What Makes A Good Crotch?
When I cut wood, I am always on the lookout for the unique. I don’t always know what I am going to find, but I know that the less it looks like wood or “regular” wood the easier it is to sell. And, even though I like to cut anything and everything wood, it just makes good sense to cut the stuff that sells. Often the lumber goes up in value because of things that happen to it after it is dead, like spalting and bug intrusions, but a lot of good things happen when the tree is alive and growing too, like burls and curly figure. I guarantee, if I ever cut a curly log, with burls, that is spalted and full of bugs, that it will sell – quickly and at a good price (for me, that is).
Every log has wood in it somewhere that is at least a little irregular. You just need to know where to look. One place that holds a lot of promise is the crotch area, another is the stump and a third is at the base of large branches.
All of these areas have one thing in common – None are regular, plain, or straight-grained. Some are better than others, but none are regular. They stand out because the grain is figured, usually referred to as curly (at least by me). The curliness happens when two directions of wood grow into each other. It is a little hard to explain, but easy to see, especially in a crotch.
This photo from Weinig custom gunstocks shows the beautiful figure from the crotch of an American Black Walnut.
A crotch is an area on a tree where a single trunk splits into two, forming a “Y” shape or an upside-down pair of legs, similar to your own crotch. In this magical area, the tree is short on space for the material that is added to the tree as it grows. With each year of growth and the addition of another annual ring of thickness, things get crowded. Wood pushes against wood and the grain starts to buckle in different directions. It shimmers in the light and looks like waves of liquid. The crotch, in particular, can be large and somewhat predictable. If the crotch is built well, the wood inside will be worth the work.
Notice I said, “If it is built well” – not all crotches are. The good news is that usually everything you need to know about the inside of the crotch is labeled on the outside. You just need to be able to read it. Here are a few keys to the language:
1. Bigger is better. The bigger and wider the crotch, the bigger and wider the figured wood. Wider crotches are also longer. Every ring of growth adds to the width, but also pushes the crotch up, adding to the length.
This white oak crotch was trimmed on both sides to 48″ to fit in the sawmill. I need a bigger mill.
2. Pointed isn’t the best. Between the two branches, at their intersection, things should be rounded, not pointed. Round inside curves show that the crotch is increasing in length every year as one piece and not two pieces crashing into each other. I like to think of a really good crotch as being “U”-shaped as compared to “Y” or “V”-shaped. A truly “U”-shaped crotch is difficult to find.
This crotch photo from Talarico Hardwoods shows a crotch with an almost perfect shape. The branches meet at an angle that is a little steep, but notice how the natural edge between the branches forms a “U” shape instead of a “Y” shape with a hard angle. This is a big one too.
3. Parallel is worse. If the branches that meet to form the crotch are close to parallel, the crotch will be long, but broken into two separate pieces. Bark from each branch gets forced into the wood as the crotch grows over it. A 90 degree angle between the two branches is ideal. Think perpendicular, not parallel. Parallel is just two branches growing next to each other, not a crotch.
This American Elm slab shows two branches that are parallel to each other and separated by bark. Notice that the “crotch” area has no special figure and is really two separate pieces. This slab is leaning against the wall opposite of the way it grew (the branches are pointing towards the ground).
4. Bulges are the worst. If a crotch is forming correctly, with no bark inclusions, the crotch itself will be flat on the outside where the branches meet. A bad crotch will have a bulge, indicating that the crotch has bark in it (bark inclusion) and the tree had trouble growing over it. It may look like one solid piece on the outside, but the inside will be divided into two pieces with bark down the middle (not exactly what you are looking for in a crotch).
This walnut crotch has branches that are almost parallel and meet at a steep angle. The crotch intersection also shows a large bulge. Both characteristics indicate a crotch that has a long bark inclusion and that most of the center cuts will separate into two pieces. Photo from Tennessee Tim on Woodworking Talk.com
These photos are from the inside cuts of the above walnut crotch. All of them have bark inclusions and the center cuts are completely separated. Photo from Tennessee Tim of Woodworking Talk.com
Besides the size, all of the other concerns above (#2 through #4) are regarding bark inclusions (which we are trying to avoid). Without bark inclusions, crotches are a single piece of highly-figured wood. With long bark inclusions, the crotch is usually unimpressive, not figured and broken.
For most of you, deciding how or whether to mill a crotch will never be an issue. At the same time, I have run into plenty of people who want to have logs milled and are especially excited about a crotch section that just won’t pan out. If you find yourself trying to decide how to cut up a tree with a crotch in it, I hope this proves to be helpful. Notice how I gently worded that and didn’t say, “Don’t mill it.” I would never say that.
Curly Cherry Bar Top Fights Back And Loses
I thought my last posting about finishing troubles was pretty monumental, that it was big and in my past. Hopefully, it was something that I learned from and would never repeat. But, in a bid to never be outdone, I have attempted to outdo myself.
I recently worked on a bar top made from curly cherry. The finishing job was like any other finishing job in my mind – easy peasy lemon squeezy. All I had to do was mix up some lye and water, slather it on the cherry to darken it, sand the surface a bit and finish it with three coats of Krystal. The lye should take about 15 minutes, the sanding about 20 minutes and the three coats of Krystal about two hours. The longest part of the whole thing should have been waiting for the lye/water solution to dry, which was about two hours. But, as all good stories go, I ended up monkeying with it for about three days. My, how time flies when you’re screwing up a good finish.
I started with the lye and mixed it with water. My first test piece looked great, so I rolled with it. I wasn’t too worried about this step because it always seems like this phase of the process magically works itself out. As the lye sits on the piece drying, spots that I worried about just seem to fix themselves. Areas that looked too light blended seamlessly with areas that quickly turned dark. The only spots that didn’t darken perfectly were under errant splotches of glue, which I stained with another favorite, TransTint dye stain, this time in reddish-brown.
After I let the lye/water solution dry thoroughly, I sanded the entire top with 320 grit sandpaper. This step too, was no big deal. The lye darkens the wood pretty deeply, so even somewhat aggressive sanding won’t expose any new lighter-colored wood. At this point, I had put in no extra time and things were going smoothly. On to the next step, I said.
It was already time to start spraying, so I mixed up a batch of Krystal conversion varnish and catalyst. I also added a little lacquer thinner to make it flow nicer. My plan was, and always is, to shoot lightly on the first coat. The logic being that the first coat is really just to get the process started and to get the wood fibers locked in place. Normally, after the first coat, I either lightly sand with 400 grit paper or scrape flat surfaces with a razor blade to smooth things out for the next coat. In this case, however, I never got that far. The Krystal never set up. It went on nicely, but I let it sit for four hours and it was still tacky. That stuff is normally sandable in 30 minutes or so. Four hours was crazy, and I knew something was wrong. And, so it started.
I decided to remove the finish with lacquer thinner and start over. It wiped off like it was going to set up on the 12th – the 12th of never. At that point, I decided to take the finish out of the equation and ordered a fresh gallon. New finish never hurts anything.
The next day my new finish arrived, and I mixed up a batch. I shot the second first coat and it went on fine. Then, as I waited and stared at the finish (like all of us do), I noticed a couple of streaks that were bumpy. It looked like there was dust in the finish, but it wasn’t dust, it was more than dust. I couldn’t figure it out.
This isn’t a good picture, but it wasn’t a good subject. The two spots that went crazy are easy to pick out even in low-res.
I waited for the finish to dry (I recommend that you always let the finish dry before you mess with it) then I sanded the bumpy spots. I sprayed the next coat and the bumpy spots were better, but still wanted to get bumpy. I had it narrowed down to two spots that just needed a little more love. I sanded them a bit extra to make sure they were really smooth. I sprayed away and the craziest thing happened. The two spots that I had just smoothed out wrinkled like crazy. They looked like I put stripper on them. I worked with those spots for a couple more tries, but they only got worse. Every time I sprayed, the margins of my repair bubbled up, and it became obvious that I was chasing my tail. Time to start over. Well, time to call the customer, tell him for the second day in a row that his top was not going to be done and start over.
At that point, I had come up with some ideas on the cause of my problems. My best guess was that the lye was messing with the chemical reaction in the Krystal that makes it set up. I haven’t had trouble with other finishes (mostly nitrocellulose lacquer and acrylic-modified lacquer) on top of lye, but this was the first time that I went over it with Krystal. The first first coat didn’t set up, which could be caused by the lye. After I cleaned that coat off, there may have only been a couple of small spots with a lot of lye in them, and those areas were exposed more every time I sanded.
I knew now that I need to make sure that the surface was clean and free of lye. I stripped down the second layers of finish with the help of lacquer thinner and started over, again. I reminded the bar top that I was going to win and that all of this resistance was futile, in hopes that it would stop with the temper tantrums and just behave. To make sure it behaved, I wiped and wiped and wiped some more on the surface with lacquer thinner to get every foreign substance out of my way.
Whatever I did, it finally worked. I sprayed the top with the first coat (for the third time) and it went on great. I shot two more coats and in about two hours delivered the top, late on the third night (I have a special policy of delivering free, late on Friday nights, after the customer has been by the shop two previous evenings in a feeble attempt to pick up their countertop). The customer was very understanding and I think, quite glad to see me. I was glad to see him too and get that thing out of the shop. Sort of….
Here is what it is supposed to look like. Notice the lack of bubbles and wrinkles in the finish.
The curly cherry really shows up nice, even when relatively dark.
- This is the area that went bad after it was fixed and ready for delivery.
The following Monday I got a call from the customer. I would normally dread a call so close to delivery because there had to be a problem, but I knew this was different. I was sure he was just calling to say how nice it looked and to thank me for going the extra mile. Not the case.
Two days earlier, on Saturday night, they had a Halloween party, which was the reason for the push to get the top done. Apparently, someone put a glow necklace on the top which proceeded to leak. The toxic chemical melted through the finish and even lightened up the lye. On top of that, along with a new bar top came new barstools with backrests and swivel seats, which swiveled nicely into the front of the bar, scraping off the finish. Back to the shop it came.
After playing with the finish it was obvious that I had adhesion issues, the finish just scraped off with my fingernail (not good for a bar top). After a break from the top, I sanded the whole thing down again, reapplied the lye, wiped it a lot with clean water and proceeded to reapply the Krystal finish. Most of it worked well, except for the front of the bar rail. It had the tiniest area of tiny bubbles that just didn’t lay down. Being a picker, I had to pick and it flaked off easily again, but only on the front. I had to work harder to get the finish off of the side rails. Below is a video of how easy the finish flaked off. Again, not good for a bar top.
S0, obviously I have a problem, one that I have never had before. The lye has worked fine for me in the past using regular lacquer. The difference this time is that I am using Krystal, which is a two part finish (conversion varnish). My best guess is that the lye is messing with the chemical reaction because my test pieces, which had no lye on them, stuck like crazy. To combat the problem, I first sprayed a sanding sealer and then put the Krystal on top. The plan is that the sanding sealer will provide a protective barrier between the lye and the Krystal. So far, so good. Hopefully, there are no new updates. They can only be bad.
What’s Going on at WunderWoods
Everyone always asks what I do. Here's the answer. Click on the photo above for a short video tour and see all of the steps it takes to go from a tree to finished furniture.