Sign Sandblasting Tools and Tips
It's easy to break into the sign sandblast business without prior woodworking experience when you use SIGN·FOAM . Some of the advantages are: you will not waste material, less time will be spent with the blasting nozzle in hand and you will not wonder about the life expectancy of your wood sign as SIGN·FOAM outperforms wood. Sandblasting is one of the most popular machining techniques used in the sign industry today. It is one of the easiest ways to produce high profit, three-dimensional signage. If you are familiar with sandblasting, it is just as it sounds. You use sand and air pressure to blast away the unmasked SIGN·FOAM background, leaving graphics behind. It is important for the first-time sandblaster to understand this technique is based on a method. We strongly suggest that you experiment with SIGN·FOAM before blasting a sign for your first paying customer.
Tips on Buying Sandblasting Equipment
Everything will fit easily in your current shop. You may already own the most expensive piece of equipment required; the plotter. With an investment of around $3,000.00 you can begin to turn out three dimension signs that pay back your investment in a few projects. In addition to a plotter you will need to invest in the following equipment:
- An air compressor: $1,200.00 - $1,500.00
- The blaster or pressure pot with nozzle: $400.00 - $600.00
- The GRAIN·FRAIM , for simulating wood grains in SIGN·FOAM :$500.00
- Oil and water trap: $100.00
- Miscellaneous : (rubber gloves, respirator, hood ) $200.00
Estimated $2,00 - $2,900
Tips for Recommended Sandblast Equipment Specifications
- The Air Compressor:Must be a two-stage compressor with at least a 5-hp engine, a 7-hp is more efficient. You will want at least an 80-gallon tank reservoir; a 100-gallon tank would be better. You are not just operating a power tool you are blasting air at the sign. Without an adequate-sized reservoir tank, the compressor will have to work overtime to supply the air required. This excess work will prematurely age your equipment. If you already own a compressor with a smaller tank, you may want to consider purchasing an extra reservoir.
- Types of Blaster Guns:
- Pressure Pot Type Gun: Both the air and the abrasive are pressurized.
- The Siphon Feed Type Gun: The abrasive simply falls into an airstream.
- Protective Gear: You will want to protect yourself from head to toe; sand can bounce off the sign with stinging velocity.
- A Clean-air Supplied Hood: Is worth the investment if you plan on doing a lot of blasting. If you are going to blast with silica sand, a hood and air supply are both absolutely necessary. You might also use aluminum oxide for blasting.
Tips for Which Blaster Gun Type to Use in Commercial Sign-making: It is recommended that you use a pressure pot gun for serious, commercial sign-making. The blaster pressure pot should hold at least 60 pounds of abrasive.
- Nozzles for Your Blasting Gun: There are two types of nozzles available; ceramic or carbide. Your choice will depend on the blasting abrasive you choose. With the setup described above; 60 pounds of abrasive, a 1/8-inch nozzle is recommended.
Tips for When to Replace Gun Nozzles: These should be replaced when they wear to 3/16-inch in diameter. If the nozzle diameter gets too large an excessive amount of abrasive will travel through the sandblasting fittings. Excessive nozzle wear and the resulting excessive airflow will add strain to the compressor motor, shortening its life.
Tips for Efficient Sandblasting Methods: The key to efficient sandblasting is to regulate the combination of pressure (PSI) and volume (CFM). Too much pressure will pulverize the SIGN·FOAM , too little pressure will cause the process to take too long.
One of the intrinsic advantages of SIGN·FOAM is its consistency as a material. Unlike wood or other HDU's available; SIGN·FOAM is consistent each and every time. This means once you have your blast equipment set, you will have little need to adjust it again. The best approach is to start slow and work up to an optimum pressure.
Generally speaking, when working with the equipment described above, blasting between 80-100 PSI will be adequate. This should generate between 15-25 cubic feet per minute of volume of sand and air running through the blaster. Using these measures you should be able to blast a 4' x 8' SIGN·FOAM sign 3/16 inches deep in approximately 30-0 minutes. Blasting this same size sign in wood could take 90 minutes or more.
Tips for successful Blasting with Abrasives
Because SIGN·FOAM is relatively soft compared to other substrates; you have a wide range of abrasives available to you. All abrasives are sold in varying grades, from fine to course. Two things will vary depending on the grade you choose speed to complete and texture. SIGN·FOAM has an even, stucco-like texture after being blasted. This is an attractive, readable background.
- The finer grit abrasive you choose, the longer it will take you to blast your sign and finer the background texture you will create.
- Conversely, the courser girt you use, the faster you will blast and the more exaggerated the background texture.
- The abrasive we recommend most is aluminum oxide. Aluminum oxide has many other advantages as well. It does not breakdown as readily as other blast abrasives and can be recycled up to 100 times when blasting SIGN·FOAM .
Safety Note on Blasting with Silica Sand: For many years, silica sand has been the most commonly used blasting abrasive. Although it will sandblast SIGN·FOAM , it is strongly advised that you do not use silica sand,as it poses a very serious health hazard. Long -term exposure to free floating silica can cause a lung disease called silicosis. Silicosis is a respiratory disease that has no cure and is 100% fatal. This health concern has led to the restriction of use of silica sand in many parts of the country, so be sure and check your local ordinances for OSHA and EPA restrictions. There are many safe alternatives to silica sand, including a coal slag called Black Beauty, glass beads, crushed walnut shell or garnet and aluminum oxide.
Safety Note and Tips to Minimize Aluminum Oxide Dust: Although aluminum oxide is an inert substance that poses none of the health hazards associated with silica sand, always take care not to breathe the dust created while sandblasting.
As a practice, SIGN·FOAM dust may be sifted through a screen to keep out unwanted debris and this mixed with the aluminum oxide will act as a buffer, actually protecting your blasting equipment from excess wear.
However, take care not to reuse the same abrasive if you blast using redwood or cedar. The fibrous nature of this dust contaminate will collect the moisture from the compressed air and likely clog your sandblaster.
Tips for Grit Size and Abrasive
Once you have chosen the abrasive, you will need to decide on the grit size. With aluminum oxide a 36 mesh is perfect. This is equivalent to #1 grade silica sand. Keep in mind the finer the abrasive, the longer the blasting time and the more aggressive the background texture; however it is possible to pulverize SIGN·FOAM by using too course of an abrasive and for too long. So when in doubt, use the finer grit abrasive.
Once you are familiar with the operation of your sandblast equipment, you are ready to get to work.
Step 1: Transfer Your Design: The first step is to transfer your design to your sandblast stencil and then on to the SIGN·FOAM . A sandblast stencil is a thick rubber tape with an aggressive adhesive applied to the back. It is flexible and can be cut by hand or on a computer plotter. If this is your first attempt at sandblasting, please start slowly. It is a good idea to practice on some scraps or sample pieces of SIGN·FOAM . What you will learn from the time and effort invested in experimentation, will reap benefits in the near future.
Step 2: Mask Your Sign: All parts of the sign that will be sandblasted are cut from the mask, protecting any smooth surfaces you wish to keep. Use a medium tack mask for pre-primed HDU, and a high-tack mask for unprimed HDU.
Step 3: Begin Blasting, 80 to 100 PSI is a good starting point for SIGN·FOAM . When you begin, stand 2 to 3 feet away; this will "widen" the blasting pattern to ensure an even background. Move the nozzle slowly and evenly from side to side in a horizontal motion. Try to blast "straight on" to avoid undercutting the letters and graphics, keep the nozzle moving at a steady pace. Stopping in one place can create a depression in the surface of the sign that may be difficult to correct. You can achieve subtle effects with HDU.
Step : Check the Depth: Once you have made two passes across the sign, pause and check the depth of your blast. This is important. The total depth of the blast is a matter of personal preference, but a depth between 1/8th and 3/8th is sufficient to add dimension. It may not seem like much, but adding this dimension along with your paint job will add dramatic depth to your projects. If you blast too deeply, you lower the strength characteristics associated with SIGN·FOAM . Also, you may have problems with the readability of your sign and very deep graphics will cast shadows throughout the day in the light.
Tips for Adding a "Grain Look" to Signs: For customers who desire the organic look of sandblasted redwood, grain can easily be added using GRAIN·FRAIM. This consists of a metal, tubular base frame and a wire frame set within. GRAIN·FRAIM is engineered with a "tension bar" that allows you to adjust the tension of the wire and control the look of the grain. The look is so successful at simulating a wood grain texture; you may find yourself adding grain as a design element often. GRAIN·FRAIM enables you to place the grain exactly where you want it. As a sign artist you are no longer limited and can achieve multiple background textures on one sign using one material. Combining the natural texture of SIGN·FOAM and the look of redwood is a great look.
Tips for Blasting when using GRAIN·FRAIM
The actual blasting process is the same, with one simple exception. You will want to support the GRAIN·FRAIM on a flat surface in front of the sign. The wires may touch the sign and must not be more than 1/2 of an inch away from the surface. This is very important, especially for a larger signs where the GRAIN·FRAIM will have to be moved. Please note as long as the wires are 1/ of an inch or closer, moving the GRAIN·FRAIMTM will not create a problem. You can remove GRAIN·FRAIM to examine your work and replace it without concern, the wires will seat themselves right where they came from and the grain will continue seamlessly.
Maintaining continuous grain across a sign surface greater than the dimensions of the GRAIN·FRAIM is easily accomplished. To begin blasting, move the nozzle back and forth in the direction of the GRAIN·FRAIM wires.
Tips for Signs Longer than the GRAIN·FRAIM: First position the GRAIN·FRAIM at the bottom corner of the sign, and then proceed to blast. To avoid leaving a "seam", do not blast up to the bracket, but reduce the depth of the grain as you approach within " of the edge of the GRAIN·FRAIM. Now simply slide the GRAIN·FRAIM across the sign, leaving approximately " of the previously blasted portion within the new blasting area. Continue blasting. The wires will line-up with the existing grain and continue the texture with no overlapping seam.
Tips on Avoiding Seams when Blasting a Sign Taller than 2' Height of the GRAIN·FRAIM: The same method of overlapping the blast area is used as described in the paragraph above. Simply blast the lower portion of the sign and to avoid leaving a "seam", do not blast up to the top of the bracket, but reduce the depth of the grain as you approach within " of the top edge of the GRAIN·FRAIM. A 2" x 4" or similar support is clamped to the board, making sure that it spans the entire width of the sign to act as a ledge to slide the GRAIN·FRAIM across. Make sure that " of the previously blasted area is above the clamped ledge to prevent a visible seam. The wires will line-up with the existing grain and continue the texture with no overlapping seam. Slide the GRAIN·FRAIM across the sign as needed.
Tips for Creating Alternating Grain Designs: When the design calls for alternate grain direction or straight sandblasted texture, remove these portions of the stencil and continue blasting as before, taking care to protect the previously blasted grain. Also, blast the sign at a slight upward angle so that the grain created will shed water [instead of trap water]. It is important to periodically check the depth of the grain you are creating. When you have achieved the desired grain texture over the surface of the sign, remove the rounding from the top of the "fins" of the grain and lower them below the raised masked area. Having done this, it will be much easier to apply the finish materials to both the background and raised areas.