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Too much suction?

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Forum topic by JustaLilJoinery posted 08-14-2013 10:42 AM 1092 views 0 times favorited 9 replies Add to Favorites Watch
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JustaLilJoinery

31 posts in 1218 days


08-14-2013 10:42 AM

Topic tags/keywords: dust collection suction safety gear guards

I got my DC all hooked up and ran a few quick pcs across the router table. I loved not having a floating cloud in the room BUT my problem is that the suction is so strong that it sucks my blade guards down so hard I have to fight it to move my workpiece…

I already tried working the blast gates and adding a run to nowhere but at the risk of sounding like I have really high class problems, what can I do about this? I don’t want to have to fight (I feel that it’s a dangerous amount of fight) and don’t like removing any safety gear unless absolutely essential.

Anyone have to tweak their systems DOWN when set up?

TIA

-- Genius may have its limitations, but stupidity is not thus handicapped. -Hubbard


9 replies so far

View Fred Hargis's profile

Fred Hargis

3932 posts in 1955 days


#1 posted 08-14-2013 11:07 AM

There is no such thing as too much “suction”, that’s whats catching the finest dust particles. You’ll need to tweak whatever you have to allow more make air under the guard. A pic of your setup may get more suggestions. How is the table built (ducting to the motor cavity?) and how big are is the ductwork drawing on the fence (cavity, whatever)?

-- Our village hasn't lost it's idiot, he was elected to congress.

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JustaLilJoinery

31 posts in 1218 days


#2 posted 08-14-2013 11:21 AM

Thanks for the quick reply. Fortunately I had these pics already on the blog I started here

Here’s the set up to the router. It’s only aprox a 5’ run from DC to router with another run off the wye to the table saw.

https://s3.amazonaws.com/vs-lumberjocks.com/mr1syqn.jpg

and
https://s3.amazonaws.com/vs-lumberjocks.com/mr1t75p.jpg

Hopefully you can see here the ducting to the table behind the cutter. I kitbashed the fence set up to take the 4” hose (it was originally only a little under 2”) in addition to the epoxy love-bandage, I also used a small strip of foam in order to finesse the fit of the hose to the fence since it was a round hose into square fence if you know what I mean.

-- Genius may have its limitations, but stupidity is not thus handicapped. -Hubbard

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firefighterontheside

13458 posts in 1318 days


#3 posted 08-14-2013 01:01 PM

I think you have to balance the amount of seal that you have to your piece and the amount of air you are actually pumping. For your dust collection to work you have to be moving air, lots of air. When you seal too good to the work piece you are not moving air. What you want is a good draft of air moving past your tool that grabs dust out of the air and takes it into the hose. The fact that your blade guard is sticking to the piece means not enough air is moving. Your air pump is trying to pump a board. Maybe you can but relief holes in the guard right near the board.

-- Bill M. "People change, walnut doesn't" by Gene.

View PurpLev's profile

PurpLev

8523 posts in 3110 days


#4 posted 08-14-2013 01:12 PM

sounds like you are creating a vacuum – you don’t want that, you want air to flow. maybe raise the blade guard a 1/8-1/4” up to leave a gap for air to flow? or drill some holes in the blade guard to allow some air intake.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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crank49

3981 posts in 2433 days


#5 posted 08-14-2013 02:06 PM

If your hood/guard is being sucked down to the workpiece there is not any, or not enough, openings in the hood/guard to allow air flow. This is defeating the function of collecting the dust. Can you raise the hood/guard to allow air flow without compromising the guarding function?

Providing a wye with a secondary area hood behind or above the cutting position would be the best way to decrease the pressure on the hood/guard without loosing the dust collecting ability.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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PurpLev

8523 posts in 3110 days


#6 posted 08-14-2013 02:16 PM

to add more context – EVEN providing a WYE to a secondary collection area isn’t really solving the problem, as the leg from the WYE going to the blade guard is still in a “vacuum” state – a secondary leg won’t change that but only reduce the suction power on this leg. opening some air inlets to eliminate vacuum and enable air to flow is the only way to go about this.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Fred Hargis's profile

Fred Hargis

3932 posts in 1955 days


#7 posted 08-14-2013 03:51 PM

Not to pile on, but it’s the lack of make up air causing the problem. Somehow you will need to allow more vent space around the guard following one of the suggestions above.

-- Our village hasn't lost it's idiot, he was elected to congress.

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crank49

3981 posts in 2433 days


#8 posted 08-14-2013 05:00 PM

Guys, that’s just what I suggested.
“raise the hood/guard to allow air flow”
A wye with a secondary hood behind the blade guard will absolutely reduce the pressure on the blade guard.
And plus it will help to catch the fugitive dust that gets out of the guard, if any.

Bottom line, you want more flow and less vacuum pressure on the blade guard.
Allowing air to enter the guard will do this.
If the guard is too small to allow proper air flow, even with it raised off the workpiece, then you need to reduce the pressure.
By opening up a wye connection, directly behind the blade guard the pressure will be reduced and the backup hood will use that dilution air flow to still catch air from the area around the operation where the dust is being generated.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

View JustaLilJoinery's profile

JustaLilJoinery

31 posts in 1218 days


#9 posted 08-15-2013 03:43 AM

I think I’ll try venting the guard with holes.
I don’t love the idea of lifting the guard since it’s already a bit of a down or up concept since visibility is low through the guard itself…time to route the router. Love my foredom for these tasks.

Thanks for putting me on the right path! It’s so cool that the path is no longer obscured by a cloud of dust lol

-- Genius may have its limitations, but stupidity is not thus handicapped. -Hubbard

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