How to Test Airsoft Air Seal

Dorsum to basics....

Exam just piston & piston head in cylinder first

ptfe will piece of work wonders but so will a new piston o-ring

getting a skillful seal is vital, getting a GREAT seal is non always like shooting fish in a barrel though

piston heads themselves are often good to crap even after trying all sorts of o-rings n stuff

A lot of piston heads suffer a mutual problem that the 2 outer diameters on the caput are not the same

often/nearly always the rear of the piston head is slightly smaller than the front end part of piston

which imho is ar$due east about face equally the rear of piston head is where the o-ring sits & seals on compression

this ways the o-ring itself is not quite as supported to seal perfectly when gun fires...

The front function of piston is the ane that could/should be a smidge smaller as seal is non there but where o-ring sits

this too doesn't need to be great as the piston on retraction shouldn't be sealing perfectly at all or you could get suction or piston/bb suck

In upshot yous shouldn't get bb suck coz the o-ring should take some play sitting in the groove of the piston head

this allows the o-ring to autumn forward, slight tiny gap betwixt o-band & rear of piston head allowing air to easily fill the cylinder on retraction

If this works effectively then past property finger over cylinder and yanking the piston make clean out of a full cylinder you should hear only a slight pop

If you lot hear a f*cking loud champagne cork pop so you got some suction - likely from an o-band as well thick for piston head's groove....

The perfect seal which is not easy to become everything as close to perfect will have very petty popular if yanked clean out of full cylinder

and when testing for pinch yous will become strong resistance very quickly and with next to no possible leaks that the piston fights back so much that y'all hear a very light pop or pip I estimate yous could call information technology from piston fighting back and air slipping past o-ring and she comes backwards resisting the force of compression......

Blimey - that is a LOT of bollox fifty-fifty past my standards....

And I haven't fifty-fifty touched on subject of piston/piston caput weights, bearings/spacers and f*ck knows what else

get the nuts as best as you can - try some other o-ring or two/dozen, stretch them simply I personally would practise any stretching on old o-ring not with lighter n crap in example you impairment the o-ring, just stretch the sod over old cylinder, place in hot water - exit to cool and repeat with more than hot h2o from kettle a few times

get out the sod say overnight - past morning it will exist stretched properly like a pair of whore's drawers and won't return back to smaller size very easily

keep a few stretched o-rings to mitt - y'all will find a time when you lot will demand them

O-rings themselves can make a big departure - even same o-ring removed and replaced on the opposite manner can make a considerable deviation

then as well gyre o-band so inner ring becomes outer band, watch for bad seams on o-rings - yup only one o-ring tin can exist installed say 4 different means and the seal itself can be affected in this little surface area solitary....

Yeah some piston heads are f*cking crap with smaller diameters at rear, the holes may non air to laissez passer well and swell/seal the o-ring against cylinder wall

so at best information technology is a lot of experimenting or trial n error to get just the piston head's seal as close to perfect as possible

(only some piston heads are merely $hit no thing what you do)

Cylinder caput tin still leak but gauge if y'all are nonetheless not able to see/hear the bad seal at cylinder head yous tin immerse the sod in absurd/manus warm water and watch for air escaping around head whilst testing compression - or plumbers trick of washing upwards liquid effectually caput and clock any bubbles

But to be honest you should know if caput yet leaks, you would feel compression loss if piston head/o-ring is good/great

heck you might fifty-fifty hear the air escaping blah blah blah......

subsequently all is done to the best possible standard.....

drop the perfect o-ring in a scrap of silicone oil overnight, shine cylinder with silicone oil and buff dry

reassmble next morning with spread of silicone grease and viola y'all should take a mofo sealing piston/cylinder caput setup

if nozzle is $hit then supplant with an o-ring nozzle of SAME LENGTH and hopefully nozzle seals on bucking ok

any other leak is going to be hop related but not in your nigh on perfect sealing gearbox (hopefully)

phew - this is curt version of Piston Sealing Engineering at the Academy of Lamentable Badtids in London btw

ahh sod it I know in that location might exist a few typo's here n there simply my fingers are killing me and you get the full general thought of what to check n exercise blah blah apathetic etc....