340PSI Compressor $19.95 + $12.95

[Team Seneca]

This weekend I experimented with a compressor idea that nobody has tested before. I wanted to take a cheap compressor (I picked one up for $19.95 from K-mart) and replace the nylon gears and see if it would hold up better.

I was able to pick up a matched gearset at work. We don't know what they cost. I asked around and $12.95 is what was estimated. I put them in place of the stock gears. The plastic gears were pressed on and the steel ones didn't really work like that, so I pushed them on and then had a tiny weld placed on the shaft to hold it from spinning. Real 'junkyard wars' type stuff here. I think epoxy might work or CA glue, but steel welds nicely to steel.

The pump test worked. The little compressor was rated for only 250PSI and it was able to fill a section of steel pipe to 300PSI. I did it 4 times over the course of 2 hours, giving it time to cool off in between. It gets pretty hot.

My last test was to see the max pressure it would work at and I got it up to 340PSI but the hose burst at that point. When I opened it up to replace the hose, the "connecting rod" on the piston was busted. I think the sudden pressure drop may have broke it or it broke and the hose failed because of that.

The arrow shows where the connecting rod broke.

oh_snap.JPG (102.09 KiB) Viewed 225 times

Either way, I think with a better "donor" compressor with better pieces or a few custom parts to beef it up and I have a good little air supply. it was a worthwhile experiment!

[Spaceman Spiff]

That's pretty impressive for a cheapo compressor. What did you power it with? That doesn't look like an AC motor. Is it the kind that plugs into the cigarette lighter / aux power jack in a car?

[SaskAlex]

How big was the steel pipe you pressurized? Do you think it could actually pressurize an average sized rocket to such pressures without getting too hot?

[RaZias]

You know there are PC fans our even exhaustion fans for bathrooms that run at 12 to 9 volts that could make a exhaustion system inside the compressor.
One to put air in and other to put air out, it can help to reduce the heat.

[Team Seneca]

How big was the steel pipe you pressurized? Do you think it could actually pressurize an average sized rocket to such pressures without getting too hot?

The pipe I used is 8 feet long and 1.5" in diameter. I picked that because it is an approximate size of and FTC. I estimated the volume to be around 3 liters. I noticed that the higher the pressure got the slower it climbed. I think this is the expected behavior. I didn't take notes on the pressure vs. time because I was recording on video but the battery in the camera died. I think it was too cold outside for it.

[Team Seneca]

You know there are PC fans our even exhaustion fans for bathrooms that run at 12 to 9 volts that could make a exhaustion system inside the compressor.
One to put air in and other to put air out, it can help to reduce the heat.

I want to get a better compressor next time. I have seen some of these small pumps with cast iron bodies that have cooling fins on them. This one had no cooling at all.

[U.S. Water Rockets1]

We've talked about this for several years. It's great to see that someone was finally able to prove that the weakness of these pumps is the plastic gears. Nice work on your test, Bill!

[RaZias]

I know you tunned it, but I wanted to know what is the trademark and model (photo of the box if you could) of the compressor.

Mine has air lose don´t no where and yours doesn´t, that´s why I am interested.

Thank you.

[manishapi]

I found many interesting stuffs

[manishapi]

thanks..

Air Compressor

[johannchung]

Wow thanks, I could definitely use one!