Seeking advice: silicone or epoxy?

Oily woods would be woods like Teak that have a high natural water resistance. In my case I'm using white oak on these first couple of brushes so that isn't a concern. And the oil finish that I'm using will only be applied to the outside surfaces, not in the hole. So, for this situation, I'm not worried about oil interaction with the adhesive. rudyt, what product do you use to seal inside the hole of your wooden brushes? I'm still curious if there is a bonding issue with slilcone adhering to surfaces that have been sealed with epoxy? The reason I want to seal the hole is not to keep the knot from falling out, but to keep the wood from rotting, splitting, cracking. Water soaks into wood like into a sponge and does nasty things over time.
Thanks Rudy Vey for your input! I visited your website and you make some beautiful brush handles! I certainly understand that your customers have different demands and concerns than I do in this experimental/learning phase that I'm in. Eventually I too will want to ensure a permanent installation, and then my decision on adhesive may change.

Sheb said:

Oily woods would be woods like Teak that have a high natural water resistance. In my case I'm using white oak on these first couple of brushes so that isn't a concern. And the oil finish that I'm using will only be applied to the outside surfaces, not in the hole. So, for this situation, I'm not worried about oil interaction with the adhesive. rudyt, what product do you use to seal inside the hole of your wooden brushes? I'm still curious if there is a bonding issue with slilcone adhering to surfaces that have been sealed with epoxy? The reason I want to seal the hole is not to keep the knot from falling out, but to keep the wood from rotting, splitting, cracking. Water soaks into wood like into a sponge and does nasty things over time.

Click to expand...

Indeed it does... Especially in the end grain.

Here's a quick update on the project. The first handle is finished and the knot gets glued in later today. Here it is in it's new home among friends!



The second handle is underway, this one is for my son. Same white oak and same general shape and size, but with a dollar coin inlayed in the bottom. It will be finished differently because my son wants a different look. The knot will be a TGN Finest badger, 24mm, set at a 50mm loft. You can see that I don't use a lathe. In fact, I only use power tools to disc sand the blank to final size and to make it is square, and I use the drill press for the knot hole and inlay hole. All the rest is done by hand with chisel, block plane, and carving rasps. Why? Just because I enjoy the satisfaction that comes from using hand tools.

I usually seal the inside of the hole with whatever finish I'm using on the outside, water-based urethane/varathane. If I don't seal the inside with a finish, I usually just rub in some of the silicone all around the inside of the hole before gluing in the knot.

I'm like 99% sure that silicone will adhere to an old epoxy finish. You might want to double-check on the actual silicon tube you buy.

Very, very nice job

it has been a while since I visited this thread, but I want to post pics of the completed brushes. the brown handled one is mine and it is shown here post-bloom. the black one is my son's and still pre-bloom. thanks again to everyone who gave suggestions and advice! much appreciated!

The short answer is epoxy. But I seldom give short answers so here's why: I read a post by and engineer who was tasked with the problem, "What sticks well to silicone." They experimented with this for some time. The answer was, "only other silicone", and that isn't very well. I recommend silicon for windows, bathtubs, spas and the like because it works well in these water-filled environments for a reasonable amount of time and fills space well. But it isn't very forgiving and it's gooey and messy to work with too.

Epoxy cleans up with rubbing alcohol when wet and will melt in acetone when dry, although this is not a method for knot removal. If you change your mind, you will need to drill it out and get a new knot. But consider this: brushes have been manufactured to last for decades; why would you not do the same?