Thread: Making a hood for drum sander

Whatever you finish up doing, make sure you can get a full-size dust extractor port on there. at least one 4" ports.

Plywood would work. Are you any good with perspex?

CHeers

Doug

I would look to replacing the entire grey cover with one that has a 150 mm outlet and is about 50 mm wider on each side and sits up about 50 mm so plenty of air can get in and sweep away the dust.

Something like this.
Sandercover.jpg

Make the port 150 mm - you can always easily add an adapter to a 100 mm port but the other way around is more or a PITA.

Originally Posted by woodPixel

Please do post your progress!

This is one of my favourite shop machines except for the terrible dust collection. The default 50mm port is woeful.

I agree

Given that there is little room between the edges, rollers and drum for air to suck past, I'd seriously doubt you'll be able to challenge a 100mm port very much.

Thats why the top has to be ditched and replaced with a complete new hood that stands off the base by at least 50mm and over hangs the sides by 50 mm and a 150 mm port is used.

From a safety point of view, I would be reluctant to lift the hood 50mm above the bottom of the rollers.
I agree with the other suggestions - perhaps the hood could be flared more to allow greater air flow.

Left field idea - 6 litre mower fuel/paint can sliced through the length.Allow for fold/crimp of sharp edge. Lightweight & allows for fixing at any point. gordo

Originally Posted by Chesand

From a safety point of view, I would be reluctant to lift the hood 50mm above the bottom of the rollers.

If you are worried about the rollers then lift it 75 mm and reduce any gaps with a coarse (e.g. 10 x 10 mm) mesh

This is the gap I'm talking of. Quite small. My stubby finger is attached for a sense of scale....


Also, there is a plate on the exit side that seems to be deliberately restricting air flow. Is it there to stop things from being sucked up INTO the drum causing a catastrophe?

Either way, not a lot of gap for air of any quantity to get past.

DSC02338 (685x1024).jpgDSC02340 (1024x685).jpgDSC02339 (1024x685).jpg

In lieu of a plywood monstrosity, I'd use extruded cellular plastic (e.g. Coroplast/Corflute). It's usually used for sign making and may be available at Home Centers. It can be creased and folded, cuts with a utility knife, and self-connections can be made with short wood screws. I made a dandy "doghouse" for my lawn mower.

I've collected quite a bit of it after political campaigns. Another great source.

Cheers,
Joe

Thanks for showing the gap (or lack of) WP. I agree that design is rubbish.

Not sure about Coreplast/Coreflute.
I reckon hoods over rotating machinery need to withstand the dropping of a length of 100x 50 mm from a ft or so above so that they don't collapse onto the rotating bits.
I would use some sheetmetal bent into a curve (this will give it inherent strength) or a strong ply box.

Something like this and add some metal strap or ply strip standoffs
Sanderhood.jpg

Maybe you could cut open a length of plastic 150mm pipe and then shape it to fit using a hot air gun.

Originally Posted by BobL

Thanks for showing the gap (or lack of) WP. I agree that design is rubbish.

Not sure about Coreplast/Coreflute.
I reckon hoods over rotating machinery need to withstand the dropping of a length of 100x 50 mm from a ft or so above so that they don't collapse onto the rotating bits.
I would use some sheetmetal bent into a curve (this will give it inherent strength) or a strong ply box.

Something like this and add some metal strap or ply strip standoffs
Sanderhood.jpg

couple of points

I believe the metal bar on the in-feed side of the drum is there to stop [or make it difficult] for stuff (clothing and fingers) to get wrapped around the drum.

Is a drum sander the sort of machine that better suits the high velocity low volume suck of a Vacuum Cleaner rather than the low velocity high volume suck of a dust collector? Does BobL have a comment?

Rather than drawing make-up air from in front of and behind the roller frame, could the roller frame be perforated to allow additional air to get close to the roller? My instinct tells me that doing so would result in more dust being thrown around the shed, but I'd like to hear BobL's thoughts.


and lastly an observation -- the Performax "originals" are fitted with a 4" port. and wider drum sanders have two 4" ports.

Originally Posted by ian

Is a drum sander the sort of machine that better suits the high velocity low volume suck of a Vacuum Cleaner rather than the low velocity high volume suck of a dust collector? Does BobL have a comment?

Ideally both, high speed air flowing over the paper helps dislodge dust from the paper, and high volume helps collect the very large cloud of fine dust that emanates from these these machines.
As it stands the standard constricted port provides neither, and the only area really getting any high speed flow is the middle of the drum.

There are also other better ways of dislodging the dust from the drum that could be utilised like using a very short (0.5 sec) burst of compressed air and then let the high volume collect the dust. Fancy units also oscillate the paper which also helps.

Rather than drawing make-up air from in front of and behind the roller frame, could the roller frame be perforated to allow additional air to get close to the roller? My instinct tells me that doing so would result in more dust being thrown around the shed, but I'd like to hear BobL's thoughts.

This is indeed an option BUT it will need be thrown around the shed unless it was to be accompanied by a significant enlargement of the currently used 2" port.

and lastly an observation -- the Performax "originals" are fitted with a 4" port. and wider drum sanders have two 4" ports.

The issue with sanders not just the number and size of the ports but also the access these ports have to the air.
Narrow slots either side of the drum are near useless at collecting fine dust.

By way of comparison the ~1100 mm long drum sanders from SCM or Felder use 2 x 150/160 mm ducts plus a 1 x 100 mm duct, for a total of 3500 CFM.
Now compare that to the home workshop size 400 mm wide sander which will be really struggling to pull more than 100 CFM through their constricted 50 mm duct.
A simple scaling suggests that if a 1100 mm needs 3500 CFM then a 400mm would need around 1200 CFM
Admittedly the big sanders can sand to a much greater depth but there's still a big gap between a theoretical 1200 CFM and and actual <100 CFM.

Originally Posted by BobL

Ideally both, high speed air flowing over the paper helps dislodge dust from the paper, and high volume helps collect the very large cloud of fine dust that emanates from these these machines.

can you use your particle detector to quantify this "cloud"
I ask as the drum sander I'm most familiar with (a Performax 16-32) has hold down rollers either side of the drum, which are mounted fractionally lower than the drum. The hold down roller at least on the in-feed side would seem to act as a deflector for the stream of fine particles being generated by the sanding drum, directing the particles up towards the top of the frame where the 4" extraction port is located. Make-up air is primarily drawn from each end of the drum and through the gap between the frame and feed rollers. I haven't inspected other models of drum sanders intended for the home workshop, but the arrangement on the Performax would seem to be drawing make-up air through all possible dust escape paths -- and on the in-feed side the make-up air is flowing in the same direction as the laminar air flow adjacent to the drum itself -- so I am a little confused.

Originally Posted by BobL

By way of comparison the ~1100 mm long drum sanders from SCM or Felder use 2 x 150/160 mm ducts plus a 1 x 100 mm duct, for a total of 3500 CFM.
Now compare that to the home workshop size 400 mm wide sander which will be really struggling to pull more than 100 CFM through their constricted 50 mm duct.
A simple scaling suggests that if a 1100 mm needs 3500 CFM then a 400mm would need around 1200 CFM
Admittedly the big sanders can sand to a much greater depth but there's still a big gap between a theoretical 1200 CFM and and actual <100 CFM.

I was referring to the 4" port on the "original" model, not the 2" tube found on the generic Chinese copies. Based on your scaling a 4" port would deliver something like (16/88 x 3500 =) 600 CFM. Not brilliant, but a lot better than 100 CFM.

Originally Posted by ian

can you use your particle detector to quantify this "cloud"

To prevent possible damage to the particle detector I am very reluctant to place the particle counter near a visible cloud or stream of wood dust - see my post in this thread - when I can see wood dust I usually move the particle counter away.

I am prepared to use the counter where there is good levels of dust control but unfortunately that isn't always what we want to know about.

I ask as the drum sander I'm most familiar with (a Performax 16-32) has hold down rollers either side of the drum, which are mounted fractionally lower than the drum. The hold down roller at least on the in-feed side would seem to act as a deflector for the stream of fine particles being generated by the sanding drum, directing the particles up towards the top of the frame where the 4" extraction port is located. Make-up air is primarily drawn from each end of the drum and through the gap between the frame and feed rollers. I haven't inspected other models of drum sanders intended for the home workshop, but the arrangement on the Performax would seem to be drawing make-up air through all possible dust escape paths -- and on the in-feed side the make-up air is flowing in the same direction as the laminar air flow adjacent to the drum itself -- so I am a little confused.

It sounds like its better than most of the ones I have seen.

I was referring to the 4" port on the "original" model, not the 2" tube found on the generic Chinese copies. Based on your scaling a 4" port would deliver something like (16/88 x 3500 =) 600 CFM. Not brilliant, but a lot better than 100 CFM.

Not sure where your 88 comes from 1100 mm = 43" so its more like 16/43*3500 = 1302 CFM.
A 4HP DC would be needed to get this CFM through a 4" port.

What you will have seen in some posts is that I use an air flow meter near or inside dust streams. This is because the air flow meter is mine and it is not affected by wood dust. The reason for using the air flow meter is because fine dust will follow any air currents.

The spamming drum will create significant air currents and and DC will have to overcome these.

You could try taping some thin woollen streamers on the edges of the hood and see where they go - like this.