Thread: 300 TDi crank pulley bolt....

daft question...

what size airline and what fittings are you using? standard 3/8th or 10mm ID airhose and fittings as you'd normally get at bunnings wont drive a 3/4 rattle gun to full noise.

Thats the key difference between the bunnings compressor Im running and the stock compressor. I have a high flow fitting thats not on a regulator that feeds a 12.7mm id line. (that and the cut out is wound up to 140psi, 5psi under the safety blow off valve).


if you dont mind paying through the nose you can get those fittings and line from bunnings but they are usually cheaper from pirtek Enzed or if its only for intermittant duration use, ebay and alibaba

Originally Posted by Blknight.aus

daft question...

Not daft at all, Dave. In fact I suspect that you are right. The last attempt I made was with a comp delivering 150l pm, but through a reg, and the most I could get was 100psi. The hose was 10mm, but I cut it down to about 3 metres in length, hoping that would help.
I've got my eyes on a big old 3 phase comp from a disused bus workshop. It has a cylinder about as big as me. I have just the spot for it, and yes, I do have 3 phase. Not much help to me now though.

what you might get away with is......


borrow a very long 3/4 or if you know the right people inch air hose with the right fittings on it, plug it into your compressor and use the hose as a "surge" tank.

it should be very easy to fit a high flow fitting to your tank and then wind the pressure up on the motor cut out.

You don't need a big compressor to run a rattle gun. You just need to let it recharge between brief bursts. I have used a 3/4 rattle gun on a 6cfm compressor with a 10 litre receiver. It all comes down to pressure and flow rate through the air line. Large diameter hoses and fittings with no restrictions are the way to go. Do away with the regulator and set the pressure switch to just below the relief valve pressure.

Aaron

Originally Posted by johntins

I bought one today It wants 150 litres pm min. I have 3 rubbish Chinese compressors which I am going to connect together. Once this is done they are destined for ebay or the hard rubbish pickup.

My Son and I just bought a new compressor for our new workshop, it has a 150lt. air tank, a 3 cylinder large bore compressor motor powered by a 12HP 3 phase electric motor, takes under a minute to cut out at 115psi and the restart is set at 85psi.
Most 1/2" hose air tools (esp. Rattle gun) require at least 85/90psi to operate effectively, so this compressor will run a 1/2' rattle gun at full bore continously, most small motored compressors have a lower startup psi. to allow the smaller motor to restart, like 50 psi., Regards Frank.

Originally Posted by Tank

most small motored compressors have a lower startup psi. to allow the smaller motor to restart, like 50 psi., Regards Frank.

I have never encountered this in any compressor that I have ever seen, cheap or good quality. There is a port in the pressure switch which de-compresses the compressor and delivery pipe when the motor switches off, resulting in the characteristic hiss. The motor and compressor can then start with no load. Some old compressors de-compressed just before re-starting.

Aaron

in tanks defence, back in his day...

low end compressors didnt have the decompress outlet line after shutdown feature. They could get away with nasty start up currents because motors were built to deal with it and had a much fatter fudge factor. However in this day and age where everything must be made down to the minimum standard possible to achieve the job to maximise profit efficiency its better to put a small bleed off check in the delivery line

Originally Posted by Aaron IIA

I have never encountered this in any compressor that I have ever seen, cheap or good quality. There is a port in the pressure switch which de-compresses the compressor and delivery pipe when the motor switches off, resulting in the characteristic hiss. The motor and compressor can then start with no load. Some old compressors de-compressed just before re-starting.

Aaron

Well, why don't you check what your startup pressure is, regards Frank.