What a Blast.................Gate

Stuart Ablett

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15,917
Location
Tokyo Japan
For the SawStop and the two router plate inserts that are going into the back bench around the SawStop, I have to put a DC duct system in, and each tool will have to be isolated from each other, so needed to make up some blast gates.

This is a further refinement of the way I've been making these blast gates in the past.

I'm doing 4" stuff (it is all actually what is called 100mm here) not the usual 6" stuff, as the 6" ducts will not make the turned needed to keep it under the back bench.

For each blast gate I start with a pile of parts.....

blast_gate3.jpg
2 main body parts
1 slider
2 guides
2 end caps
2 connector pipes
2 stoppers
2 handles

OK, got that :D

blast_gate2.jpg
I use my circle cutter to make the holes, you could also use a router and a template.

blast_gate4.jpg blast_gate5.jpg
I put one of the pipe connectors into the hole on one body piece, and the slider's hole over the pipe too, then I use CA glue to glue the guide sticks in place. The guide sticks and the sliders are cut from the same piece of 5mm thick plywood, the body of the blast gate is 12mm thick plywood, FYI :wave:

blast_gate6.jpg
I remove the slider and then with a sanding block, I sand the inside of the guides to make sure that no glue has oozed out.

blast_gate7.jpg
I also take the sanding block and sand both sides of the slider, I want a tight fit, but it has to slide easily. I then glue the top body piece in place, again, using the pipe connector to keep things straight. I use CA glue, the medium stuff for wood, but I use it sparingly, and I apply it to the outside area of the guide sticks, to stop any glue oozing out into the slider area. The CA glue is not that great for holding, it is a bit brittle, but I will take care of that in a few moments!

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I then insert the slider back into the blast gate body....

blast_gate9.jpg.....
and line up the holes with the pipe connector. I mark the left and right of the slider.

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Then I move the slider to the left, so the hole is now blocked, and the hole in the slider comes completely out of the body, this time I only mark the right side.

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Then I carefully wax both sides of the slider, between the line on the left and the line on the right, this is important, because I have to glue the stops in place later, and if you slather the wax everywhere, the glue does not stick.

I used plane old car wax, but any paste wax will do.


Cont..........
 
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Now that the slider is waxed up, I put it back into the body, and slide it back and fort a few times to make sure it slides nice and smooth, if it does not (it should!) then now is the time to take it out and do some more sanding and waxing. You want the slider to slide easily, but not be too loose in the body.

blast_gate12.jpg
Slide the slider to the left, and line up the line you marked, the waxed portion of the slider should be inside the body, take one of the stopper pieces and glue it in place. Here I have had great success with the medium CA glue, but you certainly could use white glue and a clamp, but you have to wait, and I don't like to wait :D

blast_gate13.jpg
Slide the slider to the right, and line up the hole in the body and the slider, again, the waxed part of the slider should be inside the body, and you can glue the second stopper to the slider, again, I use CA glue.

blast_gate14.jpg
Next up, I glue the two handle pieces onto the right side of the slider, easier to grip it with these small handles in place.

blast_gate15.jpg
With the blast gate in the closed position, I put one of the pipe connectors in place, I usually end up with just a bit of a gap around the pipe, the circle hole cutters are not that accurate :dunno: I find a couple of wraps of electrical tape around the pipe connector takes up the slack here. I then use some of the CA glue to stick the pipe connector in place, later I put a good solid bead of silicone sealer, as it holds much better than the glues does and it seals it too.

blast_gate16.jpg
There you have it, it is almost finished, the only thing to add is the end caps........

blast_gate18.jpg
I add these end caps with good old white glue and some clamps, leave it overnight. Without the end caps, the CA glue will fail, maybe in a month, or a year, but it will fail. The blast gates I have that with white glued on end caps are all going on a few years old, and they are going fine!

That is it, if you have any questions, please ask, and I'll do my best to explain. I took me about two hours, including taking the pics, to make all three of the blast gates.

Cheers!
 
Good tutorial, Stu. I built all of mine the same way, except I didn't glue the 2 halves together. I drilled and screwed through the corners through the runners. The runners are glued and bradded into one side. Where my down tube drops to the TS, I used 3/8" bolts to hold the halves together so I could take it apart and use as a quick disconnect, though it's not quick, so I could get my van in the shop if hail is on the way. I've done this twice. Took about 25 minutes to move the saw and all the other items to the side so the van would fit. Now that I have Dad's RAS mobile, my mobile router table, small jointer on a stand, and a mobile outfeed table, it will take a few minutes extra to get them out of the way.:rolleyes: Jim.
 
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