can understand that a buyer might the happy with the performance of a brush despite a glue bump lowering the effective loft.  However, I think that virtually any buyer will be unhappy with the appearance of a glue line just above the rim of the handle, as illustrated in the first picture of the same brush from four different sides.... The issue then becomes, how these brushes with the glue lines even got to you.  The glue line is clearly visible even upon a cursory inspection of the brushes. This raises two possibilities.  Were the brushes not inspected prior to being sent to you?  Or were they inspected and sent to you anyway, with knowledge of the clear cosmetic defect?  Both possibilities are troubling.
(04-10-2015, 03:34 AM)BSWoodturning Wrote: TheLegalRazor raised an excellent point about quality and the steps that should be taken to ensure it.  This is not intended as a criticism because I applaud the way you handled this situation.  I wanted to emphasize this point however because you correctly remarked that there are many variables (and, by extension, nuances) that contribute to brush manufacture.  

My point is that the more we understand about those variables, and their effects on brush performance, the better we are able to assess quality both as consumers and as makers. To that end, I applaud your willingness to section that brush. When I turned bowls, we would periodically cut a piece in half on the bandsaw to learn what made it good or, more often, why it somehow missed the mark. Seeing a piece in cross section taught us a lot and made us better in the process.

I appreciate these and all the other comments so far. My hope was that this would generate some discussion, including observations and insights from which we might learn something. The fact is I have yet to set a knot. So I'm no expert on that end of things. But I'm powerfully driven by general curiosity and, in this case, specific interest.

As to QA/QC, I completely agree that TheLegalRazor pointed out a fairly glaring and entirely on-topic question. I need on my part, however, to stay in bounds here as an Artisan, and I'm still feeling those out. Moreover, we owe respect to Lee, who, FWIW, approved my posting of the photos. So suffice it to say the question occurred to us also and that it has been a subject of some serious discussion. No brush is perfect, but this one was clearly beyond the pale, and it was hard for us to imagine how it and a few others could have slipped through. It bears noting that, since we caught them, no buyer's trust was violated. Just the same, we were sickened by both the discovery and consequent loss. This isn't intended to be Days of Our Lives. My view is that transparency serves a constructive purpose in this instance.

Returning to the subject of what to make out of this particular brush, here are some a more observations and thoughts.
  • I completely agree that virtually any buyer [would and should] be unhappy with the appearance of a glue line just above the rim of the handle, as illustrated in the first picture of the same brush from four different sides. That said, I've seen glue appearing above the rim to varying degrees (e.g., see photo below), and although I'd strongly prefer there be absolutely none of it, I've concluded based in part on recent consultation with some of Lee's other customers that a slight amount should probably be deemed acceptable. I'm very particular myself; however, and I'm not very interested in selling brushes I wouldn't want to buy (other than by reason of preferences related to dimensions, styles, materials, etc.).
  • I think there are probably different primary causes and contributing factors in result of which glue can appear above the socket rim of a finished brush, and I suspect important implications might be associated with some of those differences. Lee has suggested that air pressure gradients or something like osmosis can cause glue or glue vapor to migrate upwards after a knot is installed but before the glue completely sets. He has mentioned weather and, specifically, humidity and variable moisture content in hair as occasional factors. It's obvious to me, however, that in some cases either air pressure and/or possibly glue expansion (although the latter suggestion is purely speculative on my part) can cause an entire knot to emerge slightly (or not so slightly) from its original placement upon setting. I believe that's what happened with this brush. My guess is that it was originally set at closer to 50 or 51 mm than 52. Beyond the issues related to brush aesthetics and performance, this might raise questions about a knot's stability in the socket. We selected this particular brush to section for a reason. Based on prior experience with an M&F Group Buy Chief as related above, I suspected the glue ring shown above was a telltale. (BTW, I'd have sectioned that Group Buy Chief if I had the saw to do with at the time. I actually thought about attempting it by hand.)
  • Not only is there a large bubble (which presumably contained somewhat compressed air) pressing up just under the glue plug, an air pocket (or pockets) also at least partially surrounds the plug, resulting in what appears to be a very thin and probably fragile seal beneath the rim. I suspect this brush was doomed to a short and unhappy life.
My purpose isn't to flog this or rub Lee's nose in it. But it is what it is, and I'd rather put it out there myself than leave that to someone else. Besides, this way the brush isn't entirely wasted.

[Image: Slight-glue-residue_zpsan1pkey0.jpg]

3 961
Reply
 04-10-2015, 10:26 AM
#20
User Info
Ken:

I think the manner in which Lee and you have addressed this is exemplary.  Your candor and transparency are amazing.  You have turned the problem brushes into a lesson on not only glue bumps, but also business ethics.

48 5,709
Reply
Users browsing this thread: 1 Guest(s)