inserting fittings in pvc

[thisnobody]

should i use 1/8"npt which is fine thread or 1/4"npt which is course thread when modifying my sprinkler valve (plastic) and when inserting the schrader valve and pressure gage into the chamber(pvc) ?

[jrrdw]

Depends on the size fitting your installing. The blow gun for the sprinkler valve is probly 1/4". The schrader is probly 1/8". Look at it and size it up by eye.

Welcome to Spudfiles.

[jook13]

I think he is asking which will hold better? the fine thread of 1/8 or 1/4 which is a heavier thicker thread...

[thisnobody]

yes, i can get either fine 1/8 or course 1/4 as far as holding power i was wondering if there was a differnce
i would hate to launch the fittings instead of a projectile

[covey12]

yes, i can get either fine 1/8 or course 1/4 as far as holding power i was wondering if there was a differnce
i would hate to launch the fittings instead of a projectile

ive used both, and havent had any problems at all, if your really worried, position the fittings so that they point away from you during firing, but as long as you use some teflon tape you should be fine.

[thisnobody]

1/4 would probably be better if using teflon tape
the fine threads of 1/8 can easily get stripped in the pvc right
i'll go with the 1/4
thanks for the input

[starman]

I've done and seen mostly 1/4" nipples or angled bits used for this as it is the more common size. Also, 1/4" will offer nominally 4 times more pilot flow than a 1/8" will.