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Topic: Portable air compressor (Read 1395 times) previous topic - next topic

Re: Portable air compressor

Reply #25 –
The 12v Viair units are nice but the CFM at higher pressure is low.

The dual ARB is excellent, Don's project is in the link below above my post.

Here is another option, a 12v compressor I built up a few years ago. This could air up the air bags in about 6 minutes, and easily topped up the coach tires.

12v aux compressor

Here is an updated link for the compressor

ExtremeAire Magnum 12 Volt Compressor
Peter and Tammy Fleming
1991 U300 GV 40 - Sold, owned for 4 years
Downsized to Roadtrek Popular 210 class B

Re: Portable air compressor

Reply #26 –
Quote from: Protech Racing –
Find the load chart for your tires.  120 sounds like max load, printed onthe sidwall.  Way too high most of the time .
Run the tire pressure you are happy with with the sidewall pressure showing the maximum load the tire is rated for. I max the pressure on the coach as well as my bus. My fire dept also maxed the pressures. We never weighed the apparatus, just put tools and water on board and checked the tires once a week.

These are cold pressures and will be higher after a few miles or in hot weather. Not to be reduced.

A million old posts on tire pressure so will leave it at that.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Portable air compressor

Reply #27 –
At least we say the same thing every time 😇
But in Kevin's situation, I think that he is trying to solve a problem that he doesn't have.
Finding the load chart will most likely show that he has enough air pressure with what he has. Without spending any money at all.

Re: Portable air compressor

Reply #28 –
Quote from: kevo0000 –
Hya pierce, thanks for that info, just looked at the one you just showed me on ebay, but im always a bit dubious when I see the price, it just seems to be too cheap but then sometimes a cheap one can be as good as a really expensive one, I've been looking on and off all day, there are so many on the market, I'm in 2 minds which is better, at the moment I have a dewalt mains operated 120 psi with a small tank but it actually cuts out at 115 psi and the problem I find is that I will fill the tank to115 psi and get some air in tyre but as the pressure drops I have to stop and wait for the tank to fill up again, it's fine with the front tyres cause they only take 95psi but it works, but obviously il need 150psi minimum, but do you think I am better off getting a mains compressor with a reasonable size tank as opposed to a 12volt, because all of the 12volt compressors seem to have such tiny little tanks and the last thing I want is to buy something that even though it will get me 120psi, I don't want it to take like hrs to do so, I've seen a few on ebay that say they are good for heavy trucks, and in the specifications it will tell you that it takes 2 or 3 minutes to go from flat to 30 psi but when I contact them and ask them how long it will take to pump my tyres to 120 psi, I just get a reply saying that they do not know, I know its all about cfm as well as psi, so I will look at a few that some of the other members have put up, thanks alot kev
The good thing about ebay is you can see how many were sold, and you can read the feedback left by the buyers. In this case, over 800 have bought the item.
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Portable air compressor

Reply #29 –
If anyone thinks a little 12V compressor is going to fill their tires from zero, they must have lots of patience. And when the compressor starts to smoke or soften the plastic fittings, that's what "duty cycle" is all about.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Portable air compressor

Reply #30 –
My "portable" compressor at home is the Makita 5200. I found one on craigslist with a auxiliary tank for $150.  Easy to wheel from the garage to the coach on the side of the house. With the handle folded down its not much bigger than my old pancake compressor and much more capable, quieter, and easier to move. An old school, oil bath compressor will last forever compared to the disposable oil-less pumps. 6.5 CFM @ 90PSI
Makita USA - Product Details -MAC5200
Bruce & Linda
2004 U295, Build # 6268, ISL400 CAPS
2016 Ford Explorer Sport or 1985 Jeep CJ7

Re: Portable air compressor

Reply #31 –
My main compressor is an old Kellogg 2 stage compressor from my teens.  Nothing done to it and it's still great and runs everyday. I also have a Quincy compressor from diving days. Lots of divers would not go down without a Quincy on deck.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Portable air compressor

Reply #32 –
Quote from: Pierce & Gaylie Stewart –
If anyone thinks a little 12V compressor is going to fill their tires from zero, they must have lots of patience. And when the compressor starts to smoke or soften the plastic fittings, that's what "duty cycle" is all about.

Pierce
Hya pierce, I've just come up with an idea tell me what you think, my bendix tu flow compresser I have, I'm thinking of making a frame attaching the compressor to this frame, using an old washing machine 240 volt motor fitting a pulley to it, I then also would have to connect an oil pump with a small oil tank, also a separate water tank with pump, and then connecting it to a large co2 bottle, looking at the tu flow diagrams, I would also need an air dryer fitted in line between pump and tank, would this work, I'm on lockdown at the moment got plenty of time to kill, got plenty strong timber for the frame and an old plant trolley with strong wheels which I could use, do I need the correct air dryer for the bendix or will any air dryer do the job, seems a waste that I have got a good working compressor, I've even got an old washing machine motor to drive it, what do you think, any reason why this wouldn't work?
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: Portable air compressor

Reply #33 –
This is the air doubler I mentioned above:  https://www.smcpneumatics.com/VBA10A-N02GN-Z.html
Not the very expensive one Pierce posted.
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Portable air compressor

Reply #34 –
Quote from: folivier –
This is the air doubler I mentioned above:  https://www.smcpneumatics.com/VBA10A-N02GN-Z.html
Not the very expensive one Pierce posted.
Forest,

Excellent eyes to have spotted it. Now, that is in the price range for a practical device that won't break the bank. I'm assuming that they waste quite a bit of air, sort of like a home RO water system but I really don't have an ideal how efficient they are.

Kevo,

Sounds reasonable but I have no idea how much HP you would need. My old Kellogg has a 2 hp 220 motor. The motor is fairly big and heavy. As far as a tank goes, any old BBQ propane tank would be good as their burst pressure is about 960 psi. The bigger the better. At home, I use a HF inline dryer, you know, the tiny one with a pressure regulator next to it most of the time. When I'm serious, I plug into a wall regulator with filter/dryer next to it. At the hanger, galvanized pipe is mounted on the wall going way up and then down and has a drain at the bottom. Gary has expensive guns and the latest is a trick German Iwata or SATA  gun costing hundreds. It paints aircraft and I don't ever recall it spitting out any water. I use an inexpensive HF gun. Does a great job for under $50.

I think my Kellogg puts out about 12 cfm or did when it was new. The Quincy puts out more but lower pressure so it just sits outside waiting for some TLC. Lots of ideas here about building an air dryer on this page. Instead of spending $50 as he did, how about going to a junk yard and just getting a car AC condenser? https://www.youtube.com/watch?v=KgO2hTmtlvA

Our U300 has a regulator, filter/dryer next to the air hose reel.

I expect the biggest expense will be the capacitor start 2 hp or more electric motor. Try CL or F. Marketplace.  Just depends on what you are going to be doing with it. Sand blasting takes the most CFM, impact guns take a lot less, spray paint a medium amount and powder coating uses very little for most work. If the motor is too small, you can change pulley size but the compressor may jerk a bit at low speeds.

Again, YouTube has a lot of great ideas from people like you. Keep posting as the project develops.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Portable air compressor

Reply #35 –
Pierce, yes it's just another tool to make it easier to get a higher pressure out of whatever compressor you're using.  It does waste air but that air is basically free.  You're just using it to pump up to a higher pressure.  But if you're waiting for your engine air compressor to cycle back up you're wasting diesel.  Or electricity if it's an electric compressor.  Ain't no free lunch. 
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell

Re: Portable air compressor

Reply #36 –
Quote from: folivier –
Pierce, yes it's just another tool to make it easier to get a higher pressure out of whatever compressor you're using.  It does waste air but that air is basically free.  You're just using it to pump up to a higher pressure.  But if you're waiting for your engine air compressor to cycle back up you're wasting diesel.  Or electricity if it's an electric compressor.  Ain't no free lunch. 
Il be running it off my 3kw inverter 6kw start up, but what il do is run the car engine with jumper leads on the villa batteries, I had new tyres fitted back in the summer, and took the wheels in back of car to get them pumped up to pressure, but I don't want to have to take them off to keep doing that, it's nearly ready for the road but I'm not planning on going anywhere in it yet because of the lockdown, it's till end of march now, hopefully by then most people would have had the vaccine, 'where I live in Cornwall the infection rates are still quite low compared to rest of country
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: Portable air compressor

Reply #37 –
Quote from: folivier –
Pierce, yes it's just another tool to make it easier to get a higher pressure out of whatever compressor you're using.  It does waste air but that air is basically free.  You're just using it to pump up to a higher pressure.  But if you're waiting for your engine air compressor to cycle back up you're wasting diesel.  Or electricity if it's an electric compressor.  Ain't no free lunch. 
Forest,

Don't get me wrong, I'm not worried about wasting air, diesel or electricity but if you have a small CFM compressor and lose 30% because of device loss, you will need to wait longer for the compressor to build pressure. I have no idea of the loss the pressure amplifier has so the 30% was just a guess. Perhaps it's not a factor in the real world usage. Guess my question relates to how practical is it to fill a big tire from zero to 110 psi with a small compressor and a pressure amplifier?

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)
 

Re: Portable air compressor

Reply #38 –
Never filled a tire from zero, just used to top off pressure to what I was running.  If I had to fill a tire from zero or lower pressure I wouldn't use the doubler until the compressor got close to its cutout point.  At that point the doubler is much faster than waiting for the compressor to cycle.
Forest & Cindy Olivier
1987 log cabin
2011 Roadtrek C210P
no longer 1999 36' U320 build #5522
2013 Rzr 570 & 2018 Ranger XP1000
2006 Lexus GX470
2011 Tahoe LT 4x4
Previous 1998 45' 2 slide Newell, 1993 39' Newell