{ Glass Etching: Part 2 }

Harbor Freight Air Eraser Review/Tutorial

In { Glass Etching: Part 1 }, I mentioned that while initially researching glass etching, I had questions about whether or not the Harbor Freight Air Eraser works. (11/12/13 Update: Be sure to read the updated review of that particular tool at the end of this post.) In this post, I’ll review that, but you will also find out about the whole air eraser process in general, plus you’ll get to see the crazy contraption we created in lieu of a blasting box. But, first, I must back up to the beginning for those who haven’t heard of any of this before now…

Until just a couple of weeks ago, I was only familiar with the idea of glass etching using etching cream.  As it turns out, there’s a much more effective way to do so and it doesn’t require you to spend thousands of dollars on professional equipment!  Don’t get me wrong, it’s not going to be cheap if you’re starting from scratch, but there are ways to minimize the damage to the wallet & I’ll share with you how I was able to get going with this for about $60 total.

So, there’s a method of glass etching called sandblasting.  Within that concept, there are two primary methods home hobbyists use to etch. The most basic of those methods is through using what’s called an Air Eraser. (Just the name of it made it sound fun to me! I imagined I was going to be buying some kind of magic eraser that floated around in the air…) The Air Eraser is commonly purchased at Harbor Freight and is very reasonably priced.

This is what the Air Eraser looks like:

It utilizes the same concept as air brushing, but instead of paint, it’s abrasive that is being sprayed out of it at an incredibly high speed. 

The second primary sandblasting method involves a blasting box (which already has the air hose and sprayer built into it) and glass beads. This type of sandblasting supposedly gets a quicker, more consistent result than air erasing, but for my purposes, it's not worth spending the extra money at this point to go the glass bead route. So, I'm just going to focus here on the air eraser.

These are the main components required to use the air eraser:

1. Parts from the Air Eraser Kit:

• Air Eraser Tool
• Air Hose
  • Potentially an Adapter for the Air Hose

2. An Air Compressor

3. Abrasive (Aluminum Oxide is the only abrasive that can be used in the Air Eraser)

4. Safety Equipment

• Eye protection
• Face mask
• Gloves

5. Blasting Box

 

The condensed version of the process is that you’re going to hook one end of the air hose to an air compressor, while the other end is attached to the air eraser tool. The tool’s storage cup thingy (the technical term, of course) is filled with abrasive. Meanwhile, inside a blasting box (a lidded box in which you place the item to be etched; the box has arm holes through which your gloved hands will go), you’ll etch your item by holding the air tool like a pencil and then spraying from it onto the item being etched (within the stenciled area, of course). The force of the abrasive scratches away at the glass to create a very sharp looking etched surface.

 

This is a much more detailed step-by-step of each component and the overall process:

The Air Eraser Tool

The air eraser tool is very simple in terms of operation. The cap of the little container attached on the top needs to be opened and then filled with the abrasive. I recommend filling it over a garbage can, collection bowl, piece of paper, etc.—because if it spills, it’s a pain to get all of the graininess cleaned up. Then, securely attach the lid. My first air eraser turned out to not be made correctly, so even with the lid tightened down, abrasive would spray out from underneath the lid, making it completely unusable. I exchanged it for another and the second one works great. It’s absolutely key that the lid be secure, as the air pressure will escape otherwise & that reduces (or even eliminates) the ability to etch.  The air eraser is screwed onto one end of the air hose.

The Air Hose

The air hose is pretty straightforward, but there’s one key item missing from the air eraser tool kit at Harbor Freight: an adapter that allows it to connect to standard air compressor plugs. The air hose has a 1/4” end piece & it does not attach to the typical air compressor without an extra adapter. The good news is that the adapter is readily found at Lowe’s (probably at Home Depot, too) and only costs $1.50.  Of course, you’ll want to attach the adapter using wrenches to ensure a tight seal. The air hose can then be attached to the air compressor.

The Air Compressor

The air compressor is kind of a tricky deal. When you read the kit’s packaging, it basically says that you need an 11+ gallon air compressor. Ours is six gallons and that size is listed as being not recommended for use. But, here’s the thing: I’m not etching as a full-time deal. I just need 65 psi of air in short intervals. So, as it turns out, the 6-gallon air compressor works just fine.

As an example, to etch the letter “K” onto a 3.5” glass ornament, it took just under 60 seconds of air usage. When I got to my third ornament, the air compressor turned on to refill, but it was on for a very short amount of time, resulting in very little motor usage. So, I’m not too worried about burning the thing up by using it briefly and intermittently. You’re welcome to spend $300+ on larger air compressors, but you can get away with the smaller size, too. I wouldn’t necessarily go any smaller than six gallons, but that size will work just fine.

You do want to set the air pressure according to the tool’s instructions. In this case, the kit said 65 psi, so that’s what I used.

Abrasive

The abrasive is important to pay attention to, as the wrong kind/size can easily clog up the air eraser tool. Aluminum oxide is the only abrasive that can be used in this particular tool and a small sample is included. As mentioned above, additional abrasive is available at a pretty good price. You may be able to find it cheaper elsewhere, but I didn’t think $10 for two lbs. was too bad. (Keep in mind that it doesn’t use a ton of abrasive if you’re just doing small items. If you plan on etching half the world’s surface, you may want to do some research to get a better price for abrasive.)

There are tutorials out there that can teach you how to alter the air eraser tool such that baking soda (which is a fraction of the cost of aluminum oxide) will work as the abrasive. I, however, do not want to mess with the tool, as I know I’ll just break it somehow, so I’ll pay a few extra bucks for aluminum oxide and call it a day.  Other people have adapted their tools to accept glass beads (again, not for me), but there are also more advanced tools specifically built for the use of glass beads as the abrasive. Again, this review is just looking at the use of the basic air eraser tool without any modifications.

Safety Equipment

It cannot be overstated as to how important safety gear is when it comes to using this tool. You are not only risking your vision, but your lungs, too, what with breathing in all of that abrasive. It’s definitely not healthy. The kit comes with one dinky face mask, but I’d recommend getting more (and better) masks and a pair of protective glasses or goggles, too. Plus, you’re going to want protective gloves. Blasting boxes (more on that in a sec) often have built-in gloves, but if you’re making your own, you’ll want to buy some that pretty much cover your arms. Harbor Freight has some sandblasting gloves for really cheap—much cheaper than I could find anywhere else. The thing about the gloves is that it’s not necessarily a safety factor on those when it comes to the air eraser (which is much less violent than I imagine more professional sandblasting tools to be), though it definitely helps protect the fingers closest to the spraying abrasive. Instead, the gloves help keep your arms from becoming coated in the abrasive—and that stuff gets EVERYWHERE and sticks!

One other thing—though it’s not really a safety thing, I would also recommend wearing an apron to try to protect your clothing from the abrasive grains. Sure, by the time you get all of this on, you’ll look certifiably insane, but better to be safe than sorry. Speaking of looking insane, while I had already commandeered our gym for my tool assembly area, I decided to utilize the mirror wall while there…

And that’s even before I put the gloves on! (Notice the cute little air compressor filling up in the background.)

Blasting Box

So, here’s the thing—I’m cheap. I somehow usually manage to spend a lot of money overall, but I aim to be as frugal as possible for each individual item. That goal was no different for this project and the necessary blasting box. Blasting boxes serve to really protect you from flying abrasive and to keep the mess contained. There are several options out there, including some good $99 countertop options I saw at Harbor Freight. (While I keep mentioning Harbor Freight, I should point out that am in no way being endorsed by them. Going back to the thing about me being cheap…yeah, Harbor Freight’s prices are right up my alley!)  However, particularly not knowing if this whole etching thing would even work, I preemptively built my own using a 27-quart lidded plastic storage tub I got at Target for $7. It may scream “ghetto!”, but it works beautifully. Here’s a pic of it alongside my other air eraser stuff—aside from the compressor, of course:

On the front of it are two arms holes; on the side is a small hole through which to feed the air tube. Here, it’s pictured on the left because I’m a leftie, but obviously you could just drill on the other side for those of you not in your right brain. (You see what I did there? I make myself chuckle…)

While you don’t want the holes to be so small that your arms or the air hose don’t easily fit through, you also don’t want there to be too much space for the abrasive to escape. But, I view etching as an outside project anyway, so that helps in terms of not destroying the house even if abrasive escapes. I did my etching on the back patio & that kept most of the disaster outside. The rest of it seemed to stay mostly collected in the box itself.

The only thing I think I’m going to change to my version of the blasting box is to affix a push-button LED light on the inside of the box to help with visibility. I found myself taking the lid off repeatedly to make sure I was etching the whole surface. It’s not the end of the world to do that, but again, just make sure you have protective eyewear and a face mask on, and that you’re outside if you’re going to start spraying the abrasive outside of a lidded box.

The Costs

This is how my costs broke down to get started with this particular project, not counting the cost for the compressor since we already had one of those:

• Air Eraser Kit: $26
• 2-lb Bottle of Aluminum Oxide: $10
• Air Hose Adapter: $1.50
• Protective Goggles: $3
• Pkg of Face Masks: $5
• Gloves: $6
• Plastic Storage Tub: $7

Total, it was about $60 to get started. While that certainly is more than a bottle of etching cream, I think the end results from using the air eraser well justify the additional cost and make the etched items something you can be proud to give as gifts or display in your home.

Etching with the Air Eraser

This is the fun part—going crazy with a spray gun, essentially. OK, so don’t go too crazy, but do try to at least enjoy the process. At this point, I’ll assume you’ve followed the same steps as those found in { Glass Etching: Part 1 }, stopping just short of spreading etching cream, since we’re obviously not doing that with this method. One added thing you’ll have done is to cover all of the exposed surface of the un-etched piece (except for the area you want to etch, of course) with painter’s tape. I went ahead and got wide painter’s tape so that it took less time for this step. But, you’ll want to tape along the edge of the stencil, and then all around the rest of the surface so that it’s protected from the flying abrasive. If you were to slip even for a second with that thing spraying, you could easily create an etched spot where you don’t want one.

Now, using the air eraser tool like a pencil held at an angle about 1/8”-1/2” away from the surface you’re etching, start spraying the glass. You may need to tinker around with your air eraser tool to get the right of abrasive spraying out. Refer to the owner’s manual for info on what to do there. But, note that in order for it to work, you won’t see this huge cloud of sand hurtling out of the tool and onto the glass. It’s much more subtle than that. At first, I thought that I’d managed to get another broken tool after exchanging my first out due to the air escape problem. But, it turns out that it was working and I just wasn’t holding the tool correctly.

You’ll spray the area you want to etch and it will turn a light white color, almost like there’s a layer of dust on it. That means it’s working. One easy way to test it is to stop spraying and rub your finger over the surface (making sure to not lift up the stencil, of course) that looks dusty. If the light white doesn’t rub off like dust, then it’s etched and you’re good to continue. Work to etch the entire stencil area, paying close attention to the edges, and try to do it evenly so that it looks uniform. If you see some spots that still have a shine to it compared to the area around it, spray those spots and they should dull to the same degree of etching.

An easy way to make sure you haven’t missed any area is to simply turn the item around and hold it up to the light. In the case of a glass Christmas ornament, you’d then be looking through the back of the ornament and would see the stencil outline, but everything inside the stencil outline would be an even white color. If you notice clear spots, simply spray over them to get them etched. It’s as easy as that.

I found that the only annoying thing in the final part of the process is that my fingers started cramping from how I held the air eraser. I’m going to keep playing around with it to see if maybe I’m just holding it wrong, but that was my only gripe. That and the fact I ran out of stenciled items to etch, as I wanted to keep going!  Oh, that reminds me—be sure to periodically check your abrasive supply and refill as necessary. If you find that you’re no longer seeing any etching activity, first check the storage cup thingy to make sure there’s still abrasive there. If there is, but you’re still not seeing results, your nozzle may be clogged. Refer to the owner’s manual for info on taking care of that, but it’s an easy fix.

And that, friends, is how to use the Harbor Freight air eraser tool to etch your glass projects! Next up: more glass etching fun. (Yes, there’s even more to know! But, I promise what I’ve got to share is much less tedious than the technicalities listed in this post and results in an even cooler etched item!)

11/12/13 UPDATE: After a tremendously short run with my second HF Air Eraser (i.e., two days), it died. So, I bought a third one, only to find that it had the same problem as my first one—the abrasive container cup did not seal correctly, rendering the tool useless. It was at that point that I gave up on the Harbor Freight Air Eraser and bought a quality tool instead. It has already been worth every single extra penny. I went with the Paasche brand instead. Specifically, I got this one from Amazon.

It was considerably more money (about $90, with Prime shipping), but right out of the box I knew I was in for a different experience. Even though it’s practically identical to the HF version, the quality of the materials is significantly greater. And the best part: it actually works! In fact, it almost works too well. Whereas with the HF AE (when I had the one working anyway), I would find myself going over an area repeatedly to make sure it was evenly etched. With the Paasche tool, I followed the same process…and promptly cut right through the glass ornament I was etching! It’s a very powerful tool and gets the job done.

My advice: spare yourself the headache and skip the HF Air Eraser; spend the extra money to get a tool that does the job.