Thread: Joining air compressors, 1/2" outlets on toy compressors...

Originally Posted by gazza2009au

Yeah i know about the water great advice, found a ripper 3 phase compressor for next to nothing its pretty big would make for a petrol conversion quiet easily but it weighs 500kg

Disassembling to move would be the ideal way to move it i would imagine the motor would weigh 150kg

If i did go with one of these compressor conversions and use a pilot valve the blow off type are u able to modify the air outlet blow off to run a length of hose into a bucket of water to stop that loud unloading pssssssssst that will be happening every couple of minutes

That will spray water all over the place.

This is another reason why the best place for a compressor is outside.
If you can't put it outside attach a length of hose to the unloader and run the hose outside.
To reduce water build up I have auto vent valves in 3 places on my compressed air line, 2 are outside but one is inside.
I used to have them vent for 0.5 s every 50 minutes and it frightened the bejesus out of me every time they went off.
I then cut the vent time 50 ms and added a small brass exhaust vent which quietens the discharge to acceptable limits.
They are quite cheap.
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Yeah was just thinking as the unloaders going off are quiet loud it might the neighbors off, it will be an outside air compressor just due to the size it will be stationairy

Cant really imagine running much off the small compressor i thought it was a good size for a long time but using it today really left me wanting something much bigger

I understand the petrol engine will be running but that is no worse than my neighbor mowing the lawn at 7am 3 times a week i could possibly muffle the engines exhaust but that pilot unloader valve will take some consideration

The way my petrol compressor worked was it would start up and run flat stick untill the tank is full than a little pin would push the throttle back to idle untill the air reaches a low point the pin will retract and throttle the engine up again

What i want to do is vary the petrol engines throttle position manually for each time i use it based on what job if im spray painting maybe idle would be fine to maintain a full tank or if im sand blasting the engines throttle could be set at max for the day by varying the throttle per job would minimise the pilot valve releasing every 2mins psssssst psssssst pssssst once every 2 mins for 3-4 hours my neighbors would go nuts if i could nail the perfect throttle position and mantain a once a 5-8min blow off that would be ideal

Originally Posted by BobL

A small cyclone between the hose and the vac should help - well, . . . maybe reduce the number of vacs you go through

You can actually buy a cyclone for the Vacuum Cleaner, we have one on ours, and saves heaps on bags too.31155258-diverter.png

Originally Posted by KBs PensNmore

You can actually buy a cyclone for the Vacuum Cleaner, we have one on ours, and saves heaps on bags too.

Some vacs have cyclones built into them but they hold bugger all swarf.
Small external cyclones also don't hold much swarf.

For metal work, I think a larger cyclone with its own bin that can hold a decent amount of swarf is a better option.
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For metal work, an all metal cyclone and cyclone bin would enable hot dust (including sparks) to be collected direct from grinding wheels and linishers and if a hot bit of metal falls into the bin it's no biggie.
But for metal work you don't even really need a cyclone, just a metal chip/dust catching bin between the hose and vac will provide almost as much filter protection

Guys i found an absolute ridiculous deal on a what appears to be 200L (possible 250L) 37cfm compressor in really good condition its a good candidate for a 10hp to 16hp stationary honda like petrol engine as mentioned it weighs about 400kg i can put wheels on it but how will i remove it from my yard my back yard is a decent i need the compressor to go beside my shed on level ground its around 25 meters from my back gates where i will drop it off the trailer but a little worried i won't get it back up the hill, i thought about parking the car in at the gate and using a 4wd winch attached to my recovery point with U bolts than load the winch with 3.2mm marine grade stainless cable and winch it up the hill in the back yard

also would need to winch it up on the a trailer at the moment i only have a motorcycle trailer its a flat bed but not idea to roll a compressor onto unless i bolt some timber down, moving the compressor is only needed when i eventually move house

do u think it would work?

nice and windy im going to get the compressor going and blow all this dust out of the boat

Realistically i have no way of moving the industrial compressor would love one tho i picked up this 30L compressor tonight going to strip it back and use the tank only the rest will be thrown out also need to work out what fittings i will need once shes back to bare tank

My pilot air is about 60 litres this little tank is 30L so i think 90L is plenty

Down the track just might have to work out how to fill the tanks quicker

I cranked up the pilot air yesterday belt started to slip again but it ran great all morning after it warmed up

Day started of by pulling the new/old compressor apart than realised all shops were closed needed a tank fitting so had to fab one on the lathe i thought it was a brilliant excuse to use the lathe, Found a 14mm bolt and got to work spent the next 2.5 hours machining and drilling a steel bolt i cut it slightly over size for a tight hose fit i may even put it back in the lathe and make a barb on the end so the hose cannot slide off under 145psi of pressure

What i have just come to realise why on earth didnt i just machine the old insert for the bolt one of them days.... ah well i have a custom piece now, pressure testing will be tomorrow the little 30L tank filled up to 120psi it has 900kpa to 1350kpa on the tank i only need it to hold 1000kpa which is 145psi

Will update with how long it takes to fill both tanks if they work and how long between a low tank to full tank to fill also how many seconds i get of air duster gun free air before low pressure kick in previously on one tank it was 25 seconds

Not that it's any skin off my nose, but what are you really achieving by joining the two tanks together? It could be argued that you are better controlling moisture in your compressed air, but you actually aren't increasing the capacity of your compressor overall, just its surge capacity. The difference between 25 seconds to compressor cut in and 37 seconds to cut in with a blow gun is immaterial in real terms.
Another tank won't make up for an undersized pump, although it will cut down on your starts per hour. You are running a regulator with all your tools I assume? If not, you should be in order to provide a constant pressure to your tools (air tools are typically rated at 90 PSI.).
On a positive note though. The way you are approaching your projects has become a lot more professional with your increasing acquisition of tooling.

Karl makes a good point.
I've raised this before when members have posted about adding more tank volume to their small compressor but few folks seem to understand this so here we go again.

One important reason why compressors are fitted to specific tank sizes is compressor wear and tear.
The greatest wear and tear takes place at higher temperatures which on a compressor and motor happens primarily near the end of the recharge cycle.
On a one minute recharge cycle, something like 90% of the wear and tear happens in the last 15 seconds.
Adding a larger tank extends the recharge time so the compressor gets even hotter for longer than it is designed to do, on EVERY recharge .
Let's the tank volume is doubled so the recharge time is now 2 minutes, as well as the 15s from the first minute of the recharge cycle there is now another whole 60 seconds of higher wear and tear time for a total of 75s per recharge.
If the tank size has been doubled so the compressor only recharges half as often, the comparable significant wear and tear time is thus 2 x 15s for the smaller tank versus 75s for the large tank.
The net effect is increasing the compressors wear and tear time by 75/30 = 2.5 times
A likely long term result is compressor failure.,

If a compressor is used only a couple of times a month this effect will probably not be noticed this but if not, expect the compressor to eventually fail earlier than it otherwise would.

I have seen small compressors fitted to large tanks, like an elderly one I saw in a hospital basement that had a 150L tank fitted with 3 x 1.5HP compressors. The compressors operated in turns to fill the tank so even though any one compressor had to work hard to fill the tank, when one failed the others were available to do the job allowing time for a replacement.

Thanks guys i appreciate both of you explaining this, i just thought if i got that little extra time each tank fill to operate a tool i would get by im not to worried about the refill it will be something like 1m 3s the wear and tear i never even thought about

What should i do ditch the idea?

Originally Posted by gazza2009au

Thanks guys i appreciate both of you explaining this, i just thought if i got that little extra time each tank fill to operate a tool i would get by im not to worried about the refill it will be something like 1m 3s the wear and tear i never even thought about

What should i do ditch the idea?

It depends on use. if you are going to use it a couple of times a month where're it gets extra hot then as I said you probably not going to notice it but if you are going to flog for lengthy period on HD jobs every weekend then its not going to like that.

Sometimes there's no real substitute for getting the right sized machine for the job

I have found a machine that looks to be 100-120L tank and appears to be 2 electric motors joint by 2 belts inline trying to get a hold of the seller is difficult

Originally Posted by gazza2009au

appears to be 2 electric motors joint by 2 belts inline

sounds like trouble

Originally Posted by bts

sounds like trouble

If the seller ever gets back to me and i land the deal both electric motors will be removed a petrol stationary engine will be installed with a unloader valve its the only way i can figure out using a commer ial 3 phase compressor without having 3 phase power

This is the compressor i spoke with the seller this morning i said i would go pick it up than nothing never heard back from him

This is the smallest machine im looking at the other two are genuine 3 phase heavy industrial compressors just unsure how i would go moving one