Sealing threads into shower fittings

Joined
10 Dec 2009
Messages
17
Reaction score
0
Location
Leicestershire
Country
United Kingdom
I'm having a lot of trouble sealing parallel pipe threads into Grohe shower fittings (Rapido SmartBox 35600 and Rainshower 26483000). The threads are G 1/2, which I believe are identical to 1/2" BSPP: I've used Flomasta male couplers (Screwfix 69358). I first tried 4-5 turns of PTFE tape, but got leaks; quite slow leaks (the fastest produced about 1 drop/min, some others gave just barely detectable seepage), but leaks nonetheless. I then removed the fittings, cleaned off the PTFE, and tried more tape (8-10 turns) - some still leaked. I've never had trouble with sealing threaded joints I've made in the past (and, for clarity, I was winding the tape on in the correct direction - clockwise looking towards the male thread). I've now used Tru-Blu sealant from Toolstation, gave it a good long time to cure (60 hours+), and I have still had leaks.

What would people recommend? I've seen recommendations for Loctite 55, which is PTFE cord, I believe; does this have an advantage over tape? Also for Flomasta PTFE liquid from Screwfix; I went for the Tru-Blu stuff instead, as it seems the PTFE liquid sets quickly, and I was concerned that it would set, and then I'd risk cracking it when I was tightening the compression joints (which are all fine).

I'd be grateful for any advice - particularly from anyone who has (successfully!) fitted the Grohe rough-in boxes mentioned.

Thanks,

Rob
 
Sponsored Links
+1 for Loctite 55. They do however recommend scratching the threads to help keep it captive.

 
If you look at the installation video (there don't appear to be any proper written instructions) the pipes appear to have some sort of white plastic sleeve / flat olive on the end. This makes me wonder with they are intended for tap connectors rather than screwed fittings.
 
Sponsored Links
Heldite, sealing compound, dries like varnish, easy to remove works on water, steam, air etc.

 
Thanks for your replies. I'll try Loctite 55 (Old Salt, it says Heldite is not suitable for potable water - although I'm not in the habit of drinking from a shower :), I think I'll try an inert option first).

Re the video: it shows its use on iron/steel threads, but I assume it's equally suitable for brass fittings? And re scratching the threads (with a Stillson, it seems) - do you (Exedon and opps) do that? It seems to me that that potentially creates a leakage path over the top of the metal threads - wouldn't it be sufficient to just cross the cord over itself (as shown) to keep it in place?
 
Yes works fine on brass to be honest I use bit more than the video shows .If you want to rough up threads a bit hacksaw blade works fine,
 
@Jackrae : Thanks for your reply, but in my case, the two rough-in boxes do not appear to have been manufactured with that in mind: the (pictorial) instructions show threaded fittings sealed with tape. In the case of the showerhead box, the brass body is cylindrical, so that there is no flat face that a washer could seal against; it might be possible for the connections to the Smartbox (for the controls), but the sealing surface would be very narrow (~1mm).

On your general point: I can see that a sealing washer would allow for a more dependable seal, but don't radiator valves have parallel threads, sealed with PTFE tape/cord?
 
@Jackrae : Thanks for your reply, but in my case, the two rough-in boxes do not appear to have been manufactured with that in mind: the (pictorial) instructions show threaded fittings sealed with tape. In the case of the showerhead box, the brass body is cylindrical, so that there is no flat face that a washer could seal against; it might be possible for the connections to the Smartbox (for the controls), but the sealing surface would be very narrow (~1mm).

On your general point: I can see that a sealing washer would allow for a more dependable seal, but don't radiator valves have parallel threads, sealed with PTFE tape/cord?
One the first point - A very poor design by the manufacturer who obviously doesn't understand basic engineerong principles. But, as that's what you have, then that's what you must use. Rather than relying on teflon tape products to botch the fitting, I'd suggest using a setting liquid or paste sealant. In the past I have never failed to achieve quality sealing between 'difficult' fittings by using a product called "AtmosPaste". It's 2-part epoxy designed to repair ceramic sanitryware and is rated to 100c.

On the second point - All the radiator valves I have fitted have always used taper seal threads on the fitting that connects to the radiator.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top