Boiler drain nut broke off, what to do?

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
man2112
Posts: 24
Joined: September 1st, 2017

Postby man2112 » Sep 12, 2017, 5:37 pm

Hey all,

I've been working on restoring this VFA Expres Elite 2gp the past few weeks, and I ran in to an issue. During reassembly, the boiler drain plug had sheared off as I was tightening it in to the boiler. No big deal, I ordered a replacement.

Today the replacement came in, so I set to work removing the old plug.

When I did, the whole bung hole nut broke apart in to brittle, "mushy" pieces.

Attached is a picture of my boiler, now without the drain nut.

I've finally gotten everything else in this machine working, but now this makes me question the integrity of the boiler.

I only have about $200 total in the machine.

Should I get a copper or brass bung and braze a new one on?

Or should I cut my losses and part out the machine?

New boilers cost about $800 plus shipping from Europe to the US.

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samuellaw178
Posts: 1786
Joined: April 10th, 2011

Postby samuellaw178 » Sep 12, 2017, 5:48 pm

Do you have much clearance in the boiler to work with? Some quick and easy fix if you do.. p/s: maybe not such a brilliant idea considering part of the sheared off piece is still in the boiler..

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man2112
Posts: 24
Joined: September 1st, 2017

Postby man2112 » Sep 12, 2017, 5:54 pm

samuellaw178 wrote:Do you have much clearance in the boiler to work with? Some quick and easy fix if you do..

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Would that withstand the pressure? Because yeah, I have the room, I could pull out the heating coils and get at it from the other side.

samuellaw178
Posts: 1786
Joined: April 10th, 2011

Postby samuellaw178 » Sep 12, 2017, 6:07 pm

That's almost exactly how the heating element and HX on my machine are fastened to the boiler plate. It's been sealing fine for decades, so it withstood the pressure ok. As long as the boiler end is flat enough for sealing purpose .

Some pictures from my restoration to illustrate the sealing method..

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man2112
Posts: 24
Joined: September 1st, 2017

Postby man2112 » Sep 12, 2017, 7:25 pm

Interesting! I wonder what you would call a type of fitting like that? Edit: I remembered that they're called bulkhead fittings. I'll look for a copper one of appropriate size!

samuellaw178
Posts: 1786
Joined: April 10th, 2011

Postby samuellaw178 » Sep 12, 2017, 7:54 pm

I wasn't even aware they have a name! Learnt something new today :lol:

OldNuc
Posts: 1725
Joined: January 2nd, 2014

Postby OldNuc » Sep 13, 2017, 8:57 am

The failure point of the bulkhead fitting is the soft seal. Must be a high temperature material such as silicone etc.

DaveC
Posts: 541
Joined: November 20th, 2006

Postby DaveC » Sep 13, 2017, 9:06 am

man2112 wrote:Hey all,

I've been working on restoring this VFA Expres Elite 2gp the past few weeks, and I ran in to an issue. During reassembly, the boiler drain plug had sheared off as I was tightening it in to the boiler. No big deal, I ordered a replacement.

Today the replacement came in, so I set to work removing the old plug.

When I did, the whole bung hole nut broke apart in to brittle, "mushy" pieces.

Attached is a picture of my boiler, now without the drain nut.


If you can try get a brass bolt and washer (if can get a tool down there to hold the head) down into the boiler, or try a brass star washer if you can't. On the other side use a brass/copper washer and nut to seal. you may well need a sealing washer (mad made fibre etc..) or some sealing compound.

man2112
Posts: 24
Joined: September 1st, 2017

Postby man2112 » Sep 13, 2017, 7:10 pm

OldNuc wrote:The failure point of the bulkhead fitting is the soft seal. Must be a high temperature material such as silicone etc.


What about a bead of high-temp food grade RTV?

OldNuc
Posts: 1725
Joined: January 2nd, 2014

Postby OldNuc » Sep 13, 2017, 11:35 pm

I suspect that RTV of any of the multiple types would be a poor choice. If it was my boiler I would examine the failed pieces carefully and determine the cause of failure before doing anything. If it was determined the boiler metal shell was structurally sound I would probably silver solder on a replacement proper nozzle fitting. Back yard repairs on pressure vessels is a high risk undertaking right up there with welding on tire rims with the tire mounted on the rim or welding on gas tanks.

 
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