Downdraft design questions

rodw wrote:

...but will need more fan output...

I am going to get the 5HP belt drive and see what that can do.

Is it possible to overlap the zones so that certain areas of the table that would trigger two gates to be open... sort of like a transition zone?

txtrone wrote:

rodw wrote:

...but will need more fan output...

I am going to get the 5HP belt drive and see what that can do.

Is it possible to overlap the zones so that certain areas of the table that would trigger two gates to be open... sort of like a transition zone?

Possibly, but the risk would be that if the torch passes over or near a corner where 4 zones meet, all 4 would turn on which might be too much. slowing the rams down might have a similar affect,

We cut down a roll of wire reinforced rubber hose into short pieces with a chop saw today and we set up my yellow in line fan behind the chop saw with a flexible duct attached. It was actually quite effective catching sparks and smoke so I think you'll be surprised how effective this will be.

The blower delivered today, but it came with the wrong size motor. The correct motor is now slated to be here by the 24th.

In the meantime I am working on the air manifold for the actuators and also mounted a stainless cabinet (left over from a job) to the table.

When I get the electronic guts figured out I will put them on the back plate and pop them into the cabinet... if it has enough room.

Finally got the correct motor for the blower today. The 'duct' tube is out of the table and all the hardware is on hand to add eight pneumatic actuated gates.

Also found a handy rack mount from an old signal cabinet that should come in handy.

I'm impatiently waiting to see this come together! But don't blame me if it doesn't work!

rodw wrote:

...don't blame me if it doesn't work!

What? You said this was guaranteed to work! haha ... just kidding. I think it has a 50% chance of working without further modification.

While researching the various blower motors and fan types I came across air curtains. I wonder if something like that could assist a downdraft table? Just a crazy idea...

I will keep you posted as we slowly progress. The Longs Motor stepper drives showed up yesterday. I have one hobby in front of this one that is eating up a lot of time, but I am getting close to a stopping point on it.

I can only guarantee the software cos its running on Linuxcnc!
I give you > 50%

I am being cautiously pessimistic.

Well I hope this works for you. Looks like I'm joining the club.


This is a Multicam router dust extraction fan the guys next door were throwing out. I'd done them a favour by unloading a truck with my little forklift so I brought it home all of 10 metres when I came back.

They said it had a busted motor but 15 minutes later, we had diagnosed a burnt out switch and I bypassed it in a temporary fashion and its a goer!

OOPS sorry: 1925 CFM 3 HP motor which is generally as big as we go on a single phase circuit

That is a great score! It pays to be a friendly neighbor.

We made a little bit of progress yesterday. Tube is now mounted to the slide out 'trough' for easy access to actuators. Mounts for actuators are on the duct and the doors are ready to go. Still waiting on four more actuators to show up. Hopefully soon.

The bulkhead where the copper lines will transition to plastic tubes is complete.

Is that your Hilux? Also, I could not help but notice the blue stack/hang bins... we use those all over the shop. Greatest thing since canned beer. I even put some on the side of the new table to hold misc consumables and whatnot.