Laser fumes... AARGH...GAG...UGH...!

[Ddave72]

GOOD NEWS:
We just got an awesome new 24x48 ULS laser system!

BAD NEWS:
The toxic fumes are killin' me!

THE STORY SO FAR:
We've got (at present, subject to change) the laser hooked up to an industrial dust-collector blower, venting to the outside via 6" flex hose. This system worked fine (to all appearances) with our Mimaki solvent printer, but on Friday, running our first real jobs on the new (and did I mention AWESOME?) toy, the fumes were so bad I was getting physically ill.

Today, a little investigation showed that the ducting was properly installed (we suspected a loose connection above the drop-ceiling), and a quick going-over with a stick of incense (to find air leaks) showed MASSIVE blow-by at the ventilator. Apparently, dust-collectors are more concerned with particulate (duh) than fumes. I guess we didn't really think this one through too well...

SOOOO.... here's my question for all you smarty-pantses out there:
How do you deal with your laser/solvent printer fumes? What's the best (read: cheapest) solution? I'm thinking restaurant-type ventilator, mounted on the roof or outside wall, but that also sounds kinda pricey. Then again, we just dropped beaucoup bucks on the laser itself, so I reckon it'd be kinda dumb to cheap out on the thing that prevents us all from a ghastly death by poisonous fumes. Also, are there regulatory issues with venting this crap into the atmosphere? Will we need some sort of filtration?

As always, any advice, recommendations, suggestions, snide comments and/or personal, ad hominem attacks are welcomed and appreciated.

ADDENDUM:
Original system flow (pre-laser):
Mimaki --> 6" flex vent pipe up to ceiling, across to back room & down --> dust collector blower --> 6" PVC pipe to outside vent

Current system flow:
Mimaki --> 6" flex vent pipe up to ceiling --\
Laser --> new blower --> 6" flex to ceiling --> Y-connector joining flex pipes, across ceiling to back room & down --> blower --> PVC to outside

So we added the 2nd blower from the laser & tied it into the existing vent from the Mimaki, which YES YES we're already going to change since I pointed out that we were getting an ominous buildup of FLAMMABLE, POSSIBLY EXPLOSIVE solvent fumes in the big expensive box full of open flame and lasers and cool stuff like that. So I'm already on that part at least. I just really need to know some recommendations for getting the damn fumes outta here. KTHXBAI.

 

[rjssigns]

The only laser venting I have experience with was in the college's prototype lab. It was a dedicated system and utilized all steel piping that was completely sealed. Did a great job, but.. the laser cabinet still leaked. Our favorite days were engraving cherry and maple. Would make your mouth water. Cutting plastic, not so much.

Another thing is if your shop is "tight". You may have to have an MUA system.(make-up-air). Code in our area is anything over 600cfm has to have MUA. 1000cfm requires you to have an 8" heated MUA ducted system.

Call your local HVAC place. They will know how to construct a proper venting system.

 

[J Hill Designs]

dont laser PVC =)

I never had bad fumes when doing acrylic, wood or leather (the only things I tried while I had one to play with)

 

[CES020]

How many CFM is the blower?

You mention the dust collector being more concerned about the particulates. Please don't tell me you have the bag on the dust collector.

It should be hooked from the laser, to the dust collector inlet port, then out the exhaust directly outside.

You should have virtually no fumes. We have 2 lasers and I just finished moving them and putting an additional exhaust blower on (all in the ceiling, vented through the roof).

The biggest thing is CFM. That's a big ULS (We have a ULS also). 6" is BIG duct work. You might not be moving enough air. But regardless, you need to be ducting straight outside, no bag in the dust collector.

I'd just guess you need to be at about 1200 CFM for that large of a unit.

Can you post a photo or some specs of what you are using?

Also, the longer the run, the less CFM you'll be getting. You want the run to be as short as possible.

 

[Ddave72]

Wow! Didn't think I'd get any responses this week, what with holidays and all. Just goes to show this forum rocks. But you know that.

OK, first off, we decided for the time being, so we can at least run the job we're on, to take the new blower out of the loop... the laser is now piped straight into the old blower in the back room, so we're not gassing the main shop floor. So far so good, but it's a patch, not a fix.

To the comments:

CES020:
HAHAHA! Yeah, I may not know much about lasers (yet), but we did have the presence of mind not to hook up the dust bag. But thanks for asking; ya never know.

You do raise a very valid point regarding CFM though. The blower's rated @660, and on further review of the manual, it asks for at least 700 CFM. Of course, with both blowers going, that aggregate 1320 should be more than enough, but...?

Also, I misspoke about the ductwork; it's 4", not 6" as previously stated. Yeah, six would be a bit overkilly.

JHILL:
Yeah, PVC bad, poisonous, etc. We're mostly working with rowmark & similar laser-engraveable plastic laminates. Stinky stuff.

RJS:
Oh how I'd love to run some nice hardwood through it. A friend had a bonfire a few weeks ago-- all oak & cherry, and I smelled DELICIOUS afterwards!

Don't know about the air-tightness of the building. It's your basic, fairly newish strip mall sorta joint... calling an HVAC pro is starting to seem like a jolly good idea.

The cabinet is far from airtight, but there is enough draw to keep the airflow going where it should... at least INTO the pipe.

.....

NOW, as I sit here and actually RTFM, I see that ULS recommends mounting the blower OUTSIDE, and using flex pipe only in a short run between the laser cabinet and the RIGID ducting going to the blower. Oy. I guess forty-or-so feet of flexi duct would kinda cause a lot of turbulence and back pressure. Back to the ol' drawing board... wish me luck!

 

[CES020]

You do raise a very valid point regarding CFM though. The blower's rated @660, and on further review of the manual, it asks for at least 700 CFM. Of course, with both blowers going, that aggregate 1320 should be more than enough, but...?

Also, I misspoke about the ductwork; it's 4", not 6" as previously stated. Yeah, six would be a bit overkilly.

CFM's don't accumulate. You can't add 3 600 CFM blowers and end up with 1800 CFM. Doesn't work like that. 660 is not enough for that machine, in my opinion.

I just helped a guy that bought one that's about that size and his manual said he needed 1100 or so, so I'd even say 700 is on the low side. And also, you running two blowers, if they are different CFM's is a bad thing. It can create bad pressure, I'd think, which would keep the air from evacuating properly.

660 should clear the smoke, but if you're doing a lot of heavy cutting or engraving, then that's where the problem will come in. 660 would work for light engraving and cutting, but if it's something like wood or thicker plastics, you'll need the extra CFM's to clear that much cabinet, in my opinion.

I just put a 900 CFM on our Trotec, which is 17" x 29" and man, it clears the cabinet really well.

40 feet is a long run for duct work. You lose pressure over length, so the longer it is, the less suction you'll have, to some degree.

I'll post some photos when I get a chance, some time later tonight, probably, which I can get a ladder and get into the ceiling.

 

[SignManiac]

Man up and get use to the stank!

My buddy has a small unit and cuts parts for me, mostly plexiglas, and it does stink pretty bad. I know PVC is a no no.
I'm going to be adding one to my shop this coming year. Most likely a 4'x8' table and it will be in the production area alongside of the flatbed. So I'll be getting hit with fumes from both machines. Oh the fun we have in this business.

 

[CES020]

Man up and get use to the stank!

My buddy has a small unit and cuts parts for me, mostly plexiglas, and it does stink pretty bad. I know PVC is a no no.
I'm going to be adding one to my shop this coming year. Most likely a 4'x8' table and it will be in the production area alongside of the flatbed. So I'll be getting hit with fumes from both machines. Oh the fun we have in this business.

I don't agree. You would never know what we're cutting unless you were there when the door opened to take the parts out.

You can always get the air scubbers. There's another forum where a guy detailed making one from a trashcan, all for less than $200, with the charcoal and filters. If you're interested in that, PM me and I'll find the post for you.

But in general, the only thing that really is nasty is rubber stamps. Even the "laser friendly" rubber is nasty. I think there is one or two alternatives that are suppose to be friendly, but I haven't tried them yet.

 

[Ddave72]

CES020, you make an excellent point about the airflow not increasing with multiple blowers; hadn't occurred to me before, but you are correct.

I'm rather intrigued by the idea of a trash can air scrubber... haven't I seen that movie? (Apollo 13)

HOWEVER...
We currently have more pressing issues to deal with before we start d!cking around with the exhaust systen again. It pains me to admit it, but we actually set the f%king thing on FIRE this morning. No, it wasn't me, but that's not important. What is, is that we are now learning a lot more about maintenance, cleaning & damage recovery that we ever expected to at this stage, if at all. Sucks like an electrolux, but what's done is done, and we just have to move on.

So, if there's any lesson here, let it be this:

THEY'RE REALLY, REALLY SERIOUS WHEN THEY SAY "DO NOT LEAVE THE MACHINE RUNNING UNATTENDED."

Yeah, I know pretty much every manufacturer says that about every machine, and we're all jaded professionals who have better things to do than babysit a machine that is perfectly happy running itself, but LASERS MAKE FIRE. Very important. Keep a fire extinguisher nearby, and keep your wits about you if things do go pear-shaped. Bugger. I haven't even had a chance to play with the damn thing yet.

 

[Techman]

A good test of patience before purchasing a laser.
Buy a $200 remote control helicopter and try flying it around.
I promise you will learn what it will be like to get a own a cnc LASER.
And it will show you just how overconfident you are.

 

[CES020]

Wow, very sorry to hear that. I'm assuming it was acrylic. Acrylic is nasty dangerous when cutting. It can flame up in a second, without warning and left alone for about 15 seconds and it'll catch the entire sheet on fire, which burns the laser really bad.

I don't think I've ever seen anyone else catch anything else on fire.

I hope your damage wasn't too bad and you can get up and running again soon. When engraving,you're pretty safe, when cutting, you probably should use the restroom before you start a job, not during, because that's all the time it takes.

 

[Inspire]

Fumed Out!

I would recommend purchasing a HEPA based air filtration system for your laser. We were told that the fumes from the laser can also cause premature laser failure. Not sure if true. There are Hepa based solvent extraction systems that can be retrofitted available for your Mimaki and Laser on ebay.

 

[CanuckSigns]

If possible, move the dust collector outside the building, that's what we have done with our 2 lasers, we built a box out of plywood and mounted it to our roof, no more smell.

 

[Signsforwhile]

http://www.islandcleanair.com/units/2000.html

 

[ironchef]

What do you guys recommend for a mimaki mild solvent inks ss21? 600 cfm ok?

 

[synergy_jim]

we have a 24x36 and use an 800 cfm blower with dedicated 4" line to outside. if i had to guess, i would say the y pipe is killing you....

 

[Shadowglen]

We have been running lasers in our shop for the past 7 years. Our business is now called DRS enterprises . the DRS comes from our original name Dakota Rubber Stamp. We have one laser dedicated to rubber stamps and for that we run the gray trodat odorless rubber. We have tried all of the laser rubbers out there and hands down this stuff is truly almost odorless. The rowmark plastics are definitely a stinky material specially when cutting vs engraving. we have always vented out of the building using the dust collectors. The faster you can extract the fumes the better it will be but unless you have a laser cabinet that is air tight you will always get some smell. We vent our lasers out of the building and it dissipates pretty fast. I will say when we cut engraving plastics we usually have scented candles burning :Big Laugh

 

[Ddave72]

thanks everyone for the responses... the Fireball 500 is back up and running, seemingly none (much) the worse for the incident. Our awesome tech, Patrick, came and gave it a good cleaning and tune-up. The drive belt got a little melty, but it'll do until the replacement part comes in.

heh, up til now, "putting out fires" has been a metaphor as far as work goes!

now, maybe I'll finally get a chance to play with the bl%dy thing.

updates when and if.

oh yeh, whoever's tag says something about UV flatbed nightmares... welcome to my next post! (see flatbed forum... grr!)

-Ddave72-

 

[Ddave72]

Oh, and btw, still working on the exhaust venting, but it looks like we may actually do it right this time (instead of d!cking around with one half-baked scheme after another instead of doing it right the FIRST time!)

 

[synergy_jim]

thanks everyone for the responses... the Fireball 500 is back up and running, seemingly none (much) the worse for the incident. Our awesome tech, Patrick, came and gave it a good cleaning and tune-up. The drive belt got a little melty, but it'll do until the replacement part comes in.

heh, up til now, "putting out fires" has been a metaphor as far as work goes!

now, maybe I'll finally get a chance to play with the bl%dy thing.

updates when and if.

oh yeh, whoever's tag says something about UV flatbed nightmares... welcome to my next post! (see flatbed forum... grr!)

-Ddave72-

thats me.... the nightmare was choosing who to go with.... all done with that now...