Rusty NEW MoM main vents

Jim_X · September 2022

Just had three MoM #1 vents ordered for me. Not looking for a discussion on Gorton vs MoM. I can't fit a #2 vent and money is tight. Regardless, the vents all had rust in them on the bimetal strips. The vents are new, the boxes were dusty but new and no signs of water damage. The vents are new and have no signs of being installed. Date code has them made in 2020.

I spoke with MoM and they are sending me replacements and want the old new ones back to cut them open. one I pulled off the shelf a couple years back and have had in use has no rust in it.

Also spoke with MoM about no supplies having the vents on the shelf. All you can get here are Ventrite #11 and #35s. They also told me that in 2019 they stopped production in China and brought it back to the USA.

Jim_X · September 2022

Received my replacements today. All 2020 vents....and all rusty as well. Not sure what the deal is. Has anyone else seen this before?

109A_5 · September 2022

You would think they would check them before they shipped them. Maybe that is just how they are made (materials wise). Do you have an old failed one to dissect ?

ChrisJ · September 2022

109A_5 said:

You would think they would check them before they shipped them. Maybe that is just how they are made (materials wise). Do you have an old failed one to dissect ?

Rusty old bi metal is how they're made?

109A_5 · September 2022

ChrisJ said:

109A_5 said:

You would think they would check them before they shipped them. Maybe that is just how they are made (materials wise). Do you have an old failed one to dissect ?

Rusty old bi metal is how they're made?

@ChrisJ, I'm waiting for your explanation. They look unused on the outside, maybe they are 100 years old NOS item, 1920 not 2020. Maybe Scotty beamed the rust in there just to mess with @Jim_X. Maybe they are counterfeit but I believe @Jim_X got the latest ones directly from MoM.

Hap_Hazzard · September 2022

The bimetallic strip has to be made of hardened steel so it will consistently return to the same shape over multiple thermal cycles. This layer can’t be plated because this would add an additional layer of unlike metal and change the thermomechanical properties of the spring, but it is somewhat protected from rust by bluing; however, some rusting can still occur, but this will be superficial and will not affect the function of the vent.

I assume that the rust you see on new products is there because they test the finished vents before they ship them. If they want to prevent this, they could add a post-test drying step to their process, but if customers aren’t complaining, it’s not worth the expense, so I assume they don’t see it as a problem.

If the vent you have isn’t closing to steam, try turning the vent upside down and blowing into it and see if it closes. If it doesn’t, the defect is in the float or the valve seat. If it does, then there is something wrong with the bimetallic spring or how it’s assembled, but it probably has nothing to do with the surface rust.

Jim_X · September 2022

My old vent is fine, just had room to make an antler add more vents. MoM or Gorton #1 is the tallest I can really fit.

BenDplumber · September 2022

Maybe your old vent has been steam cleaned from use in your system. Install the new vent from MoM and see after some usage if it as clean as your previous one. I'm sure a account of the issue has been posted to the correct personal if they sent you a new one under warranty. A lot of surface corrosion can be from non use, just check your cars disc brakes after sitting for several days after a rain if you haven't driven it. Plenty of surface rust, drive and brake a couple of times around the block and it's fine. Test drive your new vent and see what it looks like after a couple miles, if still rusty and not working contact the manufacturer again.