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Project Information

A CS collector box and one for the RAS,. Made from 3/4" MDF and 1/2" ply for the deflector back plate.

The back plate is angled at 17 degrees, I found this angle with a 3/4" gap at the base created the ultimate venturi action in my case.

The boxes collect just about all of the dust. The exception is when I turn to 45 degrees on the CS when there is a little spillage. I may add a couple of "wings" to catch even more but for waht is lost hardly worth it….. a work in progress.

The ras box is smaller because I only use it for straight cross cuts, again captures 99% of the dust. Again three coats of Nitro based varnish for protection.

Gallery

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Great use of surplus materials (all 4). You must have created a ton of open space. What's the trade name of the nitro varnish? Is it quick drying?
Jim
 

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Jim the trade name for the varnish is "Albi" I bought it about a year or two back when they had to get rid of it because it contraveined the VOC legislation. I was only allowed to purchase it providing I was not going to sell it on. At £3 for a gallon I couldn't pass it up. I should have bought the other one which was left but couldn't carry it all home on the train.

It does dry quick, not the sort of product I would use on better projects as it becomes very sticky very quickly, ideal where durability rather than finish is the requirement.
 

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Nice builds.

Could you give a little more details on the "what, where and how" of what you refer to as the " venturi action"? Also, I notice your DC comes in from the top, whereas I'm most familiar with it coming in from the bottom. Could you share your thinking on this.

Great post, as well as all the previous "shop projects".
 

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I'm still on the cardboard mock up of my RAS enclosure. I put the 4" outlet right in line with the blade exit point with the assumption a body in motion tends to stay in motion (sawdust). It seems to work well. One of these days I need to rebuild with wood like yours. Nice job.
 

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I guss there is always room for improvement. With the RAS I addedd a sub base behind the fence, more by accident but I found the saw dust shoots right along the kerf line (preventing it from spewing all over the place), hits the back plate then gets immediately sucked under. The only spillage I get is on wide boards where some of the dust hits the fence and sprays to the right. There is so little spill I'm just going to accept that a quick vac or blast with the air gun clears it.
 

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Unique design for the CS. I am not sure how it works though…
 

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Hillbillyshooter - My DC comes in from the top purely because I have a run of machines along that same wall needing the benefit of DC and was in my case just easier to run along the wall above the machines. I guess I could have run it beneath but I had already installed the cabinets and was loathed to start cutting holes to run the ducting. Space too was a factor I was intending to fit a branch from the pipe to connect directly to the exhaust port at the back of the blade guard. It just became too tight for space and this was just the easy option.

As far as the venturi action goes, I'm not too sure of the technical or mathamatical aspect as to why it happens but my understanding is that when the volume of pressure is reduced, in this case by the small gap at the base the velocity of the air increases. It is this action that sucks the sawdust into the box. All Ican say is that it works great but I'm sure someone with a better engineering understanding will be able to elaborate.
 

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Hey pal, I haven't been on in a while, just check in every now and then….It's about time you got that d.c. up and running….I've been worrying about your health…lol. Now you know what you've been missing all this time…...cleaner air….!!! Can't go wrong with a good d.c. system…..your shop and your old body will thank you….I've been a real "slacker" this spring and summer chasing them green fish….Not done yet…Good projects…..Don't run out of things to do…...!!! Never…..!!
 

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Hi Rick - Yep can't believe it took me this long to switch onto installing a DC. If ever I have to move house again a DC will be what I plan the shop on. I'm still getting used to opening the blast gate for the machine I'm working on so I'm not totally dust free yet. It's all so confusing lol
 

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Yep…. I understand…...confusion comes with age, and we my friend, are becoming fossils…...It's pretty bad when you have to write yourself a note to remember to do something…..Just need to remember to open the blast gate on the machine you're working on, and close the rest off…..One thing to remember: When you start up the d.c make sure you have at least one b.g. open, or you can "starve" it for air, and that's not good…then just close it if not the machine you'll be running….just my .02 cents…...
 

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"bluekingfisher"-Thanks for the info on the "venturi action." Sounds like the air conditioning principal that the unit cools hot air faster than cold air-one of life's conundrums.
 

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The penny is taking a little time to drop Rick but I have a cunning plan. I'm going to paint the blast gate so when its open a quick glance will tell me which gate is open or needs to be closed. I'm also going to have a go at hard wiring the DC so I can remote control it with a "tweaker" The DC has a magnetic NVR switch so a rewire of the coil is required. I'll have to do a little home work on that.

Hillbilly - Not sure if I explained the principle very well, my knowledge of flow rates etc is quite limited. It does work well however and I guess that's all that matters eh? BTW I took a toue of your shop, some v nice projects there. The storage box for the scroll saw looks to class.
 
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