Big tools and dust collection

[drzaius]

4 hours ago, rodger. said:

i am not confident this is enough for my largest tools (13" planer, 6" jointer)

I had very good results with collection on my 13" planer & 6" jointer with just a Ridgid shop vac. The real tough ones are the table saw, SCMC, & large sanders. It's with those tools that you really need the HP.

[Dhankx]

2 minutes ago, Cheeset202 said:

Depending how deep you want to go, you can read Bill Penz's dissertation on fine dust removal in a wood shop.  At the end of reading his dissertation you will learn the following:  you need a minimum of 5 hp with at least a 14" impeller, an efficient cyclone to separate shavings and fines into a collection bin and exhaust the micro particles (the unhealthy stuff) outside.  Your ducting design needs to be a minimum 7" trunk line and 6" at your machines.  According to Bill, anything less and you are exposed to micro dust.  I have been slowly working my way to this goal, not sure I will ever achieve it because it is expensive and a lot of work!  A good dust mask and a decent DC (2 hp) to collect shavings is a good start.  If you are going to use a filter canister or bag a cyclone separator (2 stage system) is necessary.  

So what's a good respirator mask?  i started looking for a hard core one and got lost

[drzaius]

3 minutes ago, Dhankx said:

So what's a good respirator mask?  i started looking for a hard core one and got lost

One that fits your face comfortably & has HEPA filters. It's personal, you just have to go shopping & find one that fits well.

[Cheeset202]

3 minutes ago, Dhankx said:

So what's a good respirator mask?  i started looking for a hard core one and got lost

I am sure there are others who can provide a better answer but you are looking at the canister filter style, 3M makes a bunch of different ones.  I think mine has a P100 rating which will filter out vapors and that may be overkill.

[Cheeset202]

3 minutes ago, drzaius said:

One that fits your face comfortably & has HEPA filters. It's personal, you just have to go shopping & find one that fits well.

Agree!

[sjeff70]

Isn't micron filtration a better indicator of air quality?  You can get a Grizzly 10 HP machine rated at 2.5 micron and a Powermatic 1.75 HP rated at 2 microns.  HP is only an indicator of how many machines you can hook up to it, correct?  You still need to get the microns down.

[Tom King]

Air quality, if everything gets sucked through the filter, and that's the most important "if"-not necessarily how many machines.  I often use the 3hp just on one machine.  If it doesn't suck it all up, filtration matters little.  HP is generally a measure of air flow, but, of course, there are many other factors.  

[drzaius]

57 minutes ago, sjeff70 said:

Isn't micron filtration a better indicator of air quality?  You can get a Grizzly 10 HP machine rated at 2.5 micron and a Powermatic 1.75 HP rated at 2 microns.  HP is only an indicator of how many machines you can hook up to it, correct?  You still need to get the microns down.

So many variables. Duct length, number of elbows, type of filter, how well the machines can actually contain the dust for collection. The filter needs to remove particles down to .3 microns to make the discharge safe to breath. That's assuming perfect collection at the machine. The only thing a 2 micron filter gives you is easier cleanup at the end of the day.

[Tpt life]

The biggest barely mentioned factor impacting HP requirements is the surface area of the filter in a filtered system. Here I am assuming optimal and equal ducting. A smaller bag loses to a bigger pleated. You can get more machines hooked up at longer distances with no filter or lots of surface area. You are correct that if your filter chokes flow, HP is just a number. 

1 hour ago, sjeff70 said:

Isn't micron filtration a better indicator of air quality?  You can get a Grizzly 10 HP machine rated at 2.5 micron and a Powermatic 1.75 HP rated at 2 microns.  HP is only an indicator of how many machines you can hook up to it, correct?  You still need to get the microns down.

 

[sjeff70]

If you're using one tool at a time a 3 HP unit is recommended to get a good base extraction.  On top of that make sure you take the microns down to .3 with the bag filters.  Size and length of ducting should be easy to determine if you're using one tool at a time.  

You really don't know your air quality unless you measure it, so a good air quality tool is essential for measuring it. Because I'd hate to spend $2,500 on collection and it still not give me what I want. And even if you wear a mask the air quality can still be poor when you leave the shop: when you return to the shop later and kick it up, unknowingly.      

[Eric.]

What is really overlooked is the efficiency of the collection at the source.  People get hung up on horsepower and length of duct and micron bags and everything else, but seem to forget that most of the efficiency is lost at the tool port.  The giant box of a table saw is a terrible design, and the bandsaw is even worse...the two tools that produce the most fine particulates other than sanders, which usually have better designs for collection.  Without major re-engineering and customization of a bandsaw collection port, you could have hurricane-force CFM but since it's just sucking open air 8" away from the source, it's pretty much useless for "breathable air," which is the whole point of big DC systems. Yes it's gonna pull all the dust that drops into the port but that's it.  There will still be plenty of fines filling the air you're breathing.  Which is why I've basically lost interest in throwing thousands of dollars at a huge unit with 6" pipe.  You can chase your tail for the rest of your life and still not achieve 100% efficiency...so you'll still have to wear your respirator to be safe.  And if you have to use your respirator, what have you gained from the thousands of dollars spent on a big system?  Woodshops are dusty, no way around it.  The only way to be totally safe is to wear your respirator 100% of the time, which to me makes the DC more of a clean-up solution rather than a safety solution.

[Cheeset202]

2 hours ago, Eric. said:

What is really overlooked is the efficiency of the collection at the source.  People get hung up on horsepower and length of duct and micron bags and everything else, but seem to forget that most of the efficiency is lost at the tool port.  The giant box of a table saw is a terrible design, and the bandsaw is even worse...the two tools that produce the most fine particulates other than sanders, which usually have better designs for collection.  Without major re-engineering and customization of a bandsaw collection port, you could have hurricane-force CFM but since it's just sucking open air 8" away from the source, it's pretty much useless for "breathable air," which is the whole point of big DC systems. Yes it's gonna pull all the dust that drops into the port but that's it.  There will still be plenty of fines filling the air you're breathing.  Which is why I've basically lost interest in throwing thousands of dollars at a huge unit with 6" pipe.  You can chase your tail for the rest of your life and still not achieve 100% efficiency...so you'll still have to wear your respirator to be safe.  And if you have to use your respirator, what have you gained from the thousands of dollars spent on a big system?  Woodshops are dusty, no way around it.  The only way to be totally safe is to wear your respirator 100% of the time, which to me makes the DC more of a clean-up solution rather than a safety solution.

Well said!  I love my central dust system (CV1800) does a great job minimizing my time cleaning up.  Getting it to Micron dust free would cost way more than I want to do, especially on machine mods.  Wear a dust mask for the harmful stuff!  

[drzaius]

2 hours ago, Eric. said:

What is really overlooked is the efficiency of the collection at the source.  People get hung up on horsepower and length of duct and micron bags and everything else, but seem to forget that most of the efficiency is lost at the tool port.  The giant box of a table saw is a terrible design, and the bandsaw is even worse...the two tools that produce the most fine particulates other than sanders, which usually have better designs for collection.  Without major re-engineering and customization of a bandsaw collection port, you could have hurricane-force CFM but since it's just sucking open air 8" away from the source, it's pretty much useless for "breathable air," which is the whole point of big DC systems. Yes it's gonna pull all the dust that drops into the port but that's it.  There will still be plenty of fines filling the air you're breathing.  Which is why I've basically lost interest in throwing thousands of dollars at a huge unit with 6" pipe.  You can chase your tail for the rest of your life and still not achieve 100% efficiency...so you'll still have to wear your respirator to be safe.  And if you have to use your respirator, what have you gained from the thousands of dollars spent on a big system?  Woodshops are dusty, no way around it.  The only way to be totally safe is to wear your respirator 100% of the time, which to me makes the DC more of a clean-up solution rather than a safety solution.

Very true, and I find myself getting caught up in the tail chasing. I wear a mask while cutting etc & let the collector run for several minutes after to act as an air cleaner. What I really need to do is get a particulate counter to monitor the air quality & they aren't that expensive. My problem with the mask is that I haven't found a half mask yet that doesn't make the bridge of my nose hurt like hell after extended use.

I do know the my collection is pretty good though because there just is very little dust that accumulates on surfaces.

[sjeff70]

That's kind of what I was eluding too, where's the trade-off: cost vs. efficiency/effectiveness.  It seems a decent air purifier is essential.  Maybe some people put too much into their dust collection with little consideration for air purification after the fact?  Put the extra money into that.

 

[rodger.]

39 minutes ago, sjeff70 said:

That's kind of what I was eluding too, where's the trade-off: cost vs. efficiency/effectiveness.  It seems a decent air purifier is essential.  Maybe some people put too much into their dust collection with little consideration for air purification after the fact?  Put the extra money into that.

 

I have an air cleaner, and it works well. The problem is getting decent filters. I had to go to an HVAC fabrication place to get MERV 16+ filters for the inner 3 bag filter. The outside filter i also upgraded to about MERV 8.

[Eric.]

The other problem with the air cleaner is that because it doesn't clean everything out of the air you still have to wear a respirator to be safe, so once again I don't see the value in it.  If you have any dust at all in your shop, you're not safe without a respirator.  And all shops have some dust, I don't care what kind of system you have.  As soon as you walk into your shop and start moving things around, dust is gonna be kicked up and the air is no longer safe to breathe, regardless of your DC system and air cleaners.  So once again, the only way to be safe is by wearing the respirator, and at that point the question becomes: how much money do you want to spend on the DC and air cleaners when ultimately you still have to wear the freakin' mask no matter what, regardless of your investment?  That's the conclusion I've reached anyway.  

[ottacat]

I wish there was an air cleaner with a built-in particle detector. At one level of particles it would automatically turn itself on (and later off), at a higher level of particles it would light up a red light indicating it can't keep up and to serve as notice to put on a respirator. 

[Eric.]

If the shop is dusty enough to be running the air cleaner, then you should be wearing your respirator, too.  Because it might be cleaning the air, but all that dust is passing across your nostrils as it makes its way to the cleaner.  Again I just find the whole thing a wild goose chase.  You'll never achieve surgical-clean air in a woodshop.  Never.

[woodbutcher]

10 minutes ago, Eric. said:

If the shop is dusty enough to be running the air cleaner, then you should be wearing your respirator, too.  Because it might be cleaning the air, but all that dust is passing across your nostrils as it makes its way to the cleaner.  Again I just find the whole thing a wild goose chase.  You'll never achieve surgical-clean air in a woodshop.  Never.

I just dont understand why thats a goal though, surgical clean air. The air I breathe in my house, the air outside, the air almost anywhere has some level of microscopic dust floating around.

[Eric.]

9 minutes ago, woodbutcher said:

I just dont understand why thats a goal though, surgical clean air. The air I breathe in my house, the air outside, the air almost anywhere has some level of microscopic dust floating around.

True, but it's nothing compared to a woodshop.

My point is, unless you can achieve air that's clean enough to safely breathe without a respirator, you have to wear a respirator to be safe.  And at that point I find throwing thousands of dollars at a huge DC system and air cleaners kind of a waste of money...because you have to wear your respirator anyway.

If your shop is in your basement and you're trying to keep the shop from contaminating the rest of your house, then it makes more sense.  But I'm out in the garage, which is completely closed off from the house.  Even if I had a 5HP system and an air cleaner, I would still have a dusty shop and I would still have to wear a respirator to be safe.  So I've transitioned my perspective to see dust collection as more of a cleanup solution rather than a safety solution.

I know I've said the same thing like five times in five different ways, but I'm not sure I'm getting my point across.

[Tom King]

In the "shops" that I set up, and might use for a year or two, we don't have fine dust to clean up on anything, but that might be because we don't do any sanding.  All of our surface finish is done with planes.

The first few decades that I built new houses, I only had small DC's, like 1-1/2 hp, and we did do sanding, always in the garage shop, which I always built first.  In those, I wore a respirator under a battery powered filter helmet, and picked a day when a strong wind was blowing the right direction to blow the "shop" out with a leaf blower.

[derekcohen]

Tom is correct about the horsepower and the impeller size needed to suck dust. Eric is also correct about most dust collection systems being false security. 

The fact is, unless the DC exhausts outside the shop, there will be potentially lethal dust all the time unless you can find a way to clean the air quickly. 

My own DC is due for an upgrade - I have a 2 hp machine into a 2 micron pleated filter with 5" hose. Useless. It collects chips not dust. Most of the time I work with hand tools, which creates little dust, but the roughing out is done with machines (Hammer bandsaw, panel saw and jointer-planer). I wear a mask. My shop is in a double garage, and I open the front and rear doors and let the breeze blast it out. If you are in a basement, then you really need to find a way to avoid breathing in the fine dust. Remember, it is the stuff that is under 3 microns that does the damage. Be careful out there.

Regards from Perth

Derek

[Cheeset202]

32 minutes ago, woodbutcher said:

I just dont understand why thats a goal though, surgical clean air. The air I breathe in my house, the air outside, the air almost anywhere has some level of microscopic dust floating around.

The human body does a good job filtering down to 10 micron, the human eye can see to 20 micron, the micro dust in your shop is well below 10 micron.  If you can see the fine dust then your body does a good job of filtering it out.  The concentrations of invisible dust in your shop are well above what you breath in your house and outside!  As well most wood dust can cause serious health problems if inhaled over a long period of time, just look up wood dust toxicity and you will see the hazards associated with various species.  Wearing a good dust respirator is really the only way to minimize the long term effects of wood dust.

[woodbutcher]

3 hours ago, Eric. said:

True, but it's nothing compared to a woodshop.

My point is, unless you can achieve air that's clean enough to safely breathe without a respirator, you have to wear a respirator to be safe.  And at that point I find throwing thousands of dollars at a huge DC system and air cleaners kind of a waste of money...because you have to wear your respirator anyway.

If your shop is in your basement and you're trying to keep the shop from contaminating the rest of your house, then it makes more sense.  But I'm out in the garage, which is completely closed off from the house.  Even if I had a 5HP system and an air cleaner, I would still have a dusty shop and I would still have to wear a respirator to be safe.  So I've transitioned my perspective to see dust collection as more of a cleanup solution rather than a safety solution.

I know I've said the same thing like five times in five different ways, but I'm not sure I'm getting my point across.

No i totally get you now Eric. And im with you on the fact that acheiving perfect air is probably not worth what it costs with a dust collector alone. I think ill just buy a respirator and a dust collector thats good enough to keep the shop clean. 

[Dhankx]

Just now, woodbutcher said:

No i totally get you now Eric. And im with you on the fact that acheiving perfect air is probably not worth what it costs with a dust collector alone. I think ill just buy a respirator and a dust collector thats good enough to keep the shop clean. 

Same! Thanks all!