Wood Putties that are Safe on Trees

Hey all!

After last night’s stream with Peter Warren, I really think it would be good to have a list or discussion about what wood putties and/or hardeners that you have experience working with and know are safe for our trees. Also, I really don’t have experience with wood putties and bonsai, so I’ll start with a question about one…

I just checked Walmart, and they have JBweld’s Kwikwood. I’ve never used it before and can’t find info on it for trees. Do y’all know if it’s okay to use? It seems similar to what Peter used.


I’m not looking to fill holes so the tree can close over them, but I am looking to test some wood hardeners. I have a large piece of deadwood on one of my bald cypress. I want the best hardener I can find, but I want to test it out for myself.

Here’s my list of things to test on deadwood:
Smith’s CPES
PC Rot Terminator
PC Wood Petrifier
Minwax Wood Hardener
Tung oil (real tung oil)
Lime sulfur
Epoxy diluted with denatured alcohol

A bald cypress died on me a year or two ago. Now that it’s dried out, I’m going to apply the different treatments and test for penetration and rot resistance. I’ll cut the trunk into discs. My soil is very good at turning deadwood to mush. I’ve got ground termites out there as well, somewhere. I’ll bury the pieces and check on them after a period of time to see who held out the best. I expect that many of the discs will simply rot away. I’m really hoping to find significant differences in the chemical hardeners.

I will say this: Stay away from borates.
The borate wood preservatives I found were in the form of “disodium octaborate tetrahydrate.” Note the “diSODIUM” portion. Borate wood preservatives penetrate more deeply in wood that has more moisture in it. If you’re preserving deadwood that is in contact with living tissue, you’re running salts through the deadwood to attack the living tissues from the inside. The more you water, the more it is delivered. Then the living tissue dies. Just an FYI.


Thanks for the reply, Bill! I look forward to hearing about your results.

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I went through a phase back when Nick Lenz first started using epoxies and wood hardeners where I tested and experimented with all sorts of them and then moved on to test wood preservatives. Overall, for me, I found that penetrative epoxies were not very effective at preserving rotted wood and the primary variable was not the epoxy, as much as it was the process of application. As far as wood preservatives, I learned hard lessons on how toxic they are to plant life. Borates move pretty quickly via exposure to water, diffuse themselves expansively and poison soil. It killed trees outright if the treated area contacted the soil. Glycols, also tend to defuse themselves and do not what to stay put and also proved toxic in my tests. I have had minor success with treating deadwood in soil right at the soil line with very targeted and small amounts of copper sulfate. Epoxied wood that is in the soil has always eventually been breached by moisture and what wood is left is rot- accelerated. Never can I get enough epoxy penetration to be structural enough on it own. I have toyed with pressure treating applied epoxy but never have actually done it.


@crust Thanks for such a good breakdown of the different chemicals. I’m mainly wanting to fill a couple of hollows in a Chinese Elm to give the calluses a base to roll onto, and then I’ll rewound the calluses. That’s the plan anyways :grin:

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If your planning on that and embrace Peters mode my experience in the use of “epoxy sticks” is that they all are very similar. JBweld’s Kwikwood has worked well for me. JB weld has been around for ages.The stuff is designed for ease of use and is a medium density, about the density of hardwood, its light tan. Its designed for wood repair and mostly use it for that. I have used it to fill hollows and as an embedment for rock placement–it worked well enough.


Awesome thanks crust. I went ahead and bought some this afternoon. It was only like $3.50, so even if I hadn’t been able to use it, no big loss. I’m glad I got it now :grin: