Homemade (experimental) sanding hood...

[Joe Watson]

Been experimenting (crudly) and came up with this so-far; works pretty good.
Tested it out with some pine and maple - 60, 220 and 400 grit (just testing and havnt power sanded yet) and there are no visible dust particles in the air/light (still gonna pick up a 1/2 mask soon) but this is good that there is no sanding dust laying every where.
Using 60 grit on the pine, i took out a 1/16 - 3/32 thick, 2" dim collar off a piece and nothing was floating in the air.
Sorry dont have a pic of the inside filter, its all taped up for now, but its nasty with dust.

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Two 8" line duct fans, one 14x24" filter, roofing-boot and shop-vac.
The top box is make from 1/8" paneling, the 8" fans are mounted to 1/2 plywood.
Right now its all held together with screws, the tape is just to stop air leakage.
Black roofing-boot held on with a quick-release-clamp, shop-vac hooked to it by a coupler pushed through the boots rubber seal.
The top - front panel was gonna be a second filter (it may still) to get max air flow, specially when the filter starts to get clogged.

How its constructed, i can spin something 11.5" dia. with no obstruction - full lenth of bed (the back 20" half of the piece would not be under the dust hood)
The shop-vac is on the other side of the wall, which is nice, its not loud at all.

Still have more playing to do (making it smaller for one).
The roof-boot is being held on with quick-release clamps (so i can slide/move it easy), might change that to some kind of "slot, sliding thing (top and bottom)" or trash the boot idea and bend some round duct work and rig a 4" outlet (in case i end up with one of them small $80 HF potable DC ) with a reducer for the shop-vac hose.

All and all, im pretty happy with the performance, specially since its all made from left over stuff from when i built my addition (except for the two 8" fans and filter). Its not heave at all, maybe 20lbs, but it is awkward to move around - and storage when not using is gonna be a pain.
Dont know how long the 8" fans will last with all the fine dust being pulled through them - gonna try and clean them after each use with the shop-vac.

any idea's or thought's, please post

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[Richard Allen]

Looks like a good start. There are a couple of things to think about. Reverse the filter box so the fans are protected from the dust by the filter. The fans can pull the dust to the filter instead of pushing the dust into the filter. This will do two things. One, the fans will be drawing clean air so the fan will deal with less dust. Two, the dirty part of the filter will be exposed for easy cleaning with your shop vac.

The more enclosed the dust hood makes the lathe the more complete the dust collection will be. Attach 1/4" thick plywood or luan to enclose the back and side (including over the lathe bed. Attach the plywood with hinges and use magnets or velcro to hold the plywood in place and to let you swing the plywood out of the way when you need to.

[Joe Watson]

Hey Richard...
Before i started to construct the box, i mounted the two fans to the plywood and played around with filter before and filter after. Dont think these fans do not have enough power to pull through the filter. That was the first way which i wanted to do it.

Picture...
1/2 plywood with fans mounted, fan blades are about 2.5" and 5" from face of plywood (two different heights because how i cut the flange length).
Putting the filter flat on the plywood would slow the fans down drastically.
Holding the filter about an inch away made a big improvement, but the filter was "out in the open", there where no "sides" to the filter and air was just being pulled around it. I gave up on filter before and desided on the filter after because: the main "idea" behind the two 8" fans was to catch all the really fine dust from floating out to the open and have the shop vac pull all the heavy stuff. Don't know this for a fact, but im pretty sure with the filter before there will not be enough cfm to catch the finer partials.

I hear you about enclosing it more.
Hears what i was thinking about (and now adding your magnet and hinge ideas).
The top box is where all the weight is and because of this and the location being so far forward (tested it at two different angles and a couple different locations, this seams to be working the best) and wanting the ability to beable to remove the whole hood when not sanding, i needed to make "the stand/frame" a bit bigger then i wanted to (extending to the back wall), which is a pain to store and hard to move around.

So... i was thinking to make the frame permanent and just make the fan box removable (only bad thing which i can think of is when the lathe starts to dance because of unbalanced wood (slowest speed 400ish) the frame will be wiggle/swaying too (hummm... unless i frame it off the floor or ceiling (sorry thinking out loud - note to self))). Then have a peice of wood (or metal flashing (using magnets)) to seal off the 'ways' and on the back side of the frame (behind the roof boot) have something hinged (or velcro'ed) to the permanent frame that can be easily moved out of the way when hollowing out bowls...

Will keep the thread updated...

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[Richard Allen]

You must have some serious leaks in that filter box. The fans should react the same pushing or pulling if all the air is going through the filter.

Bladed fans tend not to develop a lot of static pressure. A squirrel cage fan is the style fan to develop enough static pressure for the filter. This is why HVAC use squirrel cage fans. You can often get a used fan for free from an HVAC guy.

I know you are trying to build something without spending a lot of money.

The tighter the hood is the less vacuum you need to capture the fine dust. If you have enough CFM then the hood becomes less important. You can make the hood so that you don't need to remove it. I am lucky enough to have a Oneway hood hooked up to my DC. The hood is on a rail so it can be moved out of the way. The hood also has the tailstock side able to swing out of the way. In the several years I have had the hood I have never found a reason to move the hood. This is to say that a lathe dust hood can be designed which captures the dust and can be left in place.

[Kevin W Johnson]

If those fans won't pull thru the filters, they won't push thru them any better. I'm bettin' most of the dust just bounces back out of that box and in to the room.

At any rate, whatever you use, you want to pull thru the filters.