Concrete Dovetail Bench

I enjoy making benches and playing with mixed materials from time to time.  When the opportunity came up to make something using one bag of cement I had an idea.  Incorporate a traditional woodworking joint into cement and make a modern bench at the same time.  Thus the design of a cement formed dovetail leg and a single board bench seat.

For this project I used exactly one 80lb bag of Quikrete 5000 cement.  The form I made measures 10.5″ x 18″x 1.5″.  It was constructed of melamine and screwed together.  Making forms is a simple process, you just need your design in mind and remember that the form is an outline of the end result.  Also remember you will need to remove the form easily when the cement cures.  If you are making holes inside the form use plastic that can be cut away or pulled apart for easy removal.

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I mixed the cement in a bucket with a grout mixer in a drill.  This made mixing very fast and easy.  The cement was then poured into the form and vibrated to relieve the bubbles from the bottom and sides.  Note that it helps to have the form vibrating as the cement is being poured to ensure the air bubbles come off the surfaces quickly.  Also keep in mind to use some sort of reinforcement for the structural integrity of the cement.  I used mason ladder wire in the middle of the form.  Pour half the cement, place the ladder wire, and pour the rest.

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When the cement is all in the form you will need to vibrate/tap on the form for 60 minutes, no less.  Otherwise you will have holes in the surfaces.  Allow the cement to cure per the instructions from the manufacturer.

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With the cement curing for a few days I worked on milling the wood bench.  I used a custom milled and air dried white oak board that was 11″ wide.  I cut it to 36″ long and milled it to thickness.  I would have liked it to be 1″ thick but the warping in the board brought it to 3/4″ after milling.  Any knots were filled and stabilized with tinted epoxy and the final milling was completed.

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Once the cement was cured I removed it from the form and cleaned it up with some sand paper to tidy the edges.  I placed the form upside down on the ends of the wood seat and traced out the pin locations.  Use your preferred method for cutting dovetails here.  I like using my hand saw and chisels but you can use a bandsaw as well.

Clean up the ends of the board and apply the finish of your choosing.  I went with a few coats of oil varnish.

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It is time to push the seat into the dovetails to set the with of the legs.  I wanted to add steel rope to hold the legs together and I found these Hammock Hangers looked great for this purpose.  I positioned the hangers in the middle of the legs, pre-drilled a 3/16″ hole for the 1/4″ TapCon screws, the steel rope was cut to length, the loops were made with the hoops inside (this has to be done at the same time), and I drove the TapCons in place to anchor the hangers.

To tighten the steel rope I used a turnbuckle similar to those used for gate supports.  Just turn the turnbuckle until the steel rope is stretched and the legs aren’t pulled in too much, do not over tighten.  The seat will tell you when to stop.  You can also hold a square to the seat and legs to be a guide.

Now put the bench in a nice location and enjoy.  Be sure to move this with a friend.  It isn’t rigid enough to pick up alone and the dovetails may be brittle.  Treat this bench with care and it should last for a long time.

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Here is a list of the products I used with exception of the cement (affiliate links):
Hammock Hangers – http://goo.gl/ttR6Di
3/16″ Masonry Bit – http://goo.gl/IK5P85
1/8″ Steel Rope – http://goo.gl/gpuW5C
Steel Rope Thimbles – http://goo.gl/1gIO2p
Cable Clamps (similar) – http://goo.gl/9eT0QP
Turnbuckle – http://goo.gl/1ZHRw5
Varathane Outdoor Varnish – http://goo.gl/kY5JkV

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Up Coming Bench Build-Off

The Dusty Life crew (Brian McCauley, Kyle Toth, and Myself) is hosting a Workbench building event in the late weeks of August and into September.  The event is conveniently called the Bench Build-Off.  There is a sizable list of sponsors who are pledging prizes to be given at random to several lucky builders.  You can find that list here.

Brian and I will be participating and I plan on building a 19th century Nicholson Bench.  I have drawn up a model and put together a 24 page PDF set of plans for my bench which are available here.  This bench is 8′ long 27″ wide and 31″ tall.  It features a fixed crochet on the right side, a sliding crochet on the left, and a shelf for storing your planes during a project.

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Also, I have designed a smaller version for kids if you have any apprentices running around the shop.  Plans for that are found here.  Once the kids outgrow the bench it can be used as a place to sit.

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Keep an eye out for the announcement and if you are interested in making a dedicated workbench, start planning now.

Rough Shaping and the Base Joint

In this video I show how I remove the material from the underside of the large base piece without ripping a strip off and gluing back together.  The practice is not for the novice woodworker.

I also show how I roughly cut out the shape of the base pieces and prepare them for template routing.

The base joint is also cut.

Coffee Table Design Idea: The Conic Coffee Table

My educational background is in Mathematics.  I particularly enjoyed Geometry and Calculus due to the graphing nature, as well as, the computational aspect.

Now, I will assume the reader has some knowledge/recollection of high school algebra to know that these four sections are made by passing a plane through a cone in four different ways.  Here is a diagram to refresh your memory courtesy of sparknotes.com.

Conic sections.
Conic sections.

I have a fantastic piece of Walnut that is begging to be shaped into an ellipse.

Notice the Walnut grain.
Notice the Walnut grain.

While trying to preserve the theme of conic sections (and keeping my wife and professors pleased that I am using my education in some way) I had an epiphany.  I could use the other three sections (parabola, circle, and hyperbola) to make up the base of the table.  I would use the parabola as one set of legs perpendicular to the table at one end, the hyperbola would be connected by the circle (possibly to the vertices of each other) and tilted at some arbitrary angle to connect to the table at one end of the hyperbola and the edge of the circle.  Below is a crude sketch of my design.

Preliminary design.
Preliminary design.

Of course this is all design speculation at the moment and this table would be particularly small (not a typical 48″-36″ long table).  I may play with the design and joinery options more before tackling such a table, maybe even make a full size prototype.

I think this would be quite the addition to a mathematician’s home decor and a nice conversation piece.  Maybe even set a conic model (Photo courtesy of EAIEducation.com) on top to show off it’s origin.  Perhaps I will decide to make one of these one day too.

Conic Model
Conic Model

 

Coffee Table Build-Off #CoffeeTBO

Early this year, Chris Wong of Flair Woodworks, hosted a Shop Stool Build-Off (#SSBO on twitter) and the turn out was fantastic.  The judges and entries were plentiful.  The build-off was such a success that it has prompted a second build-off, this one is of the coffee table variety, fittingly titled Coffee Table Build-Off hosted by Neil Cronk of The Cronkwright Woodshop.  This is sure to be a BIG deal with prizes and egos galore.

This Coffee Table Build-Off (#CoffeeTBO on twitter) will take place the entire month of November 2014.  Stay tuned for that build progress.  In the mean time, here is the material I will be using for the table top.

Spalted figured maple book matched set.
Spalted figured maple book matched set.

Bangle Bowl 2014

Kyle Toth and Zac Higgins put together a friendly competition encouraging woodworkers and craftspeople to come together and make bangles to show off and win prizes.  Videos and more information about the Bangle Bowl 2014 can be found at thewoodwhisperer.com/bangle-contest.

I will be posting my experience on making a bangle once the competition is closed for submission and judging begins on Oct. 23rd. But in the mean time, here is my progress in it’s current state.

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This is the canvas on which I will create a truly stunning bangle.  Stay tuned.

Bangle Bowl 2014: My First Bangles

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Here is a video of the process.

I had no idea what a bangle was when I saw the Bangle Bowl 2014 contest headline.  Basically, it is a bracelet.  But, because this was a contest, I decided to give it a shot.  The two categories for prizes are for turned bangles and not turned bangles.  Three entries will be chosen for each category and only one entry per person is allowed.  Sounds great to me.

I am entering for the turned bangle category.  Since I have a lot of poplar left from the Tatami Platform Bed and following in the path of my Scrap Wood Woodworking series, I chose to make a segmented bangle.  Actually, since I had a lot of scrap poplar, I decided to make 3 bangles so I could choose which to submit for the contest.

I cut eight 1-1/2″ segments of 1-1/4″ wide by 3/4″ thick stock to the proper angle to make a ring.

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Scrap Poplar.
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Cut to 1-1/4″ x 3/4″ and varied length.

To find the degree needed for each segment (external angle) to make a segmented ring, use the equation 360/n where n = number of sides.  Keep in mind that this calculation gives the angle in degrees of two pieces joined together, thus divide that by 2.  So the new equations is (360/n) ÷ 2, or simply, 360/2n.  This gives the result of 22.5°.  Now, that I lost you with math stuff, let’s get to the good stuff.

I made two segmented rings, glued each segment together, cleaned up the surfaces, and glued them together such that the segments were offset from each other.  Notice the slight gaps between some of the segments.  This was a non issue as you will see later.

Segments cut and dry fit.
Segments cut and dry fit.
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Segments glued.
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Gluing the rings together.
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1st Bangle blank in the clamps.
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Bangle blank out of the clamps.

The next step was to glue a sacrificial block to a face of the blank.  Before doing that I wanted to true the blank and flatten a face over at the lathe.  I used the internal grip jaws on my scroll chuck to hold the blank while I trued and flattened the blank.  Be sure not to use a roughing gouge to do this.  This is spinning end grain.  Use a bowl gouge and come at it from the outside going in to shear the grain.

I used a piece of plywood as a glue block for this blank.  Just glue it on and slide the tail stock (with no live center in it) up to the block and tighten it against the block.

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Sacrificial block glued on using the tail stock as a clamp.

Next, reverse the blank so the scroll chuck is holding the plywood block in the jaws.  This gives more material to work with on the blank.  Now drill or shape the inside diameter of the blank anywhere between 2-3/8″ to 2-5/8″.  I turned the inside true with a bowl gouge.

Inside trued just under 2-1/2" inches in diameter to allow for sanding.
Inside trued just under 2-1/2″ inches in diameter to allow for sanding.

Same as before, I glued a block onto the blank, put it into the scroll chuck, and began truing the blank.

After all the blanks were trued I had to decide on a profile for each bangle.  The first bangle I shaped was a simple convex profile.  In lathe language it may be called a bead, I am not a die-hard turner so feel free to correct me.

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After sanding up to 320 grit, I filled any gaps with wood filler, let that dry, and sanded again with 320.  The key to the process to come is to have a smooth and sealed surface.

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1st Bangle ready to seal.

The second bangle I shaped was more of an experiment.

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2nd Bangle profile.

 

Here is how the bangles are sealed.  I used wood filler to fill any gaps and then sealed the wood with white shellac-base primer.  I like shellac-base because of the fast drying time.

After several coats of primer I sanded, yet again, with 320 grit paper to get a nice smooth surface.

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The sealing materials.

Now it was time to paint the surfaces.  I put a little mineral spirits in a small container to load my paint brush and squeezed a little bit of crimson and cobalt blue oil paint on a piece of acrylic.

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Painting with oil paints.

I put the 1st bangle on an 8″ x 10″ canvas (to see if some art will come of it) and started painting a base coat of crimson red on the primed surface.

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Painting on the first coat of crimson.

I let the paint dry, sanded it lightly, and painted again to get a nice even color.  Next color was cobalt blue done the same as the crimson.

The painting set up.
The painting set up.

The oil paint was taking far too long to dry so I add a few drops of japan drier using an oral syringe.  The recommended amount of japan dryer to be added to a gallon of paint is 2-4 oz.  I did the math and converted the units to milliliters and came up with about 0.10 mL per 5 mL of paint.  I only used about 2 mL of paint per coat so I added 2 drops (about 0.20 mL) of drier, mixed it up on a plastic lid, and brushed on the paint.  Several coats of each color needed to be applied to get a nice even coat before layering on a second color.

After my 4th coat of paint I sanded the bangles with 240 grit paper and finished with 320 grit.  I wiped the surface clean and applied a wash coat of oil paint.  This coat was diluted with mineral spirits and japan drier so that the coat would leave no brush marks.  This worked very well.  I made my 3rd bangle and this is how I painted it with titanium white oil paint.

3rd bangle painted white.
3rd bangle painted white.

I was very pleased with the way the red bangle turned out.  The deep and faded red color looked great.

1st bangle painted with the diluted wash coat.
1st bangle painted with the diluted wash coat.

I wanted this bangle to have multiple colors showing through the metal leaf.  The finished painted bangle looked like a piece of pottery.

3rd bangle painted and ready to gild.
3rd bangle painted and ready to gild.

My gilding supplies laid out ready to use.

Gilding supplies. Silver, copper, dutch metal, and gold leaf.
Gilding supplies. Silver, copper, dutch metal, and gold leaf.

The Gilding Process

Before the bangles can be gilded the surfaces need to be coated with size.  I chose a fast drying oil base size so I could add layers of metal leaf for a textural effect.

Once the size is tacky, about as tacky as blue painter’s tape, the metal leaf can be applied.  I propped up the bangles on tooth picks so the size would not stick to the paper towel.

Now it’s time to gild.  What follows is a montage of photos showing the progression of the gilding.

Gilding with gold leaf.
Gilding with gold leaf.
Inside finished.
Inside finished.
Outside gilded with copper and silver leaf.
Outside gilded with copper and silver leaf.
Adding a textural random pattern for the silver and dutch metal leaf.
Adding a textural random pattern for the silver and dutch metal leaf.

Patinization

I used ammonia and vinegar to put a patina on the copper and dutch metal.  The ammonia and vinegar turn the copper brown to blueish green, does not change silver much, and turns the dutch metal to a deep bronze.  In retrospect, I should have mixed rock salt into the ammonia to make a super saturated solution in the bottom of the fuming chamber.

Silver leaf and dutch metal bangle. Dutch metal has been patinized.  Silver patinized slightly.
Silver leaf and dutch metal bangle. Dutch metal has been patinized. Silver patinized slightly.
Gilded with gold, copper, and dutch metal. Patinized with vinegar and ammonia.
Gilded with gold, copper, and dutch metal. Patinized with vinegar and ammonia.

To patinize the silver I used liver of sulphur.  First off, this stuff smells like rotten eggs, it is sulfur.

Liver of Sulphur gel.
Liver of Sulphur gel.

I used a liver of sulphur gel so it was diluted with water and then daubed on the cheese cloth that was wrapped around the bangle with a brush.

Copper and silver leaf with ammonia, vinegar, and liver of sulphur patina.
Copper and silver leaf with ammonia, vinegar, and liver of sulphur patina.

When the desired patina was achieved each bangle received several coats of spray lacquer to protect and seal the surface.

Finished bangles.
Finished bangles.

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My Bangle Bowl 2014 submission.
My Bangle Bowl 2014 submission.

Overall I had a good time making these and I learned a lot about gilding and chemical patinas.  If you are interested in learning the process of gilding and patinization, you can reference the 2004 Fine Woodworking Magazine’s article An Extraordinary Patina Finish by David Marks.

Now I am looking at adding gilding and patinas to many projects including adding my business logo to pieces by gilding with copper and patina with vinegar for the green color.

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