Thread: Need some 6"to 4" hose reducers

Thanks for fixing the photos for me Bob. A big thank you to all the contributors, Bob L., Chris Parks et al.
Bob, the 2 ys are really close and I wanted to go straight down but there are a set of drawers under the extension table.
Alternatively I might have to see if moving machinery around might alleviate this.
As for securing the system, I have 3 thoughts.
1. Use self taping scres that don't go all the way through (not to create additional static pressure and use 50mm pvc tape.
2. Just wrap in pvc tape.
3. Glue using pvc glue.

Also, thank to all the contributors of the wiki, and my thoughts are if I can do this there is no doubt anyone can do it!

Originally Posted by tomartomau

Thanks for fixing the photos for me Bob. A big thank you to all the contributors, Bob L., Chris Parks et al.
Bob, the 2 ys are really close and I wanted to go straight down but there are a set of drawers under the extension table.
Alternatively I might have to see if moving machinery around might alleviate this.
As for securing the system, I have 3 thoughts.
1. Use self taping scres that don't go all the way through (not to create additional static pressure and use 50mm pvc tape.
2. Just wrap in pvc tape.
3. Glue using pvc glue.

3. Glue using pvc glue. no no no no no no noooo how are you going to recycle in 12 months when you redesign your shed, Seriously go take a lie down.

Originally Posted by tomartomau

Thanks for fixing the photos for me Bob. A big thank you to all the contributors, Bob L., Chris Parks et al.
Bob, the 2 ys are really close and I wanted to go straight down but there are a set of drawers under the extension table.
Alternatively I might have to see if moving machinery around might alleviate this.
As for securing the system, I have 3 thoughts.
1. Use self taping scres that don't go all the way through (not to create additional static pressure and use 50mm pvc tape.
2. Just wrap in pvc tape.
3. Glue using pvc glue.

I just use self tappers and don't usually bother with tape.

Bob,
In the picture you're referring to (above)..Do chips tend to accumulate in descending branches to machines? Do they unplug easily without complication once opened? Is it worth placing the blast gates higher to minimise that accumulation? Is it worth having an initial horizontal element exiting the Y, or not worth the extra bend?

Cheers.
(found my password)

It is always a good idea to set the Y horizontally to avoid saw dust dropping into unused branches.

Originally Posted by GreggMacPherson

In the picture you're referring to (above)..Do chips tend to accumulate in descending branches to machines? Do they unplug easily without complication once opened? Is it worth placing the blast gates higher to minimise that accumulation? Is it worth having an initial horizontal element exiting the Y, or not worth the extra bend?

Do you mean like in this picture?
Blastgate.jpg

If so, then . . . .
Yes chips will tend to accumulate in the vertical when dust runs through the horizontal. What happens is that air rushing across an opening causes a pressure drop inside the vertical opening and slower sawdust travelling in the horizontal may get sucked into the opening. This is why it is important not turn a DC off at the same time as the machine.

It's definitely worth placing the gates higher up as shown in the picture by the green rectangle.
It's generally not worth using a horizontal element.

The extent of clogging depends on
- how often the vertical branch is used - if the vertical is used regularly there's less likelihood of buildup so self clearance on opening the blast gate is more likely.
- what sort of dust is travelling in the horizontal duct. If it's from a sander then sawdust will be more easily held in suspension and less will fall into the vertical. If its from a thicknesser then more will fall into the vertical.

I've had several blockages that would not self clear when I located blast gates at the machine. One case was where the horizontal was used on a TS and the vertical was connected to a planer thicknesser that was used very intermittently, some only every few months months. Once the vertical duct was completely solid with chips. I had to take teh ducting apart and pole the chips out with a blunt stick!

Locating the Y horizontally isn't always possible especially when ducting is up against a wall or if machines are directly under trunk lines. Most DIYers don't always have the space to do this but its usual better to run trunks along a line in a workshop are fewer or no machines. The Y's can be located horizontally and branched out to directly above the machines so that vertical drop down duct can be used.

This is one example I did on a remote location a few years back. Ignore the flexy implementation, we had run out of 150mm duct and just wanted to get a couple of machines into action. Also the blast gates had not arrived. Our goal was to just install the CV and the trunk line but we decided to cut and hang what 150mm ducting we had available.

Wholeshed.JPG

Even when up against a wall, diagonal verticals consumer a lot of wall space which is at a premium in most sheds. This then robs wall use from other purposes.

Excellent, thanks for replies. Bob, your Ys exiting horizontally (pic in post 23) was what I was thinking of as a "horizontal element"
Gregg.

I had some made at the local sheet metal shop, they let the apprentice make them as a task because they don’t often do shapes like that, he did a fantastic job and they charged me $20 each, perfect.