Bathtub drain retrofit project

[Dougster]

I want to retrofit my 58 year old enameled steel tub with a new plastic drain kit such as Watco or Geberit without replacing the tub itself.

However the old light colored sealant between the base of the tub and the brass drain shoe feels quite hard to the touch. I am concerned it is hard bonded epoxy rather than old hardened plumbers putty. The potential problem is epoxy might be hard to remove and scrape clean. The new drain kits use a rubber gasket, but a good seal will require a fairly clean and smooth surface restoration around the drain hole on the underside of this metal tub.

For photo see http://imgur.com/a/DZJUy (“Old steel bathtub - drain shoe and sealant detail”)

I would like feedback from folks who had a similar project re:
(a) What material is this old sealant?
(b) What is the probability of success in removing the old sealant and restoring the surface of the existing steel tub under the drain hole?

 

[frodo]

yeah, looks like bubba be put the smoosch all over it.

but, looking at the picture, it appears to be smeared on the OUTSIDE of the drain.

looks like bubba did you a favor. after you remove the shoe, i think you will find a clean surface underneath

if not, sand it till you have a smooth surface

that thick rubber gasket is just that, a thick gasket that contours itself to uneven surfaces

 

[Dougster]

This is the first I've heard of bubba! I'd like to shake hands!

Did bubba's ever use epoxy in the 50's? (I'm simply laid-back curious now, since it sounds like sanding will handle epoxy even if it's hard bonded to the metal. My impression was the gasket fluid both oozed out when bubba tightened the strainer from above, yet a thin layer might also remain between the tub metal and the brass drain flange.)

 

[frodo]

oh yeah, Bubba is famous down here for screwing stuff up.
Bubba works at the grocery store or ice cream shop, but thinks he can fix anything with duct tapte caulk and bailing wire

sometimes i would like to have a hand to mouth talk with Bubba

 

[Dougster]

Let me lay the groundwork and put a good word in for you, frodo with bubba first.

I have a similar question re. the overflow flange higher up: The existing gasket in this location is now rubber, but the tub metal appears to have flaky surface rust around the overflow port. Will sanding handle this area too (after wire brushing off any loose rust)?

( For two new photos at the overflow: again see http://imgur.com/a/DZJUy )

 

[frodo]

thats some bad rust. if you want to keep that tub

you need to grid out the rust and paint the metal.

it really does not look deep from here. but you will not know till you remove the drain and start working on it

i would hit it with a 4 1/2 grinder with a wire wheel first, then see what you have

wire wheel it to shiny metal, then use rustoleum

rust does not stop, get it alll out, if you paint over the rust it will come back

 

[Dougster]

frodo -

My original goal was to replace the old tub drain shoe & overflow assembly with plastic.

This was because the bigger project replaces the nearby galvanized drain lines with ABS, including the trap.

However given the rust on the tub’s overflow flange, a safer approach might be to keep both the old tub AND the drain assembly, and just cut away the brass slip nut below the tee, leaving a stub of a tailpiece. (I figure I can leave enough of a stub for a Fernco DTC-150 to grab, i.e. at least 1-1/16”.)

The detailed steps are in the fourth photo I just added to http://imgur.com/a/DZJUy

What do you think of this approach, e.g. am I too optimistic about the old tailpiece holding together?

Thanks for your input

 

[frodo]

try this. that thin brass pipe you want to cut. is threaded into the bottom of the tee

try to unscrew it, remove it.

then, remove the nut that is below where yyou want to cut.

install a fitting x female adapter and a female adapter

http://www.supplyhouse.com/Spears-478-015-1-1-2-PVC-Schedule-40-Spigot-x-Female-Adapter

http://www.supplyhouse.com/Spears-435-015-1-1-2-PVC-Schedule-40-Female-Adapter

 

[Dougster]

frodo -

Thanks for your drawing & instruction to use a threaded plastic adapter.

It sounds like this is preferred over a no-hub coupling given a possibly weak tailpiece.

BTW I do not think I need your second adapter because I would just be cutting away everything from that point, i.e. I will be changing all downstream lateral drain lines and fittings to ABS (see crawlspace view - photo # 7).

Also, I think I would put a HUB female adapter onto the old tub drain brass tee instead of the SPG version if I’m using ABS pipe between the adapter and a new ABS trap.

(I added three more photos 5, 6 & 7 at http://imgur.com/a/DZJUy --- showing the trap, sanitary tee, vent riser, and a view of the whole catastrophe from under the crawlspace.)

Q1. If the old brass tailpiece is corrosion-welded into the tub drain brass tee, can I just cut it off immediately below the tee’s threads? Or does the remnant that remains within the tee need to go too, ideally? (E.g. could it corrode out later and cause a blockage?)

Q2. Does an ABS female adapter perform just as well on old metal threads as PVC?

(BTW I now remember using an ABS female adapter ~ 5 years ago under my lavatory sink where the chromed brass tubular drain between the trap and wall sanitary tee was “corrosion welded” into the brass trap adapter. Unthreading the adapter’s brass slip nut (after sawing away the tube and ferule) exposed a 1.5” male slip joint thread on the body of the old adapter. This accepted some yellow tape and a 1.5” Charlotte ABS #105 SPG x FPT adapter, followed by an ABS HUB x SLIP adapter.)