Sealant for boiler

[Garry ColesParticipant @garrycoles69390]

Hi, I’m about to drill and tap the foundation ring on my boiler. If I go to deep with the pilot drill into the foundation ring, and go right through, what is the best way/seanlant for sealing the studs when I put them in. I will of course try and not to drill right through, but just in case I do I thought I’d better ask the question.

Cheers

Garry

[noel shelleyParticipant @noelshelley55608]

AVOID breaking through at all cost ! Make or use whatever it takes to prevent this happening. IF it does use a thread sealant that is good for 150*c + There are many, BUT proper preparation prevents poor product performance. In this context use solvents etc to remove ALL oils Etc before sealing. Good luck. Noel.

[DurhambuilderParticipant @durhambuilder]

I’ve just counted up on my 2” scale traction engine, there are 38 instances of holes tapped through the boiler shell (either through thickening plates or bosses) where threaded fixings go through to the pressurised water/steam space. I used Loctite 290 on the bolt threads holding the cylinder block down and a generic ptfe liquid on the steam fittings, no problems or seepage in 10 yrs steaming.

[Paul LousickParticipant @paullousick59116]

All of the studs that hold the cylinder block on my traction engine are tapped thru the boiler wall and the threads are coated with graphite type sealer. (traditional sealer used on steam engines). Full size engines use carrot bolts that have a reverse taper on the head and are inserted from the inside of the boiler.

[VersabossParticipant @versaboss]

Paaul, are these carrot bolts edible?

Sorry, couldn’t resist.

More on topic: the blue Hylomar stuff is good for steam temperatures:

– Non-hardening and non-setting
– Wide operating temperature range (-50 to +250ºC)
– Resistant to fuels, oils, coolants and gases

(Copied from their webpage).

Regards,
Hans

[Versaboss]

On Versaboss Said:

Paaul, are these carrot bolts edible?

Didn’t LBSC recommend potato water for leaky boilers?

[Nigel Graham 2Participant @nigelgraham2]

I’ve followed this thread as I have an awkward repair on a 7¼”g loco, and it would seem the only way will involve extending blind holes in a flange, through the tubeplate in which it is silver-soldered.

The flange holds the end of the internal steam pipe and the superheater’s wet header: some of the short female threads for the 2BA studs are partially stripped.

So the collective advice here is that it will be feasible, using special two-diameter studs; e.g. M6 Fine in the bush, still 2BA for the header, and one of the sealants suggested above.

””’

Carrot bolts….. Allergy advice: may have been made in premises that handle nuts.

[Garry ColesParticipant @garrycoles69390]

Hello again, thanks for your replies. I have drilled and tapped all 10 of the 4BA bolt holes and with keeping an eye on the drill depth, I didn’t go through the foundation ring at all.

Garry

[Author]

Posts