This is a section from A Beginners Guide to Woodworking: Helping New Woodworkers Make Better Projects, which is available on Amazon. Over the next couple months, you will be able to read the entire book, and I hope that you like it enough to get tour own copy. Enjoy.
Clamping cauls are pieces of wood or other materials that are used to assist in clamping. Typically, they are meant to create a certain shape, or they are meant to spread out the clamping forces so that they hit a bigger area than the clamps alone.
You will end up making these as needed depending on your project choices, but they are nice to understand as you learn about woodworking.
You will probably run into a situation where you need a clamping caul, so knowing what they are and what they can do is important.
Even as a beginner, if you don’t use these for a while do not worry. You will need them for very specific processes, and until you perform that process you will not need them at all.
For example, if you are making the bottom rockers for a rocking chair, and you are gluing them up from several thin pieces, you will need a clamping caul to bend them to the shape of the rocker.
This is many times also called a form, but it is still a type of caul. Anything that assists in shaping your work or distributing pressure can be thought of as a clamping caul.
In the above example, you can just make this caul from wood, cut to the shape of the rocker. You save both sides, and place your pieces between them with glue. When you press the sides together, they force the thin strips inside to curve to the shape of the caul.
As the glue dries, the pieces retain their shape, and they are eventually removed from the caul and used to make the rocker. You can use presses and cauls like this for many different curved parts, but you can also use cauls in another way.
Many times, cauls are used to distribute forces around the clamping area. This is either because the pieces are thin, or they are not practical to get several clamps onto. A simple flat caul can be used to spread out the pressure, and make it seem as though the clamp has a wider reach than it actually does.
For example, if you are gluing several sheets of veneer together, clamping them will not ensure that they are flat when the glue dries. In fact, veneer is so thin that adding clamps all around the piece is an almost guaranteed recipe for a lumpy final look.
Instead, use a flat surface and a clamping caul for the top. These two flat surfaces can be pressed with clamps, and together they will spread out the forces to the entire area of the veneer sheets.
A cautionary note about cauls is to either tape them with clear packaging tape so that the glue does not adhere to them, or to use waxed paper when you glue. The last thing you want to do is glue everything together, including your cauls, because it can be impossible to take apart.
Also, make your cauls yourself. You can buy cauls online or in woodworking stores, but unless they are very specific, or an extremely hard shape to make, you really should make them in the shop.
Not only will they teach you more about woodworking, but you will also understand them more because you were involved in making them.
Glue Makes Wood Swell
An interesting thing about wood is that is gets bigger when it gets wet. This can be from getting wet with water or other moisture, including glue.
When you are sizing things to glue together, especially pieces that are meant to fit inside one another, understanding this property of wood is important.
Now, the piece of wood that you coat in glue is not going to explode on you, and it’s not going to get too big too fast. It does take a little time for the glue to be absorbed by the wood, causing the surface to get wet, and making the wood swell.
This can be as little as several seconds, or as long as a minute or two depending on the species of wood.
The reason a few seconds is not a bad thing is because you can typically get your piece into the cavity in a relatively short time, and that means as long as you work without wasting time, you can get your pieces in place before the swelling even starts.
One thing that you can do to control for swelling is to test fit your pieces. If they can be put together by hand, without having to really press hard or hammer them together, you should be fine once the glue comes out.
If you need to stand on your pieces to get them together dry, the glue will make them swell just enough that they may not even fit together. When it happens, you have to wipe off the glue, and wait a while for the wood to expel the moisture and return to normal size.
If this happens to you, don’t worry. The process for removing the glue in most cases is not that involved, and you can start over again once the pieces are back to the right size. First, separate the pieces and begin taking off glue with a wet rag.
The process is largely the same as removing squeeze out, but this time you are trying to remove all of the glue.
If you have a main project that is difficult to construct, and a part that can easily be made again, start by cleaning the glue off the project. The glue on both pieces is going to be drying just as fast, so as you clean the main project, the glue on the part is still drying.
If the glue dries too much on the part, you will have to make it again, but this is far better than saving the part and having to make the whole project again.
Clean the surfaces with the wet rag, and then allow the project and the piece to dry. The rag cleaning is going to add a lot more moisture to the project, so it will take longer to dry. In that time, work on what you are going to do with that joint so the swelling does not ruin your glue job a second time.
Wood absorbs moisture, whether through glue, stains, finishes, or just water spilled on the surface. When that happens, the wood expands, and things that used to fit together may not anymore.
Consider this when you build, and work quickly when you are gluing. The more efficient you are, the less likely that you will have to take apart and clean a section of your project.
Woodworking involves taking parts and attaching them together to form a project. The way that the attachments are made is called joinery, and it simply means the joining of pieces of wood.
There are a number of ways to accomplish your joints in woodworking, and you will eventually fall into a few that you enjoy. There are also instances where a certain type of joinery is necessary for the style of project, and you might end up learning some of those as well.
Either way you go, you are going to need to know how to get one piece of wood to stick to another. Even the most simple of projects tend to have more than one piece of wood on them.
The way you get them to join together is important, because you are going to have to rely on that joint holding together for the life of the project. This is why picking out a good method that you enjoy is so important.
The most common and the most basic of woodworking joinery is by using glue. This is a process where two surfaces are coated with an adhesive, and they are held together until dry. Once the clamps are removed, the pieces are joined together.
There are a number of advantages to this type of joinery. First, the supplies that you need are very few, and you don’t have to spend a lot. All you really need is wood glue and some clamps.
You apply the glue to the surfaces that will meet up, and then you add the clamps so that the pieces stay where you want them to. Once dry, the pieces are joined, and you can then add more if necessary.
The down side to glue only joints is that they can be weaker than joints that also use another piece of wood to add strength. Though in cases of smaller projects, and projects that are not meant to be stressed along the joints, the glue alone method works just fine.
For the longest time, instruments have been made using glue alone for all of the joints, and rarely if ever has any kind of reinforcement or mechanical means been used.
They have lasted centuries in some cases, and continue to be built the same way today. Just because the glue only method may not be as strong as others, it is still very strong in general.
Another method that has already been alluded to is gluing with the addition of some other material between the joint that adds strength. This can be a dowel, or a biscuit, and it acts as a floating tenon that creates more strength at the joint.
On projects that have larger pieces, or pieces that will need to take a lot of stress like table tops, gluing the pieces together with biscuits or dowels adds more strength.
Dowels are small cylinder shaped pieces of wood that are drilled equally into each side of the joining pieces of wood.
Glue is applied, and the added material helps make the joint between the two main pieces stronger. In woodworking, dowels are used to pin pieces together because they are easy to work with, and easy to install.
Dowels are easy, because all you really need to be able to do is drill a hole and you can use dowels. Now, it does take a little skill to get the holes in the right places, but in general far more people have a drill in the shop than have a biscuit joiner.
In this way, the tools are already in place, so more people tend to go for the dowels than the biscuits.
Biscuits are small football shaped pieces of wood that vary in size, but are all around an eighth of an inch thick. They come in packages of several pieces, and you install them with a biscuit joiner. This is essentially a tool that makes a curved cut into the side of a board, enough for half the biscuit to sit inside.
The same cut is made on the other side of the board, and the biscuit is glued in between the pieces. This is a way to add strength, and help prevent the joint from coming apart when stressed.
Next, traditional joinery is a subject that you can dive deep into for years if you desire. The classic joints that have been used in furniture making and woodworking are truly some of the most beautiful around.
Also, you can study joints from other countries, where artisans have been working with different tools, so they came up with different joinery methods.
There is a huge movement in woodworking as I’m writing this to build overly complex, handmade joints. These are gorgeous to see, difficult to create, and are a true test of patience and skill for any woodworker.
If this is you, then prepare for a lifetime of enjoyment and challenge, because you can spend a long time working with these lovely traditional methods of holding one piece of wood to the next.
Some of these joints are intentionally very simple, though they are still all hand made and very strong functionally.
Others are more complex, and some are even complex on purpose. Whatever your flavor, learning how to join wood together without any non-wood materials is fun and exciting.
There are even woodworkers that create joints that require no glue. These joints hold together with pins and dowels, and are meant to be taken apart when the pieces need to move.
This is a really interesting type of woodworking, because you are creating something strong that is not held together with anything but the joints that you create.
There are a number of great books on making joints the old fashioned way, and they can keep you entertained for decades. Keeping this tradition alive in woodworking is important, because the old masters did very well with only a few tools compared to the multitude that we have at our disposal today.
It was through this simpler tool set that the woodworkers of old thought about what they were doing, and created pieces that have stood the test of time for centuries.
Getting into the mechanical means of making one piece of wood stick to the next, a fun and easy way to attach pieces is with a nail gun and glue. It’s almost too easy zipping around a project with the nail gun and firing nails into your project.
The first few times it can be a little tricky getting the hang of where the nail comes out of the gun. However, once you are comfortable that you are not going to fire shots out of the sides of your project, the fun really starts.
You can literally assemble a piece in a tiny fraction of the time that it would take to do glue only joints, because the nails are acting like tiny clamps.
Doing glue only joinery requires clamps, and many times they can get in the way of adding more pieces to your project. With brad nails, the nails themselves act as the clamps, so they are all internal, and never in the way of adding another piece.
You can work around a box, or a larger project by simply applying glue and firing nails. Once you are done, all you have to do is leave the project alone and the glue will dry. After that, the project can be handled, and you will have executed a very fast set of glue joints with nails holding them together.
The benefit to this kind of joinery is that you can complete your project quickly. If you have a lot of things to make, or you are doing an assembly line type of construction, then working with brad nails and glue is a winning combination.
As you get better and better with the technique, you will end up eventually employing several other assisting tools like quick applying glue rollers and bottles. These will let you get your glue where you need to quickly, and then you can follow up with the nail gun and fire away.
One down side of the nail gun is that you are going to be left with a lot of small holes that need to be filled. If you have a good gun, the hole will not be much larger than the head of the nail.
If you have a less expensive gun, or one that can fire narrow crown staples as well as brad nails, you may end up with a small slot that is indented into the wood everywhere you fired a nail.
If you really have fun firing nails, you will not have fun filling in all the holes. Such is life that everything fun has a down side. Once you have to fill all the holes you made while machine gun firing nails like they were free, you will be more judicious next time and only use as many nails as you need to hold the pieces together.
This is one of the tricks to working with the nail gun. You only need to fire as many nails as needed to hold the pieces together for the glue to dry. Adding more nails does nothing to make the project any stronger.
Another mechanical method for attaching pieces of wood together is nails and screws. While it is uncommon to see both on the same project, you can use nails or screws in a similar way to hold pieces of wood together.
In general, nails are a more old fashioned method of joining wood that is not as strong as screws. Again though, we are talking about a method that is very strong, and another that’s stronger than that, so there is no reason to fully stop learning about nails.
Depending on the type of nails that you use, you can make some very good joints and leave behind a nice classy look too. Nails have been used since humans have been able to make things from metal, and they look a lot different than they did in the beginning.
There are many types of nails, and you can find them in lots of different lengths and thicknesses too.
While there are certain styles of nails that are better for some projects than others, in general construction nails are used for rougher projects made from construction lumber and finish nails or more fancy looking nails are used for smaller projects.
This is just a quick and simple explanation, because depending on your project you might use finishing nails and hide them with putty. You may also use nails with bigger heads and let them be part of the final look.
There are a lot of ways to go with nails, and you should take a look at what it available if you decide to go this route.
If you are into history, and you want to use a more traditional nail, there are still places that manufacture old fashioned nails. There are even more places that harvest old nails from demolished houses and old structures and sell them.
These not only look like hundred year old nails, they are in many cases actually a hundred years old or more. These kinds of traditional materials are a pleasure to work with, and you get to tell a really interesting story whenever you show people your work.
After all, how many rustic tables are made with hundred year old nails from an old demolished barn? Probably not many, so you will have a unique piece on your hands too.
Getting back to screws, there are a number of different types of screws too, but the majority are very similar at least for the beginning woodworker. In most cases wood screws are a coarse threaded metal screw that is meant to be driven into the wood, with only the top of the head remaining visible.
In this way, you can decide how much you want the screws to be part of the design by how you sink the heads and whether or not you fill over them.
If you want screws as strictly a joinery method, and nothing that you want to see, all you have to do is sink them below the surface a little and then fill in the depressions with wood filler.
You will successfully hide the screws, though your patch work on the heads might require a little help because screw heads leave a large area to fill that might not match the rest of the wood perfectly.
Using screws, you can also work the heads of the screws into the design of the piece. If you look around, you can find very fancy looking screws in gold and solver colors that add to the look of your piece if you do it right. These are meant to be seen, and do not look out of place on most projects.
The benefit of screws over nails is that the screws hold on better. Since the screw has to be turned in order to remove it from the wood, it tends to hold on through pressure better than nails. Yes, screws can be ripped from the surface with a lot of force, but most nails will let go long before a similar screw.
Finally, though this is not a complete list of joinery methods, one that can’t be left out, that is perfect for beginners is the Kreg Jig. This is a self contained jig that makes it very easy to make pocket holes, and join pieces of wood together.
A pocket hole is an angled drill hole that conceals the head of a screw and allows you to joint pieces together either flat or in three dimensions.
You simply clamp your pieces, drill the hole to the pre-determined depth based on the material you are using, and then drive a screw through both pieces. The system makes very strong joints, and they go together really quickly.
Also, the surfaces remain very flat and flush to each other, which is great for people making cabinet face frames or other flat laying projects.
Kreg Jigs come in a number of configurations, though even the smaller jigs are easy to work with. It is recommended that you get a good clamp for the system, because the flushness of the pieces is really dependent on you getting the pieces clamped well before you drive the screw.
If the piece moves, you will end up with a joint that is slightly off, and it will require sanding or filling.
This list of joinery methods is by no means every type that is out there, and you should look around as a new woodworker for the kinds of joinery methods that you are comfortable with.
These are a good place to start, and you can make quite a few great projects using only one method for the rest of your life. If you like variety, you can experiment with other methods and add them all to your list of skills.
Either way, when you join wood together, you want to have strong joints, and the quality to last a very long time.
Part 39 – Wrap Up
I hope you liked Part 39 of A Beginners Guide to Woodworking: Helping New Woodworkers Make Better Projects.
As you can see, this is a different kind of beginner woodworking book, and I encourage you to get a copy for yourself so you have it all in one place.
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