Why Does Cherry Darken?

I don’t think I’ve ever mentioned this on this forum before but I have a Ph.D. in physics and have taken a number of chemistry classes as well so my desire for an answer to this question runs a bit deeper than normal perhaps.

I’ve done the usual Google search; also DuckDuckGo (which seemed to be more fruitful) and I’m more or less convinced at this point that the darkening originates with an oxidation process as opposed to simply saying that it’s the UV in sunlight. I haven’t done any real research other than to notice what happens in my own shop but putting all things together and combining it with what I know leads me to hypothesize that it is oxidation.

Going further, it seems that of all the possible things you could do to make it happen faster, the best way to accelerate the darkening would be to use potassium dichromate on it. Potassium dichromate is a powerful oxidizer (hydrogen peroxide and potassium nitrate) but which also has a chromium ion in the mix which would lead me to believe that it would impart a color to whatever it reacted with. I intend to buy some and experiment on some cherry scraps.

Thus far, I’ve tried putting the wood out in the sun for a couple of days and this definitely works but the wood continues to darken while in the house at almost the same rate after it’s had its moment in the sun which is why I suspected an oxidation process. The chemical treatment will be the true test. Or I could do the opposite: put a piece of cherry in a ziplock bag and suck the air out – perhaps backfilling it with nitrogen or something. By depriving the wood of oxygen, it should not darken at all.

I’ve also read that lye can be used but I’m starting to think that this would either not work as well or not work at all depending on the purity of the lye.

I could write up all this in very nerdy terms but this is my hypothesis; it only wants an experiment to check. In the interest of scientific validity, I have to say that none of this “try and see” methodology will definitively answer the question; that would take a long series of very carefully controlled experiments which I’m unwilling to undertake (or to fund).

In my career, my initial hypotheses have been found to be true by experiment about 50% of the time so this could go either way.

So I will do some testing the next time I get a chance.

I’m no expert by any means but I have more experience than I sometimes let on. I’ve been tinkering around in workshops since I was old enough to walk but I have only recently tried to do really high quality work. This usually includes putting a finish on the completed product.

But I hate putting finish on wood. I’ve already said that here. I deal with that emotion in a variety of ways.

Mostly by getting creatively lazy. First, I like shellac because it dries fast. Also, you can wipe it on with a rag instead of using a brush and then having to clean the brush.

I saw Scott Phillips on TV back in the ‘90s and he instructed us viewers to put shellac flakes into a jar of alcohol and just wait – sometimes for over a month until it dissolves. Well, I took enough chemistry to teach me that you can accelerate that process by increasing the surface area (by grinding the flakes into a powder) and by increasing the temperature. So I take an old blade-type coffee grinder that I’ve set aside for this purpose, grind the flakes to a powder, and then dump that into the alcohol. I then stick the jar out in my super-hot garage (if it’s the summer) and that stuff is mostly dissolved over night. Another day or so and it’s ready.

I’ve also taken to putting a nitrile glove on and then putting one of my old socks over that like a glove. Then I just dip my hand into the jar and wipe on the shellac. I like this because I don’t have to soak the entire rag with it and less gets wasted.

If, for some reason, I feel I need to use something tougher than shellac, I’ll use polyurethane because you can find it everywhere. I get the wiping kind (thinned) and just pour it into my sock-gloved hand and wipe away. If it’s a large surface area like a table top, I’ll just pour it onto the table directly and wipe that around.

Then just shuck off the sock and hang it on the edge of the garbage can to dry.

I’ve never had any problems with socks having lint – possibly due to the fact that by the time I throw them away, they’ve been washed so many times that all the lint is in the dryer flue.

If the thing that I make is small enough, I will go one step lazier and just dip it in the finish directly. I made some handles for a desk once and finished them in this way. This was much easier than any alternative. I put a screw into one of the screw holes and used it to grab onto and then hung the handles by that screw using a clothespin. Easy.

I also hate sanding; so I just try to avoid it by the proper use of a smoothing plane and cabinet scraper. Things usually look pretty good and I only end up having to sand curvy parts. I can deal with that. I prefer all this to using a random orbit sander just because of the noise and dust but I do still occasionally bust out the sander. There’s a time and a place for everything after all and my sander was pretty cheap.

I feel certain I’ve blogged about this before but I can’t find it so I’ll just re-tell the tale again from memory.

My Dad once made a cannon – from scratch. When you’re a kid of about 12 years old, that’s the coolest thing that’s ever going to happen to you.

It all started when he got his Atlas metal lathe. He taught himself how to turn down all sort of metal things and was generally looking around for a project to test his skills. As it happens, I had just been looking at a book that had pictures of old British warships from the late 1700’s and thought it would be cool to make a cannon. I showed him a diagram of an old deck gun and he was off. He already had a pretty impressive workshop in the back yard and his job was such that he got home about 2 or 3 o’clock in the afternoons so he had lots of time in the evenings to work on things.

I was not around for all of this but I helped whenever I could. He began by looking around for material that he could machine into the proper size and shape. We decided on a desktop sized one with a barrel of about six inches in length and about 1.25” in diameter at the base. This was all totally arbitrary but it looked good on paper. He didn’t have any metal that he could machine that was of that size so he decided to melt some and cast a blank into the right size. He could only melt low temperature stuff so it was either aluminum or brass; he chose brass. He had recently also gotten a small propane-powered forge and so he made up a mold, gathered up a handful of old plumbing parts and other brass detritus and cast himself a blank.

We also had a lot of walnut lumber laying around. He delivered the mail out in the country and noticed a walnut tree that had died or gotten knocked down in a storm. He got the permission of the owner to take it out with help from his buddies; they hauled it to a sawmill, had it cut into lumber, and divided it up amongst themselves. He built things from that stockpile for years. For this project he build the gun carriage out of some of this walnut.

He slowly turned down the blank and drilled it out to make the barrel. In the end, it was a very nice looking model. I was extremely proud of it and him. It was definitely the coolest thing around in my estimation. Nobody else’s Dad ever did anything other than go fishing occasionally or, in rare instances, kill a deer. This was way outside anybody else’s league. Then I asked:

“Do you think it would really shoot?”

At that point, he was off again. In retrospect, this is probably the last thing anybody should ever do. But we did it.

Another thing we did together was skeet shooting. To save a bit of money, we reloaded our shells and so we had a small tin of shotgun shell gunpowder. He used some of this to experiment with shooting our cannon.

As I recall (and this is obscured by about 40 years of time so my memories may not be completely accurate), he first put in a small charge (roughly half a standard shotgun shell load) and stuffed a piece of rag into the muzzle on top of it. He then pulled the bullet out of a .22 shell and poured that smaller-grained powder into the touchhole. He then put a long fireplace match on a stick and lit it from a distance. I seem to recall that he put the cannon just outside his shop door and we got inside behind the wall while he lit it and he then ducked back inside until we heard something happen.

The first couple of shots just fizzled – the powder went off but just kind of tossed the wadding a foot or so. He slowly ramped the situation up by tamping it harder and harder until it went off with a POP and tossed the wadding 10 feet or so. Finally, he rolled a ball bearing down the muzzle on top of the wadding. We had moved it out into the yard by that time and aimed the cannon at an oak tree just in case. He lit the touch hole and sprinted for the shop door where I was hiding behind the wall. It took about three seconds for the touchhole powder to burn down to the main charge.

It went off with a huge BOOM much like a shotgun would. We looked out and saw nothing. The cannon had disappeared. At first, he was worried that the entire thing had exploded like a pipe bomb but we went outside and saw it about 15 feet back. The carriage was on little wooden wheels and the recoil had rolled it back and up the hill a bit. Everything was intact.

I was thrilled. I jumped up and down with the enormous coolness of it all.

He walked downrange and inspected the tree. There was a hole there and with his pocketknife, he plumbed the depths and discovered that the ball had imbedded itself about an inch into the old oak tree.

Again, I will write this down and be official: we should never have done this. It was a potential pipe bomb. But that’s all behind us now and we achieved a shining success. Well, HE did. I was basically a spectator but the reader can imagine how awesome it was to be a part of this at your father’s elbow like that.

In the subsequent couple of years, we fired it maybe three more times – just to show it to my older brothers when they came home for a visit. The cannon was retired as only marginally safe to the bookshelf. Before Dad passed away I asked him for it and he gave it to me. It sits in my house now as one of my most treasured possessions.

Life is not a competition – or if it is, then the competition is only with yourself. But I still don’t feel that I’ve done anything in my life that measures up to this even though I have a Ph.D. in physics and have done my own share of building things and doing projects with my kids. If Dad were here, he’d probably tell a different story and would claim that this little project was no more impressive than any of my own accomplishments. I guess it’s all about the impressions you make or the experiences you share or something like that.

But he built a cannon. From raw materials: a tree and some scrap metal. That is just astronomically awesome. And he was fun to be around.

On memorial day weekend, I finally got to fire my rifle. It was awesome.

I knew that we had our annual family cookout over in Arkansas so I just waited for this opportunity. I also knew that we were going to have a skeet shooting session on Steve’s property so I felt free to take my muzzle loader along.

When the time came, I got conservative and used zip-ties to lash the thing to the mower deck of his tractor. It ended up being aimed at some dense forest and I was assured that nobody lived downrange within a mile anyway. I tied a string to the trigger and set it off from a safe distance and VOILA, it fired flawlessly.

Actually there was a fraction-of-a-second between the cap ignition and the gun firing but I count this as a success due to the fact that the barrel did not explode.

I proceeded to load and fire it normally several times. I’m was having that annoying problem of the caps not firing upon ever drop of the hammer. I have since replaced the nipple and this seems to have cured that ill. So I’m pretty excited about having a working muzzle loader. Now I need to find a regular place to go shoot and maybe some other like-minded folks.

…or as Norm would say: “Sawring”.

This is long so if you’re not into lengthy things, then skip to the bottom.

I’ve been making a craftsman style bed since January or so and completed the headboard and footboard rails last week. These were a bit wider than necessary (you know – to allow for mistakes) by about half an inch. So I needed to rip off the excess (each is 64”). Since I recently sold my table saw (and recovered a glorious amount of floor space), I intended to use the band saw. But my wonderful carbide-toothed ripping blade that I’ve had for years broke recently and defied all attempts to reweld it. During my last big cleanout, I found the old original bandsaw blade from 20 years ago that came with a low-end Sears Craftman that I had at the time. I now have a Delta but, surprisingly, it fit, so I strapped it on. It’s so dull that the wood began to smoke right away and very little cutting ensued.

So I got out my old Disston 26” rip saw that I had refurbished and went at it. When I say “refurbished”, what I really mean is that I scrubbed off the rust, oiled the handle, and made a n00b attempt at filing it. As it turns out, I didn’t do a bad job of it.

Well, that was a lot of work. After getting a few inches into it, I remembered that I had bought a jigsaw years ago at a father’s day sale – for $20. I got it out. After pushing away at that for a minute, I realized that I was smelling that same burning smell. I pulled the blade out of the kerf and it was completely bent out of shape. It had a bit of an “S” shape to it. And the memories came back of that jig saw never really cutting much of anything.

Back to the Disston. There’s nothing like necessity to force you into doing something that you kind of wanted to do anyway. Sort of like how there’s nothing like practice to make you a better musician but nobody ever wants to do that (at least I never did). Well, I sat back, remembered what I’d read (here and in the many books I have) about technique, waxed the saw plate, and went at it.

And the sweat rolled off my head like a river.

I tried this and that with my body position and after a bit, things began to straighten out and after attempting to correct the body alignment issues, the blade really began to advance. It got to feel rewarding.

I had four of these to do and after the first, I was really tired and sweaty. And now for an aside…

I used to play golf and the best game I ever played was one day when I was in danger of getting overheated. The temperature was about 115 and we went to play anyway because it was discounted and there was nobody else on the course (for obvious reasons). As I began to feel the fatigue and the effects of the heat, I dialed back my efforts. I concentrated on expending the least amount of energy possible which you do by attending to the proper technique. I just wanted to finish the game without caring any more how well I did. Surprisingly, I did better; there’s something about not caring that makes it easier to focus on your technique rather than the final outcome.

With this in mind, as I was just about too tired to keep sawing, I relaxed and tried to conserve my resources. No reason to try and force the saw because it seems not to help anyway. Just raise it and lower it and keep it straight. Surprisingly, my rate of cut went up a bit and with all this in mind, I managed to finish ripping the excess from all four boards.

Then I went and took a nap.

For the first one, I didn’t really pay enough attention to my vertical angle and ended up with more of a bevel than a real rip but that was easily remedied by some time later with a jack plane. For the later ones, I put a small engineers square next to the saw as a visual aid. It was remarkably difficult to stay vertical but with changes to my wrist position, I managed it. It took a few minutes of concentration to build up the correct muscle memory to maintain that position.

So I learned the following lessons:

1) Cheap tools are only good for their weight as a boat anchor. We all know this at an academic level but now I know it in my bones.
2) Practice makes perfect.
3) With hand tools, your bench is every bit as important as your cutting tools – both as a work surface and for holding the work.
4) When you have to, you really can rip 21 feet of 2” thick hardwood.
5) Finding yourself in a position of really having to muscle through a lot of material without your power tools to fall back on can be a really beneficial experience. Since it’s a hobby, that’s never a waste of time. Either you succeed or you learn something. Or both.

I’ve slowly been refurbishing my muzzle loading rifle and finally managed to get up to the store where you can buy such supplies.  I am now furnished with lead balls, patches, miscellaneous gear, and powder (not the real black powder by Pyrodex – a “propellant”).  To call gunpowder a “propellant” seems a ridiculous legal distinction but there it is.  Real black powder is classified as an explosive and is hard to get; “propellent” can be sold off the shelf more easily in small amounts.

Anyway, I’m ready to shoot – I just need to run some tests first and need to go somewhere that I can do them.  I don’t think I can get away with any testing in my neighborhood; firing a gun without a lead ball (simply wadded with patches) will still make a bang and I can imagine getting in trouble over that.

Saturday was the day for Cassie to graduate and since we had not yet met her family, we chose to go over there and attend the ceremony and meet the parents.  And grandparents.

That all went well and we feel better for having met them.  We then drove down to Steve’s near Winslow to spend the night.  It isn’t that far back home but his farm is so pleasant we hated not to turn down an invitation.  Now that his house is truly complete, he’s turned to a more active use of the land and has a small number of cows and some chickens.

We took walks around the property which was pleasant enough for me but, to a land owner, is necessary to make sure that all the fences are still up and in good order.  A cow with a strong enough will can make short work of a fence.  We also fished in the pond for awhile.  Trips there are always more relaxing that a weekend at a B&B so we try to take advantage whenever we’re invited.

Mother’s Day was spent in driving home.

All this week, Erin has been in Washington DC and while her twitter feed has been pretty sparse, the other kids on the trip have inadvertently kept us up to date.