another newbee DC question

[Casey Mabry]

Hello all,
I've read threw tons of post on here about DC, and have found a flood of info, almost to the point of confusion. So I thought I would ask my questions direct. For starters I have a small 16' x 14' shop with 8' ceilings. I have the standard harbor freight 2hp DC. I plan on putting my DC in a corner and running a 4"pvc pipe down two walls making an "L" shape with the DC in the middle. My tablesaw sits in the middle of the shop. When I plan on running the planer or jointer, I will move the saw to the side and attaching that DC hose to those two tools which are on mobile bases as well as the table saw. My mitre saw, bandsaw, and router table are in fixed positions. I plan on using blast gates at each tool site to maximize suction. Now for the questions:

1. how high on the wall should I mount my pvc main line? How would you recommend mounting it?
2. I will be running flexible 4"clear with ground wires out of Y joints of the pvc, do I need to ground the pvc as well? I get at most 4-8 hrs shop time a week, if that figures into the equation with maybe 1-2 hours cutting time so I not going to be building up alot of static.
3.Does this plan seem feasible? I'm tired of treating my DC like a shop vac and want to give it a permanent home.
4.Does the DC need its own dedicated breaker? I've read it's recommended they do.
Thanks in advance for any input!

[Nick Lazz]

Hello all,
I've read threw tons of post on here about DC, and have found a flood of info, almost to the point of confusion. So I thought I would ask my questions direct. For starters I have a small 16' x 14' shop with 8' ceilings. I have the standard harbor freight 2hp DC. I plan on putting my DC in a corner and running a 4"pvc pipe down two walls making an "L" shape with the DC in the middle. My tablesaw sits in the middle of the shop. When I plan on running the planer or jointer, I will move the saw to the side and attaching that DC hose to those two tools which are on mobile bases as well as the table saw. My mitre saw, bandsaw, and router table are in fixed positions. I plan on using blast gates at each tool site to maximize suction. Now for the questions:

1. how high on the wall should I mount my pvc main line? How would you recommend mounting it?
2. I will be running flexible 4"clear with ground wires out of Y joints of the pvc, do I need to ground the pvc as well? I get at most 4-8 hrs shop time a week, if that figures into the equation with maybe 1-2 hours cutting time so I not going to be building up alot of static.
3.Does this plan seem feasible? I'm tired of treating my DC like a shop vac and want to give it a permanent home.
4.Does the DC need its own dedicated breaker? I've read it's recommended they do.
Thanks in advance for any input!

Casey,
I am no expert on dust collection but went through the same process you are going through in regards to research. I read ad nauseum and in some cases was still confused. One thing I found to help with duct work and CFM was here: http://www.oneida-air.com/shop_plan_...tutorial01.php

I was also concerned about PVC and possible static electricity. It appears that is not something you should worry yourself about. I read it is virtually useless to try and ground PVC...in fact the article stated it wasn't even really possible. I will try and find it for you if I can, but bottom line is, you are probably wasting time, money and effort in trying to ground your PVC.

Good Luck.

Nick

[Chris Padilla]

You can't adequately "ground" an insulator...'nuff said. If you're worried that static electricity could ignite sawdust (it won't in a hobbyist environment), then use metal duct.

I don't know enough about the HF DC but it is possible you could get better performance with larger diameter hoses/duct (like 5 or 6").

[Philip Rodriquez]

Maybe some people that own your DC will be able to chime-in. I, unfortunately, am stuck with just guessing.

If possible, run 6" HVAC SL for 6 feet or so. From there, drop down to 5"... and reduce it to 4" at your machine! Since you have to avoid bends (as much as possible), I would try to keep everything simple and close to the ground.

I'd be willing to bet that you will not be able to run your DC more than 15 or 20 feet total and still get enough airflow to avoid clogging. I doubt, however, that you will ever have enough CFM's to get the fine-dust (which is bad for your health).

Good DC is all about air speed. Air-speed killers are long runs, small pipe, or sharp turns. Oh, and you want to go with smooth walled pipe. It reduces friction.

[Stan Mitchell]

Here's another vote for making your main lines out of at least 6" material. You'll have much better air flow over the longer distances that a ducted system requires. You can then drop to 4" flex at the blast gates.

I ran 6" PVC on my 2hp system and can have 3 blast gates open and still have good chip/dust collection.

My shop is 18x19, so the equivalent of a 2-car. I like the ducting up high and out of the way. I mounted my ducting to homemade mounting blocks that were then lag-screwed to the ceiling joists (the blocks are short pieces of 2x4 on edge with a semi-circle cut for the shape of the pipe - then plumbers tape to hold the pipe into the block).

[Casey Mabry]

Thanks for the input guys, one follow up question: the harbor freight DC has two 4" ports coming out, should I run 4" flex to the wall where the 6" main line would be attached (about 2 or 3 feet) and then up size to the 6 inch there? can you get 6" pipe and enlarger fittings and reducer fittings at the borgs?
One other note, this system and all the 4inch pvc and flex pipe I have is "hand-me down" so eventually when budget allows I do plan to upgrade to a cyclone style. Thanks again.

Casey

[Nick Lazz]

Thanks for the input guys, one follow up question: the harbor freight DC has two 4" ports coming out, should I run 4" flex to the wall where the 6" main line would be attached (about 2 or 3 feet) and then up size to the 6 inch there? can you get 6" pipe and enlarger fittings and reducer fittings at the borgs?
One other note, this system and all the 4inch pvc and flex pipe I have is "hand-me down" so eventually when budget allows I do plan to upgrade to a cyclone style. Thanks again.

Casey

Not sure I understand your question, but try to not to use flex as much as possible. You lose too much CFM.

[Casey Mabry]

Basically I don't have a 6" line from the DC. I'll have to go from 4" at the DC up to a 6" diameter line then back down to a 4". I didn't know if having to step up in size then back down would lessen the suction. I understand the larger to smaller concept, but didn't know if you could go from smaller to larger to smaller.

[Stan Mitchell]

Casey, if it were me, I'd somehow fashion a new inlet for the DC you have. I've seen a number of homemade adapters. Once you have 6" at the machine, you can run a short piece of 6" flex from the machine to the ducting.

I think that going from 4" to 6" to 4" would be a waste of time and materials.

[Alan Lightstone]

You'll see posts where many people (myself included) have modified the inlet of the HF to be 6", then run 6" duct from there. It has dramatically increased air movement on mine.

If you aren't willing to do that, remove the 6"- dual 4" adapter from the inlet and run 5" hose to your machines, reducing to 4" at their dust gates. Should dramatically improve things, though not as much as running 6"

[Casey Mabry]

does anybody have a description or pic of modifying the inlet up to 6" line? Can I find the parts I would need at Lowes or HoPo?

[Clarence Miller]

You can't adequately "ground" an insulator...'nuff said. If you're worried that static electricity could ignite sawdust (it won't in a hobbyist environment), then use metal duct.

I don't know enough about the HF DC but it is possible you could get better performance with larger diameter hoses/duct (like 5 or 6").

I am at the same stage as the beginner of this post although I have the Shop Fox 1.5 HP collector and a 22x22 shop. I was in a BORG the other day and I began to wonder if furnace snap together duct work would be tough enough for a negative pressure application. It is metal so grounding would take care of itself but am worried about the collapse of the tubing. Has anybody tried this?

[Stan Mitchell]

Casey,

After removing the existing inlet, you can replace it with one like this one from Oneida Air Systems. There are other ways of doing it, but using a 6" sheet metal sleeve with a flange is the simplest.

dlxlow.jpg

[glenn bradley]

Opinions, we all got one ;-) Assuming we have gotten past trying to run long 4" lines (bad idea IMHO) . . .

1. how high on the wall should I mount my pvc main line? How would you recommend mounting it?

High enough that it won't get in your way, seriously. there is no advantage to going as high as you can but there is certainly a disadvantage to taking up valuable wall surface with pipe runs. I hang mine and strap it to the wall with inexpensive plumbers tape (the perforated metal stuff).

2. I will be running flexible 4"clear with ground wires out of Y joints of the pvc, do I need to ground the pvc as well? I get at most 4-8 hrs shop time a week, if that figures into the equation with maybe 1-2 hours cutting time so I not going to be building up alot of static.

I would use pipe to as close to where you need to switch to hose as possible. Pipe doesn't flex (much) and the last thing your DC needs is a shock absorber in the air path. I do have one 4" flex run of 8' but most are under 4'. The blast gates stand between the pipe and the hose so I can gate out the flex when not in use.

True you cannot "ground" and insulator. Its an expression, like "mud in your tires". The material moving through the pipe creates a static charge of varying degrees based on lots of conditions. Many folks report that when the inside of the pipe gets coated with dust, the static goes away. Waiting it out was my plan but, I have to reach right past the pipe to get to one of my gates and would get a "pop" now and again. I ran a length of 16ga. insulated wire looping about one turn per foot; grounded to conduit at one end and to a strip of foil tape on the concrete at the other; static's gone. I have no fear of fire or explosion. It was just annoying and I had the wire ;-) This could be done later if you find it to be an issue.

3.Does this plan seem feasible? I'm tired of treating my DC like a shop vac and want to give it a permanent home.

As "adjusted" by the good folks here; it sounds feasible.

4.Does the DC need its own dedicated breaker? I've read it's recommended they do.

I did but, I put in a new sub-panel so, why not. It will depend on your power setup. Most unmodified garages don't allow for a 2HP DC and a 2HP saw surging at the same time without some impact to say, the overhead lights. Try it, you'll know if you need a dedicated breaker/circuit or not (I would on G.P. but, that's me). Speaking of lights, new sub-panel or not, I kept a couple banks of lights on the original house panel so even if I blow the mains to the shop panel . . . the lights stay on.

HTH

[Chris Padilla]

I am at the same stage as the beginner of this post although I have the Shop Fox 1.5 HP collector and a 22x22 shop. I was in a BORG the other day and I began to wonder if furnace snap together duct work would be tough enough for a negative pressure application. It is metal so grounding would take care of itself but am worried about the collapse of the tubing. Has anybody tried this?

I've seen pics of the 30 gauge stuff collapsing. I dunno about any thicker stuff but the thicker, the better obviously. Find out what Oneida uses for their metal gauge and you'll have an idea what to shoot for.