IT'S ALIVE! Mirrors Cleaned, Printing Fine!

In the Ag Industry keeping dust out of the cab has come a long way. In modern equipment it is accomplished by 1- Sealing the area to perfection with silicone seals, rubber seals, or sealant… depending on the area. 2- pressurizing the area with positive air pressure drawn in by a fan through a very expensive filter. Of course #2 doesn’t really apply to a Form1, but #1 sure does.

great tutorial to see how to solve a problem!! how many time or how many print do you made with the printer before had problems? thx very much for the tutorial!!

Well I just screwed up. My mirror was a little dusty and my wife had a can of compressed air sitting next to the printer. I figured a little puff wouldn’t hurt. BAD IDEA. All of the compressed air you buy these contains a bitterant to prevent abuse, but I figured no big deal. But there is A LOT in there! It spit all over my mirror! My mirror is WAY WORSE. I have requested the secret pec-pad instructions from FormLabs and am waiting…

Hi Luis & Josh,


I had three good prints at the beginning, the butterfly-clip-test, at 0.10mm, 0.05mm and 0.025mm, to see the resolutions in action. I have to say, they came out amazing! Then I had about three failed prints in a row - all my bad due to my experimentation with the alignment of the models. Once I decided to trust the auto-layout, I had two good ones and then my World Tour of disasters… thank you dust!!

Once I cleaned the mirrors and placed the models around the scared-areas on the resin tank that came with the printer and on the brand-new one I bought separately, well, I got four good prints.

So right now I just received a Sylgard 184 kit, and I’m going to re-finish the silicon-side of both resin tanks, which I will then compare with the two-new resin tanks I should get by this week’s end from FormLabs, so I’m out-of-comission for the next two days! But I will post on the re-finishing of the resin tanks and the comparison tests once I’m up and running…


The instructions are not that complicated, you’ll see, or a secret, they just want you to follow certain steps, and speaking of steps, one is missing! in the instructions for cleaning the Galvanometers, they forget to mention that there are TWO SCREWS at the bottom-back-side of the printer (for removing the back-pannel.) CAREFUL: DON’T FORGET TO REMOVE THE TWO BOTTOM SCREWS BEFORE ATTEMPTING TO REMOVE THE BACK-PLATE! (I hate to sound like I’m screaming, but is very important, since I almost bent the back-plate trying to remove it!

So the thin layer of residue are bitterants?!.. it makes sense!..

Good luck and patience!

Frank J Guthrie

Watch it Pedram: “…Contains a bitterant to help discourage inhalant abuse!..” It leaves a thin layer atop the mirrors… a thin ORANGE layer… now that makes sense, look at the picture of my mirror and you can see the ORANGE bitterant! So, the more you dust, the thicker it gets! That’s what happened to me! Check it out:

So careful, good luck and patience!

Frank J Guthrie

Thanks @Frank_Guthrie, I will stay away from the galvos during this go around. Much thanks for the rocket air blaster idea as an alternative. Incredible idea! I took the bitterant warning to a new topic and used your picture with credit to you when Sam commented on it. I hope you don’t mind. Your posts are awesome Frank.


I had the same problem: HUGE print fails (over ten in a row.) 1) Contacted Support by opening a ticket, 2) got the instructions and cleaned the BIG mirror first, 3) ran another print and got another fail, 4) cleaned the Galvanometers ’ mirrors and voila! I had three great prints back-to-back!

The Galvanometers’ assembly is held by two 2.5 Hex bolts** (like the rest of the machine,) and it only took me 5 to 10 minutes max to remove both the back-plate and the assembly, the easiest thing in the world, trust me! When you put the assembly back, you realize how well-designed this printer is. It takes less that 5 minutes, piece of cake!

So good luck and patience!

Frank J Guthrie

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Frank… Thank you so much for your post. We love helping our customers get back to printing but what I love most is having your guys help each other.
You were right to suggest that Josh (and all others) open a ticket with us at as there can be a few issues that can cause blowouts or print failure beyond dirty mirrors.

I look forward to seeing what you guys print in the future.

Hubbard at FormLabs

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I’m starting to see this happening to my printer. 10+ perfect prints and all of a sudden, prints failing in exactly the same way.

Seems to me that the mirrors need more maintenance than all the other expendables.

What a great tutorial ! I’m interested in your desktop ultraviolet oven - can you share make & model please ?

how often are you intended to disassemble your machine and clean the galvanometers. they should add that process to the video…

or better yet the cleaning method described by joshk

"“but what I did last time there was dust on the mirror was get a cotton
swab and look at it to find a loose thread. Then I carefully used the
loose thread like a hook to insert between the mirror and one of the
arches on the dust particle. That way I can remove dust without
touching the mirror or blowing it around. But I have slightly better
than 20/20 vision, a very steady hand, and lots of patience.”

id love to see someone try this on the 35.000 dust particles currently sitting on my mirror.

Haha, I remember the days when I was that ambitious. now I just use the rocket air blaster and hope for the best.

does the rocket blaster have the most air pressure of the squeeze dusters? I was thinking about getting one of those air brush compressors, and maybe a computer vac

The rocket air blaster is just a squeeze duster. It doesn’t have a lot of pressure because its hole is fairly large, but it works just fine. Lots of pressure sounds like a good thing, but I really hate to stir up a bigger dust storm than necessary. Remember everything in there is as dusty or more than the mirror. The mirror gets attention, everything else just keeps collecting.

Jim. The Ultraviolet Sterilizer Cabinet is this one:

And I learned this from the amazing Robert Vignone. Check his webpage, Mold3D:

Tons of information about sculpting and 3D Printing. Tips, tricks and all sorts of references, like this Ultraviolet Sterilizer Cabinet!

Good luck and patience!

Frank J Guthrie


Don’t waste your money and time on the airbrush compressor and the computer vacuum: they are overkill and you may damage the printer!

The Rocker Blaster is more than enough, trust me. The cleaning of the BIG mirror and the small Galvanometers’ mirror you will do once or twice per year, that’s all. Then you will only use the Rocket Blaster to “push” the dust off the mirrors, since you will always have dust in the printer, since its not enclosed in a vacuum…

I do this for every print: I check the mirrors before every print, and if I see any dust on the mirrors I use the Rocket Blaster to blow the dust off the big mirror and I also blow towards the “hole” where the small Galvanometers’ mirrors are. What I showed in this simple tutorial was my first “open-surgery” on the Form # 1, to get to the small Galvanometers’ mirrors - since the assembly is located in the back of the Form # 1, but ever since then, I’ve not had to open the printer, just check the big mirror, blow and that’s it!

I clean the big mirror every three to five prints with Isopropyl Alcohol and Sensor Swap. I use these swabs:

The material is the same as what FormLabs recommends we use to clean the mirrors - Pec-Pads Non-Abrassive Wipes. You can find them in Amazon…

Good luck and patience!

Frank J Guthrie

How do you avoid streaks with those narrow little pads / swabs?

i think my mirror needs contact cleaning, but its a tricky a job.

@Frank_Guthrie How did it go with the Sylgard 184 kit?? Where did you buy it?

I ordered a new tank and did a large print on it (which failed) and ghosted most of the tank. 1 Print, so crazy. Its just to expensive to be replacing these tanks all the time.

Anyone have any luck using the black resign on the gray setting? I read somewhere that the gray will not ghost up the resign tank as much?

Love this thread by the way, I keep coming back to it. I ordered everything I knew I would need to clean it before I even got the printer.

Hello Formlabs Forum,

I realize this post will revive this thread but I think the information is good and it gave me a place to start.

I’ve been having a string of failures and have been putting off (in a state of denial perhaps) cleaning my mirrors. I do have a ticket open with support and they are of course great to work with.

But just wanted to share…having worked in the camera business before…the process for cleaning optics (lenses) and camera sensors is the same / very very very similar to caring for your printer.

As mentioned…never ever use the Air-In-A-Can stuff. The ‘Rocket’ blasters move more than enough air…remember, we’re working at the micron scale.

One technique that I haven’t read anywhere (not to say it hasn’t been mentioned, I just haven’t seen it mentioned)…the first step I do when cleaning a camera lens or sensor (and will apply to the Form1+ printer mirrors)…using a Lens Pen (they have a retractable brush on one end and ‘felt’ pad on the other)…it’s best not to ‘brush’ or ‘wipe’…the static of the bristles or pad will lift dust particles off the surface. Just ever so lightly ‘dab’ or touch the dust speck and lift away. Then move away from the machine and use the Rocket blaster to blow off the brush/felt pad.

Also, when using Pec Pads…don’t just pull them apart…that can create ‘fuzz’ that will cling to the surface. If you carefully ‘peel’ them apart you’ll have better luck.

The ‘lolipops’ mentioned in this thread are good but honestly I prefer using my finger (as long as you’re careful to make sure your finger doesn’t overhang the pad and create a smudge. I fold the Pec Pads into 1/4’s…and then make one pass per 1/4…making sure that each pass slightly overlaps…don’t be shy to use up Pec Pads…seems wasteful but you want a clean square each pass (the logic behind only one pass is that you could potentially redeposit debris from the previous pass…or worse, damage the optic / sensor by scratching it). All passes should be mead in the same direction…then I usually go back and do passes 90 degrees to the first set (more Pec Pads). Also, it doesn’t take much pressure…better to make lots and lots of light passes than pushing too hard.

I know Formlabs recommends rubbing alcohol and I’m waiting to hear back what their thoughts are on ‘Eclipse Optic Cleaning Fluid’…I have used that product for years with my cameras and have had great results (I have no affiliation to them, just a product I like using). The key is how quickly it evaporates…only takes a few drops per Pec Pad 1/4.

Thank you to the OP for this thread…the information is still relevant and solid advice.

I use eclipse fluid on my mirrors when needed. Much less streaking to deal with. Formlabs may not recommend it but if it’s good enough for the sensor on my Nikon it’s good enough for an instrument mirror.

I would never used canned air or a compressor. The rocket type blowers are by far the best bet and they’re pretty cheap.