Thread: Blast gate gallery

My first attempt at making a blast gate, using a couple of PVC pipe lengths, some scraps of 6mm ply and scrap hardwood for handles. Simple but effective.

i created a MDF template hole to just fit the pipe, so cutting the holes for more gates in future is a quick job with a router and pattern bit. The PVC is glued into the plywood hole with epoxy, this seems to do the job well.

The two strips either side of the sliding gate have veneer shims added so the gate doesn't bind - these were a little thick so I glued them onto only one side of the gate at first, then planed them down to allow just enough thickness for the gate to slide nicely.

Then before gluing on the other side of the gate, I double-stuck taped the sliding gate in place between the side strips, and used a flush trim bit in the router table to cut the hole in the slider. That makes it exactly the inner diameter of the pipe so the whole unit is a consistent diameter throughout the gate when it's open.

Originally Posted by Ian Dobson

The two strips either side of the sliding gate have veneer shims added so the gate doesn't bind - these were a little thick so I glued them onto only one side of the gate at first, then planed them down to allow just enough thickness for the gate to slide nicely.

I've found Al from a cool drink or beer can works well as a shim in this situation.

Has anybody printed a 3D blast gate.
I found this https://www.stlfinder.com/model/6-in...eYk2rV/7679298

Wondering what results have been if anyone tried.

This project /prototype has been in my head for a few months but only recently has my health improved to the point where I could have a crack at it.

It's really just a variant of a sliding gate (SG) but because the slide follows a curved instead of a straight path though the body of the gate I'm calling it a Curved Sliding Gate (CSG).
I should stress that it is a prototype and was made entirely from materials I had on hand - there could be any manner of improvements or mods or cheaper materials/fixings used in place of those I have used.

The aim of the prototype is to make a gate that can be used on ducting that is high up out of reach and is up against or close to a wall.

Rocker Gates (RG) work really well when they are out of reach but cannot be used easily up against a wall. To be used with ducting close to a wall RGs need to be oriented horizontally but then they run the possibility of always dropping into their lower state and raising the gate requires a fixed pulley or push/pull rod of some kind.

SG are fine up against a wall like this one (red arrow), but require push/pull rods and/or pulleys to be used when up out of reach.
WWlathe2.jpg

The prototype CSG can be used up against a wall and in any orientation and operated by simple pull cords or automatically by pneumatic or other mechanism.

The following describes a gate suited to 100 mm PVC ducting and the gate constructions starts with these two items.
A 250 mm length of 100mm PVC and a 150 x 150 x (3x 16mm) MDF block sandwich with a 110mm hole turned out of the middle allowing for a tight fit of the PVC inside the hole
SGparts1.jpg

The PVC is glued halfway along its length into the MDF block.
SGparts2.jpg

Then a 120 mm radius curve is marked across the side of the MDF block and a BS is used to cut the following curve.
SGparts3.jpg

After sanding the concave surface using the 100 mm drum end on a Belt Sander, and the convex surface on the flat part of the belt, the rest is as per a usual sliding gate but with a couple of additions.

An MDF bracket is attached to the side of the gate and a rotary assembly consisting of a circular piece of PVC and a 250 mm long Al arm attached as shown below.
Attached at right angles to each end of the Al arm are 160 mm lengths of 8mm all-thread rod covered with some clear vinyl tubing,
The vinyl just pads the all-thread out to suit the size of cable clamps I used to attach the slide to the arms.

The slide itself is made from 1mm thick Polycarbonate (PC) sheet and bolted to the clear vinyl covered all-thread arms using the black cable clips.
Rotating the arms thru about 90º thus rotates the flexible PC slider through the gate body.
In vertical orientation cords attached to A/B or a/b will activate the gate.
In horizontal orientation the pull cords would need to be attached to knobs or hooks at 1/2

Compgate.jpg

Here's another view which shows more clearly see the clear vinyl covering of the all-thread and the black cable clips being used.
Compgateback.jpg

There will be a myriad of materials and methods that could be used to afix the slider to the all-thread arms - one example would be to heat and bend the end of the PC slider into a tube to side over the all-thread but I wanted a method that enabled the PC slider to be removed without dismantling the body of the gate.

Here's a view down the guts. I need to trim the hole in the PC slider so none of the slider protrudes into the opening.
Compgatebot.jpg

Finally here is a very short vid showing the sliding action.
The action is smoother and easier than the vid shows and there's enough friction for the slider to stay where its put and not move around etc due to any vibe etc.


Like I said there will be may ways to build this gate.
The whole thing could be made of MDF and PVC.
I did try using a thickish vinyl covered fabric as a slider but once under a bit of tension the opening in the slider contorted from round into oval so that some of the fabric blocked part of the hole. Also the fabric did not sit flat inside the curve sliding pathway and occasionally jammed when it went to close.

It's not a gate for every day use but if you have a couple of gates that are mounted out of reach and the ducting is up against a wall then this design might work for you.

somewhere in this missive is the answer but question is......... whats the best glue for pvc pipe and mdf ? Once glued I will add a resin or something rim around as well

I used the quick set, clear, Urethane No More Nails. Just needed to rough the PVC pipe surface up.

I've used epoxy for some gates but most have been made with a urethane glue, At home I used gorilla brand, can remember the one at the mens shed but it was a quick set type.

I have used Gorrila polyurethane and they seem to be holding up.

thanks guys now we're getting somewhere

Bandsaw8.jpg

Not all blast gates need to be large complicated affairs. I made this one by cutting a slot in the pipe with a hacksaw and shaping a piece of aluminium clad plastic to fit the shape of the pipe. The bit above the slide is a section of joiner that I slide down over the slot when the slide is removed. ie. blast gate is open.

FYI: Early on in this thread

Originally Posted by MandJ

FYI: Early on in this thread

And a few posts further back still, a one piece version
Blast gate gallery

Dam, "also ran" again

Originally Posted by MandJ

Dam, "also ran" again

There are at least 3 other one piece gates like this buried further back in the dust forum. I made my first one piece gate back in the early 80's at work. They gate was made of painted plywood, as was the ducting with a 1x 2 ft cross section.