Garage vacuum and compressed air question

Durnik

Bob
Senior User
To all,

Just an idea and some feedback would be helpful. I have a garage (2 car and very spacious), which butts up against a wall that leads to a concrete floor huge crawlspace. I'm going to put in some garage cabinets and was thinking about putting in compressed air and a vacuum system. Now, the question is; if I use 4x4 pressure treated lumber as the base (with a 1" shim on top) and leave space at the back, I could run a 4" vacuum pipe and a 1" copper pipe in the back and then "T" off to outlets in the front of the cabinets and also run it down (think right angle turn), another wall where some equipment would be stored against the wall when not in use (saw, planer, Etc.). Now, in the crawlspace I can install the vacuum and the compressor and keep them out of the garage and use sound boxes to dampen their noise and the crawlspace has an exterior wall I can vent out of for exhaust and water drainage. Total runs would be in the 30' range and I'm thinking of PVC (I know), pipe with metallic paint sprayed inside for grounding and copper for the air. Note: For the right angle turn I'd use a gradual turn not a single 90 degrees to lessen the impact on air flow.

Now, the dumb questions are:

1) I've always seen vacuums in the top of a shop with down lines to the outlets. Would a floor level set of gates harm/hurt in anyway?
2) For the compressed air, I can cool it in the crawl space and have drain lines run to use an auto drain valve when the system is turned off. I can also slope the pipes (think 1/4 inch per foot) to a line purge valve and mount the water/oil filters at the outlet wall from the crawlspace (along with a switch) so I can easily drain and purge the lines. However, I've always seen air lines "T" upwards to their outlet (which can be done), but if there any downside to running the main line that close to the floor?
3) This would leave me with a 4.5 inch toe kick, would that be out of line, throw off the look, become cumbersome, Etc?

Just some musings as I plan this out and looking for some thoughts and advice

Bob
 

JimD

Jim
Senior User
Shop vacuums pull well against resistance but are quite limited in airflow versus a DC (which hates resistance but can really move air with low resistance). So I don't think your run will kill the airflow but gentle radius turns as you plan are a good idea. I would not run 4 inch, however, if you are planning on a shop vac. It's too large and debris will settle, I think. 2.5-3 inch would be better. I would get whatever PVC pipe you find that is closest to 2.5 inches, even if it's a little smaller. No need to worry about grounding it. There is no explosion risk. You will want to avoid picking up hot metal or something else that could ignite the dust but the only thing grounding it would do is reduce the chance of you getting shocked plugging something in from static. If that is your logic and an issue then grounding is fine but don't do it to address a non-existant fire/explosion risk. It takes a very precise air to dust ratio to be an issue and then you have to have an ignition source. From a practical standpoint it won't happen.

It's been awhile but I think the PVC I used to put in a whole house vacuum in my last house was 2 inch. If you find that at a good price it would work. It is thin walled.

I just keep a little Senco compressor on the shelf of my assembly table so I have no need for air lines. It is quiet enough not to be a problem. If you have a noisy one you want to use putting it in the crawl space seems logical to me. There are plastic lines sold for this (rapid air?) too. Not sure what is best but planning to get rid of moisture is a good idea.
 

cyclopentadiene

Update your profile with your name
User
Charlie uses shop vacuums very effectively. He has the cleanest shop that I have ever seen. I would ask for his advice!
 

Oka

Casey
Corporate Member
A General comment If you have a space with a dust collector that is pulling 1200 cfm. The general rule is to keep the ventilation for that room equal to the machine cfm pull. So, you would need a 20" x 24" transfer grill to assure you are not increasing friction to the operating system. Additionally, if you wanted a cooling fan to pull air in to increase cooling circulation. This is a separate ducting exercise.

2nd thing- with pipe fittings, just for description sake there are 4 type of elbows that are common a Vent Ell which it a hard 90 deg looks like you coped 2 pipes together, A sanitary 90 looks like a common 90 deg you buy; a medium radius (sweep) which is a longer radius usually 1.5 longer in travel to the San-90; and a long-radius (Sweep) 90 which is 2 x the travel. The medium one is likely what you will want. There are others versions and specialty and ... the descriptor for these fittings vary from regional area to regional area.
 

tvrgeek

Scott
User
Under floor is great if you have room, but 4 inch ducts are pretty small for a serious DC system. I still contemplate cutting up my slab to drop the 6 inch to my TS, along with the power drop, into the floor. That is the only place the overhead is in the way.

Putting the compressor in the CS may be OK, but you should rethink the DC. For ne thing, one that actually works is 8 or 9 feet tall.

You need to do a lot more reading on the myths of static, grounding etc. There is so much clearly non scientific, untested "but it seems logical" or " I heard of" out there to rival politics. Look carefully, there is some actual guidance from real engineers out there.

I would suggest looking at PEX for the air. Pipe is rated 450 PSI and even Sharkbite fittings are over 200. Nothing wrong with copper, but think about alternatives. I too just keep a pancake in the wood shop side. Big compressor is in the other room for automotive and when I set it up as a spray booth. Using air to clean up things just puts the fines ( the stuff that kills you) into the air. Draining air lines is not that big a deal, The volume of air will blow any water out. Just be sure there is a vapor separator at the outlet end.
 

Durnik

Bob
Senior User
Thank you all for the replies. I misspoke in that it would be a DC (say 2HP for my needs), not a shop-vac. The crawlspace is 8" high at that point (I'd use the crawlspace for a true shop, but I have so many HVAC ducts all over it it's just not possible). For the DC, I can't ever imagine running more than one machine at a time, and with a max 30 foot run, I was hoping to be able to use 4 inch pipe but I'll do some more research.
 

Durnik

Bob
Senior User
A General comment If you have a space with a dust collector that is pulling 1200 cfm. The general rule is to keep the ventilation for that room equal to the machine cfm pull. So, you would need a 20" x 24" transfer grill to assure you are not increasing friction to the operating system. Additionally, if you wanted a cooling fan to pull air in to increase cooling circulation. This is a separate ducting exercise.

2nd thing- with pipe fittings, just for description sake there are 4 type of elbows that are common a Vent Ell which it a hard 90 deg looks like you coped 2 pipes together, A sanitary 90 looks like a common 90 deg you buy; a medium radius (sweep) which is a longer radius usually 1.5 longer in travel to the San-90; and a long-radius (Sweep) 90 which is 2 x the travel. The medium one is likely what you will want. There are others versions and specialty and ... the descriptor for these fittings vary from regional area to regional area.
Thank you Casey, some great wisdom and things I hadn't looked at in there I'll need to look into.
 

Dee2

Gene
Corporate Member
If you have interest, I have a box of house central vac piping, unused. Probably a few fittings. Willing to trade for a 20" Minimax bandsaw, used Corvette (under 20K miles) or reasonable counter offer. ;)

I really do have the pipe.
 

FredP

Fred
Corporate Member
If you have interest, I have a box of house central vac piping, unused. Probably a few fittings. Willing to trade for a 20" Minimax bandsaw, used Corvette (under 20K miles) or reasonable counter offer. ;)

I really do have the pipe.
:p ill trade you for a 2x4!;) or a picture of one....:eek:
 

Gotcha6

Dennis
Corporate Member
Thank you all for the replies. I misspoke in that it would be a DC (say 2HP for my needs), not a shop-vac. The crawlspace is 8" high at that point (I'd use the crawlspace for a true shop, but I have so many HVAC ducts all over it it's just not possible). For the DC, I can't ever imagine running more than one machine at a time, and with a max 30 foot run, I was hoping to be able to use 4 inch pipe but I'll do some more research.
Are your floor joists treated wood? NC Code crawl space minimum is 16 inches otherwise.
 

Durnik

Bob
Senior User
Are your floor joists treated wood? NC Code crawl space minimum is 16 inches otherwise.
Dennis, my stupidity in my measurements. It's 8 "foot" high at that part and 7 foot high in most of the rest of it. However, the HVAC primary feed and return ducting is all over the craw;lspace so I only truly have about a 10x15 foot space that's free of ducting and butts up with the garage wall. Hence my thought of putting everything in the crawlspace (6 inch poured concrete floor and well insulated but no HVAC treated air), and then I can keep it out of the garage and build sound boxes to dampen the noise.

Bob
 

tvrgeek

Scott
User
A co-worker of my wife told a story about Eastern Europe pre-wall coming down. They actually used lumber as currency.

With that much crawl space, I would for sure try to use some of it for storage at least. Even better if you convert it to a "sealed" system and it is part of the HVAC controlled space. Never enough space to store lumber, jigs etc. 6 inch floor? I bet not. Doubt it is more than 3.

For a dust collector, in reality, only a cyclone works. Most of us go through the shop-vac, bag, canister path before we wise up and do it right. The taller the cyclone, the better it works, which is why the better ones (Onedia and ClearView) are so tall. The oddball is the new Harvey which is sideways. I was tempted by it as it would fit under my outfeed table, but was not positive it has the huge volume of flow I want for a hood behind the miter saw and lathe. So, it depends on your tools and expectations. FWIW, my 5 HP CV is not as loud as the 1 3/4HP Jet I had. I use a Fein hepa vac with a small CV cyclone for my hand-held tools and for cleanup. Works great.
 

Durnik

Bob
Senior User
Copper pipes and treated lumber don't mix very well. Where copper passes thru treated, you need to sleeve it in PVC.
Thanks for the input, that part I'd forgotten about chemical reactions. However, what I was thinking was just building the base frames and stopping 4 inches back from the wall so I could run the pipes behind the base. No wood on pipe contacts so I should be good. Also, thanks to all of you for the great input and ideas. I think I've decided on a DC and Compressor in the crawlspace, I have space to put in a tall Cyclone and then vent the exhaust outside for both the air and the compressor drain. Now I just have to get to the full measuring and start the research on best way to build sound cabinets (thinking of using rock wool as I hear it's great for sound deadening).

Once again, my thanks to all of you and I'll let you know how it turns out :)

Bob
 

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