Lubricant for Plastic Threads?

[lbperry]

I have a 4" diameter gauge with a plastic case I'm mounting to a hole in a panel. The outside of the gauge case is threaded and there's a 4" collar that threads on the backside of the case to mount it in the hole. When I start threading the collar on the threads act like they want to gall up. I could brute force it and get it to thread all the way down but am afraid what'll happen after it ages a few years and I have to get it off. I think that a little bit of lubricant will go a long way to get it to thread smoothly but don't know what kind of lube to use on plastic. Anybody with any experience with what would be the best thing to use?
Thanks in advance,

 

[mark#3]

I would ask the internet the question to get an answer.

 

[DHCrocks]

try some dielectric grease. I also use the stuff on orings and it helps them glide a bit smoother on things like flashlights and what not.

 

[73surffisher]

I would think a silicon spray lubricant would work just fine

 

[Shiftless]

You can get silicon grease in a good plumbing supply place. That would be my vote.

 

[erswill]

Dry graphite lubricant powder used by locksmiths.
Rub into both threaded part with cloth.

 

[Lelandwelds]

Silicone grease or oil, Krytox if you're rich, or Dow Corning Molykote 55 Oring lube.

Don't use petroleum jelly or graphite. Chapstick or Bert's Bees works in a pinch

 

[SALIV8]

drop of gun oil?

 

[Lelandwelds]

drop of gun oil?

Some plastics and o rings are not compatible with petroleum products. Silicon oil or grease is safer and it is cheap. I don't care for the aerisol. Too thin.

(But, I use Break free or Corrosion X on almost everything.)

 

[Ole Slewfoot]

Non setting pipe dope

 

[rlitman]

Silicone grease or oil, Krytox if you're rich, or Dow Corning Molykote 55 Oring lube.

Don't use petroleum jelly or graphite. Chapstick or Bert's Bees works in a pinch

All decent options. Just to comment on silicone: Silicone SPRAY is NOT ok (or anything spray for that matter), as the volatile aerosol carriers are often not plastic safe.

While I have and use Krytox regularly, and would probably use it for this just because I have it, I wouldn't recommend buying it for just this.

The next best choice, which has not been mentioned yet, would be Crisco.

Bar soap might be a good option. Lanolin is also plastic safe, so you could use Fluid Film. Beeswax also.

Or, you could try a single wrap of teflon tape. Or a pipe dope that is specifically rated for plastic pipe (most are not).

Graphite is messy, but I'm not sure why else it would be bad. You could mix graphite with silicone grease, and the combination would likely be better than either alone. Many other powdered lubricants would be just as appropriate (hexagonal boron nitride, titanium disulfide, powdered ptfe, etc). Molybdenum disulfide, not so much, as it's best when used on a steel part, because of how it plates itself to the steel.

 

[zmaxmotorsports]

Rector seal Tplus2.

 

[alfredeneuman]

teflon tape.

That's what plumbers use on threaded PVC fittings.
It's mess free.

 

[zmaxmotorsports]

That's what plumbers use on threaded PVC fittings.
It's mess free.

The only thing I usually use Teflon tape on is brass fittings.

 

[alfredeneuman]

The only thing I usually use Teflon tape on is brass fittings.

Are you a plumber?

 

[zmaxmotorsports]

Are you a plumber?

Master.
By the power vested in me by the cities of omaha/Bellevue nebraska and across the bridge in the great state of iowa.

 

[zmaxmotorsports]

I've tried them all over the years,still the best thing I've found for lubing pipe threads that's easy to clean up.

 

[Lelandwelds]

All decent options. Just to comment on silicone: Silicone SPRAY is NOT ok (or anything spray for that matter), as the volatile aerosol carriers are often not plastic safe.

While I have and use Krytox regularly, and would probably use it for this just because I have it, I wouldn't recommend buying it for just this.

The next best choice, which has not been mentioned yet, would be Crisco.

Bar soap might be a good option. Lanolin is also plastic safe, so you could use Fluid Film. Beeswax also.

Or, you could try a single wrap of teflon tape. Or a pipe dope that is specifically rated for plastic pipe (most are not).

Graphite is messy, but I'm not sure why else it would be bad. You could mix graphite with silicone grease, and the combination would likely be better than either alone. Many other powdered lubricants would be just as appropriate (hexagonal boron nitride, titanium disulfide, powdered ptfe, etc). Molybdenum disulfide, not so much, as it's best when used on a steel part, because of how it plates itself to the steel.

Graphite doesn't stay put. It isn't oxygen safe and is corrosive to some metals. Hex boron nitride is the same as refractory? I didn't realize it was slippery.

Rector seal Tplus2.

Rector seal is good stuff. I haven't seen that one. I googled and (wow!) That Tplus2 is certainly widely used and documented. Or, did they just change the package?

 

[zmaxmotorsports]

Graphite doesn't stay put. It isn't oxygen safe and is corrosive to some metals. Hex boron nitride is the same as refractory? I didn't realize it was slippery.



Rector seal is good stuff. I haven't seen that one. I googled and (wow!) That Tplus2 is certainly widely used and documented. Or, did they just change the package?

I've been using that version of it for around 15 years I'm thinking,I like it a lot better than the nasty old #5.

 

[rlitman]

Graphite doesn't stay put. It isn't oxygen safe and is corrosive to some metals. Hex boron nitride is the same as refractory? I didn't realize it was slippery.



Rector seal is good stuff. I haven't seen that one. I googled and (wow!) That Tplus2 is certainly widely used and documented. Or, did they just change the package?

Yes, graphite can be nasty, as well as a potential corrosion issue (though not on plastic). It's also conductive. Except for Krytox and [some] teflon tape, nothing else mentioned here is oxygen safe. Not sure how that's relevant.
Oh, and I just looked up Molycote 55, and it says it should not be used with ABS or polycarbonate, so it's not as plastic safe as I had assumed.

Hex boron nitride is a lubricant, and is widely used as a release agent. It's hexagonal plates slip in much the same way as graphite, though it is white.
Cubic boron nitride is an abrasive. Both have high thermal stability (though so does graphite), though I think that the cubic form is the type you are thinking of.

I really like Rectorseal 5, and use it on all sorts of metal connections. T+2 is new to me, but the spec sheet looks like it has better plastic compatibility.

 

[Lelandwelds]

Yes, graphite can be nasty, as well as a potential corrosion issue (though not on plastic). It's also conductive. Except for Krytox and [some] teflon tape, nothing else mentioned here is oxygen safe. Not sure how that's relevant.
Oh, and I just looked up Molycote 55, and it says it should not be used with ABS or polycarbonate, so it's not as plastic safe as I had assumed.

Hex boron nitride is a lubricant, and is widely used as a release agent. It's hexagonal plates slip in much the same way as graphite, though it is white.
Cubic boron nitride is an abrasive. Both have high thermal stability (though so does graphite), though I think that the cubic form is the type you are thinking of.

I really like Rectorseal 5, and use it on all sorts of metal connections. T+2 is new to me, but the spec sheet looks like it has better plastic compatibility.

I see Krytox I think cryogenic pumps.

Once I was making a sales call at a graphite processing plant. A forklift across the warehouse started itself up, charged across the floor, and fell sideways off the loading dock. It made an impression. Graphite migrates and conducts electricity.

"Like" is a strong word for Rectorseal. If I remember correctly, it is a ***** to get off of car seats.

 

[rlitman]

I see Krytox I think cryogenic pumps.

Once I was making a sales call at a graphite processing plant. A forklift across the warehouse started itself up, charged across the floor, and fell sideways off the loading dock. It made an impression. Graphite migrates and conducts electricity.

"Like" is a strong word for Rectorseal. If I remember correctly, it is a ***** to get off of car seats.

I almost bid on a 1KG tub of Krytox grease on ebay. Someone said it was used for restoring Lionel trains. Do you need a lot? I just bought a tube of this with a "make offer". It's the food grade type too.
https://www.ebay.com/itm/dupont-krytox-Corrugator-Grease-Tube-227FG-1-76-lbs/263481928152

Yeah, graphite has even been weaponized. Graphite bombs are used on electrical infrastructure.

Yep, Rectorseal is pretty sticky. But it's still easier to clean up than Great Stuff.

 

[Lelandwelds]

I almost bid on a 1KG tub of Krytox grease on ebay. Someone said it was used for restoring Lionel trains. Do you need a lot? I just bought a tube of this with a "make offer". It's the food grade type too.
https://www.ebay.com/itm/dupont-krytox-Corrugator-Grease-Tube-227FG-1-76-lbs/263481928152

Yeah, graphite has even been weaponized. Graphite bombs are used on electrical infrastructure.

Yep, Rectorseal is pretty sticky. But it's still easier to clean up than Great Stuff.

That's a different version. I don't do much of anything currently.

I didn't know weaponized graphite was a thing. It is hell on switches and forklifts.

 

[rlitman]

That's a different version. I don't do much of anything currently...

Yeah, they've got a lot of versions. Cryo pumps probably used the oil. Thousands of dollars a gallon. That sort of grease will make your CV joints last forever...

 

[Dragfluid]

Master.
By the power vested in me by the cities of omaha/Bellevue nebraska and across the bridge in the great state of iowa.

Is your crack certified?

 

[Dagny]

yep either of the ****** sealers.

 

[Dustball]

Super Lube

Silicone Lubricating Grease with Syncolon® (PTFE)

Silicone Lubricating Grease with Syncolon® (PTFE) has a wider operating range than petroleum based lubricants; Excellent water protection and moisture barrier. Use on Plastic gears, plastic threads, as a damping medium for Dash Pots, lubricate O-Rings, electrical motor bearings and rubber components.

Silicone Lubricating Grease withstands temperatures from -40°F to 500°F.

Silicone Lubricating Grease is available in the following sizes:
92003..........................................3 oz Tube
92150............................400 gram Cartridge
92016....................................400 gram Can
92005..............................................5 lb Pail
92030.............................................30 lb Pail
92400........................................400 lb Drum

 

[zmaxmotorsports]

Is your crack certified?

I've had more than o e carpenter chase me with a caulking gun!

 

[SALIV8]

Some plastics and o rings are not compatible with petroleum products. Silicon oil or grease is safer and it is cheap. I don't care for the aerisol. Too thin.

(But, I use Break free or Corrosion X on almost everything.)

My gun oil comes in a plastic container

 

[lbperry]

Well, I tried silicone on the threads. The retainer ring threaded on the gauge case better with the silicone but still bound up before it threaded on sufficiently to clamp it to the panel. I think I may be up against a case of bad threading on the case. I'm working with the manufacturer to send the gauge back and let them figure it out.
Thanks to all for for your suggestions and comments; even though a few of them got a little weird.

 

[rlitman]

My gun oil comes in a plastic container

I think you should google a plastics chemical compatibility chart if you want to make your head spin.

 

[zmaxmotorsports]

I think you should google a plastics chemical compatibility chart if you want to make your head spin.

I remember stripping paint off a model car with finger nail polish when I was a kid.
I figured it came in a plastic bottle,so it should hurt the plastic car body right?
Tossed it in a bread pan and dumped the the remover on top and forgot it for a few days in the garage.
Came back to find a melted blob of plastic in bottom of pan.
Had a can of clear pvc primer spill on floor in front of truck years ago,burned through a nice field piece clamp on meter.

 

[Dragfluid]

I remember stripping paint off a model car with finger nail polish when I was a kid.
I figured it came in a plastic bottle,so it should hurt the plastic car body right?
Tossed it in a bread pan and dumped the the remover on top and forgot it for a few days in the garage.
Came back to find a melted blob of plastic in bottom of pan.
Had a can of clear pvc primer spill on floor in front of truck years ago,burned through a nice field piece clamp on meter.

What was your meter doing on the floor?

 

[zmaxmotorsports]

It was laying on floor of truck on passenger side next to a tool bag,lid on can wasn't tightened all the way and ran out on to it going around a corner.

 

[Dragfluid]

It was laying on floor of truck on passenger side next to a tool bag,lid on can wasn't tightened all the way and ran out on to it going around a corner.

Oh.
When I read this: "on floor in front of truck" I took that as being on the garage floor, in front of the truck.

I'll got back to my corner now.

 

[SALIV8]

I think you should google a plastics chemical compatibility chart if you want to make your head spin.

I did that and you are not kidding. wow. Thanks.

 

[pancho400cid]

cooking oil (Wesson etc.)

I have used it on a lot of non-critical plastic stuff (good on plastic zippers, etc too)

 

[4cyclic]

beeswax works pretty good, just rub a bar on the threads before screwing in.

 

[6PTsocket]

All decent options. Just to comment on silicone: Silicone SPRAY is NOT ok (or anything spray for that matter), as the volatile aerosol carriers are often not plastic safe.

While I have and use Krytox regularly, and would probably use it for this just because I have it, I wouldn't recommend buying it for just this.

The next best choice, which has not been mentioned yet, would be Crisco.

Bar soap might be a good option. Lanolin is also plastic safe, so you could use Fluid Film. Beeswax also.

Or, you could try a single wrap of teflon tape. Or a pipe dope that is specifically rated for plastic pipe (most are not).

Graphite is messy, but I'm not sure why else it would be bad. You could mix graphite with silicone grease, and the combination would likely be better than either alone. Many other powdered lubricants would be just as appropriate (hexagonal boron nitride, titanium disulfide, powdered ptfe, etc). Molybdenum disulfide, not so much, as it's best when used on a steel part, because of how it plates itself to the steel.

Not to bash Fluid Film, I use it, but a quick check of the SDS shows it is largely petroleum base with a lesser amount of lanolin. To read the ads you would think they are wringing out sheep skins into the can.

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[6PTsocket]

[emoji106][emoji106][emoji106][emoji106]
I remember stripping paint off a model car with finger nail polish when I was a kid.
I figured it came in a plastic bottle,so it should hurt the plastic car body right?
Tossed it in a bread pan and dumped the the remover on top and forgot it for a few days in the garage.
Came back to find a melted blob of plastic in bottom of pan.
Had a can of clear pvc primer spill on floor in front of truck years ago,burned through a nice field piece clamp on meter.[emoji38]

Most types of Loctite eat plastic, too. I was rebuilding a fish tank air pump with a kit. The mounting stud on the pump mounted to the plastic case with a nut. As it is a vibrating diaphram pump, there was a dab of paint on the nut to stop it from coming loose. I put the pump back together and used a dab of loctite. I came back to find the whole side ot the plastic case dissolved into a mushy blob. One adhesive that I find has no solvent effect on plastic and just binds by adhesion is Goop/E6000. Epoxies are usually not a problem either

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