How to tune your knots loft before you set them

[Loric]

Brush tuning seems to be something that a lot of brush enthusiast are confused or intimidated by. Questions come up about it from time to time, so I'm going to do a quick guide to how I start the proses. Tuning a brush, is really just finding the loft that works best for you. That could be tall and loose with great flow threw for bowl latherers. It could be low dense and scrubby for a face latherer. But more often than not its someplace in the middle.

Whatever your preference, remember your brand new knot is not broken in yet, and this will only be a starting point for your particular brush. Sure it will start to break in as you do more and more test lathers, but most knots will take some additional time to fully break in. Again, this method will only find you a good starting place for your knot. You might still have to do some adjustment latter on when things get to where they are going to go.

Different types of hair, have different characteristics, so what works for one type or even knot might not work for the next brush you have. Differences in density, backbone, etc. will require different tuning to get the same face feel. For example in general three band hair will have to be set lower than two band to have equal backbone. As you add backbone, the tips might loose some of their softness, or the skritch might become much more pronounced. Furthermore different densities of the same hair will change flow threw etc. My point is that many brush characteristics will change with the loft, and you have to find your own happy medium.

Also, keep in mind that the lower you set the knot, the more backbone it will to have but the smaller it will feel on your face. Another concern for bulb shaped knots, is that they become more pointy if you continue to reduce the loft size. Most importantly remember that the feel and performance are more important than aesthetics. However, aesthetics do give strong clues as you experiment.



As example here is a 24mm TGN Ex Finest at its sock loft. Just set in the handle at the top of the knot bed. Pardon my old soap in the beehive ribs.


Here it is at its minimum loft (for this knot bed anyway). I should have left something next to the knot in the top down pic for perspective, but it is in fact smaller at the lower loft. Also notice how much closer the hairs are in the knot. Look how mean and pointy it is! Who would want to put that brush on their face? '

About a year ago there was a bit to do about one of the major manufacturers letting brushes approaching this kind pointy shape slip past quality control... oops.

[Loric]

The left is a 25mm Muhle Synthetic Fiber and on the right is a 30mm TGN Ex Finest. Notice that at stock loft the size of the bloom is nearly identical, despite being almost 6mm different in diameter. The TGN plug gives you slightly more room for hair to be packed in, compared to the ring base that the Muhle uses. The stock lofts are very different though, so the 30mm is actually slightly smaller feeling on the face.

An example of what happens to a fan and a bulb at an excessively low loft. Both become pointy, but the bulb is much worse looking.

As you can see in the photo's of extreme lofts both bulb and fan shapes change dramatically. The fan turns into a blub, and the bulb turns into a point. At stock loft the bulb is very round and comfortable looking, though at this loft it is a bit floppy. At the minimum loft its quite pokey looking, and from my tests its not comfortable at all, especially with the backbone of a two band.

When you get your knot, it will most likely have a badger/boar/horse/synthetic factory funk to it that needs to be washed out. Give it a good cleaning with several hand lathers, making sure to pay attention to the hand/face feel as you go. Is the knot to loose to load your soap/cream? How is the backbone? The observed size?

***I feel this next section is safe for test purposes, and I have never had any problems doing it, however take care with your knots as you test out different lofts***

After you have given your knot a wash or two, what I like to do is try the same thing at different lofts. I happen to have hair ties available to me, but there are plenty of other things you could use to test lofts out. For example the bands used for organizing electrical cords, string, or even O rings. I add one hair tie at a time starting from the base of the knot, and do another test lather. Then add a second and test again. For most knots two is plenty, but some knots with very high lofts might need three or more bands. When you lather with the bands around the knot, grip it gently but securly around the top band not the base of the knot plug. A knot bed keeps the hair in place as you use a brush. With out that solid support structure, the knot can shift inside the bands, and you wont get an accurate idea of how the knot will perform. Keep this in check as best you can with some gentle but firm pressure on the top most hair band (where the knot bed would be holding it in place).

With each lather pay attention to how efficiently the brush loads, lathers, and how it feels on your hand, and how big it feels. More than likely you will find a nice sweet spot. Then when you move on to another band, this performance will start to get worse. Even with very low density/backbone knots there is a point where they become to stiff, and loose the ability to hold enough lather for 3 or 4 passes.



I only had two hair ties laying around the bathroom tonight. So I only used one per knot, and moved it up the knot. Normally I feel that adding additional hair ties gives a much better representation of how the brush will perform after its in a knot bed.

[Loric]

Here they are with "two" hair ties on them. Notice the knots tightening up. Again I apologist for the lack of scale, but you can still clearly see the knots changing.

Now that you have a loft that your happy with, measure that loft and write it down. Also, more importantly measure the depth of the knot below that loft, you will need this to figure out if you need a shim, and if so how big that shim will need to be. Let your knot fully dry over night so your adhesive works and you dont risk extra moisture getting trapped at the base of your knot.

While its is dying measure the depth of the knot bed in your handle. More often than not you will need a shim to fill in some of that space in the handle. I use a slice of cork, but anything that wont rot will work just as well. Some people even use change or ball baring to add weight. I take the depth of the bed, subtract the depth of the extra knot below your loft, and then subtract +/-3 mm for glue. That number is how big you need to cut your shim. SE blades work nicely for this, but any sharp thin knife will do for cork.

Take a small amount of silicone adhesive (less is more here) and glue the shim into the base of your knot bed. Let it dry overnight as well. The next day use a small amount of silicone adhesive (again less is more) to glue the knot onto the shim at the bottom of your knot bed. I like Liquid Nails barnd silicone adhesive, but any brand of silicone adhesive will work just as well. I tired a product labeled simply as silicone caulk once, and it never set properly, but YMMV.

The less glue you use, the better because you might need to change the loft again after your brush has broken in. After a number of shaves (10 or so) see how you feel about your brush, does it need an adjustment or are you happy with it now that its broken in. If/when it needs that adjustment, gently gently gently pull the knot out with even steady pressure. Dont force it out with one massive pull or you could damage your knot. Simply add or subtract loft by gluing a bigger or smaller shim into the bed and regluing the knot on top of it. Rinse and repeat until your brush is tuned exactly to your preference.

Most brush hobbyists like to eventually use two part epoxy to permanently fix the knot into place.. However I prefer to use the silicone as a semi-permanent solution. I'v never had a problem with the knots coming lose (especially if I use a bit of extra adhesive when I'm setting the knot for the last time), and I know myself well enough that I'll want to tweak the loft, or even the knot latter on. Who knows what flavor of the month might come along next, or how irrationally I'll get attached to the handle (Ruddy Vey I'm looking at you) after the knot looses my interest.

If your of the epoxy mind, clean out ALL of the the silicone adhesive from both the knot and handle. Then repeat the same posses described above but with your epoxy of choice.

Good luck with your customs and good luck tuning them perfectly. Let me know how they turn out!

[AABCDS]

Great posts and pictures! I rated this thread as excellent!

[MaxP]

Great post. Thanks!

[bastimret]

Thanks for a great post!

[GDCarrington]

Excellent instructional thread!

[catherix]

What a great post Loric! Looking forward to using it on my next project!
Thanks for the excellent post!

[Loric]

Thanks for the kind words everyone! I had been meaning to do this post for a while, as I had the knots and handles laying around. Catherix thinks for finally giving me the motivation to put put it together.

[catherix]

Thanks for the kind words everyone! I had been meaning to do this post for a while, as I had the knots and handles laying around. Catherix thinks for finally giving me the motivation to put put it together.

It's my pleasure, even if completely by accident!

Also, I really like the steps in there that allow for tweaking the knot after using it for awhile. Most of the time I've heard to use the 2 part epoxy but the option you presented really provides some peace of mind if you mess up. Especially helpful for a newbie like me. I would likely epoxy the knot in there after awhile myself but I think I'll keep the silicone adhesive in mind and use it for the first 10 or so lathers.

[Loric]

There is no rush with the epoxy, I'v had knots in for going on two years and have had zero problems with the silicone.

[SliceOfLife]

Indeed, very interesting read. About the silicone adhesive sealant. I used it for a number of my early brushes because hell, it was what I had laying around. Never noticed a difference until I wanted to reknot one of the brushes and was able to easily remove the knot without destroying it or the handle. It was a pleasant surprise, so yes, that's a very good idea if you aren't confident you'll be happy with the knot and loft you're going with for your first attempt.

And a good thing about going with that method is that a lot of brushes feel VERY different soaked and dry, and not always softer soaked. I've had knots that felt very nice and soft dry then got quite prickly when soaked. So while dry testing gives a good impression of many of the traits of the knot, the real ultimate test is use, and being able to still change your mind after using it a few times is invaluable.

[life2short1971]

I use a slightly different method but the reason and result is the same. I learned my lesson with the first knot I set not to be in a hurry to epoxy one in. I usually adjust the loft at least once before finding my favorite feel. Nice thread!

[oakeshott]

Great, great, great post. I've only done two restores so far, but already regret the loft of one. Didn't even know there was a solution to this. Thanks much.

[Le Buzz]

Here is what I use... it's a small rubber band. I'm not sure where I got it exactly, I found it in a drawer amongst pens and other office stuff. It's a perfect accessory when playing around with the loft on a knot.

This is a TGN Silvertip at about 47mm loft. When lathered the rubber band stays in place and gives your fingers a good grip. It takes a little practice to get it on and off the knot cleanly without disturbing the hairs, but it works like a charm.