How to quiet down air compressor

[Gamble]

I have a harbor freight 29gallon compressor and trying to quiet it down.

So I did a few things this weekend

2 3/4” foam pads under it
1 foam pad against the wall where it sits
2 hockey pucks for feet. 4 total on one end
Put 2 larger rubber wheels on the other. They were 8” and I changed them to 10”
Cnc plasma cut a flange and welded on a 90* fitting and put on a solberg filter. Also tried adding a hose to remote mount the filter.
Seems most the noise is coming from the motor, pulley and not the intake.

After all of this..the sound is the same, maybe 1 to 1.5 dB max.


So originally it was 86db before any mods. Put on the filter and out of the blue the head gasket failed. Put on a new one, added oil and then it’s 88-89db. Now it’s 87-88db after all the mods

Tried a larger air silencer and it only got louder.

Was thinking about adding strips of dynatmat to half of the tank that faces the wall. Would that help or anyone else have any recommendations ?

 

[jumbojak]

A high rpm motor on an oilless direct drive compressor would lead me to either move it outside or build an enclosure if the noise bothered me that much.

 

[Gamble]

A high rpm motor on an oilless direct drive compressor would lead me to either move it outside or build an enclosure if the noise bothered me that much.

It’s not oil less

 

[jumbojak]

It’s not oil less

My apologies. I had it in my head that the red one was 29 gallons and confused yours with the 26.

 

[The_Auto_Tech]

Not much you can do besides move it outside or completely enclose it.

 

[T_R]

Cheap compressors are loud. Put it in a shed outside.

Nothing against the HF compressor, I have one too.

I just wear my 3M hearing protector headphone when I use mine.

 

[Gamble]

I feel like it was nowhere near as loud when it was new.

Think a heavier weight oil wouldn’t quiet it down?

 

[T_R]

My HF compressor was incredibly loud from day 1.

 

[The Cobbler]

loose pulleys? worn belt? bad bearings in motor or pump? rattling belt guard?

 

[The_Auto_Tech]

The HF compressor is loud, I agree. But it definitely works. If you wanna spend double the money you can get one more quiet.

 

[Lelandwelds]

There are a few basic ways to reduce noise transmission :
Add mass
Dampen vibrations
Uncouple or isolate

Personally, I would make a three piece concrete box or just a square tube with a separate roof slab and line it with rubber stall mats from Tractor Supply. And stick it in a shed outside.

 

[rpcraft]

I have the same HF compressor and its basically the spawn of Satan's garage. It is the loudest compressor I have heard, even more so than the pancakes.. The most you may really be able do to drown out the noise is displace it. Move it out of your work space, maybe the attic, or a pit/closet outside... I hate this unit and can not wait until my house is built and I can get rid of this thing. The only reason I have not is because it works (mostly) and right now I am in an apartment with a single car garage and all it has is a 110 outlet for the garage door opener and a light socket. Probably, the first two things I buy in the new house is curtains (or blinds) and then a new 220 compressor. Dewalt has one that I'm eyeballing. it has a 4.7 hp rating with a 80 gallon tank. It does 16.1 CFM at 40 PSI and then 14 CFM at 90 PSI. It's listed for about 1031 USD right now but I'll shop around that price point to see what else is out there when it comes time. I don't think I will mind to spend a couple hundred more dollars to get higher PSI and higher CFM ratings if that is the case, then when my house is finished I am probably going to make a closet in the garage that surrounds it and the water heater and they'll both be in the corner of the garage, which reminds me I need to detail that with the designer, lol)

 

[RVDan]

I'd try some Roxul insulation between the compressor and the wall to absorb some of the noise

 

[Jeff May]

Moved mine outside... poured a small slab of concrete and built an enclosure around both of them. Just be sure to install lots of vents. I put a row around the lower portion of the enclosure and several higher up. Its been 4 years and no problems. I can just barely hear them when they kick on, plus, it freed up floor space inside...

 

[Bigbandguy]

The HF compressor is loud, I agree. But it definitely works. If you wanna spend double the money you can get one more quiet.

This is true.. mine is 15 years old ... and except for a very infrequent oil change and occasional tank drain it does nothing but sit in a corner and do its job. Recently a landscaper was doing some work in my yard and had a leaking tire on his bobcat requiring frequent refilling. That compressor ran ALL DAY and did what was needed. Mine is a 26 but it is definitely an oil type. I think a Roxul lined box would be a good bet but thus far I just walk outside til the tank fills.

 

[Lelandwelds]

I'd try some Roxul insulation between the compressor and the wall to absorb some of the noise

Roxul is used to absorb sound. Add a high mass enclosure and you should have it whipped. If you use a metal enclosure, add the car stereo Dampening asphalt or rubber sheets. Stick it outside and annoy your neighbors.

 

[The_Auto_Tech]

This is true.. mine is 15 years old ... and except for a very infrequent oil change and occasional tank drain it does nothing but sit in a corner and do its job. Recently a landscaper was doing some work in my yard and had a leaking tire on his bobcat requiring frequent refilling. That compressor ran ALL DAY and did what was needed. Mine is a 26 but it is definitely an oil type. I think a Roxul lined box would be a good bet but thus far I just walk outside til the tank fills.

Glad to hear yours has been holding up! Mine has been in since February and I really like it. It's paid for itself easily already.

 

[rnscustom]

We put a hinged panel in front of our big dust collector with rolux on it . Cut the noise in half

 

[Gamble]

I don't think I have room to build an enclosure around it.

The fan cage doesn't make noise. The pulleys seem tight. The belt has some slack, doesn't seem too loose or too tight. But also I'm not sure what should be normal on that?

If I push on the motor it seems to have less vibration so I think if I put some longer bolts and hockey pucks under it, that may help a little bit. but not sure it's going to be worth it.

If I can figure out a way to drop the noise a fair amount I will keep it. Otherwise I want to look into the eastwood scroll compressor when it comes out, but it's also $1200. I think it's lie 67db. But would just be nice to be working with less noise.

 

[LX-Markham]

If I push on the motor it seems to have less vibration so I think if I put some longer bolts and hockey pucks under it, that may help a little bit. but not sure it's going to be worth it.

Vibration from the rotating assembly being out of balance is likely a large source of your noise problem.

Mine was hugely out of balance. I didn't have any options like moving the compressor outside, or building an enclosure. I took apart the compressor and had it balanced. Made a big difference. Wrote about it in another compressor noise thread.

the humming you can here in the 'after' clip is actually the motor that can now be heard over the compressor.

 

[Gamble]

Was the pump/engine out of balance or the wheel?

I could buy a new pump assembly for $100 on eBay. But I am already $50 into gaskets, $20 in wheels, $20 hockey pucks and $20 in a silencer

 

[LX-Markham]

I removed and balanced the pulley first to rule it out. It was not the culprit.
Oddly, the wrist pins were out of balance, but the main source of imbalance was the crank counterweight. It was way undersized.

Drilling out the crank and installing malory metal slugs was going to be cost-prohibitive. So they externally balanced the assembly by adding weight to the pulley. Still a bit of vibration because of the pulley offset, but way better than before.

^^^that big chunk of metal was how much the crank was out by!

 

[Gamble]

Holy ****!! That’s a lot
I was wondering if there was a good way to slow down the RPM if that would help any.

 

[Firebrick43]

Look for a compressor that has a 1750 rpm motor and turns the pump 500-600 rpm. The pumps will be much larger as a result and more efficient.

A lot of older compressors were built this way and some of the Quincy and champion compressors still are. I think some of the IR are to but they have speed most of the big box store models up (smaller pump) to compete on price.

I have a polar air that is built this way and you can talk on the cell phone right next to it and the person on the other line can't hear it.

 

[jgorm]

I built a box around my old one with 1" foam board on the inside. Made a huge difference. I'm going to try hanging carpet on the walls and hanging in front of my new hf 60gal.

 

[Gamble]

Think dynamat on the tank would help?

 

[pop pop]

While reading this I too wondered if the tank worked like an amplifier.

 

[lakelandcat]

IF its a oil compressor try changing your oil to a good synthetic oil, it will help with your vibration and keep your comp. running smooth a lot longer. If it's a new comp. you need to change the oil anyway because it is prob. a break in oil thats in it from the factory.

 

[Gamble]

IF its a oil compressor try changing your oil to a good synthetic oil, it will help with your vibration and keep your comp. running smooth a lot longer. If it's a new comp. you need to change the oil anyway because it is prob. a break in oil thats in it from the factory.

I will try this. Thanks

 

[theoldwizard1]

Simply building a 6 side box around a noise source will usually just make the item HOT !

Noise radiates from a source in all directions. If the source is next to a wall, or worse, in a hard wall corner, the reflections will just go in the opposite directions.

If you want to "wall it in", the walls need to have a 6-12" gap at the bottom to let air in. The wall should be about 4" with lots of insulation. Make sure there is adequate space between any hot surfaces and the insulation. A metal plate that sticks out about and addition 3" near an exhaust will make a huge difference.

Last do NOT PUT A LID ON IT ! Build the walls high, but not up to the ceiling. You will not hear noise going straight up.

 

[Gamble]

While reading this I too wondered if the tank worked like an amplifier.

Found this and it was cheap. I'll stick some to the back side of the tank facing the wall and leave the front side alone for now and see if it works any
https://www.amazon.com/dp/B01KZ5X7KO/?tag=atomicindus08-20

Ordered some more hockey pucks to mount under the motor and will see if that helps any.

Simply building a 6 side box around a noise source will usually just make the item HOT !

Noise radiates from a source in all directions. If the source is next to a wall, or worse, in a hard wall corner, the reflections will just go in the opposite directions.

If you want to "wall it in", the walls need to have a 6-12" gap at the bottom to let air in. The wall should be about 4" with lots of insulation. Make sure there is adequate space between any hot surfaces and the insulation. A metal plate that sticks out about and addition 3" near an exhaust will make a huge difference.

Last do NOT PUT A LID ON IT ! Build the walls high, but not up to the ceiling. You will not hear noise going straight up.

Not sure I have room to build an enclosure around it.

 

[Gamble]

I have the same HF compressor and its basically the spawn of Satan's garage. It is the loudest compressor I have heard, even more so than the pancakes.. The most you may really be able do to drown out the noise is displace it. Move it out of your work space, maybe the attic, or a pit/closet outside... I hate this unit and can not wait until my house is built and I can get rid of this thing. The only reason I have not is because it works (mostly) and right now I am in an apartment with a single car garage and all it has is a 110 outlet for the garage door opener and a light socket. Probably, the first two things I buy in the new house is curtains (or blinds) and then a new 220 compressor. Dewalt has one that I'm eyeballing. it has a 4.7 hp rating with a 80 gallon tank. It does 16.1 CFM at 40 PSI and then 14 CFM at 90 PSI. It's listed for about 1031 USD right now but I'll shop around that price point to see what else is out there when it comes time. I don't think I will mind to spend a couple hundred more dollars to get higher PSI and higher CFM ratings if that is the case, then when my house is finished I am probably going to make a closet in the garage that surrounds it and the water heater and they'll both be in the corner of the garage, which reminds me I need to detail that with the designer, lol)

Since you have the same one would you mind comparing your results to mine? I am just using a free db app on my phone. I can send you pics of how mine is setup and how far my phone is. Would be interesting to see how they compare

 

[Lelandwelds]

I removed and balanced the pulley first to rule it out. It was not the culprit.
Oddly, the wrist pins were out of balance, but the main source of imbalance was the crank counterweight. It was way undersized.

Drilling out the crank and installing malory metal slugs was going to be cost-prohibitive. So they externally balanced the assembly by adding weight to the pulley. Still a bit of vibration because of the pulley offset, but way better than before.

^^^that big chunk of metal was how much the crank was out by!

You went the extra distance.

Look for a compressor that has a 1750 rpm motor and turns the pump 500-600 rpm. The pumps will be much larger as a result and more efficient.

A lot of older compressors were built this way and some of the Quincy and champion compressors still are. I think some of the IR are to but they have speed most of the big box store models up (smaller pump) to compete on price.

I have a polar air that is built this way and you can talk on the cell phone right next to it and the person on the other line can't hear it.

Say that again but louder.

IF its a oil compressor try changing your oil to a good synthetic oil, it will help with your vibration and keep your comp. running smooth a lot longer. If it's a new comp. you need to change the oil anyway because it is prob. a break in oil thats in it from the factory.

Mine was shipped dry but I hear a voice of reason.

Found this and it was cheap. I'll stick some to the back side of the tank facing the wall and leave the front side alone for now and see if it works any
https://www.amazon.com/dp/B01KZ5X7KO/?tag=atomicindus08-20

Ordered some more hockey pucks to mount under the motor and will see if that helps any.


Not sure I have room to build an enclosure around it.

It certainly works on floor pans! I used an asphalt based one twenty years ago. It stunk but damn! It killed sub woofer vibration and rattle.

Horse stall mats work great and are almost as cheap as pucks. I would want the harder puck for motor mounts ( never thought of that) but mats for compressor floor.

Mass is a big deal. They used to make adhesive lead sheets and mass loaded vinyl for sound proofing. I bet double sided foam tape and lead ingots would do something good.

 

[Finky198]

I can concur on the IR compressor we have one of their new 7.5hp 80 gallon from tractor supply and it came with a WEG 3250 rpm motor. It’s definitely noiseir than its 1750 rpm counter part but it still a WEG motor and I have little doubt in its build quality. Although I would replace it with its lower rpm counter part if the need arose.

I did the usually rubber mounts on the floor. I also remounted the motor, pump, and panel on rubber conveyor, Which reduced the noise noticeable, but by far the biggest difference was modifing the intake. The final step for me is to put up an insulated wall and door in the back corner where the compressor sits to eliminate what’s left of the noise.

Take a look on the forum and on the web there is plenty of info on intake silencers.

 

[Gamble]

Already have the intake silencer.

 

[Finky198]

Sry I missed that I guess you sol.

 

[4 Ever-Fish N]

Good thread. I'm thinking about putting my air compressor in the storage shed. I would have to add about 30' of pipe. Would this change the efficiency of the compressor? I have a 30 gallon Craftsman compressor that's about 10 years old.

 

[Lelandwelds]

Good thread. I'm thinking about putting my air compressor in the storage shed. I would have to add about 30' of pipe. Would this change the efficiency of the compressor? I have a 30 gallon Craftsman compressor that's about 10 years old.

Not if it was 1/2" or larger pipe especially if in a loop. Piped systems have way more feet. Think of it as adding more air storage.

 

[brownbagg]

there was a story where I guy took the inlet filter off and replace with a large junkyard airfilter off a car, like a japanese plastic box that on the fender. he found one with cheap replacement filter, some like toyotas are outrangeous, but it took 70% of the loud sound with it, just by moving to bigger inlet filter. the video on youtube some where.


here it is

 

[Gamble]

there was a story where I guy took the inlet filter off and replace with a large junkyard airfilter off a car, like a japanese plastic box that on the fender. he found one with cheap replacement filter, some like toyotas are outrangeous, but it took 70% of the loud sound with it, just by moving to bigger inlet filter. the video on youtube some where.

Have you even read this thread?