Saturday, April 22, 2017

Tealight Candle Holder Featuring Lichtenberg Figures

     After my initial foray into Lichtenberg Figures, the machine ended up being put on a shelf to gather dust as predicted.  While it was inexplicably enjoyable to electrocute wood, the end results were underwhelming to me.  What do I do with a bunch of wood panels with Lichtenberg Figures on them?  By themselves they didn't merit hanging on a wall or giving as gifts.  In fact, the only piece that I was overly pleased with was my hiking stick with the figures burned at the top.  I decided that the best use for the Lichtenberg machine would be to add a decorative touch to pieces that were functional or decorative in their own right.

     As summer approaches and yard work threatens to monopolize my time, large projects in the shop have to take a back seat.  Faced with a little free time over last weekend I decided I could squeeze in a small weekend project, and maybe even find a way to incorporate Lichtenberg figures.  After taking stock of the materials I had on hand, I decided to make a tealight candle holder, since I had some tealights leftover from lathe projects I had done in the past.  As always, the first question to answer is what wood to use, so my first step was to do a little experimenting.

     The first pieces I cut were two pieces of poplar and a piece of mahogany.  These were chosen because they were small cut-off pieces from other projects that were already about the right thickness, and they were close to the top of my wood pile.  I also pulled out some small pieces of maple and walnut, but they would need to be planed, so I saved those for batch two.  I cut the wood to size and drilled the holes for the tealight candles.  I found in previous experiments that in order for the figures to work well in harder woods they needed two or three coats of electrolyte solution, and time to absorb between coats, so I went ahead and prepped the wood for burning.  Below are my experiments and observations burning the first three pieces.  I really do learn something new every time I get this machine out.

     The top piece in the picture above was the first piece.  The problem seemed to be that too much of the electrolyte solution dripped over and soaked into the edges of the piece, causing most of the burning to take place on the edge, not the surface.  The bottom piece above was the second burn.  For this one I made sure not to paint the electrolyte all the way to the edge, leaving a thin, dry boarder around the edge of the surface.  Unfortunately the poplar proved too eager to catch fire and burn, leaving thick smudgy lines, which was not the desired effect.  So far, two pieces burned, two lessons learned.  Just when I was getting a little discouraged, the third piece (in the middle above) brought me a pleasant surprise.  While I was hoping for a little more detail, the mahogany burned like no other wood I had tried previously.  On other woods the pattern started at both electrodes and snaked through the wood until the two ends got close enough to arc.  On the mahogany, the burn seemed to start instantaneously all throughout the wood and quickly begin to arc.

     Based on that experiment, I decided that Mahogany might be the wood to use for this project.  On the bright side, I happen to have some lying around, but on the other side, it is very expensive, and I hate to use it on a dinky little project like this.  In the long run I decided to go ahead and use a little of the Mahogany I had on hand.  What's the point in having it if I never use it for anything, waiting for that perfect project that never comes.  I ripped a length of it, planed it down to a little over a quarter inch, and cut that length into four pieces ready to be burned.  Below is the result.

     I was very pleased with the way these turned out.  You'll notice in the picture that each of these pieces has a lighter area around the boarder.  This is a result of not painting the electrolyte solution all the way to the edge.  I learned early on in the experimenting process that the electrolyte solution always discolors the wood after the electricity has been applied.  It doesn't have the same effect without the electricity, so I can't just go back and apply more around the edges after the burning.  In this case I kinda like the effect, so I don't mind it so much, but it's something to keep in mind.  The other thing to take away from this is that the patterns got better as I went along.  In the picture above, the top piece was done first, and they continue down in chronological order.  I did the first coat of electrolyte on all of them at the same time, and then went back and did the second coat immediately before burning.  This means that the pieces towards the bottom had longer for the first coat to soak in than the top pieces.  This seems to have resulted in a better burn pattern, but also a deeper discoloration from the electrolyte solution.  So it seems to be a trade-off, but the main takeaway is that on harder woods, it is better to give it a little more time to let the first coat of electrolyte solution soak in thoroughly before applying the second coat and burning. 

       OK, so now the burning is done.  Time to put the machine back on the shelf and finish up the project.  I needed some sort of legs or base to hold the mahogany up high enough for the tealights fit down through the holes.  I had a couple of ebony turning blanks that I had purchased because they were on sale, and I think the black color of ebony will go great with the mahogany.  After squaring, cutting, and drilling the ebony, the only thing left is to add a little polyurethane and do the final assembly.

     Typically I would spray-finish this type of project with lacquer or something similar, but I was out of lacquer and I had some polyurethane-type finish lying around.  Since I had never experimented with spraying this particular finish I decided to brush it on... big mistake.  Between the dry-time, the sanding, and the 3-4 re-coats the finishing took forever.  A weekend to build, a week to finish.  It's time to go get some more lacquer.

And here we have the finished product.  I think they turned out well, and they gave me a chance to play with my Lichtenberg machine again, so all-in-all I'm very pleased with this project.

Tuesday, April 11, 2017

End Grain Cutting Board

     End grain cutting boards make great gifts, and are not incredibly difficult to make if you take the time to make sure all measurements and cuts are precise.  The basic concept is to have the wood grains line up vertically so that the knife's edge actually goes down between the grains  instead of cutting across them.  This improves the life of the cutting board, and keeps your kitchen knives sharper for longer.

      The first consideration when planning out a cutting board is to pick the woods that will be used.  While it's good to think about the contrast and color coordination of the wood, there are other important factors.  Most importantly, some woods can cause allergic reactions, and even be directly toxic, which makes them a poor choice for use in a cutting board.  The second consideration is the hardness of the wood.  It is important to use a dense hardwood to extend the longevity of the board, and it is also good to make sure that the woods don't vary too much in hardness to keep the joints from stressing as the wood moves over time.  I always like to use Hard Maple in my cutting boards as it is very easy to work with, and it also has innate anti-bacterial properties.  I chose Purple Heart as the contrast wood, mainly because I like the color, and I have used it before along with Maple to make end grain boards.

       One more quick note about my wood choices, it's always good to know the characteristics of the wood that one is working with.  While Purple Heart is a pretty wood, it does like to chip and tear-out, which can be annoying, but it's not a show stopper.  Be sure to make shallow passes on both the planer and jointer to minimize tear-out, and maybe start with the wood a little thicker than needed in case it takes a couple of extra passes through the planer to get rid of tear-out.  The Hard Maple won't have as many issues with tear-out as the Purple Heart, but it does tend to get burn marks when sawing, especially when cutting two inch thick pieces like we will be doing here.  My trick to dealing with the burn marks is to cut pieces 1/16 to 1/8 inch wider than needed, and then make a second cut on each side of the piece, only taking 1/16 to 1/32 off on the second cut.  This will get rid of the burn marks, and typically will not make new burns when cutting such a small amount.

      OK, time to stop rambling and get to building...

     I was able to get some nice 8/4 Hard Maple stock for this project, but I was unable to find any 8/4 Purple Heart, so a couple of Purple Heart 2"x2" turning blanks will have to suffice.  There was no need to start planing down the whole slab of Maple, so I cut what I needed on the radial arm saw.  There is always waste on a project like this, so it is important to cut a little longer than I think I will need.

     Once the boards are cut, it's time to run them through the planer.  Everything needs to be absolutely flat on both sides and uniform thickness.

     Once the boards are flat, use the jointer to get one edge perfectly flat and perpendicular to the planed surface.  No need to worry about the other edge, we'll get that on the table saw.

     I know I mentioned it previously, but precision is key to making one of these cutting boards turn out well.  It is important to make sure that everything is perfectly square on both the table saw and the jointer or it will stick out like a sore thumb on the finished product.

Now that the board is flat and square it is time to rip some 2x2 strips on the table saw.  Pretty self explanatory.

Next cross-cut the strips to length.  I'm not worried about the length being perfectly precise, or else I would use a sled with a stop, or set a stop against fence, but if the length is not perfect it can be cleaned up after the first gluing with the table saw.

I like to line everything up before getting ready to glue, just to make sure there are no gaps, and everything lines up correctly.

Time for the first gluing.  I'm not the best at this step.  The strips always seem to want to slide and move on me while I am trying to clamp them.  Consider this step practice for the second gluing.  If things aren't perfect after this step they can be cleaned up on the planer and the table saw.  If things aren't perfect after the second gluing then either the project will go into the scrap heap, or be prepared to spend days sanding.  Let the glue dry for 24 hours.

I didn't take any pictures of the clean-up work after the first gluing, but if you've seen one board go through the planer, you've seen them all.  First I cleaned up the glue that squeezed out from in between the strips with a razor blade. Then I ran the glue-ups through the planer again to get all the rest of the glue, and make sure that they were perfectly flat.  This step is very important because sometimes, if the first glue-up is clamped too tight, it will cause the whole piece to bow upward in the middle, which can cause major problems with the second glue-up.  Once the glued-up boards are flat, use the table saw to get one flat edge, perpendicular to the lengthwise strips.

Time to cut the second set of strips.  Technically we are cross-cutting here, but I'm using the ripping fence to get uniform strips, so I'm not sure what you would call this exactly.  Cross-ripping?

You can see the burn marks on the maple I was talking about earlier.  This is where you want to cut these strips a little wider than you need, and then go back and cut off 1/32 to 1/16 of an inch to get rid of the burn marks.  Trust me, nobody wants to be sanding burn marks out of the end-grain after the glue-up, it would take forever.

As I pointed out before, always line up your pieces the way you want them before gluing, and this is an example of why.  If you look closely in the picture above, you can see that the edges of the new strips aren't perfectly parallel, so they leave thin little gaps between the strips at the top and bottom.  This is because I didn't get the boards perfectly flat on the planer after the first glue up.  Luckily, I can use the table saw to fix this at this point.  If I had gone straight to gluing, it would be too late, and the whole thing would end up in the scrap heap.  There is not much that can be done if you end up with gaps between the boards after gluing.  Gaps will leave places for bacteria to grow, hence making the cutting board possibly hazardous to your health, not to mention unsightly.  So let's get this fixed up and move on.

This is much better.  No gaps.  Let's take it over to the gluing bench.

This gluing needs to be as perfect as humanly possible.  Sanding end-grain is an extremely slow and tedious process.  It is already going to take a lot of sanding just to remove the excess glue that won't come off with a razor blade, but if your boards are off by even a little bit be prepared to sand for days.

No pictures of the sanding process either, so you'll have to use your imagination.  Imagine a 48" belt sander with an 80-grit belt.  You would think it would chew through wood faster than you could feed it, but not on end-grain.  Make slow even passes until all the glue marks are gone.  Don't assume that you will get those last few marks during clean-up sanding because you will just end up going back to the belt sander after wasting hours with the hand sander.  Once I am satisfied with both faces of the board, I change the belt to 120 grit to get the sides of the board.  I also round the corners of the board on the belt sander, just for aesthetics.

 After the belt sander, and before I do the final sanding, I like to use a hand router to round over or chamfer the edges on both faces of the board.  This is not only aesthetic, but also helps to get ones fingers under the board when picking it up off of a flat surface.  To clean up the scratches from the belt sander I use a random orbit sander starting with 60 grit, followed by 80, then 120, then 220.  When the sanding is done, take a break, you deserve it.

This particular cutting board is going to be a gift, so I thought I'd personalize it with a little bit of wood burning.  This should be done on the side of the board so as not to mar the cutting surface, and it is much easier to do before oiling the board.

I like to take several days to oil the boards to make sure the wood is fully saturated.  Always use food grade mineral oil, and if it is a gift, it doesn't hurt to give a small bottle of mineral oil with the board so the recipient can add some oil from time to time.  Since I had the oil out, I grabbed a cutting board from the kitchen that I made for my wife years ago so I could freshen up the oil on that one too.  Apply the mineral oil liberally and allow to soak for 30 mins to an hour minimum.  Flip the board over and repeat, and repeat, and repeat.  After doing this for a few days I am satisfied that the board is saturated.  I do the last two coats with a product called "Butcher Block Conditioner", which is made from bees wax and mineral oil.  It is very thick when it first comes out of the bottle, and you have to heat it up to melt the wax.  The wax helps to seal the cutting board so that it doesn't dry out as quickly.  Speaking of drying, I will let this board air out for a few days before gift wrapping it, otherwise the recipient might unwrap an oily mess.

And that's all there is to it.  Mark and Kara, if you are reading this, I hope you don't mind me making a blog post out of your wedding present.  We had a great time in Lewisburg, and I wish you both all the happiness in the world.