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Hello everyone,

I am hoping to expand a bit in the shop and would like to build a downdraft table into part of a new bench. I have run a really makeshift one off of the dust collector but it left a lot wanting as the blower was undersized to begin with and then went through too much ducting.

My questions are:

Is there a benefit to making it with a high powered furnace blower(1500 cfm or so) pulling through filters as opposed to a dust collector blower (1.5hp w/ 6" opening) attached right to the table and emptying into a bag? Either option at this point might cost me the same amount of money. It seems it would be easier to clean just a bag but I am not sure if the pull would be the same.

Is there an optimal hole size/pattern for the surface of the table? I have been using pegboard with countersunk holes which I understand is too small. I am wondering if anyone has a setup they are very happy with.

Thanks for any help you can give. I have read through the Pentz webiste and googled many others and they give contradictory advice on many things. That is certainly one thing the internet excels at! I will appreciate any help anyone has to offer.

Thanks everyone,

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Burton, Here is a link to a page on my website that describes the downdraft table that I built a few years ago.

http://www.peterjosephguitars.com/Peter ... Table.html

I'm more than satisfied using a furnace blower and as you will read, I changed the pulleys and upped the CFM a bit. It's nice and quiet and really works well. Using the molded plastic shelving has worked out also and it's always easy to find spares... I bought the pkg. that has five shelves. The shelf unit is in one corner of my shop and I know just where to go to exchange the grating...

I use my shop vac to clean the filters regularly and change them as necessary. I have double layered the filtration. With some lesser grade filters above the fine ones to catch the big stuff...

I included a duplex power receptacle on the side of the unit that I use to plug-in my ROS or router.

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Peter

Burton...I built one similar a few years ago. The only difference is that I drilled hundreds of 1/2" holes in 1/2" Baltic Birch....something I would never like to do again. I use 2' x 2' x 2" filters and a 3/4HP motor within a standard squirrel cage fan. I don't know how I ever managed without one.

Here are some pics:

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JJ
Napa, CA
http://www.DonohueGuitars.com

here is a link to another:
http://www.woodworkersworkshop.com/plan ... _table.htm

You guys are fancy. I don't have one but now, I think I'll build one too.

Burton,

Be on the look out, making you a fresh set tomorrow. Just got what I need today and will be finishing em tomorrow.

Todd

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Todd Lunneborg
http://www.tlguitars.com/
http://www.fretboardjournal.com/

Thanks guys! I appreciate your responses, links, and photos very much.

Peter and JJ, those looks like what I was imagining for the blower style table. I am excited to hear that they have been working well for you both. I am definitely leaning in that direction.

Jack, I had seen that link before and been impressed by it. Thanks for linking it again here.

Todd, I have been drinking Corona's every night waiting for those! Thanks again for doing it.
(to offset the inside-jokiness of this I will say that Todd is making me some Mexican clamps and no, I don't know what they are either)

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Burton
http://www.legeytinstruments.com
Brookline, MA.

HaHa I just posted this on JJ's thread
I was just contemplating building a sanding table today while working on setting up a shop.
Maybe it is best answered here on this thread since it is a newer thread.



I have a blower that I pulled out of my neighbors heating unit when he replaced his and already have a cart on wheels ready to go.

also wondering if the exhaust disperses well with it blowing down

Thanks
Dennis

I did not make it, but used a few, the one that worked well had the angled baffles as in the link that Jack posted, otherwise the edges don't get suction.
Rob

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I found an old drafting table , the small 42" sq. type that has folding legs . Built a plywood box and mounted the folding gear under and mounted a 4" duct directly to my system . I used pegboard for the top and then put the "nonslip" shelf stuff over that and it makes a good stowaway down draft table and works very well. Some say pegboard doesnt work as good , however seems ok to me , and I have a very good collection system so the suction is very good.

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Not shopbuilt, but Delta used to make a nice DD sanding table- plastic tub with a slotted top-intended to be hooked up to your DC-about 2 feet by four feet and the "tub" is about 6 inches deep. I lucked into one for $50 and fairly close shipping. It is a well-made product. It is not suited for use with filters making it a shop air cleaner, but it really works well for sanding. I am planning on making a rolling frame for it because it is unwieldy enough that it is a pain to drag it out of its corner and hook it up. If I make a frame for it then it can be rolled where needed and can serve as a work surface for other activities.http://www.amazon.com/Delta-AP075-Shopmaster-Downdraft-Collection/dp/B0001LQZKC

For the lazy and well to do, there is the Rockler kit at $300+ price for a fan, switch, plans and maybe something else -it can end up as a nice final product but that price always kept me from hitting the "Add to ....etc."

Burton, don't hesitate to stop by a Heating/Cooling business and ask them about pulling a blower out of their boneyard. I did when I was building my air filtration unit (which I'll convert to a DD sanding table), and they just gave the motor and fan fan for free. Never hurts to ask.

Darrin

Hello All,
Are you guys spraying nitro pr just using the table for sanding? And if so, are you using explosion proof fans ? I really like the compact design of the unit that is pictured, it looks like the way to go...as long as you don't go boom! I would like to find a small blower with a TEFC motor and use that maybe for spraying & sanding. The only exp-proof blowers I have found cost $$$$$!
Thanks,
John

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John Nowicki

SANDING DUST ONLY Not sure where you got the idea for spraying lacquer on a downdraft table.

A spray booth with exhaust directed outside is necessary for any chemical fumes. And yes, an explosion-proof would be required for Nitro lacquer.

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JJ
Napa, CA
http://www.DonohueGuitars.com

Burton, did you check out the Charles Freeborn plans in the Tutorials section? viewtopic.php?f=10117&t=15875

Thanks guys. I appreciate all the input.

Robert- I was planning on the baffles on the inside. That is good to know that those examples worked better.

Darrin- I did look around and made a bunch of calls and maybe it is just city places but no one was helpful at all. I may try again before I buy one.

Darrel- Thanks for the link, I had forgotten about that tutorial. I need to look at it again.

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Burton
http://www.legeytinstruments.com
Brookline, MA.

Burton,

When I had my house built I specified an A/C system with Honeywell HEPA filters as the final filters just up-steam of the blower suction. They are large pleated paper filters. The pleats are about 3" to 4" or so deep and the dimensions are about (guessing without measuring) 24" x 24". Of course, in addition, there is a standard fiberglass furnace filter (the 1" thick type) at the duct entry upstream of the Honeywell HEPA filter. I change out he HEPA about every 18 months for my home and it costs about $19 as I recall.

The units discussed in the replies above appear to be good for housecleaning, but not for breathing health as they do not appear to capture the small most unhealthy dust. A HEPA is needed to do this. If you worked out a 2 stage filter system with HEPA as the final stage it should not need to be changed (plugged) overly frequently. You and your family's lungs will thank you for it in the years to come. You could even run it as a "room" filter too to clean the air in your shop when you are not sanding.

If you are interested in the actual HEPA model I have I can give you the model number as a reference. I buy them by the case (much cheaper) from an A/C contractors' supply company and then use them over several years so that I save money and do not have to chase them down every time I change them out (one upstairs and one downstairs).

Bill Pentz has a plan on his site with careful his study of hole and surface size versus air flow for the best results.

Good luck.
Ed