The very term “sandblasting” is somewhat misleading. In our industry, the process doesn’t use ordinary silica sand and it isn’t traditional blasting. True sandblasting is used for industrial applications like removing paint and cleaning metal parts, whereas what we do when we decorate glass and other substrates with beautiful, detailed images using the technique is better described as “sandcarving.” Besides, it just sounds better. Here’s a look at what you need to know about sandcarving in the Recognition & Personalization Industry.
Understanding the Terminology
The first step to learning a new skill is to learn the jargon that goes along with it. In the case of sandcarving, the jargon is pretty straightforward but there are a couple of terms that can throw the newcomer.
Sandblasting vs. Sandcarving: In this article, I will use these terms interchangeably but technically, these are two very distinct things as I previously mentioned. What we do uses the same basic process as sandblasting but on a smaller scale.
Masks/Stencils: In sandcarving, “masks,” aka “stencils,” contain the images to be carved. A stencil has open areas which expose the surface to the sprayed abrasive stream and allows the material to be eroded, and it has closed portions that protect the surrounding areas of the material that won’t be blasted. Note: “Masks” can also refer to tape, paper, vinyl or other material that is used to protect the areas of the object to be blasted that are not covered by the design mask/stencil.
Grit/Media/Abrasive: The material used to sandcarve objects is often referred to as “grit” or “media” or “abrasive” and can consist of many things, even ground up walnut shells. Mostly we use silicon carbide or aluminum oxide for decorative sandcarving. These are industrial abrasives designed for this purpose. We never use natural silica sand like you find on the beach (partly due to health concerns related to breathing silica dust).
Abrasive is measured in “grit sizes” such as 150 or 180 grit, and the size you choose depends on the substrate being blasted. In general, the larger the particles, the faster and deeper they cut. For example, in the case of blasting bricks, you might use a large particle grit size as low as 70-100 whereas most glassware is blasted using 180 grit silicon carbide. In case you’re wondering, the grit size numbers pertain to the mesh count through which the media is filtered, so the smaller the number, the larger the particles.
Blast Cabinet: This is where the actual sandcarving takes place. Although most cabinets look pretty much alike, they aren’t. What is important to understand at this point is that there are two basic types: The siphon type and the direct pressure type. The preference is to have a direct pressure type. It requires less compressed air, produces a stronger stream of media and doesn’t require a constant shaking of the cabinet to keep media where the blasting tool can pick it up. It also keeps the used and unused media separated which can greatly reduce the frustration of stopped up nozzles. You can identify a direct pressure cabinet by a pressure pot standing next to the cabinet and the fact that the nozzle has only one hose which delivers both media and compressed air simultaneously.
A siphon type cabinet uses a nozzle with two hoses and draws the media from the bottom of the cabinet. A direct pressure system stores the unused media in the pressure pot and the used media in the bottom of the cabinet. The used media can later be reused after being sifted through a screen to remove large particles and unwanted debris.
There are a number of other terms you will need to learn but these will be clarified as we go along.
Sandcarving Equipment & Supplies
There are two major suppliers of sandcarving equipment, supplies and training in our industry. They are Rayzist Photomask, Inc., located in Vista, CA, and IKONICS Imaging which is located in Duluth, MN. Both offer similar product lines including their own versions of the various photoresist stencil material, blasting cabinets and related equipment. Both offer training opportunities in their own facilities and across the country at various trade shows in addition to a variety of free educational opportunities. The IKONICS line of products is also available from JDS Industries.
There are at least seven items needed to do sandcarving. Those are:
- Blasting cabinet: An enclosure, usually metal, where the blasting process takes place.
- Air compressor: A source for compressed air. The higher the air capacity, the better.
- Blasting media: An abrasive material that passes through a nozzle under pressure and onto the substrate to etch a design.
- Mask or stencil: Stencils can be made from a variety of materials, including brass, rubber, vinyl, heavy paper or light sensitive film.
- Exposure unit: This is used to expose and process photoresist stencils in-house for sandcarving.
- Water source: When using most of the light sensitive films to make photoresist stencils, you will need a sink and faucet to spray the exposed film with water to wash out the exposed areas of film.
- Computer with software, a printer and paper: To create your sandcarving designs, you will need a computer and printer plus some kind of design or graphics software. Most people probably use CorelDRAW for this but any graphics/design software, including the free versions you can find online, will work.
About the Blast Cabinet
Ultimately, this will be the most important and most expensive equipment decision you will make in connection with sandcarving. Blast cabinets start at less than $100 for a benchtop model and climb to over $14,000 for the largest top-of-the-line model from IKONICS.
If you are thinking, “I didn’t pay that much for my first house,” I sympathize with you. I didn’t either. However, the old adage “you get what you pay for” comes into play here. The difference between Harbor Freight’s $180 floor model blast cabinet and an average cabinet from one of the two industry-based suppliers, at about $6,000, is like comparing a Cadillac Escalade to a bicycle.
First, buying a “hobby” cabinet like a low-end model from Harbor Freight isn’t representative of the total cost. (There are actually lots of cabinets in this price range available from other sources, including Amazon, but the Harbor Freight makes a good example.) Along with the basic cabinet, you will need to add some other things and, although these aren’t expensive, they will require some expertise to install. Included will be several hoses, quick-disconnects, water separators, adjustable pressure gauges, an auxiliary blow nozzle and several blasting nozzles. These are all required just to make the thing work.
If you are even halfway serious about sandcarving and you decide to go with one of the inexpensive hobby cabinets, you will want to add a pressure pot so you can convert the cabinet from a siphon type to a direct pressure type air supply. This will not only require installing a pot (available from Harbor Freight for about $120), it will require some experimentation to get it to work smoothly. Along with the pot, you will have to change the type of nozzle you use. You will also want to add some kind of dust collector, so you can see what you are blasting and that too is available from Harbor Freight for about $150. That will probably require cutting a hole in the cabinet and connecting the collector. You will probably want to mount the dust collector as far away from the cabinet as possible since it is about as loud as a Shop-Vac (in fact, some people use a Shop-Vac). At the very least, you will want to wear ear protection.
Now that you have spent close to $500 for your “inexpensive” hobby cabinet, you are on your own. Blasting cabinets aren’t really complicated if you understand the principles involved but they can certainly be intimidating to a novice. What if things don’t work like they should (and they probably won’t)? Who do you call for help?
This isn’t to say that someone who just wants to “test the waters” and see if there is a market for sandcarved products shouldn’t go the hobby cabinet route, but before you invest a ton of time and money into an entry level blast cabinet, look carefully at the differences that really separate the two types of cabinets. If you are serious about adding sandcarving to your business model, don’t waste your time trying to work with toys. True, the professional cabinets cost more, even the least expensive is about $4,000, but these professional level cabinets come completely assembled and ready to load abrasive in. Just connect an air hose and start personalizing products.
Once you work with a cabinet for a short time, you will begin to see some of the problems that can occur, the worst of which is probably not being able to see through the window to view what you are blasting. Inexpensive cabinets have no provision for either keeping the glass clear or protecting it from the abrasive. Many professional cabinets include an “air curtain” to keep the abrasive dust away from the glass so you can see. They also feature stick-on protective film to protect the glass.
Technical support in a new venture is invaluable and when you purchase one of the professional cabinets, you get continuing technical support. This can easily mean the difference between success and failure of a new company or a new profit center. Continuing education is offered in a variety of forms, including online where you can watch and re-watch instructions until you have mastered a new technique. Educational videos are free to anyone, including YouTube videos, but translating from what you see being done with a professional cabinet and one from Harbor Freight can be confusing.
Pay attention to the many features included in the professional cabinets. One model can be raised and lowered electrically to allow the operator to either stand or sit while working. Others include the ability to blast objects using “templates” in a “tapeless port” without having to mask anything more than the area being blasted which brings a huge labor savings.
Automatic abrasive filtering is another feature of some cabinets. This eliminates having to manually filter used abrasive back into the pressure pot and places the abrasive that can’t be used any longer in a plastic bag so it can be easily and cleanly discarded.
Foot switch operation is another feature of the professional cabinets. Although this feature can be added to the inexpensive cabinets, the cost can run as much as $400. I built a foot switch for my test cabinet using a control and foot switch from Amazon and an old power supply (a Wall Wart transformer that converts AC to DC power) to build a working control switch. This requires some experience with electronics, and the control must be installed where it controls clean air and not the flow of abrasive. Even this makeshift switch cost about $50 to build and who knows how long it will last?
Finally, the way the cabinets are made matters. The less expensive cabinets are made of thin steel and are painted. Blasting within a painted cabinet will soon remove the paint and mix it in with the abrasive which isn’t good. Better cabinets are welded steel that is about twice as thick as other cabinets and is then powder coated for long life and to resist the abrasive. While the inexpensive cabinets may be a way to get started, they won’t hold up to heavy use while the professional cabinets will be an investment you will make only once in a lifetime.
About the Air Compressor
This is what IKONICS Imaging recommends on their website: “This will vary with the size of nozzle and type of blaster. For example, a pressure pot with a 3/32" nozzle may only need 7 CFM of air at 40 psi. A siphon-fed blaster may require double that amount. It is always better to have MORE air flow capability than you need.”
Here is the translation for novices: The most common nozzle used in sandcarving is 3/32" (based on the opening at the end of the ceramic nozzle). If you have a pressure pot system (the pressure pot is a containment vessel that stands next to your blast cabinet that holds the blasting media), you will need a minimum of 7 CFM at 40 psi of constant air from your compressor. If you have a siphon-fed system (this means the blast media is in the bottom of the cabinet and sucked up through a hose into the nozzle), you will typically need 14 CFM at 40 psi of constant air. In short, with a siphon-fed system, you’ll need a much larger compressor and air storage capability which translates into more money.
Compressors are sold based on a variety of variables. Ideally, everyone would just buy the biggest compressor they can find and that should be fine but those monster compressors are expensive, very heavy and take up a lot of space. All compressors are loud and should be located as far away as possible to reduce the noise. Additionally, a lot of the larger compressors require a 240 volt electrical connection.
There are several recommendations various experts have made about what compressor to purchase. Those in a nutshell are:
- Buy the biggest compressor with the biggest storage tank you can afford.
- Buy something bigger than what the cabinet manufacturer recommends.
- Buy one with a cast iron head. The specifications will indicate the type of head.
- Don’t just look at how much air it can put out, look to see how long it can put out the required amount of air. Most compressors require a cooling off period to equal the amount of time it has to run. This is why a bigger storage tank is preferable. Some compressors have an 80/20 cycle time which is terrible for sandcarving as it means for every two minutes you are blasting, you will need to let the compressor cool off for eight minutes.
- Little “pancake” compressors may work for small jobs but should be avoided.
- If you aren’t sure which compressor to buy, ask about the return policy. Take a compressor to your shop and try it out. You should soon know if it is too small (it will run more than it cycles off). Compressors put off a lot of heat and a too-small compressor will burn up in a very short period of time, especially if the head is aluminum and not cast iron.
About Support Products
Of course, there are other nice things and some simple tools to use in a sandcarving operation and although they may not be “must haves,” once you use them for a while, you will wonder how you got along without them:
Wire Wheel: This is sold by both Rayzist and IKONICS and looks like a brass wire wheel like those used in hand drills to clean off metal only this one has a wood handle. It is used to pop air bubbles in a mask.
Masking Materials: As I mentioned earlier, one type of “mask” is the mask used to create the design (photoresist film) while the other is just a protective mask that goes around the photoresist film (mask) to protect the areas that you don’t want to blast. All kinds of materials can be used for this protective masking, including butcher paper, painters’ tape (I don’t recommend masking tape because it does nasty things when it gets wet), etc. Although some people cut their blasting mask large enough to cover the entire object, in my opinion this is a terrible waste of the photosensitive film and can be very expensive. If you have a vinyl cutter in your operation, you can use your vinyl waste as a protective mask. Probably the best thing, however, is blue painters’ tape. It behaves itself when wet, removes easily, comes in a variety of widths and isn’t too expensive.
Gauntlets: Most blasting cabinets have a pair of 6" or 7" openings in the front for your arms with rubber gloves semi-permanently attached. If you are comfortable using these, that’s fine but many people are not—especially people with small hands. For these folks, installing a pair of gauntlets is a good solution. Gauntlets are rubber or cloth boots that attach to the arm openings in place of the rubber gloves. On the opposite end there is an elastic opening rather than a glove. This allows you to insert your hands either bare or with a pair of gloves that fits your hands. Both IKONICS and Rayzist sell a version of these for 6" openings.
A key equipment component is an air compressor that is large enough to handle long run times, such as this one from DeWalt.
Gloves: There are a thousand types of gloves that can be used with gauntlets—even hospital type gloves—but I prefer “mechanics’ gloves” which are available from hardware stores or online. I especially like a pair sold by Harbor Freight for about $3.
Vacuum/Reclamation System: This is a specialized vacuum that removes and recycles blast media from the blast cabinet. There are actually several reasons for adding a vacuum and/or reclamation system to your operation if your system didn’t come with one from the factory. First, abrasive is expensive to buy and expensive to ship. Being able to reclaim and recycle it saves money. Perhaps even more than that, having a vacuum/dust collector on your system helps keep the viewing window clear so you can see what you are doing inside the cabinet. Both companies offer blasting cabinets with these built in. If you want to add one to a system that doesn’t have one already, IKONICS offers three ranging in price from about $800 to $1,750.
Pressure Pot: It is possible to convert a siphon system to a pressure pot system. Just add a pressure pot, a little plumbing and you’re all set. New plumbing is required to and from the pressure pot and a different type of nozzle will probably be needed. Chances are, you will also want to add a foot switch if you don’t have one already since the better nozzles for this type of system don’t have “buttons” or “switches” to control the flow of air and blast media.
Education: Both IKONICS and Rayzist offer a variety of educational opportunities online or at tradeshows as well as hands-on training in their base facilities in Minnesota or California. There are also several training manuals and online articles available by experts like Ruth Dobbins, John and Judy McDaniel, Butch Young and Randi Hodges. See the sidebar accompanying this article for more information.
In this article, I’ve covered the basic equipment you need to get started in sandcarving. Be sure to watch for articles in upcoming issues which will discuss photoresists and laser masks for sandcarving in detail.
To quote John McDaniel, a sandblasting expert and owner of CorelDRAW Help, Inc., from one of his many articles, “Do not be intimidated by sandblasting!” All of this may sound a bit overwhelming in the beginning but in reality, the basics are very simple. True, some people do multiple depth sandblasting that produces amazing items and you may do that as well, but for now, just focus on the very basics and let your skills grow over time. In a year, you will look back and likely be amazed at all you have accomplished. Sandblasting is fun, relatively simple and can produce products that demand a great profit margin—what’s not to love?