Knot setting

bernie01

Member
Joined
Aug 6, 2019
Location
Otford, NSW
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I set the Oumo knot into the TF handle on Thursday using Selleys 'Wet Area' silicone, and left it until today to ensure it was well set. Soaked the brush in a glass of water for a few minutes to check the bloom and the tips, tried it on my face and then squeezed it and gave it a good shake. The knot fell out! Now deciding whether to reset with more copious amounts of silicone or go straight to epoxy. It felt pretty good on my face so may use epoxy, but was planning to do a test lather before this happened. No big deal I guess, will think about it while the knot dries.
 
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I set the Oumo knot into the TF handle on Thursday using Selleys 'Wet Area' silicone, and left it until today to ensure it was well set. Soaked the brush in a glass of water for a few minutes to check the bloom and the tips, tried it on my face and then squeezed it and gave it a good shake. The knot fell out! Now deciding whether to reset with more copious amounts of silicone or go straight to epoxy. It felt pretty good on my face so may use epoxy, but was planning to do a test lather before this happened. No big deal I guess, will think about it while the knot dries.

What size is the opening on the handle, and the size of the knot base?

It should be a firm fit even without silicon or epoxy.

Great looking Brush.(y)
 
I just used a couple of pea-sized dabs of ordinary Selley's Sealfix silicone seal repair (purple tube) that I got from Woolworths. Just on the bottom of the socket. Gave the knot a little twist as I ever so lightly pushed it in. My SynBad was a very loose fit in the handle, but NOTHING will get the knot loose again.
 
The knot is 26mm, the bore is 27.5mm. It's a pretty firm fit. The knot was constricted, I used the cardboard/paper tube that the knot is supplied in, plus a rubber band; I don't think that was the problem. I notice now that the base of the plug is slightly concave, perhaps that plus a paucity of silicone was the issue? I'm wondering if I should sand the plug base flat, or at least a little flatter?
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Hi Bernie. I recommend roughing up the glue plug all around the sides and underneath with a course sandpaper, like 120 grit or so, being careful not to damage fibres where they attach. You need to remove the "shine" on the glue plug so that whatever adhesive you use, it will have a chance at sticking. The inside of the handle knot socket may need a good clean now too given the silicone that was in there. The knot socket has a tool finish, so won't need roughing up with sandpaper like the glue plug, but if there is any residual silicone still in the socket, it probably won't help your next adhesive to bond well.
Hope this helps.
FWIW, I use 2 part epoxy adhesive, but I do understand why silicon is preferred when there could be a desire to remove the knot without harming it.
 
Thanks Troy, yes the plug is quite shiny so I will do that next time! I've cleaned up inside the handle but will give it a wipe with 120 grit as well. The knot is a firm fit; I can push it in and hold the brush upside down and it won't fall out unless I shake it. I think I might try one more time with silicone, if that fails then epoxy it will be!
 
Did you smear any silicone on the knot base itself? Let is sit a few seconds to start to become tacky before slipping it in, give it a gentle push in and twist to make sure it's seated well. Considering this handle had a knot in it previously, how's the inside of the handle looking? Is there existing epoxy that needs to be removed?
 
Thanks Wilkie, no I did not put any silicone on the plug itself. I was concerned about getting silicon on the fibres so just put silicone into the handle itself. Yes, there was epoxy from the former knot which I ground out using a Bunnings 'Chinese Dremel'. So it was all cleaned up. I think I just erred on the side of caution with the silicone, so will try again using a bit more of a blob and also roughing up the bottom of the plug like Troy suggested.
 
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Since your redoing it, clean the inside base of the handle with acetone. This will clean off the silicone residue and add to your already good advice above for prepping.
Won't acetone eat away at the resin? I melted a bit of an old Yaqi brush that way

Thanks Wilkie, no I did not put any silicone on the plug itself. I was more concerned about getting silicon on the fibres so just put silicone into the handle itself. Yes, there was epoxy from the former knot which I ground out using a Bunnings 'Chinese Dremel'. So it was all cleaned up. I think I just erred on the side of caution with the silicone, so will try again using a bit more of a blob and also roughing up the bottom of the plug like Troy suggested.
Chinese dremel lol, they are good for some things. I used my father's drill press and a cutting Dremel bit to clean the inside of my Billygoat out. made the whole wider than it was in the process. Prick of a task.

Hopefully, it takes this time round!
 
I suspect the problem might have been a combination of that concave glue bump and insufficient silicone. Not to worry, you'll have it licked next time. (y)

Don't necessarily expect it to be easy to remove the knot again afterwards though. When I thought my SynBad could do with a taller loft, I failed in all my attempts to get it out. I even put the knot in a vice and yanked on the handle with a 24" pipe wrench. All that exertion had the result of making the knot a bit more "bushy", which gave me just the effect I needed. :happy:
 
Won't acetone eat away at the resin?

On the inside when dipped with the end of a cotton cloth and wipe around. Yes some resins it will react and take away the shine. Tape up what you want to protect. Good thing with acetone, is that it dries up really quick and makes a really clean contact surface before gluing. I have prepared a few cheapy resin brushes and no issues. Yes I was cautious and aware of the melting issue.
 
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