J. Phil Thien's Projects

Having watched this forum for a while, I would not dismiss Chuck's thoughts too quickly.  I really like the revision of moving the blower up to shorten and straighten the total travel.  I am not convinced that longer travel before the impeller is different than longer travel after the impeller.  Perhaps the technology of an impeller is different than how I use a straw...

I am very interested is the question of what are the negative consequences of using 6" smooth ducting with an impeller that is designed and speced for 5" flex ducting, since I am going to be doing the same on mine.  If it is going to kill the motor sooner, I am okay with that, but if it will reduce the total suction that does not sound like an improvement.  I am ready to learn more.

-Will

Quote from: Chuck Lenz on November 15, 2010, 05:28:26 PM
Instead of trying to bend the plastic, why not make a mount for the plastic.

I would be inclined to make the window flush on the inside so that dust and chips do not pile up inside the mount and make it difficult to see.  I like JakesDad1's idea.  I am thinking that I will cut a window into the steel drum that is below my separator to create a window.

Great suggestions on this thread by all.

-Will

I found 55 gallon steel barrels (previously used for mollasses, so no concern for toxics) for $30 on craigslist.  (I live in Vancouver, Canada, but there is probably someone trying to get rid of barrels near you too.)  While steel is harder to move around than plastic it also introduces almost no elasticity in the system.

-Will

Generally, I do not see a problem, but I would think about the possible efficiency of having the HF impeller housing  attached directly to the top surface so the pipe going through is only going down into the separation chamber.  This eliminates some distance and possibly flexible hose between the impeller housing and the separation chamber.  As you are planning to use 6" pipe you will need to replace the cover of the impeller housing (as the hole in the HF DC cover is only 5"), so you might just use the top surface of the separation chamber as the impeller housing.  I would think that you would need to provide some kind of gasket to make sure that you do not get leaks between these two, but that should be manageable when combined with sealant.

Those are my $.02.

-Will

I have read that Squirel cages do well as air cleaners, when combined with furnace filters.  This setup moves large volumes of air at low pressure and is good for removing the fine dust that may escape the dust collector.  There are a number of different designs you can find on the internet some in hanging setups some in down-draft sanding tables.

-Will

I think shop-vac and squirel cage offer opposite qualities, but neither is ideal for dust collection.

The shop-vac will have very strong suction, but not be able to move that much volume, so it works well for a small set-up but may not be able to pull enough air to get a 55 gallon separator working efficiently.

On the other hand, the squirel cage will work well for large volumes of air, but cannot deal with any significant resistance, as you will need to pull heavy dust through a separator.

I would recommend getting a dust collector with an impeller designed for the amount of air you need to move and the suction necessary to keep the dust suspended until separated.  I also have a Harbor Frieght DC that I use with a 55 gallon barrel.

If you do try it, please post about your results.  I would love to find out I am wrong.

-Will

I would go with side entry that is above the drum with the "top hat" separator.  This increases the capacity of the drum that is available for dust (separation chamber is now above the entire drum) and increases the suction by removing the drag of a few more curves (and perhaps some flexible hose), and avoids having to cut into the drum.  Every way a slightly better arrangement, except that now the blower is attached to the drum (which could make emptying the drum more difficult).

-Will

Quote from: Negative_Zero on June 23, 2010, 03:23:43 PM
combine the separator and the DC into a single unit

I think Chuck misunderstood the point I was trying to make (because I did not make it clearly, I admit).  I am thinking of having the blower and the separation chamber connected with the shortest possible fixed pipe, rather than a longer run.  For example, see what VAwoodworker did - see http://www.jpthien.com/smf/index.php?topic=262.0.  I expect that the efficiency of having fewer turns and no flexible hose in the system may improve results more than the advantage of having separation occur closer to the source of the dust, but like duncsuss I would would interested in actual test results.

-Will

Without any empirical basis, it seems to me that it would be better to have the separator close to the source of dust because there is less distance to pull the dust and debris in the air flow, so less chance for it to collect in the pipes.  However, if you can combine the separator and the DC into a single unit the increased suction may make even more difference.  Having the shortest sections of turns and flexible hose seems to make the most difference.  Also, if you have the separator near the tool, you will have to either move it around, which may not be convenient.

-Will

I would be concerned about the reduction in suction if your blower has to pull air through two separators, or are you thinking that you would only use one or the other, depending on the task.

-Will

I am planning a similar project.  The only modification I have considered is to have the waste barrel be able to drop vertically to be cleaned out, so I do not have to move the blower/separator assembly.  Perhaps I will have a spacer below the barrel that I wedge in for use and then remove the spacer to empty the barrel.  This allows you to entirely elminated flexible hose at the blower end of your dust collection.

Not much of a modification, but all the good ideas were already taken!

-Will

There is an excellent article in May/June 2009 issue of Fine Woodworking about how to dust proof any table saw.  I think also you would be wise to add an overhead guard with dust collection running on a split-off collection line.

But the connection to your separator is limited, the main question is the filter that must catch the dust that gets past the separator.  There are many comments that the Harbor Freight DC filter bag is not sufficient for this issue, and many have installed canister filters to address this (also increasing airflow because of larger surface area of canister filters).

The issue around a separator is whether it reduces the airflow so not enough dust is caught (it seems that Phil's baffle reduces this concern, but you still need enough static pressure to pull the dust into the air flow) and whether the separator keeps enough of the larger waste out of the filter to reduce the need to clean the filter to maintain suction.

-Will

There is one in the May 2010 issue of Wood Magazine that expires in July 2010.  I have not seen these coupons online, but if somone has, please post.

-Will

This looks like exactly the project I was thinking to build to intercept most of the debris before it gets to my 2hp HF DC.  I am thinking that I will build a single unit with a 5" input that attaches the blower directly above the baffle and the motor directly above the blower, with the output from the blower feeding into the DC filter/collection bag.  If I build the baffle unit from plywood it should be strong enough to carry the weight of the motor and the blower, with the catch barrel clamped from below (and able to be separated and lowered for emptying with the motor, blower and baffle staying stationary).

One question I could not answer for myself is the angle at which the baffle is oriented.  It seems to me that the flat part of the baffle in this design is horizontal (i.e., parallel to the ground) while other baffle designs seem to be slanted.  Is this appearance just the because of the way things were photographed?

Also, how far down into the swirling air should be central vent be to minimize the sawdust that is picked up and sent into the DC.  It seems that most have the central pipe only going 1-2 inches below the top surface.

Finally, I am planning to use a galvanized steel garbage can.  Is a 2hp HF DC likely to collapse that if there is blockage in the air flow?

Thanks for this great baffle design and this example of how to implement it!

-Will