Getting Marelon valve tailpieces pointed the right way

[Tin Kicker]

I installed a couple of the 1" Forespar Full Flow thru hull valves and the handle for each HAD to be in a certain orientation. The problem came when installing the 90 degree tailpieces because when the elbows threaded down snug, one was almost opposite the direction it must go and the other was about 90 degrees past where I needed it. How to get them pointed in the right direction?

I came up with the following 4 ideas:
1. Lots of PTFE tape only changes the direction by a few degrees.
2. I found some plastic/nylon plumbing packings that are perfect in both ID and OD, which get the tail pieces closer to the right direction.
3. Another thought is to use a lathe to trim the threaded end of the tail piece.
4. I could also use a non- hardening joint compound, but the tail piece will not be fully seated. Note that Forespar says to NOT use a permanent cement like 5200 so the tailpiece can be removed in the future. One good reason is to occasionally put some Marelube on the ball.

I wrote an email to Tech Support at Forespar and got the following answer which is worth sharing:

You will be better off using 3-M 4200 to seal and act as a glue for holding a right angle hose barb in the direction that you require. The 4200 will allow you to remove the barb at a later date if needed.
Randall Risvold
Forespar
sts@forespar.com
949 858 8820 ex. 102

 

[Loren Beach]

That idea from Forespar sounds practical. In past years I have used a good sealant to do just that, when making the final turn and trying to achieve the output angle that was needed.

 

[Kenneth K]

I had the same problem a few years ago. I used a belt sander to take a little material off the bottom of the fitting (a lathe might be even better).




Some Marelon valves/fittings have a raised ring around the inside. I think this ring acts as a seal against the surface it is mated to. After sanding my Marelon elbow, I could see the imprint that the raised ring left on my sanded fitting, so I knew it was "square" and would seal well. I always use general purpose PTFE pipe sealant on my Marelon fittings--never had a leak. But, if the fitting isn't screwed down tight, you'd need to use an adhesive sealant (like 4200) to hold it in place.

 

[peaman]

1. Lots of PTFE tape only changes the direction by a few degrees.

For this option, note that most plumbing supply sources should have available double thickness PTFE which might be easier to deal with. It is yellow in color, and is the only type allowed for use in a propane system, which is how I learned about it.

 

[Pete the Cat]

I am not sure this is common, but I recently had a 90 degree tailpiece from a Marlon valve that I believe was installed at the factory, completely disintegrate when I attempted to turn it. It did not break off, it didn't just crack, it completely dissolved into peanut sized crumbs with very little effort. It is possible that this was some aftermarket PVC by a PO, but it made me. nervous about these pieces. Had something hit it, it certainly would have been catastrophic. FWIW.