Airborne dust from random orbit sander

[Thomas Wilson]

Today I am sanding stair treads and thought I would see how well I could collect the dust and show some particle count readings from a Dylos 1100 Pro. I have everything I can reasonably think of and want to see how well it works. I have a large Oneida 5hp dust collector connected to a downdraft table, a vacuum hooked to the sander, and two air filters. This is the best I think I can do with hobbyist sanding equipment. So how well does it do? The answer is “decent but you still need a mask.” I got readings of 4300 on my Dylos meter while sanding at 120 grit. Here is the reading I got a picture of. When this picture was taken, the air filters had drawn the reading down while I took pictures of other things and was not sanding.
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Without sanding and with only HVAC filtration, ie just walking in the door in the morning, the particle count rate is 500 this time of year in the shop. With air filtration and no work going on, the small particle reading can get down to 10.

For reference, Dylos DC 1100 Pro literature says

Air Quality Chart-Small Count Readings


>3000
Very poor


1050-3000
Poor


300-1050
Fair


150-300
Good


75-150
Very good


0-75
Excellent




Here are the measures I took to collect dust.

I have the Rockler downdraft panels and made the box according to the plans.480962
I arranged the stair tread with two rows of holes at the back and one row at the front. Even with a huge dust collector, air flow is modest. I think it would help a lot if I were to remake the box for a 6” port.
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The Porter Cable sander is hooked to a shop vac with small Dust Deputy.
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I ran a JDS air filter (single speed) and a SuperMax air filter on its highest speed while sanding.


I also wore hearing protection for all the air noise.
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I tried to figure out what does the most good. I checked the bin of the Dust Deputy and the main Oneida dust collector. I think more was in the Dust Deputy but it was hard to tell because the dust collector bin was not empty to start with. The filter on the shop vac had been recently cleaned and still looked good.
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Here is the bin on the main dust collector. It is 2/3 full of planer shavings. There is some light colored sanding dust on top if you look closely.
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I will have another batch of stair treads next week. I may try the same experiment with one or more of the mitigation measures turned off to see what does the most good.


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[Thomas Wilson]

Hmm. Problem with the pictures. I will have fix it tomorrow.

[Maurice Mcmurry]

I rarely use any sander without dust collection attached.

[Thomas Wilson]

Me too. I maxed out all my dust collection tools on this job, still not too good. I never had a way to measure the collection before I got the Dylos. This evening I went through the stack of treads again with180 grit. I used a different PC sander with a better dust shroud. That improved things to 1400 small particles count rate. Better but still need a mask.

[Jim Becker]

Fine particles from sanding can be really insidious...and even with the best extraction and other methods in use, still fill the air with "stuff". PPE is kinda necessary, but many of us, including myself, "forget" to use it a lot of the time.

[Frank Pratt]

A particle counter is a valuable tool and it's really interesting to see how much dust is produced from which tools. The air in my shop is normally better than the air outside or in the house. My counts won't compare to the Dylos because it measures per cu meter and I believe the Dylos is per cu ft. Before starting any work in the shop the .3 micro count is around 160. After running the table saw for a while it drops down to around 20 to 50. So that's better than 100% collection.

[Keegan Shields]

There are some important factors that may be contributing to your poor results:

1. The amount of "suck" on a shop vac can be quite a bit less than on a dust extractor type vacuum. I noticed this when I upgraded from a shop vac (higher volume) to a dust extractor (higher velocity, less volume).
2. Using a cyclone will lower your systems efficiency (arguably a trade off worth taking).
3. The design of the sander's dust extraction system will have a big impact on how much fine dust escapes into the air.
4. The piece your sanding - stair treads are nice and big, but I've noticed more dust escapes when sanding smaller parts that don't cover the entire sander pad (for example a 4' long, 1" wide piece of wood).

I remember Bill Pentz's article stressing that dust capture at the source was the most important element in keeping the fine particle count down. That makes complete sense to me as cleaning entire volume of air in your shop frequently enough requires big, expensive equipment. Perhaps a different sander/dust extractor combo would make the most impact here. Kind of like the best strategy for keeping plastic out of the ocean is to collect is at the ports as opposed to filtering it out of the oceans "Great garbage patch".

I understand the caution about fine dust exposure, but lets not forget frequency and length of exposure play a huge part in these types of risks. Sanding for 15 min once a month is an whole lot different than sanding for 8 hours once a week.

[Derek Cohen]

We forget that hand sanding also produces large amounts of dangerous fine dust.

Hand sander hooked to vacuum cleaner ...

https://i.postimg.cc/j5NSZQCy/Finishing-The-Drawers-html-6237eaad.jpg

Regards from Perth

Derek

[glenn bradley]

Interesting stuff . Thanks for posting. I run a vac hose directly to my sander. I can actually watch spoil from previous hand sanding getting sucked up an inch ahead of the path of the sander. I also use a Dylos and it indicates, despite what I see, that tiny particles are getting airborne. I don’t do a lot of power sanding but always use the vacuum. If I’m going to sand for more than just a few minutes I use the vacuum and wear a respirator.

[Thomas Wilson]

The vacuum collection on the tool seems to collect the most dust but it is not enough. The downdraft table pulls a lot of dirty air away from the operator. The air filters remove dust from the general air of the room. The message is all that is not enough. You may or may not cough at 4000 count rate but it is bad for your lungs.

My suggestion to all woodworkers is that unless you can see that count rates in the room are ~300-500 wear a mask. My results show that it is very hard to keep ambient air breathable. 4000 cpm is bad for your lungs but it does not seem terrible to breathe. The air is not noticeably dust laden. Don’t trust your body’s short term reaction to determine whether you are safe. Effects are cumulative so wear a mask.

[Maurice Mcmurry]

My dad has only one lung due to lung cancer, as well as 3 other cancers. He never smoked. He spent many years in his wood shop without any dust collection or protection. Some of the young kids who helped at the factory and other wood shops in the area also played guitars together. They called themselves "WoodBooger"

[Thomas Wilson]

I did a lot of woodwork with no dust collection available in the 70’s. I still have my lungs but I think function was reduced by it.

[Stan Calow]

I try to do as much of my sanding outside as possible. Even in winter. I keep a tote with ROS, paper, and extension cord, always ready to leave the shop.

[Maurice Mcmurry]

I suspect un-regulated particle board with formaldehyde etc. did not do Dad any good. There are some imported plywoods that give me a bloody nose very quickly if I do not use a good mask.

[Alan Lightstone]

I'm a big fan of maximizing air filtration in my workshop (and everyone's for that matter). And I always use a vacuum with my machine sanding (Festool in my case).

I really did find some substantial improvements in dust collection by modifying the air filters with better filters (doubling the size in one example), but just taping on extra filters was not always beneficial as it reduced air flow / air exchanges per hour. Here's the link from a few months ago when we did a bunch of tests on this. https://sawmillcreek.org/showthread.php?291720-Which-Air-Filtration-is-Better

My ambient particle count here is also usually about 500 (unless a Saharan dust storm comes through). My running rule is that I wear a respirator in the shop until the count goes below that. There's no way I even think about walking around my workshop with particle levels like Thomas demonstrated after sanding without a respirator. One nice help I find, is that I hooked up a digital timer to my homemade air filter, and it runs for 45 minutes, 3 times a day, with the first run in the morning before I go in my shop. I find that makes an impressive difference in the baseline ambient particle count in the workshop, so I'm always starting from a healthier baseline, and less likely to have to wear a respirator.

[Thomas Wilson]

Alan, I remember your discussions of air filtration with David Morse and your well-done tests of your system. I appreciated them very much. I don’t plan on doing anything so elaborate. I am just posting particle count rates for various activities. I will log count rates and mitigation measures I use for information. When I get back to the shop, I will also check air velocity around the tools and downdraft box using a Testo hot wire anemometer to give a quantitative measure of air movement for my dust collection components. I think numbers are useful for people compare to and evaluate their own shops.

I am making information about shop dust a small crusade because even as a hobbyist I think I damaged my lungs before dust collection and filtration were widely available. When I started setting up my current shop, I hoped my high end equipment might be sufficient that wearing a mask would not be necessary. What I’m finding is that it is not. I will also say that while 4000 count is bad for your lungs, it does not seem too bad while breathing it. The air is not heavily laden with dust. I am not coughing my head off when I take the mask off.

[Ron Selzer]

I appreciate all the effort different people have put into monitoring the dust in THEIR shop and what they do to lower it.
I do not wear a mask in the shop except when cleaning out the dust collector bin, my choice
I don't recommend that anyone not wear a mask and hearing protection in any shop unless the air monitor shows dust in the air is low and noise levels are down.
Ron

[Tom Bussey]

I read an article one time that stated that, do to all the contaminates in the air around us. Like smog, smoke, dust, industrial fumes pollen in the air and so on, that just breathing is just hazardous to your health. But on the flip side, not breathing is clinical death in four minutes.

Over 150 people have died on Iowa roadways this year, and it will probable more that double by years end. Have you stopped using any other form of transportation other than leg power? How many people die from abusing prescription medicine? How about obesity? The other day an older man went fishing below our dam, fished there all his life, and never went home. Slipped and his hip waders filled up with water and he went down.

I have a friend who never smoked or worked in wood at all but has a lung problem and has a life expectancy of 2 to 5 years.

I have been woodworking for 50 years. I have 4 dust collectors and dust canisters on all the sanders and 3 shop vacs on router tables and still can't get it all. If I take a planning cut on my table saw, Saw Stop with overhead dust collection. And it doesn't do any good if it is not turned on, so it gets turned on, and I still can't get all the dust. Did I mention two air filters hanging from the ceiling. and a fan with a pleated filter?

I do the best I can and then I get on with my life. If I was that worried about fine dust then I would quit woodworking as a hobby and take up golf. But then I would have to be worried about being struck by lightning. So I would have to stay in the club house and have a drink. but then I might become an alcoholic.

[Ric Jones]

i built a sanding vac box, and attached to dust collector, and found it was just ok, came across a festool vacume and walla, what a difference, the vac table is setting on patio relegated to being just a table, soon to be sold.
i did just purchase a few other festool tools, choked on price, but we will see i'm especially excited about the 150 OS, it goes into action this week, see how that works
rj in az