Air compressor expansion tank question

[newpain01]

Hey everyone!

I need some advice on getting a bit more air when I am sandblasting which is honestly not often to justify getting a bigger compressor. I do it probably a couple times a year such as blasting ATV wheels or some similar sized parts and maybe a lot of smaller parts.

I have a DEWALT 3.7 HP 60 gal. 1-Stage 155 PSI which delivers 11.5 SCFM at 90 PSI and another 10 gal compressor which doesn't work.

The idea is to connect the dead compressor to the air system so I can have an expansion tank to capture additional moisture and add more CFM for sandblasting because my dewalt cannot keep up and is constantly running when I am sandblasting.

I am wondering, should I just connect the dead compressor with a Tee to the air line without removing the motor and it's compressor or are there any other better ideas for adding a bit more cfm?

Another option I was looking at was adding a 100lbs propane tank (which should be around 20gal) instead of this old compressor, so that might be something I can do later on.

Any advice appreciated.

 

[PoorUB]

You can just tee it in as long as the fittings are large enough. Keep in mind all you will gain a a little more time before the pressure drops, and a longer run time to refill, so it is kind of a lost cause. So blast for a short time, and wait a short time to refill, or blast longer, and wait longer to refill.

 

[GeoBruin]

Hey everyone!

I need some advice on getting a bit more air when I am sandblasting which is honestly not often to justify getting a bigger compressor. I do it probably a couple times a year such as blasting ATV wheels or some similar sized parts and maybe a lot of smaller parts.

I have a DEWALT 3.7 HP 60 gal. 1-Stage 155 PSI which delivers 11.5 SCFM at 90 PSI and another 10 gal compressor which doesn't work.

The idea is to connect the dead compressor to the air system so I can have an expansion tank to capture additional moisture and add more CFM for sandblasting because my dewalt cannot keep up and is constantly running when I am sandblasting.

I am wondering, should I just connect the dead compressor with a Tee to the air line without removing the motor and it's compressor or are there any other better ideas for adding a bit more cfm?

Another option I was looking at was adding a 100lbs propane tank (which should be around 20gal) instead of this old compressor, so that might be something I can do later on.

Any advice appreciated.

You're not going to get more "CFM" by hooking up a dead compressor. You're simply going to add a very small amount of additional storage.

Assuming your 10 gallon tank is rated at 150 psi, that equates to about 2.34 cubic feet of compressed air at 90 psi. If your blast cabinet is consuming just 15 CFM, you will consume those extra 2.34 cubic feet in just under 10 seconds. So that's what you're buying yourself, about 10 more seconds of blasting before you drop below your regulated pressure.

This is why, for continuous use cases like grinding, sanding, painting, and blasting, more storage isn't the solution. It's a higher rated pump that can keep up with the continuous air demand.

 

[OccupantRJ]

Go on marketplace or Craigslist and buy a couple of cheap portable compressors to tie in while you are blasting. I see them for as low as $50 needing a pressure switch or such. This is as cheap as you will likely get more cfm. I have played the game over many years and have tried several methods. Cfm of the pump(s) are what matters for more than a few minutes. I now have two 20 cfm compressors that I run alternately for my blast cabinets to spread wear between them. My 160 sq ft insulated compressor room gets hot enough that I have a thermostatically controlled vent fan set to 90 degrees f to control heat buildup on the compressors.

 

[rlitman]

...So that's what you're buying yourself, about 10 more seconds of blasting before you drop below your regulated pressure...

Exactly. Plus an extra 14 seconds waiting for the compressor to catch up. So in the end, you're not actually getting more overall blasting time.

 

[theoldwizard1]

You're not going to get more "CFM" by hooking up a dead compressor. You're simply going to add a very small amount of additional storage.

TRUE !

But if you are doing small items (no bigger than a wheel) then this might "get you through the job" without having to wait for the compressor to "catch up".

 

[theoldwizard1]

Go on marketplace or Craigslist and buy a couple of cheap portable compressors to tie in while you are blasting.

This does work, but you have to make sure you plug them into different electric circuits or you will be tripping breakers !

 

[finn]

I would spend the time investigating what’s wrong with the spare dead compressor. If it can be repaired relatively inexpensively it might be worth fixing it and plumbing the outlet in parallel. That way you truly do get additional cfm.

 

[The Cobbler]

I agree that the best way is to (maybe not the best way, but an option) is to plumb in another compressor . you actually won;t even need a second tank, you could plumb it in to the existing tank .

 

[theoldwizard1]

I agree that the best way is to (maybe not the best way, but an option) is to plumb in another compressor . you actually won;t even need a second tank, you could plumb it in to the existing tank .

Nephew borrowed my 2hp compressor to parallel with another 2hp compressor for a big sandblasting job.

 

[dkmc]

Sandblasting and the laws of physics are pretty much set in stone no matter how some people would
like to try to bend them. When I see 3.7HP and Sandblasting in the same sentence, it makes me squint a bit.
Sandblasting IS CFM and pressure. I'd say the absolute minimum HP needed to get any blasting
done in a syphon cabinet would be 5 real hp. And even then things will move slowly. 10hp starts
(40-ish CFM @ 70-80PSI) to become productive, even better with a pressure pot type cabinet setup.

 

[newpain01]

Thanks for the responses, appreciated.

I'm glad I asked for opinions instead of wasting my time adding tanks.
I've been looking at 5HP 80 gal compressors but at this point I don't do enough sandblasting to justify the price, maybe in the future.

Go on marketplace or Craigslist and buy a couple of cheap portable compressors to tie in while you are blasting. I see them for as low as $50 needing a pressure switch or such. This is as cheap as you will likely get more cfm. I have played the game over many years and have tried several methods. Cfm of the pump(s) are what matters for more than a few minutes. I now have two 20 cfm compressors that I run alternately for my blast cabinets to spread wear between them. My 160 sq ft insulated compressor room gets hot enough that I have a thermostatically controlled vent fan set to 90 degrees f to control heat buildup on the compressors.

I could definitely add another 20-30gal compressor.

I would spend the time investigating what’s wrong with the spare dead compressor. If it can be repaired relatively inexpensively it might be worth fixing it and plumbing the outlet in parallel. That way you truly do get additional cfm.

It's an old Campbell Hausfeld 10 gal compressor, the electric motor works fine, but the pump doesn't build enough pressure. I have not tried disassembling the pump to see what the issue is and I doubt I can get parts for it anymore.

 

[OccupantRJ]

Thanks for the responses, appreciated.

I'm glad I asked for opinions instead of wasting my time adding tanks.
I've been looking at 5HP 80 gal compressors but at this point I don't do enough sandblasting to justify the price, maybe in the future.


I could definitely add another 20-30gal compressor.


It's an old Campbell Hausfeld 10 gal compressor, the electric motor works fine, but the pump doesn't build enough pressure. I have not tried disassembling the pump to see what the issue is and I doubt I can get parts for it anymore.

Remove the head and check the valves. There are likely simple reed valves on that and small units with bad motors are out there. It could simply need carbon buildup cleaning which is a regular maintenance item anyway.

 

[joe_padavano]

I do a lot of automotive restoration work as a hobbyist, so media blasting, air tools, and HVLP paint guns were a concern for me. Having struggled with an undersized compressor for years, I finally put together a frankepressor about ten years ago. Rebuilt RolAir K30 pump, brand new Baldor 7.5 HP single phase motor, used tank. 23+ SCFM makes media blasting almost a joy (well, except for that grit in the shorts thing...). The compressor doesn't even breathe hard. Since then I've picked up a lot of used air tools, many of which have large SCFM needs, and again the compressor doesn't even breathe hard. If you have any troubleshooting/assembly skills at all, it isn't hard to put together a great compressor for a fraction of what a new one costs.

Of course, if more is better, too much is just about right. I recently picked up a used compressor at a machinery auction with a 40 SCFM pump at 10HP. There are several 10 HP single phase motors near me on FB marketplace, so that's the next project.

 

[Citation]

Thanks for the responses, appreciated.

I'm glad I asked for opinions instead of wasting my time adding tanks.
I've been looking at 5HP 80 gal compressors but at this point I don't do enough sandblasting to justify the price, maybe in the future.


I could definitely add another 20-30gal compressor.


It's an old Campbell Hausfeld 10 gal compressor, the electric motor works fine, but the pump doesn't build enough pressure. I have not tried disassembling the pump to see what the issue is and I doubt I can get parts for it anymore.

As ORJ said, it's quite possibly reed valves. If this is an oil free compressor it also may be the "ring seals". The teflon rings that act to seal the piston to the cylinders are known to wear out over time. They used to be a common, cheap repair part. However, it seems those parts are getting harder to come by for a lot of Sears compressors. Still, if you can get it fixed and if the pressure ranges are acceptable, that would likely add 4CFM to your current setup and may be the difference between having to listen to the compressor(s) all the time vs having to listen to them all the time AND wait for the air pressure to build.

Do keep in mind that most consumer compressors and even some of the pro-summer 240V models don't like running non-stop. So occasional blasting work should be fine but at some point these pumps may overheat if they don't get enough down time between recycles.

 

[newpain01]

Remove the head and check the valves. There are likely simple reed valves on that and small units with bad motors are out there. It could simply need carbon buildup cleaning which is a regular maintenance item anyway.

Looks like there is not much inside other than those reed valves, need to see if I can get a replacement.

I do a lot of automotive restoration work as a hobbyist, so media blasting, air tools, and HVLP paint guns were a concern for me. Having struggled with an undersized compressor for years, I finally put together a frankepressor about ten years ago. Rebuilt RolAir K30 pump, brand new Baldor 7.5 HP single phase motor, used tank. 23+ SCFM makes media blasting almost a joy (well, except for that grit in the shorts thing...). The compressor doesn't even breathe hard. Since then I've picked up a lot of used air tools, many of which have large SCFM needs, and again the compressor doesn't even breathe hard. If you have any troubleshooting/assembly skills at all, it isn't hard to put together a great compressor for a fraction of what a new one costs.

Of course, if more is better, too much is just about right. I recently picked up a used compressor at a machinery auction with a 40 SCFM pump at 10HP. There are several 10 HP single phase motors near me on FB marketplace, so that's the next project.

Which motor / compressor pump have you used?

As ORJ said, it's quite possibly reed valves. If this is an oil free compressor it also may be the "ring seals". The teflon rings that act to seal the piston to the cylinders are known to wear out over time. They used to be a common, cheap repair part. However, it seems those parts are getting harder to come by for a lot of Sears compressors. Still, if you can get it fixed and if the pressure ranges are acceptable, that would likely add 4CFM to your current setup and may be the difference between having to listen to the compressor(s) all the time vs having to listen to them all the time AND wait for the air pressure to build.

Do keep in mind that most consumer compressors and even some of the pro-summer 240V models don't like running non-stop. So occasional blasting work should be fine but at some point these pumps may overheat if they don't get enough down time between recycles.

It's an oiled compressor and I recently changed the oil so I think it just needs new reed valves. It's definitely lower pressure than my Dewalt which is 155psi. I can't get much info on it as there is no tags or stickers on it.

 

[The Cobbler]

@newpain01 , I am assuming the motor just runs & doesn't build as much pressure versus it shuts off at a lower pressure than you think it should?

 

[newpain01]

@newpain01 , I am assuming the motor just runs & doesn't build as much pressure versus it shuts off at a lower pressure than you think it should?

@The Cobbler Yes, the motor runs, but doesn't build much pressure and there is a knocking sound from the pump. I only let it run once and it took close to 20-30 min to get to 100psi before shutting off.

 

[Citation]

Looks like there is not much inside other than those reed valves, need to see if I can get a replacement.


Which motor / compressor pump have you used?


It's an oiled compressor and I recently changed the oil so I think it just needs new reed valves. It's definitely lower pressure than my Dewalt which is 155psi. I can't get much info on it as there is no tags or stickers on it.

Look at the blow off valve. What's the pressure rating? If it's greater than your other compressor's peak pressure you should be fine

Also with the reed valves you generally will see obvious damage. What did you see?

 

[joe_padavano]

Which motor / compressor pump have you used?

I said in that prior post that I have a RolAir K30 pump and a Baldor 7.5 HP single phase. If you are asking about prior compressors, there were a string of smaller units that were inadequate. All were under 5 HP.

 

[newpain01]

Look at the blow off valve. What's the pressure rating? If it's greater than your other compressor's peak pressure you should be fine

Also with the reed valves you generally will see obvious damage. What did you see?

I did not see any damage, I think the reed valves look fine, but I'll take some photos and share here. I did not have much time to mess with it further, but will take a look in the next few days. Honestly, I just feel it's a lost cause and wouldn't want to spend more money on it as I don't think it's going to help much.

I saw an 80 gal with a 5hp motor and a bad 3 cylinder pump for $300 on marketplace in my area, so I've been thinking about maybe getting that and adding the 5HP pump from Harbor Freight which makes around 15CFM at 90psi (or any other better pump if anyone has recommendations in that price range).
I could at least try fixing that pump (14CFM@90psi) before I get a new one.

Adding that inline with my Dewalt should get me around 26CFM which I think should be enough for occasional sandblasting and painting and total price would be around $550. For that money I can't get anything with similar specs. I would have to run another 240V line but that's easy.

Last year I could get an 80 gal tank for $100, but prices have at least tripled since then. Most people want $300-$400 for a rusty tank with nothing on it now.

Any thoughts?

 

[OccupantRJ]

A couple of my friends have used the HF pumps with success. I made a couple of fittings for them to attach the pump output lines to their existing tank input piping by brazing two acceptable fitting halves together to create a proper fitting on each end.

 

[308guru]

Scoop up all the Craigslist compressors/tanks you can find. Tie them all together for like 10000gallon capacity. Flip the compressor on a day or two before hand and you'll be set.

 

[PoorUB]

For years I used a "real" 2HP, 20 gallon compressor and when I needed extra air I connected an small 3/4HP I had. It probably got close to 8 CFM.

I have a 5HP, 80 gallon Curtis I am tempted to sell as I do less and less in the shop. I still have the 20 gallon compressor and a 1-1/2 HP Rollaire I could tandem up if I need to that would get about 10 CFM.

 

[newpain01]

For years I used a "real" 2HP, 20 gallon compressor and when I needed extra air I connected an small 3/4HP I had. It probably got close to 8 CFM.

I have a 5HP, 80 gallon Curtis I am tempted to sell as I do less and less in the shop. I still have the 20 gallon compressor and a 1-1/2 HP Rollaire I could tandem up if I need to that would get about 10 CFM.

Mine is currently at 11 CFM and I've been really happy with it, it handled any task I've thrown at it, but since I modified the sandblasting cabinet with a metering valve and a triggerless gun (which also came with a bigger nozzle), it's having a difficulty keeping up. At this point it runs all the time while my foot is on the trigger.

I guess I could try getting a better gun with a lower CFM requirement and see how that works since I don't sandblast much and most of those parts are small motorcycle/ATV parts.

 

[newpain01]

So, I ended up picking it up today for $250. The previous owner said the compressor pump is bad, it gets up to 60psi and then it keeps running and doesn't make more pressure. I am planning to disassemble it and take a look. Other than that, the tank looks solid but I am going to hydrotest it just to make sure and the motor is 5HP and supposedly works.

Any ideas how to safely get it off the truck? lol

 

[Shoreline_]

5hp single phase is around 25 amps at 240v. If you wanna know if its really a 5hp, check the current rating on the motor date plate.

 

[OccupantRJ]

Mine is currently at 11 CFM and I've been really happy with it, it handled any task I've thrown at it, but since I modified the sandblasting cabinet with a metering valve and a triggerless gun (which also came with a bigger nozzle), it's having a difficulty keeping up. At this point it runs all the time while my foot is on the trigger.

I guess I could try getting a better gun with a lower CFM requirement and see how that works since I don't sandblast much and most of those parts are small motorcycle/ATV parts.

My 20 cfm unit runs all the time I am blasting. It cuts off 45 seconds after release of the foot pedal. I make my own air jets so I have it sized for that action on purpose.

 

[Citation]

So, I ended up picking it up today for $250. The previous owner said the compressor pump is bad, it gets up to 60psi and then it keeps running and doesn't make more pressure. I am planning to disassemble it and take a look. Other than that, the tank looks solid but I am going to hydrotest it just to make sure and the motor is 5HP and supposedly works.

Any ideas how to safely get it off the truck? lol

Looks like a prosumer 5hp. I suspect it draws 20 amps or so. If you take the motor and pump off the tank you may find that you can reasonably man handle the tank around. Certainly two people can lift it. As one person you can probably slide the tank to the edge of the bed then gently tilt it over to the ground (does depend on your bed height). Get it in position then reattach the pump and motor.

As for not building pressure, probably a bad reed valve. If the pump is bad and can't be fixed cheaply, get a HF "5hp" pump. They are sufficient for most prosumer users.

 

[newpain01]

5hp single phase is around 25 amps at 240v. If you wanna know if its really a 5hp, check the current rating on the motor date plate.

This motor is rated at 22amps. I don't doubt the rating as this is a model sold by Home Depot (C801H).

My 20 cfm unit runs all the time I am blasting. It cuts off 45 seconds after release of the foot pedal. I make my own air jets so I have it sized for that action on purpose.

My 11CFM runs all the time as well. I am hoping that connecting both now will get me around 25+ CFM and they will run less. What kind of gun do you have and how do you make your air jets? Do you mind sharing some info that? Appreciate it!

Looks like a prosumer 5hp. I suspect it draws 20 amps or so. If you take the motor and pump off the tank you may find that you can reasonably man handle the tank around. Certainly two people can lift it. As one person you can probably slide the tank to the edge of the bed then gently tilt it over to the ground (does depend on your bed height). Get it in position then reattach the pump and motor.

As for not building pressure, probably a bad reed valve. If the pump is bad and can't be fixed cheaply, get a HF "5hp" pump. They are sufficient for most prosumer users.

It's a Husky 80 gal Model C801H at Home depot.

I does draw 22 amps. Appreciate your advice, that is exactly what I had though of too!
I removed the motor and the pump off the tank and then laid the tank down in the truck and got it off with a help of a friend. We then put it on a hand truck and wheeled it into the crawlspace where it's going to stay.

I have not reinstalled any of the parts yet. I was thinking to disassemble the pump head and check the valves/pistons.

Does anyone know where I can get replacement parts for this pump? (Husky C801H)

 

[OccupantRJ]

@newpain01, look at my Abrasive Blasting Resource Thread for more info in general. There is a link to my shop built blast gun in the first post.

The Abrasive Blasting Resource Thread

Edit: Keep checking on all the various links throughout this thread, as some are ongoing projects and may have had information added since you last viewed them. There are lots of GJ members who have blast cleaning equipment, so I am starting this thread for all of you to input information and...

www.garagejournal.com

 

[larry4406]

Does anyone know where I can get replacement parts for this pump? (Husky C801H)

Google...

Husky C801H, 901032 Parts | Master Tool Repair

Get repair parts for your Husky C801H, 901032 Air Compressor at Master Tool Repair. Easy to shop site with on-line schematics, tech docs, and how-to videos.

mastertoolrepair.com

https://www.ereplacementparts.com/models/compressor/husky/id811185/c801h/

 

[Citation]

I'm going to guess that the pump is the same one on some of the Coleman Powermate compressors (and likely a lot of other brands). This might also be of help

Repair Parts for the Coleman Powermate model PLA4708065 Stationary Air Compressor - www.mastertoolrepair.com - Page 2

We have Repair Parts for the Coleman Powermate model PLA4708065 Stationary Air Compressor! Our site is easy to shop and we have online schematics, tech docs and videos available.

mastertoolrepair.com

 

[Shoreline_]

You think someone switched out the pump? Good to hear you have a full 5hp. If you wanna switch out the pump if it doesn't make 5hp worth of air lemme know. I may have something kicking around.

 

[newpain01]

You think someone switched out the pump? Good to hear you have a full 5hp. If you wanna switch out the pump if it doesn't make 5hp worth of air lemme know. I may have something kicking around.

No, I don't think anyone switched out the pump, everything looks original.

I took the motor and pump off so I can move it, will disassemble the pump this weekend and take a look, but it's possible that I might need to switch it out for another one, let me know what you have.

 

[newpain01]

Took the pump apart and since this thread has changed directions, I opened a new thread for diagnosing issues on the old pump.

Link to new thread: https://www.garagejournal.com/forum...ump-repair-3-cylinder-husky-5hp-80gal.553243/