Re-thinking dust collection... a 'new' way to do it?

[REK Knives]

I have never wanted to vent air outside because my shop is heated and cooled... and in order to do that you have to have some way for fresh outside air to come in your shop, which wouldn't be heated or cooled without a heat exchanger (from what I've been told)

So I though I was reduced to getting a traditional filter set up. But I was talking with my FIL and he had a good point... what if you had a supply line (from outside, fresh air) and an exhaust line (the blower end, that would pump air out of your shop). You would then position 2 hoses at each station... a fresh air hose and an exhaust air hose. This way the air that is not climate controlled would only be traveling a short distance and not heating/cooling your entire shop.

This would eliminate the need for a large footprint for a traditional filter, and it would also lower costs significantly.

Has anyone actually done it in this way? I know a lot of guys suck the air out of their shop but their shop isn't heated or cooled.

 

[Stacy E. Apelt - Bladesmith]

Rick Manchard has a similar system, IIRC.

 

[REK Knives]

Rick Manchard has a similar system, IIRC.

I'm really curious how well it works, I'll try to reach out to him and ask. What's attractive about it is that it saves room, no filters required, higher volume of air can be moved (no clogged filters), and it can be done in climate controlled space (I think anyways)

 

[Lorien]

would fresh air be forced via an inline fan of some kind into the shop?

 

[REK Knives]

would fresh air be forced via an inline fan of some kind into the shop?

I don't think it would need to be... I would have an inline dust collector blower (only) that would be on the exhaust side... So if the supply duct had a direct supply to outside air the exhaust duct would automatically extract the fresh air from that point instead of in the shop

 

[Lorien]

the down side to a system where particles aren't trapped is that particles can't be disposed of properly. Filters are a pain in the ass and an extra cost, but they do allow waste to end up where it's more or less supposed to go, as opposed to blowing around your immediate environment, while at the same time not affecting the temperate of the work area

in Rick's case, from what I understand, he doesn't really use toxic materials for his handles and works with mostly low alloy steel. Resins, glass and carbon fibers, plastic, chemicals used to make those things, and some of the components of high alloy steel aren't good for living organisms, so it might be an idea to consider a way to trap most of the exhaust particles. Maybe like a cyclone type set up where there's no filter, all the stuff just gets forced into a holding area that can just be dumped in the garbage.

 

[Stacy E. Apelt - Bladesmith]

Ricks system is on the wall behind the grinder. It brings in fresh COLD air at the top and exhausts the grinder dust out at the bottom behind the grinder.

 

[REK Knives]

the down side to a system where particles aren't trapped is that particles can't be disposed of properly. Filters are a pain in the ass and an extra cost, but they do allow waste to end up where it's more or less supposed to go, as opposed to blowing around your immediate environment, while at the same time not affecting the temperate of the work area

in Rick's case, from what I understand, he doesn't really use toxic materials for his handles and works with mostly low alloy steel. Resins, glass and carbon fibers, plastic, chemicals used to make those things, and some of the components of high alloy steel aren't good for living organisms, so it might be an idea to consider a way to trap most of the exhaust particles. Maybe like a cyclone type set up where there's no filter, all the stuff just gets forced into a holding area that can just be dumped in the garbage.

That's a solid point... Cyclone may be the best way to go with this system, as that will at least trap most of it. Thanks for chiming in!

 

[Pinoy Knife]

a close friend has his set up to draw the air from below his grinder and blow it directly outside..
mine has a steel drum and going from the drum to outside.. that way most of it gets caught by the drum
and whatever else goes outside ... you can easily hook up a steel garbage can out thereto catch whatever comes out
so you can dispose of it differently if you wish..
both of these have lots of power and very little loss of heat in the winter....

 

[Stacy E. Apelt - Bladesmith]

One option that fits your desire is to place the cyclone and blower OUTSIDE the shop. A small shed will keep the elements off it. This exhausts the air and keeps the noise outside. This may not work in urban locations with neighboring homes 10 feet away but works very well in more spaced out homes or in rural locations. Use an incoming air supply as you planned to keep the warm air in the shop. It would also allow a good spark bong setup and still keep the dust collection equipment and noise out of the way.

I would suggest a hanging continuous air cleaner for the shop to catch the airborne fine dust. No matter how good any dust catch system is, a lot of super fine dust gets airborne.

 

[REK Knives]

a close friend has his set up to draw the air from below his grinder and blow it directly outside..
mine has a steel drum and going from the drum to outside.. that way most of it gets caught by the drum
and whatever else goes outside ... you can easily hook up a steel garbage can out thereto catch whatever comes out
so you can dispose of it differently if you wish..
both of these have lots of power and very little loss of heat in the winter....

So where is your fresh air supply coming from? do you have a duct routed over to your grinder to supply it?

One option that fits your desire is to place the cyclone and blower OUTSIDE the shop. A small shed will keep the elements off it. This exhausts the air and keeps the noise outside. This may not work in urban locations with neighboring homes 10 feet away but works very well in more spaced out homes or in rural locations. Use an incoming air supply as you planned to keep the warm air in the shop. It would also allow a good spark bong setup and still keep the dust collection equipment and noise out of the way.

I would suggest a hanging continuous air cleaner for the shop to catch the airborne fine dust. No matter how good any dust catch system is, a lot of super fine dust gets airborne.

Yeah I thought about it, good point. I'm in a rural area w/ plenty of land so that wouldn't be a problem. I also have a continuous air cleaner in the shop (Fox) that I change out air filters on regularly but I need something (other than a shop vac) for when grinding handle material.

the only thing I'm wondering is if it's 20°F outside in though if it would freeze my hands off on the grinder with the cold air passing past them lol

 

[Pinoy Knife]

my buddy uses a "Squirrel cage" fan.. it works by drawing the air in through the inlet side and everything has to go through the fan blades/fins.
mine is a impeller motor like most closed style dust collectors.. a shop vac is not built for dust collection (kinda works)
the biggest thing is to try to separate as much as possible before blowing it outside .. i use a aluminum dryer vent through the wall.

 

[REK Knives]

my buddy uses a "Squirrel cage" fan.. it works by drawing the air in through the inlet side and everything has to go through the fan blades/fins.
mine is a impeller motor like most closed style dust collectors.. a shop vac is not built for dust collection (kinda works)
the biggest thing is to try to separate as much as possible before blowing it outside .. i use a aluminum dryer vent through the wall.

yeah makes sense, but my question basically is trying to figure out where the supply air is coming from... if you don't have a specific opening in your shop for the air to come in through it will come around the cracks in your doors and windows and created a negative pressure in your shop (i.e. the air outside your shop is always trying to get in so it can supply the suction).

 

[Pinoy Knife]

yeah makes sense, but my question basically is trying to figure out where the supply air is coming from... if you don't have a specific opening in your shop for the air to come in through it will come around the cracks in your doors and windows and created a negative pressure in your shop (i.e. the air outside your shop is always trying to get in so it can supply the suction).

well my shop in completely insulated with R15 .. all cracks are spray foam sealed.. like Stacy said you can just build a small "Shed" outside to house the collector
and just bring in the hose to draw it out.. the only "Bad" thing is you are stuck with dust extraction in 1 place only.. the close off gates/etc kinda work..

 

[Rick Marchand]

Here is the basic concept of my system.... I've since changed it up a bit to work with other grinder configurations but this in the basic concept. I teach classes, now and for insurance purposes, I had to have my shop accessed by air quality, electrical, gas and fire inspectors. They were actually impressed with the efficiency of semi-closed system.

 

[REK Knives]

Here is the basic concept of my system.... I've since changed it up a bit to work with other grinder configurations but this in the basic concept. I teach classes, now and for insurance purposes, I had to have my shop accessed by air quality, electrical, gas and fire inspectors. They were actually impressed with the efficiency of semi-closed system.

View attachment 2163379

Excellent thanks for the pic and input Rick!

So does your exhaust dump the air back outside on the other end of your shop or where does it go?

I'm still thinking about placement on a 2x72 4 wheel grinder... I was thinking exhaust could come from below since the bottom of the platen will be shooting the dust downwards anyway.

Is your shop heated and cooled? how well does this work in the coldest part of winter or the hottest part of summer?

 

[Rick Marchand]

The dust is exhausted outside into a metal bin. The nasty stuff is the fine dust that hangs in the air. The issue is that the fine stuff tends to get pulled along the belt and forced back out into your face, so you need an exhaust port placement that strips the fine particulate from the air current created by the belt. The best way to see where that fine stuff is going, is to run a piece of chalk across your belt while it's operating. You'll see where the problem areas are. You also have to consider the fact that once you add a fresh air intake, you now have essentially a "blower effect" that will change the air current. You end up needing a well thought out dust shroud with multiple ports to control the air flow and optimize the removal of particulate. That's only the dealing with everything in the shroud... now, you need to see to the fire-breathing end of the system. Most of the large dust that hits the bucket is too heavy to hang in the air but you still get a bit and it needs to be addressed.... but it complicates things even more because of the sparks. I detest those inline spark arresting bucket contraptions. I chose to remove the fine dust in that area by installing another exhaust port that pulls from the side, rather than gulping sparks and large particulate, directly. I'll try to get some pics. I haven't hooked up my latest Square Wheel grinder to the system yet but I still have the old Grizzly set up.

A semi-closed loop system pulls much less from the room, itself. There is no noticeable drop or rise in temperature. BUT if I block that outside air intake, your ears will pop and doors will slam... outside temps will soon become inside temps.... lol.

 

[Rick Marchand]

Some pics of the Grizz

 

[Nathan the Machinist]

I would like to point out that recirculating air in the shop can be hazardous to your health if you're not getting the finest particles out. And those fine particles require HEPA filtration.

A cyclone system will do nothing to stop the finest particles. Which are the ones that can harm you the worst.

A lot of those dust collectors with filter bags or big pleated filters that are not HEPA have the effect of sucking the finest particles in and then blowing them back out everywhere at velocity. The increase in air flow can actually increase the amount of finest particles in the air.

I think if those particles are made of something like sawdust (these collectors were frequently intended for woodworkers), it's probably not particularly harmful. I'm sure they're not good for you, but if those particles contain a lot of chromium and vanadium, it might be more cause for concern.

Here in our shop, we mostly vent outside.

I like Marks design.

 

[REK Knives]

I would like to point out that recirculating air in the shop can be hazardous to your health if you're not getting the finest particles out. And those fine particles require HEPA filtration.

A cyclone system will do nothing to stop the finest particles. Which are the ones that can harm you the worst.

A lot of those dust collectors with filter bags or big pleated filters that are not HEPA have the effect of sucking the finest particles in and then blowing them back out everywhere at velocity. The increase in air flow can actually increase the amount of finest particles in the air.

I think if those particles are made of something like sawdust (these collectors were frequently intended for woodworkers), it's probably not particularly harmful. I'm sure they're not good for you, but if those particles contain a lot of chromium and vanadium, it might be more cause for concern.

Here in our shop, we mostly vent outside.

I like Marks design.

Thanks Nathan, I agree - for filters HEPA is the only way to go. I actually snagged a 2000cfm air filter (novair 2000) that I was going to convert for a dust filter since it has 2 pre-filters and a HEPA filter but if this works it would probably be much cheaper.

I'm going to try it out on my new fiber laser when it comes in... Already ordered the duct work and have the blower installed.