Air Compressors

[egaito]

Sanctuary is equipped with an engine mounted compressor and a tank on the wall, probably about 3 gallons, to run the horns.

The tank is of unknown age and condition. The system leaks down pretty quickly once the engine is shut of, so it's as good a time as any to look at the system as a whole.

I'm thinking of putting in an electric compressor, and a new tank, that will be large enough to run a few air tools, all falling into the 4-9 cfm range for flow requirements.

I have found several 2hp, 3 gallon compressors that put out 4-5cfm at about 90 psi, but can't find a calculator to see how much "duty time" that would offer an air tool that requires 6 cfm to run. I know, that the bigger the tank, the more reserve it provides, but does anyone know how to calculate the reserve/run times based on tank size?

Another thought is to use a component approach....compressor motor, mounted remotely from a larger tank. By larger, I'm speaking relatively of course, meaning larger than what's there, but I'm not trying to get an auto-body shop compressor and tank in the ER.


What have you guys seen or done? Any pictures or project notes?

 

[Boatsb]

"but I'm not trying to get an auto-body shop compressor and tank in the ER."

Why not?


Really if you are going to add a system do it the Hatteras way.

A 110 volt 20 gal 5 HP oil less will be great in there and it can be piped around for all sorts of jobs.

Look at Harbor freight or northern tool for cheep ones too.

 

[Bayside Bert54]

Mine has an electric Porter Gable ... the relatively small type they sell at Home Depot to run a nail gun. Probably $150.

 

[REBrueckner]

I can't imagine a three gallon storage unit will power much of anything unless the compressor is running continuously, but it depends on the pressure required by a device.

A gallon is only about 0.134 cu ft (I know that seems awfully small but I just double checked by measuring a gallon container of milk)

Try searching air compressor tool......

here is a calculator.....http://www.northerntool.com/catalog/buyersguides/aircompressors/

I don't know what you plan but unless you already have to air tools you can use aboard seems like an air compressor approach instead of electric is an expensive and perhaps inconvenient way to go aboard a moderate size boat...

 

[yachtsmanbill]

I'd pull the POS engine unit and shitcan the tank. Mine was rotted out from neglect and access, and patched, and leaks again. The engine driven unit takes fuel also. Go with a pancake compressor as stated before. A 3 gallon tank at 125 psi will fill up toys and fenders like nothing. Your not planning on using a 3/4" impact to pull the heads off the motors are you??
The one on the Roamer is a $10 throw away 250 psi tire filler upper and a 1-1/2 gallon fire extinguisher for the reservoir. At 125 psi, it will give 2 LONG sets of danger signals from the D2 Kahlenberg horns.
Just a note... the newer compressors are direct drive rotary units and the noise will run you outa the room!! Make a soundshield for it! Buy a little used belt driven job! ws

 

[Brian Degulis]

I don't know how to calculate it but it's going to be next to nothing unless the tank is very large. You realy want to have a compressor with a little more CFM @ whatever pressure required to run the tool your thinking about. The engine driven compressor you have now will be more powerfull at idle than any direct drive compressor your going to find at home depot.

You don't mention what kind of tools your talking about. Things like brad nailers and staple guns don't take much regardless of the CFM required because they don't run continous. A grinder or sander or needle scaler do and take lots of air. IMHO the best bet for the do it yourselfer is electric rotary or constant run tools. Pneumatic for nailers or staplers.

Another thing to consider is the quality of the tank you put in your boat. I would not put anything but an ASME certified tank in a boat. Just about no small self contained home Depot compressors will have that. In fairness the OEM tank Hat used is probably not ASME either. I had a tank on a small portable blow up on a boat. It's like a small bomb when it goes it blew the windows out of the saloon and partially blew the side structure out. I just replaced the tank on the 60C with a small ASME ran around $300 a non ASME runs around $50.

Brian

 

[Bill Allen]

Since this is my business I'll pipe in. It's really about duty cycle. SInce most of these units are oil free you can also use them to scrub the bottom if you have one big enough around 2 hp. Run them to hard and the heat will burn out the rings right after the valves die. You really should avoid the noise cover since they're air cooled. Of course a hot engine room, if your running them when the mains are on will shorten the lifespan. There's really no secret to compressors, it's about cfm, both in what they will make at rated psi and what your tools will use at rated psi. The fly in the ontiment is they both lie, compressors are rated at a perfect enviorment which means they almost never put out what the state and of course the tools are rated as using less air then they do. A two hp (not develops) will run an impact wrench, a blow gun for a little bit, just watch the duty cycle, run it way above the duty cycle and it'll suffer an early death. Tanks really don't need, nor will they be asme rated on these units. True they can fail quite badly but drain the tank of water occasionally and keep paint on the exterior. I wouldn't sugest less then a true 2 hp at minumum if you want to use them for more then just horns. When you're looking at them, pay attention to rated hp on the motor, not develops. The cfm on a dcent two stage compressor should be just a tad under 4 cfm at it's rated hp. With a two stage able to run higher pressure and better volume.

 

[Angela]

I don't want to take out the engine mounted compressor; it works well and serves its intended purpose well. We want to install, in addition to the engine mounted unit, an electric compressor to use onboard when we are working on the boat. I still want the engine compressor to run the horns because without it, I'd have to go start the genny to blow the horns, and that's not a good set up. I'm not always running the genny when we're underway, and when you need to blow the horns, there's no time to go downstairs to start the genny.

We want to put a valve in the line going to the tank so that we can select from where the air input is coming. Unless we are actively working on the boat with air tools, the valve will always be pointed toward the engine mounted compressor. We just don't want to have to be running the engines to use the air tools in the slip, especially if we're working on the engine that's driving the compressor engine.

There is an air tool - a needle scaler - that we are going to use to de-rust a lot of stuff on the engines and the motor mounts in preparation for repainting. And, there are many times when we wish we had an air compressor to do this or that. It's not an expensive addition and I believe we will get a lot of use out of it as we continue to upgrade and improve the boat.

 

[Angela]

Another thing to consider is the quality of the tank you put in your boat. I would not put anything but an ASME certified tank in a boat. Just about no small self contained home Depot compressors will have that. In fairness the OEM tank Hat used is probably not ASME either. I had a tank on a small portable blow up on a boat. It's like a small bomb when it goes it blew the windows out of the saloon and partially blew the side structure out. I just replaced the tank on the 60C with a small ASME ran around $300 a non ASME runs around $50.

Brian

Excellent advice. Thank you, Brian. That was something of which I was unaware.

 

[Boatsb]

I don't want to take out the engine mounted compressor; it works well and serves its intended purpose well. We want to install, in addition to the engine mounted unit, an electric compressor to use onboard when we are working on the boat. I still want the engine compressor to run the horns because without it, I'd have to go start the genny to blow the horns, and that's not a good set up. I'm not always running the genny when we're underway, and when you need to blow the horns, there's no time to go downstairs to start the genny.

We want to put a valve in the line going to the tank so that we can select from where the air input is coming. Unless we are actively working on the boat with air tools, the valve will always be pointed toward the engine mounted compressor. We just don't want to have to be running the engines to use the air tools in the slip, especially if we're working on the engine that's driving the compressor engine.

There is an air tool - a needle scaler - that we are going to use to de-rust a lot of stuff on the engines and the motor mounts in preparation for repainting. And, there are many times when we wish we had an air compressor to do this or that. It's not an expensive addition and I believe we will get a lot of use out of it as we continue to upgrade and improve the boat.

Angela put a compressor under the bridge or in another space that is not heated by the engine room if you can. No need to hook it up to the other system if it already works fine. Keep it simple and you will find it is less of a problem.

A friend has a 6 HP with a 30 gal tank under his bridge ( not a hatt though) and uses air tools, sanders, blow guns etc. all the time. Total cost of about $300. By the time you install it somewhere and pipe it and valve it and run power half your engines could have been painted.

 

[Brian Degulis]

Ang a needle scaler is a great tool to have. You want a high speed short stroke scaler. A slower longer stroke unit will break cast iron and damage thin metal. It's a continous run impact tool don't get a cheap one it won't run very long at all. Something like this is what your after look at E http://www.mcmaster.com/#needle-scalers/=5oohc4


You will want at least 6CFM continous to run it. I know the spec is 3 but you'll need six to run it properly. With that set up you clean up engines gen sets mounts whatever you want quickly and easily.


Brian

 

[egaito]

Ang a needle scaler is a great tool to have. You want a high speed short stroke scaler. A slower longer stroke unit will break cast iron and damage thin metal. It's a continous run impact tool don't get a cheap one it won't run very long at all. Something like this is what your after look at E http://www.mcmaster.com/#needle-scalers/=5oohc4


You will want at least 6CFM continous to run it. I know the spec is 3 but you'll need six to run it properly. With that set up you clean up engines gen sets mounts whatever you want quickly and easily.


Brian

Thanks Brian, that's exactly what we're looking for. The compressors I've been digging up are rated at 4 to 5 cfm. Tanks sizes range from 3-4 gallons. Do you feel that would yield completely unacceptable results running it in "bursts" or will it just be a slower process to get the work done? This isn't production work so I don't need 100% duty-cycle, but 10% would obviously get old pretty quick.

BTW, does anyone know the specs on the engine driven pump?

 

[egaito]

Ang a needle scaler is a great tool to have. You want a high speed short stroke scaler. A slower longer stroke unit will break cast iron and damage thin metal. It's a continous run impact tool don't get a cheap one it won't run very long at all. Something like this is what your after look at E http://www.mcmaster.com/#needle-scalers/=5oohc4


You will want at least 6CFM continous to run it. I know the spec is 3 but you'll need six to run it properly. With that set up you clean up engines gen sets mounts whatever you want quickly and easily.


Brian

What you're saying about stroke and speed make sense, but given your experience, what do you consider short stroke? I'm finding strokes on these from 1/2 inch to 2 5/8" Shorter stroke, and higher beats of course mean more precision, which is spelled $$$$. I want a good and useful unit, but it's not going to be a production tool for us. It will probably be well oiled and wrapped up most of its life once the initial job is done. Above all, I don't want to damage anything! "Hey Ang, where did you put that JB Weld?"

 

[SKYCHENEY]

The Bendix compressors on our engines are rated in cubic feet per minute. They will pump more air than you will ever use. I think the smallest one is something like 7 or 8 cu ft/min and they go up from there.

 

[Brian Degulis]

What you're saying about stroke and speed make sense, but given your experience, what do you consider short stroke? I'm finding strokes on these from 1/2 inch to 2 5/8" Shorter stroke, and higher beats of course mean more precision, which is spelled $$$$. I want a good and useful unit, but it's not going to be a production tool for us. It will probably be well oiled and wrapped up most of its life once the initial job is done. Above all, I don't want to damage anything! "Hey Ang, where did you put that JB Weld?"

You could probably get by with 6 CFM Worst case would be it's to small and you ad another compressor to it.

You want 1/4" stroke or it will be limited in use longer than that will damage small parts could break castings like on you engines and gen sets. It will also be dificult to hold.

You can buy a chinese hammer or crow bar maybe even a wrench for a fraction on the price of something good and for a typical boat owner it will probably last. A needle scaler is diffrent it's an impact tool that's trying to break itself apart. If you buy cheap your going to abandon the idea or buy again because it's not going to run for long. Your going to spend around $500 to get something decent. The up side is that $500 scaler will do $8000 worth of work before you need to replace any parts. If you've got a lot of rusty stuff to clean up or machinerey with loose paint on it your probably going to use this more than you think. Projects that would takes days will now take hours and come out much better.


Brian

 

[Brian Degulis]

Nothing beats sand blasting with a big machine 100 HP or so. A good scaler beats a 15 HP sand blasting rig by a mile. Blasting isn't really practical unless you can take the part off because it's just such a mess.

Brian

 

[Glory]

I'd recomend a a check valve to sepreate the two compressors, you might consider a check valve for an air brake system, check Bendix Air Brake Systems on line.

as for the leak if you can't find the leak, by sound or soapy water you might want to check in the over head at the lower helm.

In the older 53/58 the air hose for the horn passes through the deck above the overhead.

JM

I don't want to take out the engine mounted compressor; it works well and serves its intended purpose well. We want to install, in addition to the engine mounted unit, an electric compressor to use onboard when we are working on the boat. I still want the engine compressor to run the horns because without it, I'd have to go start the genny to blow the horns, and that's not a good set up. I'm not always running the genny when we're underway, and when you need to blow the horns, there's no time to go downstairs to start the genny.

We want to put a valve in the line going to the tank so that we can select from where the air input is coming. Unless we are actively working on the boat with air tools, the valve will always be pointed toward the engine mounted compressor. We just don't want to have to be running the engines to use the air tools in the slip, especially if we're working on the engine that's driving the compressor engine.

There is an air tool - a needle scaler - that we are going to use to de-rust a lot of stuff on the engines and the motor mounts in preparation for repainting. And, there are many times when we wish we had an air compressor to do this or that. It's not an expensive addition and I believe we will get a lot of use out of it as we continue to upgrade and improve the boat.

 

[DCMY #92]

I had a 110VAC 2HP (oil lubricated) shop compressor in the engine room (41DCMY) for years. It did a good job with the horns, tools and other maintenance. I found compressed air particularly useful when eel grass clogs the A/C cooling water inlet. I made up a blowgun that fit into a bleed fitting on top of the strainer. A couple shots of air and grass went back the way it came.

When I installed a new and larger ships battery and inverter the old compressor had to go to make room. Attached is a photo of the compressor I installed. You can also see the small homemade after cooler, pressure switch, unloader, relief valve, water trap and quick disconnect fitting for an air hose. The compress is a 12VDC oilless unit that is very compact, heavy, pulls allot of current and is very noisy (but no more so than other airless units). The heavy conductor and large circuit breaker added to the cost, but it fits the space I had available and fills the 2 1/2 gallon remote tank to 120psi in less than a minute. This pressure is higher than most need, but the Kahlenberg horns really like it. The photo doesn't show the compressor very well. It's about 16 inches long overall.

This compressor and the remote tank I installed with it are intended for air suspension systems in low riders (jumpers) and off road vehicles. It even has a little red K&N style air filter on the front. I don't suggest everyone would be pleased with this setup, but it works well for my needs.

 

[SKYCHENEY]

I'm more impressed with the shiny white paint. Nice Engine room.

 

[habanero]

I have a great little silent compressor in the engine room to run the heads. Very reliable and easy to maintain. I have quick connect ports running all through the engine room for ease of hookup. Here is a link

http://www.silentaire.com/silentaire/images/pdfs/2009/Sil-Air 50-24-V Brochure.pdf

Mike
"Habanero"55C