First time swapping-out knot (advice/suggestions)

[mathyou9]

I steamed-out the knot from my current brush handle. This will be my first time swapping a brush knot, so I'm just looking for some advice and/or suggestions.

Attached is a picture if my brushless handle. Whatever the stuff is inside (adhesive? structural component? or both?) as you can see there was an air pocket in it. The old knot sat right on top of it.

Before adding the new knot, should I fill-in the air pocket with epoxy (or something else) and let it dry/cure? Or should I remove some of the interior as to make it more uniform [albeit, substantially deeper]?

Being my first time doing this (with only a general idea of what I'm doing) I'm all ears. Thanks.

 

[Big Jim]

Using a large quantity of epoxy would damage the handle, as the epoxy heats up and expands while curing. I don't know if your metal handle could take that but I'm sure you would rather not find out.

It does help to level the floor and build it up higher. It is common to fill the area with coins, washers, or even steel or lead shot. Leveling out the bottom and spacing the knot up with coins is very common. Using epoxy in the build-up with other materials is fine, as the quantity is reduced.

 

[FL shaver]

I'll give the minimalist point of view on this one, though there are many great ways to get a finished product here. You could simply clean up the inside edge as much as possible, order the correct size knot, and set it by coating the plug and inside wall of the handle with Devcon 5 minute epoxy, shove the knot in to the desired loft (If it is the ideal size knot, the knot will push out against the walls of the handle and hold it there until the epoxy sets.), then turn the works upside down to let the epoxy get between the side of the plug and the inside of the handle. That'll set the knot and never let water inside the handle. If more weight is desired, you'd drill out more material and put some coins or similar in the handle with some epoxy.

 

[azrichter]

FL's idea is probably the simplest way to go.

If I wanted a very flat bed for a knot, i would fill the void with slow-setting epoxy. I have some 30 and 60 minute epoxy and it works beautifully---rock solid. Slower set epoxies generate less heat. I honestly don't think there's enough heat to damage a metal handle, and I've not had a problem with filling a styrene plastic handle (which melts pretty easily) entirely with slow-set. However, to be on the safe side, I set the entire handle in a water bath as the epoxy is setting up---this draws excess heat from the handle.

If it was me I'd probably use a cylinder-shaped abrasive stone on a dremel or drill press to clean out the opening a little, then level it with a layer of epoxy. I like to clean out the old glue/crap in there and replace it with nice, clean, hard epoxy.

As for how much glue to use, I've found a way to avoid guessing or having to set a gooey knot into the opening.

Small graduated measuring cups (they hold about 30mL) that you get at a hobby store are perfect for this. Fill the knot opening to the brim with water. Press your knot in as deep as it will go---this will push a volume of water out, the amount of space the knot needs in there. Remove the knot and pour the remaining water into a measuring cup and note the volume. This is a maximum amount of glue that you can use. I usually back off from this by a couple of mL to be safe. Make sure to dry the inside and the knot after measuring. Measuring carefully, mix this amount in a cup, pour it in and set the knot. This method prevents me from using too much and making a mess, but also allow me to fill the opening enough to keep water out.

This might sound more complicated than it really is. The best advice I've gotten is to go slow and usually you'll figure out what you need to do.

 

[blackhhawk]

^^That's so simple, yet very logical. Mentally noted. I have a brush I plan on re-knotting. I am going to do this.

 

[azrichter]

^^That's so simple, yet very logical. Mentally noted. I have a brush I plan on re-knotting. I am going to do this.

Go for it!

Thank you for your service, btw, Blackhawk. Deeply appreciated.

 

[mathyou9]

Thanks for the replies.

I've gone ahead and drilled out the old epoxy so it's all level. I plan to fill in the space with three or four coins and go from there (just twiddling my thumbs now waiting for my TGN brush knot to arrive.)

 

[blackhhawk]

Go for it!

Thank you for your service, btw, Blackhawk. Deeply appreciated.

Thanks!! What kind of epoxy should be used and where could it be purchased?

 

[goh2499]

Any 2 part marine/waterproof epoxy should do. If you pimatin up in the mixing syringe it's a little more by the once but easier to use. As mention before the fast setting epoxys generate more heat then slower setting epoxys and for a metal handle it shouldn't matter.

 

[JaxJim]

FWIW, if you don't want the additional weight of coins, washers and the like, and want to fill the cavity with something a bit more substantial than cork, hot melt glue works very well. Using a glue gun makes quick work of it, too, and if you get any glue where you don't want it, clean up is easy. Just make sure the handle is sitting level so you'll end up with a level shelf for the knot.

Good luck, mathyou9-- that's going be a great looking brush when you're finished with it.

 

[azrichter]

If you plan to do much of this, get an 8oz kit of epoxy at a hobby store or online. They may come with 4 oz each of resin and hardener. I like slower epoxies...more working time and a little stronger when set. If you are careful to wipe and close bottles carefully, you'll get a lot of use out of this much epoxy. I use it for a lot of stuff.

 

[mathyou9]

Being my first re-knot (and as I said, "with only a general idea of what I'm doing") I'm very pleased with the results.



I ended up not using any coins because the width of the knot was slightly larger than I was anticipating. As such, the knot didn't actually fit down into the hollowed-out part (where the coins would be) due to the slightly-smaller diameter of the metal lip inside. So I just filled the void entirely with epoxy and used the metal lip for the loft height. I ended up using 2-hour marine epoxy, so there wasn't much heat. In fact, the metal handle didn't even conduct any noticeable heat during curing (OTOH, when I steamed out the original knot, the handle remained too-hot-to-comfortably-handle for a good 20-30 minutes; so the slow-curing marine epoxy was nothing compared to that. )

As for how much glue to use, I've found a way to avoid guessing or having to set a gooey knot into the opening.

Small graduated measuring cups (they hold about 30mL) that you get at a hobby store are perfect for this. Fill the knot opening to the brim with water. Press your knot in as deep as it will go---this will push a volume of water out, the amount of space the knot needs in there. Remove the knot and pour the remaining water into a measuring cup and note the volume. This is a maximum amount of glue that you can use. I usually back off from this by a couple of mL to be safe. Make sure to dry the inside and the knot after measuring. Measuring carefully, mix this amount in a cup, pour it in and set the knot. This method prevents me from using too much and making a mess, but also allow me to fill the opening enough to keep water out.

azrichter, I'm so glad you offered this suggestion. It worked like a charm (I never would have thought of it.) I wasn't as precise as you described (I just eye-balled the appropriate levels) but had I not utilized your method, I'm pretty sure I would have over-estimated and made a mess. A very small (and I mean very small) amount of epoxy happened to ooze out, though. I used masking tape to protect all handle and brush surfaces just in case (you never know when you're doing something for the first time.) But even with the masking tape and slow-curing time (and the small amount of epoxy that it was) it wasn't anything a paper towel couldn't handle. As a plus, with the slight overflow of epoxy, at least I know epoxy has filled all the empty spaces inside the handle.

FWIW, if you don't want the additional weight of coins, washers and the like ...

Funny you should say that. The handle is actually quite heavy from the get-go (I seriously wouldn't be surprised if it was filled with lead; that's how heavy it is.) So be it coins, cork, or in my case, epoxy, the additional weight of anything (except maybe lead, mercury or gold, of course) is unnoticable.

 

[Big Jim]

Congratulations!

It looks really nice and I'm sure you will put it to good use.

 

[FL shaver]

That is a nice handle and restoration. Enjoy it!

Sounds as though you experienced the knot holding its place in the handle when you wedged it in there. I hope to feel that with every restoration. Then I know I probably have the largest knot possible for the opening. The only knot I was a little iffy on was a boar knot which didn't seem to bulge out at the top of the plug like the badgers. Using it without any issues now, though.

 

[azrichter]

Nice!!! I'm glad my suggestion was helpful. I agree...it's nice to know that what's inside the handle is sealed up.

Elegant looking brush. You've got me looking for a metal handle!


Which TGN knot did you use?