Why We Do It
Many people cut scroll saw projects for selling at craft fairs and shows. Some more intricate fretwork patterns and portraits can take a great many hours of cutting to complete. In order to make more effective use of your time and make scrolling profitable, you can use stack cutting to cut multiples of a pattern at once.
While increasing production speed is a great reason for stack cutting, it’s not the only one. When cutting very thin wood, the wood doesn’t offer offer much resistance to the blade. This can make it difficult to cut intricate designs accurately. This is why I will always stack at least one extra layers when cutting 1/8″ (3mm) material and often recommend doing so in my pattern instructions unless the piece is simple like a plaque backer.
Double-Sided Carpet Tape
There are several ways you can go about stack cutting. I am going to begin by discussing the technique I used when I first started. This method is easy to set up and doesn’t allow the layers to move at all if done properly. An advantage to using this double-sided tape method is that your pieces of wood can be of different shapes and sizes when stacking them together.
The first thing I have to mention about this method is tape selection. There are many different kinds of carpet tape available to choose from and some will work much better than others. You want to avoid any tape that has a foam core because when you try to separate your layers of wood after cutting, the foam will split and you will have great difficulty removing all the adhesive and foam from the wood. I have had great success with fabric core tape in the past however it can be hard to find. If you can find fabric core carpet tape you may want to give it a try.
I am currently using Scotch Brand Outdoor Carpet tape CT3010 which works great. This is definitely the strongest sticking tape I have used so you only need tiny pieces to hold your wood together. It does however still require a little work to get the adhesive off. This tape will also leave traces of glue behind on your scissors which can easily be removed with mineral spirits.
Some points to remember:
- Be sure not to stack together more layers than your scroll saw or blades can handle. I generally don’t recommend stacking to any more than 1/2″ thick with really hard woods because any thicker than that will require you to reduce your feed rate significantly. With very fine blades, I find 3/8″ total thickness of hardwood as optimal.
- You’ll want to use very small pieces in the work area to hold your layers together if you use the recommended tape (~ 1/2” square pieces unless you are working on something really big).
- Keep the tape pieces away from any delicate areas in the pattern to reduce the chances of damaging your scrollwork when you separate the layers.
- You can be more generous with the tape in waste areas on the wood however it is best to have one or two very small pieces in the work area to prevent your layers from moving when the waste is cut away. This way your layers are held together firmly even as you approach the last part of the cut.
- To separate your layers, carefully slide a small knife in between the layers near where the tape is and gently pry apart by twisting the knife until the tape unsticks. Repeat this for each piece of tape.
- The remaining tape should come off more or less in one piece leaving a small amount of adhesive residue on your wood. I recommend gently shaving the majority of it off with your knife and, if any still remains on the wood, you can use alcohol or mineral spirits to clean it up.
Packaging Tape Method
Another common way to stack cut is to use packaging tape to hold your layers together. When using tape like this, it is best to cut all of your pieces of wood to the same dimensions before stacking them together. You then go around the entire perimeter of the wood stack with pieces of packaging tape. This is generally quicker to get set up than carpet tape and is my preferred method.
As a side note, an added bonus to using packaging tape is that the tape will lubricate your blade and greatly reduce the chances of getting burn marks while you cut. It is often a good idea to use some sort of tape all over your pattern: Either masking tape underneath the pattern or packaging tape over the pattern.
Additional points to remember with this method:
- When cutting, be sure you do all of your inside cuts on a piece before cutting its perimeter so that your layers are held together the entire time you are cutting.
- You will have to plan your cuts so as to always be sure that you wood is held together tightly from all sides. As you cut pieces off, you may need to add more pieces of tape to be sure your layers don’t move with respect to each other.
Conclusion
I believe most if not all scrollers out there will eventually have a use for stack cutting. Sometimes a particular pattern requires multiples of the same piece, other times you may want to do multiples of a project, or you may just want to add an extra layer of wood to thin stock just to have some extra resistance when cutting. In any of these cases, stack cutting is an effective technique that will make your scroll saw time easier. While these two methods aren’t the only ways to stack cut, I find they are easy and effective.