OzarkChris
Gold Member
Just my $0.02, when it comes to tape 
dope. On all of hydraulics I've done maintenance on I've used both or none. Really depends on the SOP of the company. At home, because I typically buy used implements, loaders, tractors etc, I have a multitude of different fittings (and usually the one needing replaced didn't get restocked when I used it the last time 
). What I've found that works best for me both at work (if I have a choice) & home boils down to the type of fitting and type of material. For NPT(M) I like either a thick tape (e.g., yellow for gas/propane) that is wrapped to 2nd thread or a flexible when set paste (again being careful not to go to the end), think aviation or gaszilla type. The reason for this is Not to stop leaks, but to facilitate removal when it fails again. For BSPT (JIS-PT) & BSPP (JIS-PF) I typically only use flexible paste. Metric taper (especially on flair end) I use thick tape - easier than using the wide brush on paste. Straight threads (SAE & ISO 6149) I only use hydraulic rated pastes unless the fitting already has some dried stuff on it from the factory. JIS B2351 and DIN I've used both thick tape and flexible paste with good results. Finally, the 4 bolt flange, obviously use the o-ring/gasket but use some red/blue thread lock (depending on size) to keep the bolts from vibrating out. All of the various types of ends these fittings can have on them really don't seem to make much difference except the banjo bolts where I will use regular tape (not thick) making sure I don't have tape to close to hole or end I really have had issues with people using paste on these. As mentioned in another post, the type of material the fitting is made from really makes a difference too. SS is the worst, if you even think about putting two pieces together without something they will weld each other together before you even pull them from the shelf - well maybe not exactly, but you get the idea. Some of the Chinese parts I've had to use (penny pinching employers) have been pot metal that has been chromed - pretty but don't last and need tape/paste to keep from leaking. Other nightmares have included regular gas black pipe (not rated for pressure), fitting that have had both tape & paste (NEVER A GOOD IDEA!!) And as been mentioned in another post, old plugs that have been over tightened destroying the bottom & taper - short of replacing the housing, re-drilling and tapping with next size up there really isn't much you can do to truly fix it, paste, thick tape will help short term, but ...
Hope this helps!
dope. On all of hydraulics I've done maintenance on I've used both or none. Really depends on the SOP of the company. At home, because I typically buy used implements, loaders, tractors etc, I have a multitude of different fittings (and usually the one needing replaced didn't get restocked when I used it the last time ). What I've found that works best for me both at work (if I have a choice) & home boils down to the type of fitting and type of material. For NPT(M) I like either a thick tape (e.g., yellow for gas/propane) that is wrapped to 2nd thread or a flexible when set paste (again being careful not to go to the end), think aviation or gaszilla type. The reason for this is Not to stop leaks, but to facilitate removal when it fails again. For BSPT (JIS-PT) & BSPP (JIS-PF) I typically only use flexible paste. Metric taper (especially on flair end) I use thick tape - easier than using the wide brush on paste. Straight threads (SAE & ISO 6149) I only use hydraulic rated pastes unless the fitting already has some dried stuff on it from the factory. JIS B2351 and DIN I've used both thick tape and flexible paste with good results. Finally, the 4 bolt flange, obviously use the o-ring/gasket but use some red/blue thread lock (depending on size) to keep the bolts from vibrating out. All of the various types of ends these fittings can have on them really don't seem to make much difference except the banjo bolts where I will use regular tape (not thick) making sure I don't have tape to close to hole or end I really have had issues with people using paste on these. As mentioned in another post, the type of material the fitting is made from really makes a difference too. SS is the worst, if you even think about putting two pieces together without something they will weld each other together before you even pull them from the shelf - well maybe not exactly, but you get the idea. Some of the Chinese parts I've had to use (penny pinching employers) have been pot metal that has been chromed - pretty but don't last and need tape/paste to keep from leaking. Other nightmares have included regular gas black pipe (not rated for pressure), fitting that have had both tape & paste (NEVER A GOOD IDEA!!) And as been mentioned in another post, old plugs that have been over tightened destroying the bottom & taper - short of replacing the housing, re-drilling and tapping with next size up there really isn't much you can do to truly fix it, paste, thick tape will help short term, but ...Hope this helps!
Many of us, in a certain age bracket, can make fun of this! 