Copper piping plan

[lloydh]

I've decided that I might as well plumb in my new compressor with 1/2" copper to help with air temp/water vapour when spray painting down the road.

I'm planning to solder where possible (exceptions being ball valves and tees).

I know that horizontal piping should be angled down slightly (min. 1 in 100) with the flow of air; is this achieved while using normal 90deg elbows? I ask because other than 45deg elbows I can't see anything in between and I don't want to crack the solder and cause leaks by forcing an angle.

 

[madkayaker]

A normal 90 will be close enough to give the drop over the run

 

[jondog]

How about putting a slight bend in the pipe?

I did this (see picture) with an internal spring and my knee.

 

[hunter27]

Clip, clean and flux your pipe,fit the fittings pre cleaned to the correct fall, don't fit any clips to close to your joints and when you are happy with it solder the joints. if soldered properly and allowed to cool the joints are very tough. cracking is usually caused by the joint moving before the solder is cold or because the joint was plunged into cold water whilst still very hot.
1 in a 100 is no problem with these joints but try to avoid to much flux unless you intend to flush the pipe out with warm water before use.

Pete

 

[lloydh]

Thanks for the replies, I'll see how it looks and add a slight bend if necessary.

Out of interest, would there be any benefit in using a pipe bender to create corners instead of using elbows? That would be another way to create the drop angles, and might be beneficial for flow?

 

[madkayaker]

A spring works well and will maintain the bore without deforming it

 

[Mikey D]

Pipe bender much nicer than spring .... but spring much cheaper to buy if you dont already have a bender

 

[jondog]

Pipe bender much nicer than spring .... but spring much cheaper to buy if you dont already have a bender

I bought a spring for this reason. Producing a 90deg bend is achievable but not with a tight radius (the tube collapsed on my first practice because I was being too ambitious!). Where I needed a nice and precise angle with a tight rad I just used a 90deg elbow.

I'm not an expert by any means. My airline was plumbed in with copper pipe last weekend and it was the first time I had done any form of plumbing I have a few pics if you would like me to write up in a pm.

 

[Luke]

slight falls are no problem with 90 degree joints etc,there's enough flex in the pipe to just use the clips to angle it.

I use compression joints and have a 300L tank and 50L tank, as well as two other compressors. The manifold is all done in copper, using ball valves, and I have two 6ft vertical U loops which work pretty well as a water trap.

 

[superls]

im not sure how much bending springs are but my 15 and 22mm pipe bender was only £20 from a local discount tool place, its only a silverline one but had done everything ive asked of it,

 

[dan.taylor.1]

is copper pipe rated enough for compressed air? I wouldnt have thought water ever gets to 120psi! or am i wrong?

Dan

 

[the snooper]

is copper pipe rated enough for compressed air? I wouldnt have thought water ever gets to 120psi! or am i wrong?

Dan

i read somewhere its rated at 895 psi

 

[Luke]

This PDF from Yorkshire Copper gives a minimum of 39 bar for 15mm copper pipe.

A good starting point in my book

 

[lionleg]

15mm copper pipe will easily cope with compressed air. Seen it used many times in industry. As for drainage, just make sure your take off points go up. That way, any water remains at the bottom of the pipe.

 

[dan.taylor.1]

Fair enough, cant see any standard compressor reaching 39 bar!! might consider it to do my workshop when i get it built, although i think plastic with push fittings may work out cheaper unless you get a bargain on copper piping!

 

[PSweeney]

for bends, far be it from me to suggest buying a bender for B+Q and returning it when it doesn't perform as well as you expected...full refund please.

 

[normspanners]

Just a point your drops to your quick releases should come off the top of your 'main' then go down to the QR, also the last drop in the line should have just a tap on it not a QR, to drain the water out.

 

[lloydh]

I've been assembling quite an array of parts and tools for this little project

I ended up purchasing 22mm copper pipe because I wanted to maximise the cooling effect and I found a pretty good price... and I always end up over-engineering this sort of thing.

While the B&Q pipe bender idea has its 'merits', I bought a Silverline one for £20. I'm not normally a Silverline advocate but pipe benders seem commoditised and I'll certainly be returning it if it's not up to task.

I've actually altered my original plumbing plans slightly by moving my compressor — this means I'll be redoing some wiring that I paid an electrician to do The upside is that it simplifies the piping such that I really only need one run with drains at each end. I'll tee off the main line as normspanners suggested into a filter/reg then QR.

I'm also considering picking up a used refrigerated air dryer. Would there be any reason to design a 'bypass' into the plumbing for when I don't want refrigerator dried air or could I just leave the drier switched off and run the air through it anyway?

 

[lloydh]

Update & auto drain question

I bought a Silverline one for £20. I'm not normally a Silverline advocate but pipe benders seem commoditised and I'll certainly be returning it if it's not up to task.

Well that was a mistake!

I finally get some free time to commence the plumbing and quickly discover that the Silverline is creating some pretty nasty creases in the pipes - and with 22mm at least, the effort required is quite colossal.

I traced the creases back to a casting mark. Faced with waiting out the return/replacement process or grinding down the casting defect, I opted for the latter. Seemed to work.

I've been considering plumbing my filter exits into the nearest drop leg, after the ball valve (see picture below). The brown (brass) bits are a couple of check valves which I imagine would be necessary to stop air trying to enter the filters' exits when opening the ball valve.

Does this setup look OK or are there better ways of doing this?