blast gate suggestions

[Terry Achey]

I'm finally getting around to "hard piping" my DC and after reading several resources mentioned on this site I decided to use 4" S&D PVC. I was planning to install gates right off the PVC wye's and then probably some flex from there to the tool. I'll probably go with a metal self-cleaning type unless you the "panel of experts" steer me in a different direction.

My questions are:


what type gates do you suggest that are compatable to the I.D. of the S&D pipe and the 4"flex? (of course these are two differing dimensions.)
where do you purchase your suggested gate?
what else should I be thinking of in terms of gate location, etc.?Thanks in advance;)
Terry

[John Keeton]

The best pricing I found on on the self-cleaning blastgates was at http://www.blastgateco.com/index.php I ended up getting mine from Lee Valley because I was ordering some other items and the pricing was close enough that shipping made the difference. I think they carry the same gates - they are all imported.

I didn't use pvc so not sure on the ID. The best price I found on flex was http://www.ptreeusa.com/dusthose.htm I got the #377 roll (50').

Best of luck in getting your DC up and running! Why did you decide on 4" instead of 6"?

[Jim O'Dell]

I built mine. With a router and a home made circle guide and some playing with some scrap, I got it where I can route a hole that is a tight friction fit on my 6" PVC. For flex, just put a short piece of PVC on the gate, and slip the flex over it as normal. There are several designs that people here have done. The one I built this weekend is 3/4" MDF on the outside sandwiching 1/4" for the slider part. Previous ones were melamine shelving material, and the center slides a little better. They are self cleaning, and work fine. Jim.

[Larry Fox]

I did what Jim did - built them. I based them on the design in the link below.

http://web.ripnet.com/~scater/Blast_gates.htm

Very easy and economical to build.

[Stan Tilley]

Larry, thanks for the link. Very helpful to your fellow creekers.

[Jim O'Dell]

Well, it took me a while to find it, and I see Larry has posted a how to link. But here is a little picture tutorial I did on making the blast gates I built. Thought it might help. http://www.sawmillcreek.org/showthread.php?t=42643&highlight=BUILDING+BLAST+GATES Jim.

[Jim Becker]

Make your own gates if you can budge the time. You'll have a better product and will not have the losses often caused by commercial gates due to mis-sizing for non-standard materials (PVC S&D is not really a "standard" duct work method in the dust collection industry, despite being popular with home woodworkers) or because of manufacturing methods and desing. (aluminum gates reduce the inside diameter of duct by close to 1/2" due to the thick rim)

Making your own means they will fit exactly to the duct work you have chosen.

[Thomas Pender]

Terry,

John Keeton finished his reply to you with:

Best of luck in getting your DC up and running! Why did you decide on 4" instead of 6"?

My question as well, for 4" pipe, whether PVC or Metal, is probably insufficient for effective dust collection on trunk line. While it may be all there is at the machine level given the inadequate size of most import dust ports, it is really much better to use 6" and reduce it with a Wye (e.g., Oneida and others sell 6/6/5 or 6/6/4 Wyes and other reducers as well - one of the virtues of metal pipe are the great availability of different stuff).

BTW - I have had decent luck with plastic blast gates and Oneida sells them and so does Grizzly. Plastic gates have the virtue of being cheaper, although some say they do not contain the dust as well as the metal ones. I think Jim Becker and Jim O'Dell are right on to suggest you can fabricate your own. When I do things like that I always feel, perhaps unjustifiably, better afterwards - kind of like building a jig you can use many times.

[Stephen Edwards]

My questions are:


what type gates do you suggest that are compatable to the I.D. of the S&D pipe and the 4"flex? (of course these are two differing dimensions.)
where do you purchase your suggested gate?
what else should I be thinking of in terms of gate location, etc.?Thanks in advance;)
Terry

I bought my blast gates from Harbor Freight. ITEM 97497-0VGA. They cost $2.99 each and work perfectly.

Following the advice of a fellow woodworker who had already been through installing his DC system, here's a simple, cheap and effective method in response to your first question, if you are using the thin wall 4" S&D pipe:

Cut a short piece of your 4" S&D....perhaps 10-12 inches in length. Put a couple of heavy beads of good quality latex caulk around the circumference of the inside of one end of that short piece. Do the same thing all the way around one of the nipples on the blast gate. Then, slip the pipe over the caulked nipple of the blast gate and clean up the excess caulk, making sure that you have a good seal.

Now you have a blast gate attached to a short piece of PVC. Let that cure for 24-48 hours....mine cured completely in about 36 hours. Now, your pipe slips into your wye coming off the main line and the 4" flex hose fits around the other nipple on the blast gate. You're done.

I know that many folks say that the 4" pipe is too small for sufficient dust collection on the main trunk line. So far, I've had no problems at all using the 4" pipe and I've ran a lot of material through the jointer and planer. I have about a 30 foot run from the DC seperator to the planer. I built a home made seperator that eliminated clogging at the intake port of the DC unit itself.

Best of luck with your new system!

[John Keeton]

I am sure installation and maintenance has a lot to do with the function of the blastgates, and I really have not had my system up long enough to have much experience to speak from. But, it seems that the big issue when I was researching was "self-cleaning" gates and I don't think the Harbor Freight gates are self-cleaning. They apparently work fine for Stephen, and I have never used them so don't know. Others have posted several times regarding the "wish I had gone with self-cleaning" remorse and that is why I went with the more expensive ones.

I agree with Larry, Jim and Jim (sounds like a Newhart TV show??!!) with making them if you have the time and are so inclined. Seems the end product would be much better.

[Terry Achey]

Guys,

Thanks for all the responses to my questions. Although building would be fun, time is definately a factor so I'll probably go along with Stephen's blast gate suggestion.

In response to the "why 4" questions.... I certaily wouldn't argue the benefits of having a 6" trunk line. But here's why I settled on a 4" PVC trunk and branch lines.


I've had the shop up and running for about 4 months now. I've been using my 2hp dust collector by simply stringing 20' coils of 4" flex to the different tools (TS, JT, BS, RT, PL and downdraft table) until I was sure where I wanted to establish the final resting places for the various tools. Spent lots of time dragging the hoses around teh shop but I did indeed achieve my goal of understanding where I wanted to place the pieces semi-permanently. I have all but the TS on mobile bases.Although I read much on the links provided here about the terrible friction losses associated with flex pipe, my experience was that I had no problems with plenty of air movement to capture the dust and chips rather effectively. No problems with build up in the pipes even with two hoses connected to different tools and no blast gates installed. I even installed a ceiling suspended ceiling suspended 1 micron filter unit but rarely had to use it because I didn't experience much dust. Most dust I get is when ripping boards on the TS but a 6" trunk isn't going to collect that.

I orignally thought I would purchase the commercially made metal DC pipe and fitting until I saw how crazy expensive the fittings ands pipe cost. I also didn't care for the friction losses with standard metal duct fittings. So, I decided to go with the PVD S&D based on best friction loss for pipe and fittings and the fact that the pipe and fittings are readily availble at Lowe's, HD, etc. and easy to add or revise later.
All my major tools (with the excecption of the planer) will be within 25 feet or closer to the DC and the trunk will be about 30" off the floor along two walls.I promise to "man up" and let you know if my 4" system fails to perform.:cool:

Thanks again folks for all the responses. I really do appreciate how willing everyone is to help each other. What a great site!

Terry

[Jim Becker]

Just be aware, Terry, that 4" duct limits you to about 300-350 true CFM at the velocities dust collectors typically supply. It's pretty much entirely because you just can't physically fit any more air in that size pipe... Most dust collection "experts" (real or imagined) will tell you that you need a true 600+ CFM to truly clear a tool of the dangerious fines.

[Rob Diz]

You know, Jim really hit on a key point. Most folks will say their DC does a good job because it clears the big chunks. But it's the little little pieces of dust that are really dangerous to your lungs. If you are trying to keep things safe, then consider using a larger trunk line.

I am about to replace teh 4 inch flex tubing I am using in my shop. Yes, the visible stuff gets picked up, but the small stuff, who knows. Lowes and HD have 26 ga snap and lock 6 inch and 5 inch metal piping. I will be using this for my trunk line, and I will only be going down to 4 inch right at the blast gate. From all that I ahve read, it will greatly improve my CFM. It will also be lighter than the 4 inch PVC, and will be easier to reconfigure if I ever want to move things around or add on to the system.

Lowes has a better selection of the 5 inch fittings, as well as transitions down to 4.

I can't yet comment on total cost as I have yet to buy everthing - but it's likely to happen before I take on my next big project.