Threading Lube For Plastic Pipe

Klay Anderson

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Jan 30, 2020, 12:16:47 PM1/30/20

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So--I've a tap and die set for plastic pipe (think sprinkler system). Any ideas for the best lube for threading same? Dry alone snaps the pipe. I think petroleum products will attack the plastic. Silicone?

tabb...@gmail.com

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Jan 30, 2020, 1:34:45 PM1/30/20

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On Thursday, 30 January 2020 17:16:47 UTC, Klay Anderson wrote:
> So--I've a tap and die set for plastic pipe (think sprinkler system). Any ideas for the best lube for threading same? Dry alone snaps the pipe. I think petroleum products will attack the plastic. Silicone?

Silicone, soap, vegetable oil, maybe rubber-safe red grease. No idea which is best. If you're snapping the pipe you might be cutting too deep in one go. I don't know if warming it slightly would help.

NT

Fox's Mercantile

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Jan 30, 2020, 2:01:06 PM1/30/20

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K-Y Jelly.
Water based lubricant.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

peterw...@gmail.com

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Jan 30, 2020, 2:49:32 PM1/30/20

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On Thursday, January 30, 2020 at 12:16:47 PM UTC-5, Klay Anderson wrote:
> So--I've a tap and die set for plastic pipe (think sprinkler system). Any ideas for the best lube for threading same? Dry alone snaps the pipe. I think petroleum products will attack the plastic. Silicone?

Three things:

a) warm the pipe. Even a few degrees will make a large difference. Ideally, you will want the pipe to be just below the plastic stage, but unless you have a "bending box" don't try this at home. About 100F is close enough for your purposes. Anything below about 60F, it will be very brittle.

b) If you run lubricant over the pipe while cutting - such as with a Ridge Cutter - there will be no issues.

c) And if you never (repeat, NEVER) will need to use solvent fittings on that pipe, good old Vaseline will do the trick nicely.

Then, there is the obvious: Cut slowly. Cutting too fast overheats the pipe, and if you overshoot into the plastic stage, all you will do is make lots of scrap. Use only (repeat, ONLY) Schedule 80 or Schedule 120 pipe. Schedule 40 pipe is too thin to take a safe thread and also withstand any level of operating pressure. Did I mention: Use ONLY SCHEDULE 80 pipe, or better.

Peter Wieck
Melrose Park, PA

et...@whidbey.com

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Jan 30, 2020, 2:50:35 PM1/30/20

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On Thu, 30 Jan 2020 13:00:58 -0600, Fox's Mercantile <jda...@att.net>
wrote:

>On 1/30/20 11:16 AM, Klay Anderson wrote:
>> So--I've a tap and die set for plastic pipe (think sprinkler
>> system). Any ideas for the best lube for threading same? Dry > alone snaps the pipe. I think petroleum products will attack
>> the plastic. Silicone?
>
>K-Y Jelly.
>Water based lubricant.

Yeah, K-Y is good for screwing. Sorry. I couldn't help myself.
Eric

peterw...@gmail.com

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Jan 30, 2020, 2:59:36 PM1/30/20

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On Thursday, January 30, 2020 at 2:50:35 PM UTC-5, et...@whidbey.com wrote:

> Yeah, K-Y is good for screwing. Sorry. I couldn't help myself.
> Eric

But not for the stated purpose. Not enough persistence. When done in the field, contractors really prefer to use a Ridge Cutter for PVC or CPVC pipe.

https://www.zoro.com/static/cms/product/full/Z_J2L0fo5oy.JPG

Somehow, I don't think the OP wants to invest at that level, unless there is a great deal of "screwing" to be done....

Did I mention: Schedule 80 or 120 pipe only?

Michael Terrell

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Jan 30, 2020, 7:23:13 PM1/30/20

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On Thursday, January 30, 2020 at 12:16:47 PM UTC-5, Klay Anderson wrote:

> So--I've a tap and die set for plastic pipe (think sprinkler system). Any ideas for the best lube for threading same? Dry alone snaps the pipe. I think petroleum products will attack the plastic. Silicone?

I had to thread some 1" Schedule 80 dry. No problems, other that I couldn't find anyone with a handle fot that large die when I needed it, so they were cut by hand. Don't force it. I did a quarter turn, backed the die off to clear the treads and took another pass until I had what I needed. I was making mounts for some GPS antennas for frequency and time standards. I had to pole mount them to clear a metal roof.

Tim R

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Jan 31, 2020, 1:27:16 PM1/31/20

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On Thursday, January 30, 2020 at 12:16:47 PM UTC-5, Klay Anderson wrote:

> So--I've a tap and die set for plastic pipe (think sprinkler system). Any ideas for the best lube for threading same? Dry alone snaps the pipe. I think petroleum products will attack the plastic. Silicone?

I don't know what is "best," but last time I did this I used dish soap and it worked.