How often are you emptying your dust bin/ bags/ barrels? I'm trying to get some idea if my setup isn't big enough and spending to much time emptying sawdust. Currently every day to every 3 days my dust storage is full. Takes about 15 minutes or so to empty and be up and running again. How about you?

Single barrel under the hopper. I'd say on average it gets emptied twice a day. Some days none, other days maybe six times.

It takes 5 minutes I suppose to empty. Stepping away from a machine, going out to the barrel, emptying the barrel, reinstalling the barrel, walking back to the machine. Actual emptying probably only takes a minute and a half.

My personal opinion, if you're doing anything other than turning on the blower, it's taking too long and eating up time consuming capital rather than producing it. Ideally you're blowing into a dumpster or trailer, and somebody else is either paying you for it, or at least hauling it away for free.
Not the situation I'm in, but what I'm working towards.

I am in the same boat as you at one to three days for a two barrel dc. I am a 1 man shop so I am not paying people to stand and wait for the dust collector to be up and running. I foolishly bag up my shavings for a chicken farmer to take away which takes time but then again I am not filling a dumpster that I have to pay for.

3x a day to once a week depending on what I'm working on. Making moldings makes fluffy chips, lots of tablesaw work makes a finer powder. On average I would say 2x a week. One man show. My chips get thrown into a mulch pile of a landscaper. Like spit'n in the ocean.

We have a recirculating blower system and 40 yard dumpster. We have it emptied after several weeks. It holds several tons. We could not find anyone to take it for free or not. We pay to have it hauled and dumped. If you work with Walnut (which we do) no one wants it. If you don't produce a tremendous amount they are less likely to want it.

One tip if you are going to blow it into a dumpster, have a trap door put on the bottom of the T below the rotary air lock. When they are dumping the dumpster we put a garbage can or self dumping hopper under it. It saved us from valving and getting a second dumpster.

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Thanks everyone, the replies kind of give me a good reference point. Karl, I wish sawdust cost us nothing once it was made! Bill, I'm jealous of your setup! Someday for me on that one. Do you recirculate your air or just exterior vent?

We have a few different collectors. The big 20hp fills up every 3-4 weeks, takes 2 guys 30 min to change bags and get back up and running. The Cnc and bander are on a baghouse with a RAL on it, empties in a single drum. That is a quick change out when needed, just sliding the next can under.
We have someone that takes it all, not sure what he does with it though...

As Karl said, dealing with sawdust isn't making money...

We blow the air back into the building. We started without a sound arrestor and it was LOUD! We added sound arresting muffler and it quieted it down more than you would have thought.

Dustin - You are spending about 20 hrs a year on this. That is not too bad in context. Five years is considered good pay back time, so 100 hours x your hourly shop rate is the maximum cost for any changes. If your hourly rate is $90/hr , then you have $9,000 to make improvements. But you will still have some time in dealing with shavings unless you have a way to isolate the bins and so you can keep working, and the dustman just comes and gets it, then leaves.

I need to do some actual research and talk to some salesman. There is such a thing as a sawdust boiler.

That sounds like an exceptionally good way to handle sawdust. I spend about $1200 on average during the winter heating my shop.

I have no idea what the cost of entry is, or what the storage requirements for sawdust is. But it's something I want to look into.

Karl - A sawdust burning boiler, steam powered turbine, feeding system to get fuel into boiler, and generator and inverters to use the power, as well as a watchman. That is the basic setup for co-generation. I looked at it for my employer in the early 90’s and it looked like at least 150K.

At the other extreme, I once bought a P-metic collector, fabric filter above, plastic catch bag below. I could fill it in 20 mins easily. It took 15 mins to empty and get back to running. I could fill bags all day, tho rarely did.
I added up my time one day, and I realized I had spent the time that would easily pay for a new system. I ordered a real system the next day.

David, at $150k, I'd be looking at a 25 year payback at $1200/month, and five months of heating per year.
A bit long ROI for me.

Solar would likely be a better option. I think I figured 8 years going that direction. I talked to the city about that, they weren't real excited about an acre of solar panels on the ground. My roof line is north/south, so not a great option.

When I was running a large shop, we looked at boilers to get rid of wood waste and the cogeneration of electricity. The payback was within the doable range, but the owner of the company just could not stand the idea of having a watchman do nothing. State law requires a watchman with a watchclock and 24/7 observation.
It just killed him to have to pay someone for nothing.

If you are entertaining burning waste in any way I would contact your insurance company early in the process.

Has anyone done a briquette press, then burned them in a boiler or stove?

I had a briquette press for about 6 years. It is a lot of messing around. You need a holding bin of some sort for the sawdust and then a conveyor or auger to the press. Then you need to store the bricks. My press put the bricks in an elevated gravity box and I filled feed sacks and sewed them shut. I kind of enjoyed it for a few years but it was very dusty and time consuming. They also created a lot if creosote in my outdoor woodburner. I gave up on them and would never go back.
When figuring payback or ROI on anything you must also add something in for repairs.

I agree with Gary about Briquette presses. It is a lot of messing around. When we first set it up we sold them for $5 per bag. There was a demand but the buyers would hang around the shop whenever they came. If you do this would be better to find a wholesale outlet. We abused ours over feeding with the moulder and had it outside under the bag house. Parts came loose that we didn’t notice and we broke it. I bought mine directly from Europe. The company was good but long distance trouble shooting and parts is tough. Better off to find a company that has support here if you go that route.

It was down for quite a while and I built a 14 yard dump trailer fed by a closed loop transfer. This is way more cost effective than the briquetter. We sold sawdust to the same place Dustin sometimes brings his In montrose. That was also a hassle because of the distance and the trailer not so roadworthy. I now have a local rancher that mixes it with topsoil and he takes all I have. Several high end horse people here and they all took a load but never called back. Didn’t like the sanding dust. If you do a trailer go the extra expense for a tandem. Sawdust gets very heavy!
I have it set up now with a holding box above that I can connect to the dust transfer loop. Make bricks in the winter to heat my home and into the trailer in the summer. They do burn nice in a wood stove but as Gary mentioned dusty to store.

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I have gone the briquetter route, and have never looked back.

I have a Weima 820 that has 2 cubic meter surge bin that automatically triggers itself to on when it senses planer shavings starting to fill it. The discharge pipe empties into a 1 1/2 cubic yard self dumping hopper that when it's filled is the equivalent of 15 cubic yards of planer shavings.

On a busy day we will fill the hopper, on slower days, it may take a day and half to fill it.

My cost justification comes from not having to worry or deal with the hassles of disposal. Before the briquetter I discharged into large plywood bins that the horse people would come and pick up for free for bedding. The hassle always being, keeping the walnut shavings segregated, then always hoping they could come in a timely manner to get me unloaded.

Now, in the summer time, I just dump them in a dumpster and have them disposed of. In the winter time I have a wood burning furnace I heat the shop with. I generate enough wood waste on a daily basis that I don't need to save up briquettes for my heating load. I have what I would call a corral, that when filled holds a 3 day supply, which is about 4 yards.

Mark

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Mark, if you don't mind me asking, what did that press set you back?

Dustin,

Back in 2015 when it was installed, it cost $68K.

I have 4 dust collectors in the shop. 2@ 20hp, 1@ 10hp, and one 7 1/2hp, all with rotary airlocks. The 1 pictured is where my planer, moulder, and sander along with the router and a small shaper discharge into. It's the planer shavings I needed to take care of. The others deal with "real sawdust", that is, the load coming off of rip saws or a beam saw. Those I'm content to let fill up self dumping hoppers and run those to a dumpster outside to be hauled away.

It would have cost me more to have silo's installed to discharge in, and I believe as much as having a transfer system blowing into a 40" semi trailer. My electricity savings is substantial. I am only running the collectors that need to run, rather then having a 75hp central collector running the whole shop all day long.

To further save on electricity, all of my machines are tied into an EcoGate system where the machines turn the dust collector on and off when a machine is turned on, as well as open the gate for that particular machine. They are set to turn the collectors off after 4 minutes of no load on the system.

Dust collection and the associated waste in not a romantic thought compared to a high tech wiz bang machine that increases productivity, of which I am a firm believer in, but this set up has taken a major headache off of my plate and improved our through put.

Mark