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Can be used a washer pressure as a compressor ?

Posted: Fri Oct 31, 2008 11:10 am
by RaZias
I saw this site and they point cheap and powerful compressores.

http://test.clwebhost.co.uk/acatalog/karcher.html

Is it possible to use a water pressure washer to feed water rockets ?
They can make 100 to 200 bars !

Their end hose are connectable to 9mm nozzle.
Karcher_KAK291MD.jpg
Karcher_KAK291MD.jpg (21.03 KiB) Viewed 199 times

Re: Can be used a washer pressure as a compressor ?

Posted: Fri Oct 31, 2008 2:41 pm
by Tim Chen
RaZias wrote:I saw this site and they point cheap and powerful compressores.

http://test.clwebhost.co.uk/acatalog/karcher.html

Is it possible to use a water pressure washer to feed water rockets ?
They can make 100 to 200 bars !

Their end hose are connectable to 9mm nozzle.
Karcher_KAK291MD.jpg
I don't think these will work with a gas. I had heard this suggestion before a few times and do not recall any success stories. If you can buy one of these for cheap at a garage sale or on ebay and try it out, we could know for sure if the myth is busted. :D

Re: Can be used a washer pressure as a compressor ?

Posted: Fri Oct 31, 2008 3:56 pm
by RaZias
In fact I own one. I going to try it in 2 weeks.

Re: Can be used a washer pressure as a compressor ?

Posted: Fri Oct 31, 2008 4:37 pm
by Spaceman Spiff
RaZias wrote:In fact I own one. I going to try it in 2 weeks.
I think the problem is that much pressure generates a lot of heat and if you put air in it then the heat builds up and it burns out. The pressure washer with water going in is cooled by the water and it doesn't burn up. I once had a house with a well for drinking water and the pump in the well only went to 60PSI but when we had a drought one year the well went dry and the pump burned up.

Re: Can be used a washer pressure as a compressor ?

Posted: Fri Oct 31, 2008 6:29 pm
by andicirk
ok dumb question what if you used the pressure washer with (x) amont of water (x) being the optimum level of water for your bottle , the washer wouldnt need to run for long and with a "no return valve" on the setup so you deliver the water over say 10 - 20 seconds at the sametime as the air.

just an idea........

Re: Can be used a washer pressure as a compressor ?

Posted: Sun Jul 08, 2012 4:41 pm
by RubberDucky
I was thinking of something like this but it involved filling the rocket completly full of air first. With the rocket full of air to say 100psi and no water you switch a valve and use the pressure washer to fill the rocket. By shrinking the space inside the rocket you would icrease the pressure by how much not sure. Im going to try this once i can build a high pressure rocket.

Re: Can be used a washer pressure as a compressor ?

Posted: Sun Jul 08, 2012 11:39 pm
by Muzza
RubberDucky wrote:..... By shrinking the space inside the rocket you would increase the pressure by how much not sure.
Assuming you are going to load 1/3 water , you are shrinking the volume to 2/3 of the original, so the absolute pressure would increase by 3/2 (or half as much again).
So using your 100 psi example, 100psi (gauge) = 114.7 psi (abs)
114.7*1.5 = 172 psi (abs) = 157psi (gauge)

Your actual result will be a bit higher than this as the air will get warmer as it's compressed, leading to a higher pressure

Re: Can be used a washer pressure as a compressor ?

Posted: Mon Jul 09, 2012 12:54 am
by Nick B
This is the direction I will be going by next summer. I've already put some thought into a few ways to translate it into a launcher or rocket. It's just too simple and cheap to overlook.

I should have a workable rocket by then.


I'd push for it now, but I'm trying to scale back our research and enjoy it more instead of rushing through it and burning out on the hobby too soon.

Re: Can be used a washer pressure as a compressor ?

Posted: Tue Jul 10, 2012 2:45 am
by RubberDucky
Cool thanks for the info. I have a gas pressure washer that is 2700psi so it might work for this. As soon as i figure out how im going to make my high pressure rocket ill be giving this a try. But ill be trying for a rocket able to hold at least 900psi. Thanks again

Re: Can be used a washer pressure as a compressor ?

Posted: Tue Jul 10, 2012 12:04 pm
by Nick B
RaZias wrote:In fact I own one. I going to try it in 2 weeks.

Dude... :? ??????????

Re: Can be used a washer pressure as a compressor ?

Posted: Tue Jul 10, 2012 12:08 pm
by Nick B
RubberDucky wrote:Cool thanks for the info. I have a gas pressure washer that is 2700psi so it might work for this. As soon as i figure out how im going to make my high pressure rocket ill be giving this a try. But ill be trying for a rocket able to hold at least 900psi. Thanks again


Same here.

I have a 1200 one and 3000 psi one. They both collect dust.

Re: Can be used a washer pressure as a compressor ?

Posted: Wed Jul 11, 2012 11:50 pm
by RubberDucky
Thought of another way to use pressure washer to get high pressure for the rocket. It goes like this. You take a large pipe that will take the pressure and a good length. You want cap both ends and put this pipe up on end. Put a tee on the bottom. One side goes to the air compressor and one side to the pressure washer. Of course valves on both sides too. Then an air line at the top running to the rocket. The larger pipe will have larger volume then the rocket so this might be a better way to try this.

Re: Can be used a washer pressure as a compressor ?

Posted: Sat Jul 14, 2012 11:18 am
by Nick B
Saw a pcp pump on the wallyworld web site.

Tempting.
Especially if they have it at the store.

No pressure washer, inverter, or car battery needed to haul around, ..... or torch set oxy tank.

And I may be able to replicate the air line for a longer line assy. I know I can replicate the connectors at work or home.

Re: Can be used a washer pressure as a compressor ?

Posted: Sat Jul 14, 2012 10:55 pm
by U.S. Water Rockets1
RubberDucky wrote:Thought of another way to use pressure washer to get high pressure for the rocket. It goes like this. You take a large pipe that will take the pressure and a good length. You want cap both ends and put this pipe up on end. Put a tee on the bottom. One side goes to the air compressor and one side to the pressure washer. Of course valves on both sides too. Then an air line at the top running to the rocket. The larger pipe will have larger volume then the rocket so this might be a better way to try this.
This idea does have merit. It is something you can consider but you need to understand the volume of your rocket and how this relates to the pressure you want to reach. If you want to put 10 times the pressure inside a volume of a rocket, you need 10 times the volume of air in your displacement tube as the rocket holds. A 1 liter rocket with 10 bar pressure will need 10 liters of air in your displacement tube. The size of the rocket and the pressure you want to put in it will determine if the size of the displacement will be too large to build.

Re: Can be used a washer pressure as a compressor ?

Posted: Fri Jul 20, 2012 2:28 pm
by Blenderite
This sounds quite interesting. If I can ever get my hands on a pressure washer I might try this. Something to think about!!!

-DogLover