Sunday, May 29, 2011

Veneer Tools: Hammer

When I started in business the veneer market was dominated by Albert Constantine and Sons in New York City, a firm which has long ago disappeared from the field, for many reasons. At that time they supplied every tool and all the veneers in the world. I still have early price lists, and my mind reflects on the time I could purchase sawn Brazilian rosewood veneer for 28cents a foot.

Whenever I had extra cash, like $50 or so, I would order the "marquetry special" which consisted of a large box of "scraps" which was like Christmas. Each time I would anticipate opening the box, where I would find satinwood, boxwood, ebony, teak, mahogany, and woods I never identified, but were amazing colors and character. I think the cost was about 50cents a pound for the mix.

No more...

Since they were the experts, when they published a book on "Veneering Simplified" by Harry Jason Hobbs, I eagerly ordered it and followed the advice religiously. On page 53 was the illustration of a veneer hammer, which I immediately built, exactly as illustrated. Their hammer was made from a "discarded floor buffer" and it was horrible! Combined with the glues Mr. Hobbs recommended using (Elmer's Glue-All, Constantine's Contact Cement, and Titebond) I managed to destroy much of the veneer I had purchased.

As a direct result of reading what Mr. Hobbs wrote, I started to research protein glues and seek out other types of veneer hammers to solve the problems I had experienced. Finding antique veneer hammers is a rare treat, and I have discovered only two in my search. Adding to that collection is a typical German made veneer hammer, and a variation of that form which was made for me as a gift from Yannick Chastang, after his second "stage" in my workshop.

The Hobbs hammer is in the foreground of the photo. It is huge, clumsy and the blade is way too thick. Think of the pressure difference between sneakers and high heels. You need pressure, and a wide piece of metal does not work. The small hammer on the left is my favorite, since most of the hammer veneering I do is related to antique restoration, and that hammer reaches into the smallest corners. Next to it (going left to right) is another antique hammer with a more traditional shape. Next to that is the modern German version, which has a large iron head, and then the Chastang version.

Both the hammers with the iron head have the advantage that the iron can be placed in the hot water of the glue pot double boiler and quickly warmed up so that they can be used to reheat and reposition any piece of veneer, without having to use an iron. Both the antique hammers have wood heads, with a rather thin piece of iron for pressing the veneer. The iron is smooth and slightly rounded on the edges so as to not damage the veneer.

I suspect the veneer hammer is called a "hammer" only since it looks like one. There is never any hammering involved. Rather it should be called a veneer "squeegee" or veneer "sliding thing for pressing out the glue." In fact, it is not held like a hammer but the handle is used for driving the tool across the veneer, while the head is pressed down with the other hand.

Hammer veneering is a simple task, and should be practiced by any person who wants to work with veneer. You need a hot glue pot, toothing plane, scrap of wood and some veneer, along with a veneer hammer. You put the hot glue on the prepared wood, place the veneer face down on the hot glue, apply glue to the veneer (glue side up) and quickly flip it over. The face is now up and has some hot, slippery glue on it, ready for the hammer. You press down with the hammer in the center of the veneer, holding the handle in your left hand and pressing down on the head of the hammer with your right. (I am right handed; switch these instructions if you insist on working left handed.) By driving the hammer from side to side at a slight angle to the grain direction, you work to push the glue out to the edge. Work quickly, and, if the glue sets too fast, have an iron ready to reheat the glue. You need to continue until glue emerges from all sides of the veneer and gels. At that point you are done.

The clamping is provided by atmospheric pressure, which is tremendous. You create a vacuum under the veneer by pushing out all the air, and the glue prevents air from entering, so the atmosphere holds it in place while the glue continues to loose moisture and set. Think of how the shower curtain sticks to the tile wall when you press out the air. Same effect.

Hammer veneering has been used for centuries by artisans with very simple workshops. No need for a press, or large collection of clamps. You build up the pattern in place, cutting through the freshly laid veneers and removing the waste strips, hammering the joints tightly together. Absolutely fantastic for adding string inlay; simple and quick.

I made the Hepplewhite work table shown here using only a veneer hammer, and you can see the extent of detail which is possible. It was fast and easy, and, since the protein glues set rather quickly, I was able to build this project on a series of steps, each taking about 3 hours. Three shifts a day for a week, and you have something to brag about.

Saturday, May 28, 2011

Veneer Tools: Saw

I find it ironic that I can collect literally hundreds of unique and different woodworking tools related to chair making, cabinet making, carving, turning and other trades, but, when it comes to specific veneering tools, the choices are few.

Of course, there is the glue pot. I have also spent some time discussing the toothing plane. I still need to post information on the veneer hammer. The veneer press sits in the corner demanding attention, but, as I look around what is a pretty sophisticated veneer workshop, there are not a lot of different tools that I see.

You might be surprised to hear that I think veneering is a relatively simple procedure. I know what you are thinking, "Marquetry is so complicated!" However, in my mind, the marquetry is fully assembled and applied as a simple sheet of material, exactly like you apply a sheet of veneer.

Using animal protein glues and either presses or veneer hammers has been the standard method of application for several centuries, and some very sophisticated products have emerged from essentially primitive workshops.

The first type of saw to be developed for cutting shapes in veneer was the fret saw, developed in Italy sometime in the 16th century. The French developed the chevalet during the 18th century, and other countries devised foot operated frame saws to cut curved shapes.

The simplest form of hand saw for making straight cuts on veneer has a blade which is held with a wood handle in different forms. The most commonly used hand saw today has a round handle with a small blade having teeth on both sides, top and bottom. This tool is what I started with over 40 years ago, and I determined some 39 years ago that it was worthless.

I always wondered why someone would design a tool with a round handle, offset from the blade in such a way that a) you cannot control the blade, b) you need to remove the blade to sharpen it, c) the teeth on the top of the blade are sharp and will (eventually) cut your left hand so that your blood will stain the maple veneer you are holding, and d) must be used right handed.

I got the answer one day many years ago at a tool meet. You know the situation: early in the dawn, tool dealers meeting in a secret place, first-timers eager to set up early, old-timers picking through the boxes and waiting for the best time to open up, bad coffee, bad donuts and worse cigarettes. I always look around to see where the small cluster of pros are gathered together, and then crash their party with some smart remark, sure to endure me to them.

As I approached them this morning, I could see they were passing around a single tool, and I overheard them asking each other, "What the blank is that?" (They didn't say "blank"...) When they saw me, one of them said, "Ask Pat, he might know", and they handed me the tool. My first response was, "How much?" I was told it was $75 and I quickly handed over the money. Then I informed them that I had just purchased a very rare English veneer saw from the end of the 18th century. They were not pleased with this response, and I walked away in search of more entertainment.

As you can see, this saw has a open tote handle, like a dovetail saw, but was made with a veneer blade. It works wonderful: you can control it perfectly and you can sharpen it without removing the blade, but it can only be used right-handed. I am convinced that this is the model which eventually was transformed into the round handled tool that is sold today.

The French developed a different type of veneer saw. The handle is large and directly on top of the blade. The saw is easy to sharpen, and can be used in both directions, right and left-handed as well. It is still manufactured and used in France. It has been my saw of choice for many, many years.

Now my good friends at Tools For Working Wood, in New York are bringing to market an improvement in this design, made by Gramercy Tools. I have been fortunate to receive this tool, along with several different blade designs, for testing. Working with Gramercy directly, we have suggest blade designs which work specifically on thicker, sawn veneer material. At this point, there are several variations of the blade, along with the tool available on the Tools For Working Wood site, linked to this blog.

It is important to understand how the blade works to sharpen it properly, for any hand held veneer saw. The blade is absolutely flat on one side, which presses against the straight edge. There is never a "set" on a veneer saw. By that I mean that all the points of the teeth are exactly in line with each other, unlike a panel saw or dovetail saw, which requires a "set". The teeth are flat on the one side, like I said, and only sharpened on the other side, using a stone. The sharpening needs to create a bevel which extends past the gullet of the teeth. So, if the teeth are, for example, 1.5mm long, then the bevel needs to be about 2.5mm long. The result is a knife edge, flat on one side, with teeth. As the tips of the teeth wear down, you need to use a triangular file to deepen the gullet, and then resharpen the bevel on a stone to continue.

I want to thank Gramercy Tools for devoting their creative energies to improving on this tool, as well as working on other specialized veneer tools like the lifting knife and veneer hammer. I am hoping that their products will inspire woodworkers to return to traditional veneer techniques and gain an appreciation of how much fun it is.

Now, if we can just get someone to make a good double boiler glue pot...

Saturday, May 14, 2011

Animal Protein Glue

I have never had any difficulty speaking in front of an audience. I have given hundreds of hours of lectures, as well as quite a bit of television. Generally, I speak about Decorative Arts, focusing on antique furniture issues. Quite often, when I speak about living and conserving wood furniture, I am asked, "How do I find a good craftsman to repair my antiques?" I usually respond like this: "Ask the prospective restorer if they have a glue pot, and what kind of glue and finish they use."

It has been my experience over 40 years that, if the woodworker uses protein glue, shellac and wax, he understands antiques. It is essential that reversible methods and materials be used in restoration, and that the glue and finish selection is as close to the original as possible. Using modern adhesives and finishes will negatively affect or completely destroy the value of the object. All furniture is subject to damage, either by wood movement or actual use or abuse over time. Therefore, the repairs need to be reversible.

I have never missed a chance to promote or discuss the virtues of animal protein glues during my career. For example, when the Society of American Period Furniture Makers organized, I quickly joined the group and began contributing to their Journal, which has evolved over the past decade to become a great source of furniture making research. In January, 2002 (Volume 2) I contributed an article, "Why Not Period Glue?" The inspiration for that article was that, after attending two SAPFM conferences at Williamsburg, I realized that the members of this group were very concerned about early furniture, construction methods, using antique tools, and even shellac finishing. The one thing I noted in talking with many members was that they generally used modern synthetic adhesives without even thinking about it. So, I raised the obvious question in my article.

Later, in March 2008, I wrote an article, "Hide Glue" in Fine Woodworking (Issue #197), which attempted to reach a much larger audience. This followed the feature story, "How Strong is Your Glue?" (Fine Woodworking #192, August 2007), where both hot protein glue and my Old Brown Glue were tested in objective and scientific conditions. I also made a video with WoodTreks, which discusses the preparation and uses of this glue.

Traditional animal protein glues have been used in all cultures for thousands of years. The protein is organic, easy to cook and adaptable with many diverse types of additives. There are quite a few different sources of protein, and each produces a different type of glue characteristic. Rabbit, fish, animal bone, hide, blood and other materials all have been used for making glue. In America, generally starting after the first World War, synthetic glues were developed and introduced, which quickly replaced the traditional glue pot in the workshop. Other countries continue to use old fashioned protein glues even today.

There are many misconceptions about using animal protein glues, which I address in my published articles. I believe that these beliefs are a result of authors who do not have direct experience with the material, and simply include in their writing "facts" which were previously published by other authors with little experience. Statements like "It smells bad," or "It goes bad quickly," or "Make only what you need at one time," or "It is not as strong as modern glue," or "It is difficult to use," are false.

I have posted a chart here which I use in my class to explain the simple properties of this glue. There are only two factors to consider when working with this glue: heat and water. If there is any problem at all, just figure out which of these two factors needs to be adjusted to fix the problem. Either add or subtract water or raise or lower the temperature. Or both.

You will note from the chart that both of these factors combine to determine the viscosity. Think of water, for example. It is either solid (ice), liquid or air. It can change from one state to another and back again, over and over, simply as a question of temperature. Animal protein glue is the same, It is either solid, gel or liquid, also as a function of temperature, with the addition or removal of water as a second important factor. More importantly, this glue has the property of changing from one state to another, again and agin, without damage. This is what makes it reversible.

It is important to understand that you must add cold water to the dry glue to fully hydrate it before adding heat. If the glue is a solid slab, the way it is sold in Europe, it must be broken up into chunks and soaked overnight. If the glue is granulated, or in pearl form, it hydrates much quicker. You will know when it is hydrated since it turns into a thick gel. Then you need to put it into a double boiler and raise the temperature to 140 degrees to use it.

I don't have the time here today to discuss all the features of this hot glue. Read my articles, some of which are posted on and let me know if you have any questions. Get some glue and play with it.

I want to discuss briefly how I came to make Old Brown Glue, which has enjoyed increasing success in recent years. I was fascinated by how early 19th century cabinetmakers were able to veneer columns. For years I tried, without success, to do the same using hot glue. Then, about 20 years ago I joined an international group in Paris which focused on marquetry conservation issues, including modifying protein glues to do a specific job.

That experience led me to do my own research on using urea to reduce the gel point of hot glue. I cooked 37 different batches to test the recipe and finally succeeded in a formula which did what I wanted it to do. Essentially, the urea attaches to the Hydrogen bonding sites and thus reduces the temperature at which the liquid glue turns to gel. Since urea and protein collagen are natural, organic materials, this glue is non toxic in nature.

After perfecting the recipe, I was able to veneer columns without problems and you can read about this technique in Fine Woodworking (Issue #173) December 2004. The Master Class article, "Low-tech method for veneering columns," featured a desk I made on the back cover of the magazine.

I start with 192 gram granulated protein glue made by Milligan and Higgins. I cook it in the bathroom at the shop, add the urea and the "secret" ingredient and put it into bottles. It takes some time, and I will never get rich doing it, but I am pleased that the demand is such that I need to cook a batch every other week.

Old Brown Glue has a shelf life. We put a date of 8 months on the bottle, and each bottle has the batch number on the top. I am currently shipping batch 150. It can be kept in the refrigerator and will remain good for over a year. It needs to be warmed up to use it, and I just place the bottle in a pan of hot tap water when I use it. You can heat and cool it as many times as you want, just don't dilute it.

There are three indicators that the Old Brown Glue has gone bad: 1) It has a very liquid viscosity at room temperature (it should be a gel in the bottle), 2) It smells strongly of ammonia, and 3) It has mold visible inside the bottle. If a bottle is past the date on the label, please take the time to do a test before you use it on your project.

Saturday, May 7, 2011

7 Meters of Greek Key Assembled

Last week Patrice spent some time preparing the material, setting up the jig and laying out the design. All that preparation time was rewarded with only one day required to cut nearly 2000 individual pieces, in 17 different shapes to size. Exact size.

Since we required two lengths and two widths of Greek key for the border of this table top, it was important that all four lengths be exactly the same length; 2.5 meters for the sides of the top and 1 meter for each end. The four lengths needed to fit together precisely at each corner, If each element was slightly off in size, even a fraction of a millimeter, the results would not work.

I have posted the paper (computer generated) design showing the plan, with some details of the ends and center elements. Note the design has a center "T" component on each length where the pattern flips left and right. That change in the pattern is required if all four corners are to be the same. So, standing in the center of each side of the table, the client will see the pattern as a mirror image of itself, with the center "T" creating the flip, left and right. It is surprisingly not obvious unless it is pointed out.

What is not shown here is the two strips of wood, mahogany and ebony, which will be added to the outside of the design and run the length of the table. That will add some width and make the decorative effect more pleasing as well as more in keeping with the size of the top. All the elements are sawn veneer, 1.5mm thick.

I also show the two sides of the assembly board, upon which Patrice built the design, face down with hot protein glue. By using the traditional French method of stretching Kraft paper on a board, it is possible to lay out the pattern directly on the paper first, with pencil and ruler. This allows the assembly board paper to provide an exact scale for the elements to be glued in place. That simple method guarantees that the pattern will end up at the precise location necessary. In fact, the error over 2.5 meters is less than 1/10 of a millimeter.

By stretching the Kraft paper on two sides of the same board, we were able to build the entire pattern on a single assembly board. The next step is to apply mastic (diluted hot protein glue and fine hardwood sawdust) to fill any gaps, and level the surface (which is the glue side). At that point the Greek key is completed, and we can cut it away from the board and apply it to the table top, with the paper on the face. After application, the paper and surface glue is simply removed with cold water and scraping.

By this method it is fairly quick and easy to create a rather complicated running pattern on a piece of furniture.

You can search this blog for more information on the assembly board process.

Monday, May 2, 2011

More Toothing Plane Info

One of the first mention of a toothing plane is in the classic tool reference book, "Ancient Carpenter" by Henry Mercer. On page 127 and figure 120 he illustrates a "toothing plane" with the purpose of "scratching the surface of a slab of veneer to help the glue to stick."

The use of the Tooth Plane is very well desceribed ca.1815-1816 by James Smith in the "Panorama of Science and Art": "With this kind of plane, however hard the stuff may be, or however cross and twisted its grain, the surfacwe may be made everywhere alike, and will not be rougher than if it had been rubbed with a new fish-skin. This roughness may be effectively removed with the Scraper."

Joseph Moxon (who does not mention a toothed iron) tells us in "Mechanics Exercises" (ca. 1703): "But if it be very hard Wood you are to Plane upon on Box, Ebony, Lignum Vitae, &c. It is set (the iron) to 80 Degrees, and sometimes quite upright. So that these hard Woods, are, indeed more properly said to be Scraped, than Planed."

James H. Moncton, writing in "The National Carpenter and Joiner" (1873) states, page 6: "Veneering is a very simple operation and every carpenter ought to be able to do such work when needed; the surface of the material, upon which the veneer is to be laid, should be well scratched with at tooth plane..."

The conclusion is, in general, that the toothing plane is used both for leveling the wood surface, both on the carcase and the veneer, as well as providing an improved glue surface. I have used toothing planes for over 40 years and there is always one close at hand when I am at the bench.

I have posted some pictures of toothing irons. The oldest is by James Cam and was made in 1780. Note how much of the tooth is ground away. Normally the iron has grooves which are at least 1-2 inches on the end. The teeth grooves are made exactly like a rasp is made. The iron blank is annealed so that it is soft. Then, using a punch chisel, the maker punches the grooves along the end of the iron. The spacing between the grooves is determined by the use of the iron. Coarse, medium or fine grooves each has a purpose. Since the punch chisel is held at an angle, the grooves are slanted like teeth on a saw, producing teeth which are slanted when viewed from the end. Once the grooves are formed the iron is tempered and the bevel is ground using a wet stone. Never use a dry grinding stone since the temper of the teeth will immediately be destroyed.

To sharpen the iron, never put the grooved side on the stone. It is a simple matter to refresh the bevel side using wet stones (water or oil). The bevel angle is not important, but should not be too shallow, or the teeth will have a tendency to break off.

Toothing planes have a large range of angles, with the blades set often between 80 degrees and 105 degrees. I also use the iron by itself in my hand to reach difficult areas. I also have toothing irons which have been ground to a rounded end for concave surfaces.

When you select a plane, look for the length of grooves that are left. Longer is better. Also, look at the condition of the bevel. Many irons are improperly sharpened.

Good hunting!