TOP TEN TIPS: THINGS TO KNOW BEFORE HIRING A SANDBLASTER

1. Best Prep for Restoration

Compared to other methods, sandblasting is the best way to both strip previous coatings and corrosion, as well as leave the optimal surface profile for a new coating to adhere correctly. When we talk about surface profile, we are referring to a specific texture of the metal’s surface.

For stripping the coating, sandblasting is the most time-efficient method at removing one hundred percent of the coating. You can use grinders, sandpaper, and other methods, but these will be extremely time-consuming compared to blasting, and often, they don’t remove 100% of the material. They also don’t leave the perfect profile, which leads to our next point.

For coatings to adhere absolutely perfectly, there needs to be a microscopic etch on the surface of the steel. If you have a perfectly smooth surface, your coating is not going to actually adhere to the surface. It will only sit on top. It may look good for a couple of years, but as soon as any moisture or corrosion starts to appear underneath that coating, your entire paint job will begin to lift and have a catastrophic failure. The best way to avoid this is by sandblasting and achieving that ultimate profile.

2. Types of Blasting Media

eIt is important to know that there are many different medias when sandblasting, but ninety percent of projects can use a standard media. A standard media is a slag, such as copper slag, nickel slag, or coal slag. We use copper slag for most of our projects. Some other specialty medias include: walnut shells, corncob, and soda. Walnut shells are sometimes used on log home restorations. This media is good because it biodegrades, so there is no cleanup required. Corncob is also good for this reason, but it is not good for log home restoration because the corn attracts mildew inside the cracks of the logs. Soda is good in certain applications where you do not want to get very aggressive. An example would be delicate fiberglass or extremely thin antique steel. It will not leave any profile and will disintegrate upon impact. You are basically using a powder to strip a surface. It is extremely slow compared to most medias and it is actually toxic for grass and plants. However, it is practical in specific situations.

Two other medias are crushed glass and glass bead. Crushed glass is recycled bottle glass. It works well, but it is expensive. This is comparable to copper slag. We don’t use crushed glassed very often because it performs exactly the way copper slag does. Glass bead is a very expensive media to use, but it leaves a polished finish. On a microscopic scale, this glass is not crushed. It is broken into spherical beads of glass. They are not sharp and they leave a very smooth surface. Glass bead is not good for stripping a surface; it is only good for leaving a smooth surface on bare metal.

3. The Importance of Equipment 

Not all blasting companies will have the same equipment. The most important aspect in sandblasting productivity is the amount of air the sandblaster has. A lot of very small companies will use a 185cfm (cubic feet per minute) air compressor. These machines are on the low-end of blasting productivity. At Horton Industrial, the minimum amount of air we like to use is with our 375cfm air compressor. With this amount of air, we are able to basically double the productivity of most sandblasting companies. Our biggest compressor is 600cfm, which is large enough to power two to three blasters at once. If you hire one blaster at $120/hour with a 185cfm air compressor, he will only get half the work done in the same amount of time as a contractor using a 375cfm air compressor. If the company using the 375cfm air compressor charges a little bit more, it is absolutely worth the extra money because of the increased productivity. 

It is also important to ask the contractor what other equipment they own. For example, we have a Vecloader 616 industrial vacuum that we use to clean up after many of our sandblasting jobs. It is a 170-horsepower diesel-powered vacuum that makes large clean up jobs go extremely fast. 

4. Hire a Sandblaster with Experience

While sandblasting may seem like a laborious type of trade, it is actually extremely specialty and requires experience and expertise to meet industry standards. If you hire a contractor that isn’t a professional in the trade, they could easily cause damage and actually destroy your project. There is also the possibility that they will be unfamiliar with safety precautions (see #6).

5. Beware Dustless Blasting 

Dustless blasting is when you mix water with your blasting abrasive to suppress dust when sandblasting. It is useful in certain applications, but it is definitely overestimated. The only time we use dustless (wet) blasting is on concrete in public areas, where we need to create the least amount of dust as possible. Often people recommend using dustless blasting in the automotive industry…Don’t fall for it! Dustless blasting is the last thing you want to do on any project involving steel for a few reasons.

The first reason: moisture is the enemy of steel. Within hours of bare steel being exposed to moisture, it will start to oxidize (AKA rust). Removing rust is the whole point of abrasive blasting in the first place.

The second reason: some blasters use a rust inhibitor mixed with the water when they blast. This is also a big no-no. Another main point of blasting is to remove chemicals from the surface of the steel. This rust inhibitor is just another contaminant that will cause a paint failure in the future. We personally know of many cases where ten-thousand-dollar paint jobs have been put on cars, and the paint has lifted and started to peel after only a couple years, just because of the rust inhibitor being used when blasting.

All in all: do not fall for the dustless blasting ploy. It is simply a marketing scheme by a company to trick people into buying their sandblasting machines.

6. Safety Precautions 

Abrasive blasting is an extremely dangerous procedure. You are dealing with hazardous abrasives flowing through high-pressure airlines, often in precarious locations. It is one hundred percent doable to reduce these risks, but many contractors don’t bother/don’t know the risks. If they get injured on your job, you could be liable.

On all of our jobs, we take every safety precaution into consideration, such as confined places, working from heights, led paint testing and abatement, hazardous work sites, etc. We also provide our employees with co2-monitered blast hoods, air respirators, and hearing protection. We take every precaution to protect our employees and anyone in the vicinity of our worksite. We do this to ensure the safety of everyone and to avoid time-loss incidents.

7. Get Your Bid in Person

Have your potential sandblasting contractor come and give you an in-person bid. Make sure they see the project before giving you a price. Every blast job is different and needs to be evaluated individually for an accurate quote to be given. You do not want to have a contractor give you a high price because the pictures you sent made the job look harder than it actually was. You also don’t want the contractor to walk off the job on the first day because they didn’t know what they were getting themselves into.

For the best interest of all parties involved, have the potential contractor come to the site and see the project in person.

8. Prepare Your Neighbors

Sandblasting can be loud and dusty. If you simply prepare your neighbors ahead of time, we have found things go over much smoother. Tell your neighbors to park their cars inside, if possible. Have their kids play inside for the duration of work hours. Simply have them prepared to expect heavy-duty work to be taking place. If your sandblasting contractor is a professional, they will make sure your neighbors are not affected by blasting, other than the noise. 

9. Realize No Project is the Same

Every project is different! Just because a dump truck costs a certain amount to sandblast and you have the exact same model that also needs sandblasting, the price could vary. The cost of blasting is highly based on the amount of corrosion and paint to remove, rather than the model of the vehicle. Even the same exact item could cost different prices if it needs to be re-sandblasted because there will likely be different amounts of corrosion/coatings on the surface.

10. Consider Sandblasting for a Variety of Industries

Abrasive blasting is a process that can be utilized in many industries. The following are specific industries with some details to go along with them.

LOG HOME RESTORATION: The first step in restoring a log home is actually stripping it down to bare wood, removing any paint or stain that was previously applied. Sandblasting is actually an extremely effective method and is preferred by most log home restoration professionals. Sandblasting is the only method that will take you down to bare wood and allow you to stain a lighter color than what was previously on that wood. We blast many log homes every year.

MARINE: In the marine coating industry, sandblasting is basically the only method for professional paint prep. On ships, coatings are subjected to such extreme conditions that it is imperative that only the best coating work is done. If surfaces are prepped with methods other than abrasive blasting, the lifespan of the coating will be dramatically shortened and you will be redoing the work much sooner.

AUTOMOTIVE: Media blasting is the first step in the automotive restoration industry. It is important to start with a fresh base when doing auto body repair. You do not want to put your paint job on top of somebody else’s pile of bondo. You never know if they used good products or what could be hiding underneath the bondo.

CONCRETE: Concrete is another application where sandblasting is widely used. We often sandblast waste water treatment facilities, sidewalks and driveways, and concrete buildings. Media blasting is an effective way to take coatings and grout off the concrete, as well as provide a great profile for coatings to adhere to concrete correctly.

There are several things to note before hiring a sandblasting professional, but each item will help ensure you have the best experience when restoring your project!