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Ive been watching some vids on car speaker fabrication.
The dude who does the series has this table mounted douverlackie that seems to do a decent job.
Have a squiz and tell me what you think.
Ive been doing something similar already on the tablesaw and this is an interesting modification to help round up some of the free sanding dust.
https://youtu.be/573ADU-IyYY
Good little concept for those with a existing setup like that.
I've been thinking about knocking up something like this to connect up to the dusty while sanding.
Drilled and trenched like a vacuum press bad base, it would make a difference to those that don't have a sander connected to a vac like the festool system and i'd like to think it would complement the festool sander and festool vac.
it could be dual use as a table when not sanding.
I saw this guys table too.
He has a neat dust collector.
https://youtu.be/ycVRDaGF-DY?t=496
If you made the table with 20mm holes on a 96mm spacing you would have an MFT which could then use the festool clamps and MFT dogs as well as a sanding table. I find that I prefer to sand my pieces while they are clamped with the clamp set on the MFT as they don't move around.
Or if you have an MFT table you could just box in the underside and achieve the same result.
The first one has the right idea about having larger holes on the outside but overall there's not enough total hole area so there won't be enough flow even to feed a 100 mm duct let alone a 150mm.
The second one is much better in terms of total area.
These things really only work for medium small size of work stuff, as so as the work piece is too large any sanding performed more than half a meter away from the holes results in the finer dust floating away with the warm air currents.
FWIW I've made a number of these down draft tables for labs where open containers of moderate to low levels of toxicity chemicals were in use.
Normally a fume hood would be needed but we had so much air flow through the lab to control dust (mainly external dust, skin cells and clothing fibres coming of the operators) that we could use these tables.
These days we would be required to use fume hoods.
I like the second one over the first, as it would be cheap to knock up.
I like the idea of the 20mm holes to enable festool dogs and clamps for holding while sanding, if you reduced the hole spacings to 64mm centres, it would open the vacuum area and still allow working with a 32mm system
Any movement in the top due to the extra holes could be fixed by inserting a few 25mm dowels machined down to 20mm at the box height required.
It makes a big difference to overall extraction to have as much of the air as possible drawn in by the right of holes on the outside.Quote:
Originally Posted by bryn23
This is partly because of the way these things work and because the work usually obstructs the holes near the middle of the table
A simple way to improve the second one would be to increase the number of holes around the edge and reduce the number of holes per unit area as you go towards the centre.
He did a rather cool test using dry ice at 2'10": https://youtu.be/573ADU-IyYY?t=130
Hmmmmm . . . . . a very cold gas that is denser than air.Quote:
Originally Posted by woodPixel
It would have been better if he used steam or incense.
I thought the same thing, Bob. But then, wouldn't it just be better to use sanding mesh like Abranet on a sander with an attached vac, and capture as close to the source as possible? With the possible exception of hand sanding I don't see the advantage?
For full belt and braces you could do that on a down draft table and on overhead fume hood as well. :UQuote:
Originally Posted by richmond68
I don't know Bob, are you sure the dust wouldn't just hover in the middle, unable to decide which way to go? Sounds like the same thing as buttering a cat's back and then dropping it :wink:
Air will come in from the side and sweep up and down.Quote:
Originally Posted by richmond68