You are here:

Plumbing in the Home/pipe thread sealing compount on plastic


i put pipe thread sealing compound on a plastic fluidmaster fill valve.....then i read the label on the tube of the thread sealant not put on plastic pipe threads.
called fluidmaster they said the stuff will eat/melt the plastic threads and cause a leak...on their fill valve..... what will really happen to the plastic threads?

Hey Bob,

    That's a really good question and I'm sure it's a common thing for people to do.  Some thread sealants are simply a teflon formula which doesn't have anything caustic or solvents in the mixture.  Some however, have solvents and such for creating a tighter bond... in some applications like, for gas pipes and high pressure systems or steam, different kinds of sealants are needed to prevent leaks.

    If the sealant that you used is a basically white or off white compound then I wouldn't be too concerned.  But if it is blue or yellow or red in color, then it may be one of the special blends with the solvents in it.  You can wipe off as much of the sealant as possible with a rag and then re-install it. Or you could just wait and see if a leak develops.

Plumbing in the Home

All Answers

Answers by Expert:

Ask Experts


Thomas Ambler


I am experienced at troubleshooting and solving all types of plumbing problems. Issues related to specific manufacturers fixtures and specifications though are beyond my field of expertise. I have dealt with problems in both rural and urban areas, and with water supply and drainage systems. Plumbing issues can be very obscure... such as odors, stains or occasional seepage. I have even had to chase rats from a customer's sewer line.


I have 25 years experience dealing with plumbing systems (which also includes hot water and steam heating systems). My main expertise is in diagnosing and solving problems. I have worked in construction and installation of new systems but do not regard myself as an expert in that area.

Asbury Park Press, Seattle Times, Denver Post.

I completed high school and one year of college. I served 4 years in the Marine Corps and have education in electronic and electrical troubleshooting and repair. I have attended classes on installing and repair of oil burners, and I have EPA universal certification for air conditioning and refrigeration. I am now enrolled as a full-time student at Everest college to re-train for a new career. Any donations of financial support would be greatly appreciated.

Past/Present Clients
All of Denny's Restaurants in NJ, Several Burger King stores, I have done work at two different homes for Bruce Springsteen. I have also worked for Jim Johnson (of J&J) and his family, Whitney Houston, Steve Forbes and many others.

©2017 All rights reserved.