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V.A Melle
08-22-2006, 2:48 AM
Hi- anyone got settings for cutting through MDF 3,4 and 5 mil thick? I need to cut all the way through for a project and oh I have a laserpro 30w spirit. Any help? I do have air assist. 2" lens-basic stuff.

Another weird question mdf produces alot of smelly air from the glues I have to wear a mask. Is it possible to connect a charcoal lined air filter to the exhaust? is that even possible. or what is the best way to not drive people crazy. Does anyone even sell filters for this kind of work. Working with wood is fine but a friend complained of headaches when I worked with mdf in the past. Please help-thank you!

Joe Pelonio
08-22-2006, 8:22 AM
I've cut mdf 1/8" and 1/4". I started with the manual's settings for Oak and then reduced the power until I got just through with little charring. On my 45 watt Epilog it was 12sp/100pw/5000freq for 1/4", 25/100/5000 for 1/8". I had no smell issues, though I didn't go hang around the exhaust vent outside, but no smell noticeable inside the room. Some people are sensitive to any odor. Around here it's cutting ABS that smells and gets people upset.

Filter systems are available but costly, figure $1,000 and up from what I've seen. Combination of charcoal and hepa made for lasers. You could probably come up with something homemade but make sure to keep the air flow going since it's cooling the laser.

This one is $1,750:
http://www.odorcontroller.com/pdf/rsu12-20CHR.pdf

John Esberg
08-22-2006, 4:47 PM
Melle,

You should not be breathing in such vapors. Your body was not designed to inhale burnt glue and wood chips. If you are wearing a mask to do this work, you obviously need to rip apart your equipment and find your problem. I'm seriously concerned for your saftey. Please understand, there is a high percentage of woods that are toxic, if not carcinogenic, when inhaled. This is no laughing matter, please don't risk your health.

If you would like to talk about methods to trace out your ventilation casualty, please feel free to email me with a phone number. My Navy day job has put me through a lot of training in ventilation systems and environmental controls.

V/R,

John R. Esberg

Dave Jones
08-22-2006, 7:47 PM
Cutting MDF generates hydrogen cyanide gas. It is very bad stuff. You need to at least exhaust it out to a large open outdoor space.

I have a filtering system with an electrostatic smoke extractor followed by dust, HEPA and charcoal filters. It was expensive (over $4k), but does a great job. The electrostatic inline filter catches a large amount of the smoke, extending the other filters about 10 fold (they're expensive to replace). You soak the electrostatic plates and wipe them off to clean them. The system is made by electrocorp.

Pete Simmons
08-22-2006, 9:28 PM
Cutting MDF generates hydrogen cyanide gas.??????


Take a look at the MSDS sheet I do not think it is Cyanide.



It contains Urea-Formaldehyde - Bad stuff also, and NOT good to breath, but not cyanide.

Dave Jones
08-23-2006, 1:04 AM
On the MSDS I found it says (under Reactivity and Stability Data):

"Thermal and/or thermal-oxidative decomposition can produce irritating and
potentially toxic fumes and gases, including carbon monoxide, hydrogen cyanide, polynuclear aromatic hydrocarbons, aldehydes and organic acids."

Lee DeRaud
08-23-2006, 1:53 AM
On the MSDS I found it says (under Reactivity and Stability Data):

"Thermal and/or thermal-oxidative decomposition can produce irritating and potentially toxic fumes and gases, including carbon monoxide, hydrogen cyanide, polynuclear aromatic hydrocarbons, aldehydes and organic acids."That phrase "can produce irritating and potentially toxic fumes and gases" is not quite the same as "cutting MDF generates hydrogen cyanide gas".

"Thermal and/or thermal-oxidative decomposition" translates to "burning": I might be concerned if we were burning pounds of the stuff, but cutting it with a laser burns quantities more suitably measured in milligrams. And at the rate a typical (non-industrial) laser burns it, even that small quantity is getting mixed into hundreds of cubic feet of exhaust air.

Try not to panic.

John Esberg
08-23-2006, 7:22 AM
In the case of high CFM blowers, a person is most likely not at a point of serious exposure. There is no doubt of this.

But in the case of having to wear a mask due to overwhelming fumes, it's a whole new ball game. It's a fairly safe rule of thumb that when fumes come to a level of irritation and a person voluntarily dons PPE, it's time to engage in a bit of engineering. In our case, there's no serious reason for the average small business owner to consult an EPA certified engineer. There's no need to drop a hefty sum of change for a "Sniffer" to accurately check toxic levels. Simply fix the ventilation problem.

Joe Pelonio
08-23-2006, 8:39 AM
In the case of high CFM blowers, a person is most likely not at a point of serious exposure. There is no doubt of this.

But in the case of having to wear a mask due to overwhelming fumes, it's a whole new ball game. It's a fairly safe rule of thumb that when fumes come to a level of irritation and a person voluntarily dons PPE, it's time to engage in a bit of engineering. In our case, there's no serious reason for the average small business owner to consult an EPA certified engineer. There's no need to drop a hefty sum of change for a "Sniffer" to accurately check toxic levels. Simply fix the ventilation problem.
Exactly, if there are fumes inside something is wrong, clogged ventilation duct, bad seal on laser door, fan broken or loose, maybe the motor runs but the fan is loose on the shaft. Even when doing the smelliest material
I have no smell in the room.

V.A Melle
08-24-2006, 9:58 PM
anyhow I have a ventilation problem there is nothing wrong with the machine -I just have to find a better way to exhaust it out to our poor environment. And I have a neighbor who does complain about anything that smells-you'd think she'd pick up her own dog poop from the yard:) I'm just being a pain:)

I had a thought -I took a look at Woodcrafts hawaii store the other day and yeah the exhaust system and filters are very expensive and the nice lady behind the counter thought I was crazy for wanting to make own jimmy rigged filter but here goes...

Could I connect the exhaust hole to a tube (like the tube that connects from lazer to exhaust) into a box Id build that would house a hepa filter fan with ionized air switch (not sure if that matters)that has a charcoal filter. And It would suck the air through it and hopefully it wouldnt stink so bad. Anybody think it would work?

Or buy a charcoal filter cut to size-fit in hole- and let it blow through.
What do you think?

Joe Pelonio
08-25-2006, 9:25 AM
Any of those things would help some. See what they are doing on the commercially made filter systems and try to duplicate it. Usually they will show the cutaway view on their websites.

Be careful to maintain sufficient flow, any filter will slow it down and the
air is also cooling the tube. You may have to use a more powerful fan or add a second one.

Dave Jones
08-25-2006, 10:38 AM
You are definitely going to want a fan on the far side of the filter so it is sucking the air through the filter. Most exhaust fans don't have the oomph to push air through a filter, but can pull it through.