Introduction: Use Duct Tape, a Sandblaster, and a Torch to Make a Sign
There are a lot of ways to make the artwork on a sign. I decided to try something new. It turned out faster than carving and the result was exactly what I was looking for. I still used a couple computer programs to design the sign and for the griding, but I wanted to keep it as low tech as possible. Kind of a tribute to times before all the CNC routing and 3D printing. (Not to say that I am anyway against such things and have a huge desire to own anything high-tech!) This is a nice project to get back to getting your hands dirty.
Yes, we can mark this down as another use for duct tape!
Before we go any further, I need to address some safety concerns. You need to be very comfortable with fire, and have an environment where you can use open flame. Sandblasters are very messy and you need to be prepared. Also, a well grounded knowledge of woodworking is not necessary, but will come in handy. I will try to fill in any gaps in how to work with the wood where I think it is unique to this project.
Materials you will need:
Hardwood boards glued into panel (size is up to you, but you should have it rather thick). I chose 2" thick rough cut hard maple. It will work better if you use a closed grained wood (no open pores).
Metallic tape, usually used in automotive applications
Sandblaster and relevant equipment i.e. mask, gloves, sand
MAPP gas torch
Small butane torch
Xylene or other solvent
Scotchbrite pads/steel wool 0000
Artwork, either full size or to scale with gridlines
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: Make Your Artwork and Transfer It to Your Sign.
Prepare your board by sanding the face to a nice finish. I found out that if you have any irregularities such as sanding marks or gouges, the charcoal will settle there and you will have black marks on your light background.
Cover the entire front side of the board with one layer of duct tape followed by one layer of the metallic tape and then another layer of duct tape. You only have to cover the area you will be doing your artwork with all three layers, but to be on the safe side, cover more than you'll need. Better to have too much and be protected than to find out later that you don't have enough layers and your wood burns.
Make your artwork. Either draw it directly on the board or use a computer. I used a computer and used a font that was inherently irregular. This helped with any oopses I had during the process. Transfer your artwork to the board. If you only have a scale drawing, as I did, you'll have to grid out the drawing and the board. Then it is only a matter of sketching the artwork using the grid as a guide. I used ViaCAD Pro to make the grid on the artwork. This way I was able to make 1" squares to scale very easily.
When working with grids, it is important to have a system with which you can have the grids in exact proportions to each other. To grid in ViaCAD Pro, you need to open the artwork in a 2D project and set your dimensions to match your sign. You can then draw the horizontal and vertical lines by "snapping" them to the workplane grid. It works best with 1" squares. Using the computer program saves you from doing some math!! I've done it with other pieces and I know from experience, the computer is the way to go! However, you can also do it without the computer by using a ruler on your scaled copy and figuring out the right size to make your small squares to match with your larger squares. For instance, if you make your small squares 1/4" to match with your larger 1" squares, you will have a sign that is 4 times larger than your piece of paper. If your paper is 8.5" x 11", then your sign will be 34" x 44".
Lay out your grid on your tape covered sign using the T-square, ruler and the Sharpie. You should have 1" squares. If your sign is not exactly square, you will find out in this step. If this happens, just choose a side to call "normal" and work from there. Just make a mental note to trim your sign at the end (before varnishing). If you end up trimming, use a straight edge guide and a circular saw. To keep the saw from leaving marks where it skids along the surface, just put a couple rows of painters tape on your board where the saw will slide along the straight edge.
To sketch according to the grids, just count your squares and draw the design in each square individually. This works great in breaking down a large project into more manageable pieces (1" squares to be exact).
Step 2: Cut Out the Artwork
Cut out your artwork using the razor blade. Being careful is important, but remember, your blade is not the worst this duct tape is going to see. I transfered the cutings to a seperate piece of paper and used them again as a stencil for painting. Worked great!
Step 3: Sandblaster!
Time to sandblast. The soft texture of the duct tape allows it to withstand the sandblaster. Make sure you don't destroy it with too much pressure though. It'll take some time to get the feel of how high to set the sandblaster and how close you want to be. You'll want a pretty good relief into the wood. This gives the piece some good depth. You'll also be able to introduce some texture at this point. On some of the really small detail, such as the shine of the horses eyes, I had to use a rod to hold the duct tape in place while sandblasting.
Step 4: Burn Baby Burn!
You guessed it! Now it's time to burn! I used a MAPP gas torch at first in the larger areas, however, this is not necessary. It was too large and a little hard to control. Notice in the pictures how the tape is melting and the metallic tape is rolling back. If this happens, just wait for the metal to cool and carefully stick it back down. The duct tape burns well so you'll have to watch out and use the flame sparingly. Better to burn a section and let it cool while burning another section. If you burn too much too closely, you'll overwhelm the tape layers and still get charred wood underneath. This happened to me in areas with really fine details. Don't stress too much if this happens though. I'll tell you a way to deal with it later. I had to keep putting out volunteer fires that would start on the duct tape. The last layer of tape incidentally would start bubbling underneath it all, however it still did a great job in protecting the wood.
Need I remind you to be careful?! Open flame, burning wood, burning duct tape... BE SAFE.
Remove tape layers and remaining residues. I had to use a chisel to scrape the melted glue off most of the edges, but it came off pretty easily. The melted glue left a very sticky residue along the edges which I found came off very easily with Xylene. You need to be careful not to pull charcoal out of the lettering with the solvent onto your light colored wood. You can wipe off any smearing with a clean cloth, however the charcoal will settle into the pores and irregularities of the wood. This is why you need a nice smooth surface before starting and a closed grain wood.
Step 6: Time to Sand
Sanding at this stage is to clean up any overburned areas around your artwork. Some areas may have gotten hot enough to burn through the layers. The most susceptible areas are the small intricate ones. One nice thing about relieving the artwork first is that if you have a section that burned, you can remove the burnt layers with either sandpaper or a chisel and get the light coloring to show again. From a distance, you will never know that it isn't the same height as the other light colored wood. Use the steel wool in the artwork itself to remove any soft grainy charcoal. This will leave a rather smooth surface and also make the black more uniform. This stage should only be done after your solvent has fully dried from the previous step. (With xylene, this doesn't take long). This is when you need to get the sign to where you think it is finished and ready to varnish. Here are some close ups of the results I got at the end of this stage.
Step 7: Finishing Up
I chose to use marine varnish, however, you can use anything you like. The main thing to watch out for is the first coat needs to start in the charred areas. Put a light coat on being careful not to stray out of the burnt areas. This is because the varnish will act like a solvent for the charcoal and you can smear the dark pigment onto your light colored wood. After you have a coat in the artwork, then you can finish coating the rest of the sign. If you had some "coloring outside of the lines" with the charcoal, and it hasn't dried yet, you will be able to use your brush to "erase" the oopses with this coat. I used a foam brush for all the varnish coats. Worked well. As usual, the main downside is getting small bubbles in the coats. I found there is a vast difference between extra cheap foam brushes and just cheap foam brushes. The really cheap ones had more problems with creating bubbles. Of course, you can always just use a standard paint brush, but I dislike cleaning brushes. Expect to put at least 3 coats on. More the better. Remember to varnish all sides of the sign the same. This will help it weather well and resist warping.
Well, there you have it. If you either don't have access to the high-tech gadgets that are out now, or if you just want to try something new and more hands on, here's a great way to do it. I hope you have success in your adventure.