I'm still new around here and am going to start by building a small router from Crankorgan's plans. I was doing some reading on using MDF and found the following which I think is worth reading by anyone else who might be using it. Although there is not much to be cut, I may just switch to a top quality plywood instead ( which also contains glue ).

http://www.design-technology.org/mdf.htm

" Disadvantages: -MDF can be dangerous to use if the correct safety precautions are not taken. MDF contains a substance called urea formaldehyde, which may be released from the material through cutting and sanding. Urea formaldehyde may cause irritation to the eyes and lungs. Proper ventilation is required when using it and facemasks are needed when sanding or cutting MDF with machinery. The dust produced when machining MDF is very dangerous. Masks and goggles should always be worn at all times. Due to the fact that MDF contains a great deal of glue the cutting edges of your tools will blunt very quickly. MDF can be fixed together with screws and nails but the material may split if care is not taken. If you are screwing, the screws should not be any further than 25mm in from the edge. When using screws always use pilot holes. Urea formaldehyde is always being slowly released from the surface of MDF. When painting it is good idea to coat the whole of the product in order to seal in the urea formaldehyde. Wax and oil finishes may be used as finishes but they are less effective at sealing in the urea formaldehyde "

Through work I use more MDF then the average person. I am a finish carpenter in new homes. I use way to much of the stuff. I use a good resperatetor when cutting lots of in inside. I am not talking about a dust mask, it is a charcoal filtered full blown resperator.

Carbide toothed blades last for a long time. I used the same blade in my Skill saw for almost 5 months. You will also need to use a finer cut blade to make a nice smooth cut. You can force the saw through it and it will leave a rough sawn look to the edge. If you let the blade cut and clear the dust it will come out smoother.

There is also a water proof type of MDF called MEDEX. It is the same saw dust but the glue they use to bond all of the particles together is a water proof type.

MDF will work a little better because of the weight factor. Weight is a good way to dampen vibration. MDF does not have an end grain, open areas between plys, plug to fill holes in the surface sheet, and is for the most part flater then ply. It by far smoother and paints better then ply. This is of course not a furniture grade of plywood.

It is best if you can do most of your cuts outside or with a vacum going to help get rid of the dust. You should see the floor after I install a walkin closet built out of MDF. There is a layer of dust you can loose tools in. The dust WILL get every where you don't want it.

Dru.

Good info. Most people dont even realize that just inhaling run-of-the-mill wood dust can cause major health problems over time...

Ahhh the beauty of man made products. I don't think the building of one cnc router with MDF will put you off the deep end. I would recommend using a decent dust mask, especially if you are more inclined to be effected by fine particulates but no need to go into panic mode. You will probably encounter just as many other harmfull products or byproducts in the construction of your router from grinding dust to the very paint you will spray to seal in the urea formaldehyde of the MDF. MDF is the preferred product because it is non directional, dense, consistent thickness and usually flat. Just a note in closing, urea formadehyde is present in most furniture, carpets, drapes, and even the glues used in plywood

And here I was told that urea formaldehyde was used to make your lungs "tough" :D

I'm thinking of doing my first build out of MDF. I saw some at Home Depot and like the weight and flatness (as well as the price:) ). I too have concerns about the dust and urea formaldehyde associated with mdf cutting and sanding and would like to proceed with my build as safely as possible. I'm going to buy a respirator and will wear eye protection when working with mdf (well, also with any other material, but ESPECIALLY with mdf) but I also want to collect as much of the dust as possible to ensure my safety (as well as others around me). I don't have much room in my garage to do my work at the moment and prefer not to work with the mdf indoors anyway so I was hoping to do most of my work right outside my garage or at least in the garage doorway. However, I don't want dust to be flying around toward my neighbors' houses and don't want that dust to settle in the driveway (I don't want my dogs or any visitors to have to breathe or come in contact with mdf dust or urea formaldehyde). I was hoping to rig something up that will collect as much dust as possible and I may possibly even enclose (somehow... :confused: ) the immediate area where the dust will most likely fall to. What type of shop vac would collect mdf dust the best? Any specs or features that I should look for when buying one? What other safety precautions should I take when working with mdf? Any advice would be really appreciated. Thanks!

M

You can't be to careful when it comes to your health.
Cheap dust masks don't filter out the very fine particals that are the most dangerous long term. There is a heap of info on Bill Pentz web site.
http://billpentz.com/woodworking/cyclone/index.cfm
Bill suffers dust related health problems caused by his wood working hobbies.
His cyclone has been built by several zone members.
Paul

I think this information is useful and might be accurate, but it's incomplete and is a bit deceiving. How much is tolerable? How much is too much? If I breathe a little of it, am I going to die?

Ozone and carbon monoxide can easily kill you, but we breathe both gases everyday.

"Urea formaldehyde may cause irritation to the eyes and lungs". "May cause irritation". Irritation is a very vague word. Water, in excess, 'irritates' your skin.

All I am saying is don't throw MDF under the bus without a bit more investigation. I get the feeling this information came from a source that had an agenda - like a plywood manufacturing company or ?.

It's interesting that they don't mention anything about the dust being explosive. I imagine this would be the environment required (saturated) to produce any harmful effects greater than simple, temporary irritation.

If inhaling sanding/routing dust from MDF is as dangerous as that article leads one to believe then I should have been dead (or at least severely 'irritated') 15 years ago.

Obviously, common sense is needed when handling any material - especially when it's in a form can be respirated, such as dust from any source. A dust mask, ventilation and common sense make a lot of sense.

Geoff (or is it McGyver?) - chime in here - you are the chemist, right? How bad is Urea Formaldehyde to us?

Scott

Scott, you do bring up some good points. I'll be honest, the mdf dust and Urea Formaldehyde release do worry me but I would still like to work with mdf, but in the safest way possible. The lack of specific information on how bad Urea Formaldehyde really is, is what both worries me and keeps me interested in mdf. Is it bad enough that it can be dangerous to anyone within certain distance or does it linger even when it seems that the area is at least visually clean? Are the somewhat vague information and warnings overexaggerated at all? I, too, would like more detailed and specific answers to questions like how bad it really is. Don't get me wrong, even if the warnings are slightly exaggerated in order to get people to use more safety precautions, I still intend to wear a respirator mask (not a simple dust mask but rather the kind that has replacable filters) and do what I can to collect dust and particles as best as possible. BTW, thanks to anyone sharing their knowledge on this topic and/or putting in their two cents.

M

I've cut MDF for years and have no problems. Like was mentioned, use the best dust collection you can. The BP site claims that the finest dust is what does the most damage to your health, but I've also been told that that stuff is only inhaled and exhaled like the air we breathe.

http://www.norbord.com/MSDS_MDFEng_2006.pdf

Here is the "Material Safty Data Sheet" (MSDS) for MDF.

Would a shop vacuum work well for dust collection? I have a 2.5 peak hp Ridgid wet/dry vac. If not, I could get a 5 peak hp one. Would either of those be strong enough to collect most of the particles?

M

Yup. Read the MSDS.

If you grind up an entire sheet of MDF into a respirable powder and then blow it all into a small room while you stand in the room breathing deeply without respiration protection, it is likely to cause some irritation.

Scott

Toxicity depends on two things: amount and length of exposure.

For instance, if you were walking along and happened to get a puff of asbestos dust thick enough to make you cough but never had exposure to asbestos before or after, the chances of developing asbestosis are pretty well nill. It could possible cause cancer later but again, the chances are pretty low.

If you worked in an area with a tiny amount of friable asbestos (dust) in the air for 30 years, your chance of developing asbestosis is still pretty low but the cancer risk is orders of magnitude higher.

If you work in an area where you breathe very high levels of friable asbestos then your chance of developing asbestosis is pretty good but your chance of developing cancer is actually lower than the example above - because asbestosis will likely kill you before cancer develops.

Many deadly poisons can actually be beneficial or even essential to health - in small enough doses.

Oh and if you didn't already know, be careful around red cedar as it is a sensitizer. Prolonged exposure can make you alergic to it even if you didn't start out that way.

Would a shop vacuum work well for dust collection? I have a 2.5 peak hp Ridgid wet/dry vac. If not, I could get a 5 peak hp one. Would either of those be strong enough to collect most of the particles?

M

The hard answer is NO! They do not trap particulate less than 5 microns.

This is the kind of dust collector you need.
http://billpentz.com/woodworking/cyclone/DocsOrders.cfm#MedicalRisks

This is a Cyclone build it your self vacuum.

Read and be aware of what you can do to protect yourself.
Hager

Also depends on whether you smoke or not. If you do then you've destroyed a lot of the little hairs in the windpipe that continualy ripple and push dust/ fibres up out of the way of your lungs.

That's why smokers are more prone to problems from asbestos than non (I'm a smoker btw, not having a pop or anything).