Epoxy Green or Make'em Wait

[crbuildersinc]

Hey Everyone,

I recently joined NCWW and here goes my first post. Actually it's my first on here or on any forum. Haha hope I did it right!

I have a friend who had a local sawmill cut him a live edge handrail out of sweet gum. It is 3" thick and 20' +/- long and roughly 10" wide. We plan to cut a recess the bottom to fit over a knee wall above his stairs. The recess will be 4.75" wide, 1.5" deep and will run the entire length of the handrail.

I have been told that you can use a good epoxy to finish green wood and by sealing all sides you wouldn't have to let the wood dry first. I keep WEST System 105 epoxy resin in the shop and would probably use it for the finish. Usually I'm all about trying something new even when i don't think it will work and I've learned a lot from many mistakes! But I hate to waste all that epoxy if it doesn't work. I wouldn't be able to attach it with screws or the penetrations in the finish would allow the moisture to get out. My plan was to use a good flexible adhesive that would stay soft and allow everything to move a little.

My first idea was to let it dry; but patience doesn't seem to be my friends strong suite. So now I'm hoping someone has tried this before and if not guess I'll be the guinea pig!

Open to any thoughts or ideas!


Thanks, Chris

 

[FredP]

make em wait. oh and nix the sweet gum. it will likely end up lookin like a pretzel. might just take the knee wall with it. JMHO.

 

[Kent Adams]

Maybe use a cut-off and see what happens. Its a good question you have.

 

[Phil S]

Welcome to the site. Your first question is very interesting. Common sense says you should let the wood dry before coating with epoxy, but it happens often in boat building - Back in my boat building days I used fairly green wood (+20%) to steam bend ribs and then coated them with epoxy shortly after. It worked and I never saw a problem, doubt it would make any difference but I always used System Three epoxy not WEST. One word of caution here, apply the epoxy when the temperature is dropping not rising. Air escapes from the wood when the temp is rising and the air will create bubbles under/in the epoxy coating. I am thinking this might happen more in "wet" wood.

I am with Fred on maybe not using sweet gum as it is very prone to twisting as it dries

 

[Jeff]

Welcome Chris. You've chosen an interesting topic and questions for your introductory topic. A few thoughts.

I have been told that you can use a good epoxy to finish green wood and by sealing all sides you wouldn't have to let the wood dry first.

1. Who's telling you this and what's their basis for making such a claim? Maybe it works on smaller pieces of green wood but that's not what you're working with. My impression of that advice: It's balderdash!

2. Why did your friend choose sweet gum for this application? It's notorious for bowing, twisting, and turning = a pretzel, even under the best of conditions so you guys are already disadvantaged coming out of the gate.

3. Which West epoxy hardener do you plan to mix with your 105 resin? You've got about 44 sq. ft to cover so you'll need a long open time.

4.

We plan to cut a recess the bottom to fit over a knee wall above his stairs. The recess will be 4.75" wide, 1.5" deep and will run the entire length of the handrail.

I'm lost! What's this supposed to look like and what's the function? Got a sketch or a picture?

 

[Gofor]

Sweet gum is a bear to get to dry straight. I have had some luck with 2" x 10" x 8' boards that I slabbed out with a chainsaw mill. It took about a year with the stack stickered and lashed together with 5'000 lb cargo straps tightened around the stack about every 18". I still had some twisting splitting from the ends. Some of the boards also developed stress cracks when being cut down to size after drying for a couple years.

As you already have the wood, you could mill it and secure it in place and then wait and hope for the best. (allow at least 1/8' - 1/4" more on the width for shrinkage as it drys). I would not seal it at this time, hoping for having it secured in place to let it dry for several months. If you need to coat it at all to minimize hand oils from staining the wood, use a thin coat of spray lacquer. Unless you have it strapped/clamped/screwed, etc to a flat surface, your chances of it drying anywhere close to flat and straight are slim to none. As Fred mentioned, this idea has the hazard that it will also warp out the knee wall its attached to.

Best case: it drys okay and then you can sand and put the finish on it. Worst case (and most likely) is you will have to replace it with a more friendly wood.

Sweet gum grows like a weed and gets fairly large, so would seem to be a good lumber source. The fact that you seldom see it used is an indicator that there is a reason.

Go

 

[crbuildersinc]

 

[crbuildersinc]

Thanks Guys,

Jeff they're not the best answers but they are honest...

1. Who's telling you this and what's their basis for making such a claim? Maybe it works on smaller pieces of green wood but that's not what you're working with. My impression of that advice: It's balderdash!

One of my friends had read something about how to finishing wood that's green, so I looked around on the internet

2. Why did your friend choose sweet gum for this application? It's notorious for bowing, twisting, and turning = a pretzel, even under the best of conditions so you guys are already disadvantaged coming out of the gate.

He walked around in the woods and found a tree that he liked. Then he figured out what kind of wood it was when he brought it to my shop.

3. Which West epoxy hardener do you plan to mix with your 105 resin? You've got about 44 sq. ft to cover so you'll need a long open time.

Not sure probably the 207 Hardener.

4. I'm lost! What's this supposed to look like and what's the function? Got a sketch or a picture

I have posted a sketch.


I've never used sweet gum or heard of anyone using it. I did know it was unstable but didn't realize just how unstable....

 

[Jeff]

Chris, thanks. I'm not being critical but I am trying to learn and understand right along with the rest of us.

I've never used sweet gum or heard of anyone using it. I did know it was unstable but didn't realize just how unstable....

Now you have the "Spin" about sweet gum lumber. It can be nice but usually more like lipstick on a pig!

One of my friends had read something about how to finishing wood that's green, so I looked around on the internet

I sure can't find a connection linking green wood/wet wood and finishing/sealing using epoxy and I'm usually successful at finding hard to find stuff. There's tons of stuff about epoxy finishes on dry wood.

Thanks for posting the sketch. Gotcha now.

 

[crbuildersinc]

Jeff, no worries. The only way to learn is to ask questions.....I ask a lot of questions!!

I tried to find the site I read about epoxying green wood and no luck. I started on a bowl turning site then went to a boat forum I think. I did find something int interesting that y'all may already know.

"Water in wood comes in two flavors...that inside the cells and that between the cells...and once the wood is seasoned to equilibrium with the air and the water inside the cells is gone, no amount of soaking will raise the moisture content to the point where a few days or weeks of air drying won't return it to air equilibrium, depending on thickness."

I may have been reading about wood that was wet but had already been seasoned, not sure. May have just read what I wanted to read, not that I would do that.....

 

[smallboat]

have you checked the Gougeon Bros site?
http://www.westsystem.com/ss/the-105-system/
They have a very wide assortment of applications detailed there, not just boats.
Also a lot of engineering studies- they may have experimented with application at differing moisture levels.
Also the WEST System Manual is available for free download, all 400+ pages of it.

Must say I've had a good response from their technical service guys.
Actually got a live call back while I was in the shop.
Looked at the phone and thought "I don't know anybody in Bay City, MI"
Then quickly realized who it was and picked up.
Helped me out, gave me his name and direct line and his supervisor's in case he wasn't available.
Can't beat that.

 

[smallboat]

I didn't mean to avoid your question, just figured you might as well go to the source.

my assumption is this isn't likely to give you the results you want.
if it works at all you could end up with your dado firmly boded to your wall with the rest twisting and splitting away from it

 

[Tarhead]

I have a crime prevention strategy: If prisoners were required to split Sweet Gum as their source of heat in the winter there would be less crime.