What air compressor should I buy?

Iain, BSP threads come in 2 types. Parallel or tapered.

As above the PCL fittings are a pretty much industry standard & reasonably reliable.

Steve.

P.S. As NDIY says male only. 

Steve.

Edited By Steviegtr on 27/12/2020 13:41:51

All female BSP are parallel. The male threads could be either. Low pressure is often taper (fitted with a filler and jointing compound or with PTFE tape. High pressure installations usually include a rubber inserted washer as the seal (Dowty washer).

Either PCL or Euro type will do just fine and are easily obtained. Yours look as if they should be Euro.

If you are a LiDL shopper an advantage of the Euro type is that they periodically do air tools, accessory kits, airlines and sets of connectors of very acceptable quality at economical prices usuing Euro connectors. Good way to get extra equipment. Especially as the prices make "I will only use it a few times." purchases viable.

LiDL prices mean I'm slowly switching from PCL to Euro. Too much invested in PCL to be worth the switch at proper trade supplier prices but its viable at LiDL ones.

The Euro style ones have a larger through bore than PCL so theoretically pass more air at a lower pressure drop. Which may be important for blasting and similar. Must get round to changing the connectors on my blaster to see.

Chinese air connector threads can be obscure, crazy or both. I found one that measured as being Admiralty (obscure) but I suspect it was supposed to be American and the copier cocked up (crazy).

Clive

Clive

Just had a read back through this thread and on page 1 you say that you are using your Guyson cabinet to blast at well over 100 psi. I would say that is way too high and you should normally be able to use half that pressure.

You may well accelerate the time taken to do the job, but the blast media breakdown rate will be terrible and you will use a lot more of it. You will also be causing a lot of internal wear to the gun and anything in contact with the moving blast media.

How do I know this ?.....Well I have been chief design engineer at Guyson's for nearly 33 years and I have picked up a few things along the way. My forte is designing the big automated and robotic stuff for production line work, but the basic principles are exactly the same as on the small hand cabinets.

One easy way of getting more from less so to speak, is to get a bigger or additional reservoir on the compressor.
It will not solve the problem entirely but will allow longer spells of blasting before waiting for the compressor to catch up.

I will soon need to get my own blasting facilities sorted out, when I retire I will lose my free access to all the equipment at work.

Phil

Sorry incorrect, all female BSP threads are not parallel, they may also be tapered. You may use a tapered male thread in either a parallel female or tapered female thread these are accepted as sealing on the thread with an accepted compound. Parallel male threads are not considered as sealing on the thread and should not be used with tapered female threads and as correctly stated are sealed with a conforming washer.

Paul.

Ian,

Most air fittings are straight, use PTFE tape. The coiled hose will drive you mad and restrict your flow as well.

Don't forget to fit a filter regulator to replace the joke one and a decent on/off tap.

You can get BSP black iron fittings at your local plumbers merchant

Phil

Thanks for the heads up on pressure for blasting.

Hafta say I just took the advice of a mate who had done a fair bit of blasting professionally, mostly outside stuff and inside huge tanks, but he also had his own cabinet, not Guyson but professional grade, a little bigger than the one I have now and set things to what he said. According to the gauge on the cabinet I have about 80 psi at the gun so its not as bad as it sounds.

I shall have to have play at lower pressures next time. Blasting is not something I do much of. But when my experienced friend moved 150 miles away ....

Clive

Loctite make an excellent pipe joint product, 577, where PTFE tape is difficult to apply.

As Has been mentioned earlier, price and quality must be considered. BUT what ever you buy, wire the compressor through a direct on line starter rated for the full load current of your motor !!! Failure to do this will nullify any guarentee. This is NOT to be confused with a No volt release. The quality of many cheaper motors is questionanble and the Non return and unloader valves also ! At least a DOL may save the motor and show up a fault with out smoke. If using a 3Hp/2.2Kw motor on a 13amp plug expect trouble as if run for long things will get hot. If buying second hand at the lower end of the quality range then The safety of the pressure vessel (tank) MUST be considered. If there is no test on the tank, it must be considered as a parts only deal. HOW do I know ? Asked to repair an 11year old unit, the unloader/ cutout leaked badly so fit new, tried to run it, motor u/s, new motor £160, NOW it runs ! This unit was spotless and LOOKED like new. After a few seconds a small puddle appeared under the tank ! It had corroded through, a tiny pin hole. Customer unhappy and me £250 out of pocket as a new tank is costly.

I should have done a hydraulic test FIRST ! and condemed the unit , at that point customer would have accepted it and I would have got paid. Noel

I've spent quite some time on Amazon looking for what I think is the correct connect. I have some candidates such as this .

But I'm really not sure.

Would someone be kind enough to point to an actual product (don't care from where) or point to a specification.

This is probably not hard to you men of the world, but to an air virgin, it's truly daunting.

Iain

Your link looks OK

Some late comments.

Schrader air line fitting are still used in industry, in both 1/4 and 3/8 BSP, at least . I prefer them to PCL or Euro.

If you want to find the sizes /pitches for BSP fittings, look at Zeus charts.

American National pipe fittings (NPS or NPT ) differ both in thread form and pitch; 60 degree (Instead of the 55 degree Whit form of British Standard Pipe ) and the pitch also differs, so they are non interchangeable. i.e. 1/4 BSP 19 tpi 0.508" diameter. 1/4 NPS 18 tpi, 0.540 diameter.

Howard

This is not going well.

I ended up buying this. Mainly because I thought it was the right thing, but more that I could get it the next day (bless, Amazon, bless).

I have one bit of bad news and one bit of half bad news.

The bad news is that the connectors from the tool kit I got do not work with the allegedly Euro set purchased from Amazon.

The tool kit connectors are exemplified by the one on the tube. The kit connector is exemplified but the male connector at bottom left. They are quite different.

the picture below shows the innards of the Euro connector and the one on the compressor.

Quite different!

The half bad news is that the screw thread on euro connectors sort of matches the thread on the compressor. Sort of because it only screws in part way. Certainly less than the existing connectors. Which makes me think that the female thread is also tapered. And I'm not sure I can (Per a comment above) reliably use a non tapered male with a tapered female.

I'm stuck for what to do next. I don't know what the two mystery connectors are (the one on the tube and the one on the compressor connector). I've also struggled to find any male tapered connectors on Amazon (at least without paying a substantial price -and amazon includes BSP in searches for BSPT it would seem).

So. If anyone knows what the actual connector is on the compressor I can attempt to find a convertor. If anyone can recommend a supplier of BSPT connectors (at a reasonable price) I can replace the current connectors.

I'm still a bit stuck with what sort of tools to get. The ones I have already (as per the connector on the tube) or the Euro ones which Lidl/Aldi will provide cheap tooling for.

I really am stuck here, so any input would be appreciated.

Iain

There is some cross-over between the standards used by couplers. There are couplers made by PCL that will connect with Euro, ISO B12 and XF according to Air Technique Ltd. Have a look at https://www.air-compressorsdirect.co.uk/pcl-coupling/multi-fit-couplings

Your tube is likely a Chinese 'looks like a Euro connector' copy. If the connector does not freely swivel on the tube it will knacker anything you plug it into fairly quickly or the tube will twist up badly.

From the same seller alleged maker Dandlionsky you can have this Euro set, except the connectors look nothing like your Euro set by the same maker.

Be prepared to change the connectors on every air tool you buy, I do, but then I buy PCL and connectors bought in the last century still fit todays connectors.

Wait until tomorrow and go to a motor factors and buy proper PCL couplings. What you have, at that price will be nothing but trouble and leaks. They look like chromed mazak. Buy good quality hose that is a type of rubber, NOT pvc, in winter pvc and cheap hose will not bend. If you invest in good gear it will serve you well and last for years. I bought a CP 1/2" air impact wrench OVER 40 years ago,not cheap, it's never needed repairs. I was recently given a cheap copy, looks the same but has HALF the power - you get what you pay for ! Good luck. Noel

I use menda hose in Glasshoughton near Castleford. They have everything you will ever need under one roof. Great & helpful guys too.

Steve.

OK. A bit more Internet research and I think what I have are hiflow couplers. More specifically automatic hiflow couplers. Automatic means that you don't pull the sleeve back to insert the plug. Something I've been doing because, well, it seemed right.

It turns out that I can push both types of connector into my outlets, though I've not yet discovered if they actually seal and supply air - midnight is a tad late to pop out to the shed (especially in the current near-zero weather conditions!)

This has been the most useful site so far, but it's taken a lot of time to get this far! I will report on if the connectors actually work, tomorrow.

Iain

The connectors actually work!

I've plugged in the air gun to the coil and successfully blown air at things. The coiled hose is fairly useless at distributing air - despite it being 5 metres uncoiled, I feel it's not really meant to be stretched that much.

As my next step on the route to being producer of air (hot or aromatic as you choose), I've ordered what I think is some straight pipe which is enough to reach round my shed (and some), which is enough to experiment with, albeit not where I want to end up.

Whilst the compressor seems to work nicely and isn't too loud (I could have a conversation without needing to raise my voice), the mains cable is ridiculously short, so I need to sort out some wiring (a suitable extension cable).

In the medium term, I'm thinking of running a pipe round the shed to the workbench, mill and lathe.

Whilst this seems simple enough (some pipe, some T connectors and some sockets), the options and language is still a bit beyond me.

I may well talk to Mendahose, Steve, and see if they can cut through the ....

Still, up and running!

Iain

Edited By JasonB on 29/12/2020 17:20:02

A lot of the noise from a compressor comes from the air inlet/filter. Adding some more pipe could reduce the noise, it is all a matter of experimentation.

Edited By old mart on 30/12/2020 20:44:12