Wednesday, September 26, 2012
Sawdust Sucks! -Adventures in Dust Collection
Prior to the instillation of this system I had no dust collection of any kind. Sometimes I would use a mask, sometimes I put a box fan in the door and blew it all over the parked cars. I was lazy about using masks and sawdust snot blowing or nose bleeds were common. I never thought much about it until my son started to work with me. My stupid should not be his stupid. I have had a blower fan for years, on the self, in the barn, back on my parents farm. Not doing a whole hell of a lot out there. The cost associated with a system was more than I felt we could absorb until an opportunity for free ducting presented itself. Naively I thought that having this pile of duct would somehow knock the price down a huge amount, it didn't but more on that later.
Video: Overview Of Project and Ducting Pile
As it would turn out the person who put this heating system in was apparently a HVAC genius. Only two 90 degree fittings in the whole pile, something I didn't notice until I picked it up. It was all also 5 inch, appropriate for my system but rare as an honest politician when it came to finding fittings here in Montana. Also the fittings were very expensive, again like politicians. Who cares, I am stubborn and tend to place an unnecessarily strong value on working with what I already have so I committed. I purchased fittings from Audubon Plumbing Supply Co who were hands down the least expensive I found for my peculiar 5 inch tastes. It would have been nice if they got back to me on the questions I asked but I figured it out myself in the end. For the flexible lines and fittings I used the good people at Peachtree Woodworking Supply but I will go into that later, first we need to get sucking.
My blower came from the scrap yard, that should have told me something. It is 1HP with an 11 inch fan. Much, much smaller than those I have seen but the thought of flipping on a 3 or 5 horse motor to suck dust from my palm sander made my ears itch. Besides when I plugged it in I noticed two things right off, despite being a mere 1hp that thing sucks and the bearings howled like demons in hell. I pulled it a part to see what could be done. I think it was a bulk mover blower of some sort, nothing big had gone through the impeller but the motor had taken a massive beating at some point. I had to work some magic.
Video: Blower Motor Repair
After banishing the bearing demons I left the motor plugged in and running for an hour to check for overheat or vibration issues. It passed with flying colors. I am still worried about it operating normally at 20 below but time will tell. I can say this, whether you find and fix or buy a new blower, secure it to a board and play in the stream of air with a 3 year old. Trust me it is just one of those things that is good for the soul. Protect the inlet from little fingers because it isn't so good for them.
Let me just start out by saying I wanted a Clear Vue Cyclone. I wanted one in the worst way. If I was honest I wanted to watch shit swirl around in it. I would film it and post videos on youtube. Clear Vue will sell just the cyclone and I could have it at my door for about $700. Unfortunately it needs 4 or 5 HP do work at the efficiency they are capable of. At 1 HP it is a massive overkill and would simply work like a regular cyclone. It would be like shooting gophers with a shotgun, fun but not entirely necessary. I went with the Super Dust Deputy from Onida. I thought long and hard about building my own cycle from the Clear Vue plans but I rationalized the time spent versus likely hood of getting it done before winter and decided to buy. The Super Dust Deputy is intended to add cyclone prefiltration to those roll around bag blowers you see from places like Grizzly, Harbor Freight ShopFox or others. On the plus side my blower was a better size match for these units. At first glance my Deputy was smaller than I expected, but on reflection I realized I had images of big commercial cyclones dancing in my head. It was well packed and shipped with only a small dent on the cyclone inlet lip.
Video: Cyclone Out of The Box
The box wasn't damaged so it must have clunked into something in the factory. No big deal, pliers will straighten it right out. I would have liked to seen continuous welds on all the parts rather than stitch welds but I figure warping must be an issue during assembly. All the seams have been caulked and look tight. I think adding some sort of hard points to attach mounting hardware would be a bonus. I will figure out a way to mount it, but a bracket would be nice. Maybe it was an extra.
I know that it is strange to locate the filter outside but that is the location I have and it will keep the noise down inside. The cyclone inlet is right at floor level meaning all the runs but one will move down hill. Not sure how much that will effect the system but it can't hurt! Essentially the motor/blower will be directly coupled to the cyclone, as a single unit and hung from the wall outside...in the rain. Some sort of protection for that will have to be developed but all things in good time. Note, I suck an extra piece of roofing tin out over the eaves above meaning the rain will have to blow back 18 inches to get on the unit. I am sure it will happen but not often.
Video: Cyclone Location
I ended up mounting the unit in two pieces, blower/motor and cyclone separately as I had to hang it by myself. The cyclone is mounted to a 1 1/4 plywood flange standing rather than hanging. This is how it would be mounted if it was being retrofitted to an existing dust system. With the motor mounted separately and a simple connection between the two, it means the cyclone is not being asked to hold any additional weight. The motor is bolted right through the side of my shop with 4 carriage bolts. The astute among you might notice it is tipped some. Oops. As I was working solo trying to hold that dang thing above my head and then mark/drill I figure that was close enough. If I had to do it again I would make a plywood drilling template and get it up there right. I am not normally a fan of hanging something like this from the building but as the siding on the shop (ex-barn) is 120 year old, 1 1/4 inch thick, 12 inch wide clear fir I think it will be fine. One modification I did make was to swap the 4 inch air return line out for a 5 inch. 5 inch flows way more air and I thought it would just help the system function better. I had the pipe anyway so why not?
Video: Mounting the Cyclone
Building the fine filtration box was a key element of the system, I am not doing this for cleanliness but for dust hanging in the air after all. I had an old file cabinet that I wanted to use as the filter station as it was about the right size for what I imagined in my head. In trying to source filter media I fell back on my heavy equipment roots and started to look at big air filters. After checking out the 'special' wood dust filters recommended for these applications I realized they were little more than heavy truck air filters repackaged. Close anyway. At 5 micron filtration, the wood dust filters are not as fine as a motor filter. I started asking around for truck filters and the first one to come in was from a 2004 Peterbilt. It filtered on the inside, was tall and narrow at about 10 across. I liked it but felt I needed more. The next time I was in Missoula with a load of scrap I stopped in at Watkins-Shepard to ask if they had any used filters. I am not sure what they run as their fleet truck but the filters I found were perfect. Shorter but much fatter, they stacked on each other forming a huge air filtering monster. The nice people at Watkins just let me dumpster dive and I came up with three, two were replaced with very low miles and the third was a mess and is borderline unusable. I cleaned them out, stacked them up, sealed the box and I had a very slick filter housing that takes up no more space than a water cooler. Truck filters can be had for as little as $50 new and trust me, they are up to the task.
Video: Fine Filtration System
The last part of the system was a collection bin. I am using a 30 gal paint barrel. I picked that one because the lid fit nice and we had it at the shop. I also had a 55 but thought that might be a hassle to deal with. the 30 fills fast when running the plainer so I see myself overfilling and making a mess at some point in the future. I use aluminum ducting to connect it and while it seems to be ok so far it is not ideal. I will look around for some good UV proof 6 inch rubber stuff and replace it as needed. The hard part is finding some place that will sell me only 2 feet of it. Because the clamping ring fit loose I ditched it for 5 rubber bungee cords. Seems to work. I think the whole unit leaks a little meaning more fine dust makes it into the filters so more work is needed but I just had to get the shop back running so this is what it will be for the winter. Sometimes you just have to work with what you have.
Video: Dust/Chip Bin
Well it is done. I figure even with sourcing free pipe and blower it still cost $600+ to get it up and running. Additional scrounging might have saved more but not much. I know it isn't the peak of efficiency but it does work great. Now I don't have to worry so much about having my little boy up working alongside me. No bloody noses or sawdust buggers for him!
Well the system has been in use for a long time now and I still feel it was the BEST modification I ever made to my shop and the tool I use the most. I have made no modifications, it all runs exactly as you see in the last video. I am still on my same truck filters and will blow them out after every 4 or 5 vacuumings because the vac just can't quite get it all clean. That dumb aluminum duct to the sawdust bin is still there though wrapped with tape for most of it's length now due to cracking. We all saw that coming.