Brandon Acker, president of Titan Abrasive Systems, joined the CoatingsPro Interview Series to discuss key criteria for contractors and other users to consider as they evaluate blast media, blasting equipment, and other elements of the blasting process for surface preparation.
Topics discussed on this recently released podcast include the purpose of abrasive blasting and its real-life applications; the correlation between abrasive blasting and the ultimate success of a coating system; decisions that may need to be made related to blast media, equipment, and safety needs; and much more.
Read on for a Q&A transcription of portions of that conversation, and listen to the complete episode at the embedded link beneath this article.
Q: Can you give us an overview of the abrasive blasting process? What is it, and what is its purpose within a coatings application?
Acker: The abrasive blasting process has been around for over 100 years now. With us, we use air. We’re air blast equipment, so we use compressed air to propel an abrasive. It used to be sand, but now there are many, many different kinds of abrasives. We want to propel that abrasive against a surface to either clean it or to profile it. You can take paint off, profile steel for a new coating, remove rust to clean it, all that can be done.
We do it with air, whereas some do it with wheels that are throwing that abrasive at the product. We’re propelling it with compressed air to clean or prepare that surface for coating.
Q: Beyond simply what you all do, can you give us an idea as to the whole spectrum of blasting?
Acker: Ours are used in various industries, depending on products and the size of products. With our air blasting, you’re using blast rooms and blast cabinets. You’re putting that object in there, and propelling that media against that surface to create that profile. When that media hits that surface, it’s key for your coating process to get that proper profile so that the coating sticks.
Depending on the material you’re blasting, the finish that you’re trying to achieve, and how deep of a profile, you can pick from a range of different medias. Sometimes, you might just be using plastic media to clean the surface. Or, you may want to use something more aggressive like a steel grit or aluminum oxide to actually profile that surface because you’re going to coat it. You want that coating to stick better and to eliminate any failures with the coating. You also have your choice of the equipment that you use to blast it, whether it’s by air or wheel.
Different medias are going to give you different results, and each of those medias will also come in various sizes, which is also going to change the profile that you get on the on the material. So, you have to determine what that material is that you’re blasting, as well as the finish that you want.
A lot of times, your coatings will give you that information. The coating will spec out what mil profile needs to have, and we’ll help to make sure we get that through the use of our equipment or through the proper media. We’ll get that desired profile for the coating. Each coating can have a different spec on that profile.
Q: What other tools might a contractor be thinking about in this process, other than the blast media or piece of blasting equipment? For example, you mentioned compressed air, and I think air compressors. There’s also certain PPE [personal protective equipment] that needs to be worn when blasting, and especially depending on the choice of material.
Acker: They have to think about themselves, or the operator. That’s number one. You have to think of yourself, or for the employee who is doing the blasting. You want to keep them safe and healthy, and you want to make sure you have nice, clean air that they’re breathing in there.
PPE plays a big role in it. You’re going to want a helmet, something to cover your head and so you’re not breathing it. Obviously, when you’re doing abrasive blasting, it’s dirty. It creates a lot of dust from the media. There’s dust and debris coming off of the surface of whatever you’re preparing. If you’re blasting paint off, or mill scale, or rust, that’s going to be airborne.
You want to make sure you have a good, air-fed helmet on. You’ll have either a compressor or breathing pump that feeds that helmet, and that’s going to keep it from fogging up. You may need a CO [carbon monoxide] monitor, depending upon your source of air for that helmet. If it’s coming off a compressor, you want to make sure you have a CO monitor on there.
Beyond that, you’re going to want a some sort of suit or uniform. That’s going to keep dust off, and protect your body a little bit from any ricochet coming off. There’s also gloves and boots.
As far as where you’re blasting, you’re going to want to consider that as well. We make large equipment, like a blast room. If you’re doing it inside, that’s going to contain the mess. If you’re a contractor blasting outside, it is a messy operation. You’re probably going to want to contain that; it could be in a tent.
If you’re blasting a large bridge, which I’m sure a lot of people have seen if you’re driving over one that’s over a river… you’ll know when they’re blasting it, because they have it tented off. It’s a lot of work to enclose that and to contain that mess — all the media and what’s being blasted off — from being either airborne or falling into the river below. So you definitely want to think about the environment you’re blasting in and how you’re going to contain that.
Q: What tools are available to verify that a blast went according to spec? How important is achieving that standard to the ultimate success of a coatings application?
Acker: It’s very important to get that proper profile on there to improve the quality. There are tools out there. Just like there are gages that will measure that thickness of a coating, there’s also gages that will measure the amount of profile as well as the depth of that profile. You can measure. You can also test blast, and then measure that profile to see if it’s deep enough, or perhaps too deep of a profile. You want to hit that happy medium.
You may have to either change your pressure you’re blasting at, or change to a different media or a different size media to control that profile. There are instruments out there that you can test that with.
You want to achieve the correct profile. All coatings are a little bit different, so they will usually spec that profile depth. You want to make sure you adhere to that manufacturer’s recommendations. If it’s improper, there will be issues with the coating. It may not be right away, but it will shorten the lifespan, and it can cause failure of the coating, to where it’s not going to adhere.
Too little of a profile is going to leave it kind of smooth. It makes it to where that coating doesn’t have anything to bite into or to grab on. More than likely, you’re going to get a failure, in that the coating can peel or come off.
If you have too much of a profile on there, you’re going to find that it takes a lot of coating to cover that profile to sink in. You’re going have multiple coats or a lot more material that you’re applying. You don’t want that because it’s to get going to get costly to put that much coating on. If you’re using twice as much coating, it’s going to cost a lot more than if you get that proper coating for the profile.
There’s a lot that goes into it. But you definitely want to achieve that proper profiling to make sure your coating gets its longevity and you don’t void any warranties on the coating. You the coating to last, do its job, and protect that substrate.
The complete interview with Brandon Acker can be listened to below. For more information, contact: Titan Abrasive Systems, (215) 770-2400, www.titanabrasive.com.