Removing a rusted boiler plug

Most homeowners never have to do this, but on this forum there are many DIY, so I'll pass this on. The plug in the picture is one inch. The tools I used were a cut-off wheel, a drill, and a reciprocating saw.


Cut or grind the square casting off the plug leaving some thread exposed beyond the face of the boiler fitting. Drill 4 small pilot holes.


Enlarge the holes a little at a time in a sequence. Drill all the way through and hopefully you'll have an opening large enough for a saw blade to go through.


Cut towards the edge but not into the steel threads. The hole is tapered. When you make contact with the steel, the screeching will warn you. It is only necessary to get within a 1/16" of the steel. Cut into quarters and then make an eighth cut to make it easier to punch that piece out. The rest of the pieces will then fall out.


Punch the pieces out. Retrieve the pieces with a thin pencil magnet. It should take less than 10 minutes for each plug.

Good tip, But should I use this procedure AFTER I twisted off the square end of the plug? Or BEFORE the frozen plug gets messed up by trying to remove it?

stoker-man wrote:Most homeowners never have to do this, but on this forum there are many DIY, so I'll pass this on. The plug in the picture is one inch. The tools I used were a cut-off wheel, a drill, and a reciprocating saw.

aaextra 043.jpg

Cut or grind the square casting off the plug leaving some thread exposed beyond the face of the boiler fitting. Drill 4 small pilot holes.

aaextra 054.jpg

Enlarge the holes a little at a time in a sequence. Drill all the way through and hopefully you'll have an opening large enough for a saw blade to go through.

aaextra 052.jpg

Cut towards the edge but not into the steel threads. The hole is tapered. When you make contact with the steel, the screeching will warn you. It is only necessary to get within a 1/16" of the steel. Cut into quarters and then make an eighth cut to make it easier to punch that piece out. The rest of the pieces will then fall out.

aaextra 050.jpg

Punch the pieces out. Retrieve the pieces with a thin pencil magnet. It should take less than 10 minutes for each plug.

Or one can use a torch and heat up the plug and threads and use the correct size pipe wrench with a pipe on the handel for extra leverage and break it loose no chance of screwing up the threads with a saw blade

Was that a hollow cast plug or a solid forged plug?

But I like the approach in the absence of blasting the external area around the threads with a blue flame. Sometimes the square head becomes so rounded or buggered, you may not be able to use the Rigid.

Cap wrote:Was that a hollow cast plug or a solid forged plug?

But I like the approach in the absence of blasting the external area around the threads with a blue flame. Sometimes the square head becomes so rounded or buggered, you may not be able to use the Rigid.

The torch works 99.9% of the time see it done on a weekly basis Cast plug on the return some of the older ones used forged plugs either way the torch works .

coal berner wrote:

Cap wrote:Was that a hollow cast plug or a solid forged plug?

But I like the approach in the absence of blasting the external area around the threads with a blue flame. Sometimes the square head becomes so rounded or buggered, you may not be able to use the Rigid.

The torch works 99.9% of the time see it done on a weekly basis Cast plug on the return some of the older ones used forged plugs either way the torch works .

What size welding tip do you use on your torch? Oxy/Mapp or Oxy Acetylene

Cap wrote: What size welding tip do you use on your torch? Oxy/Mapp or Oxy Acetylene

I wouldn't try cutting it out with a torch. I'd just heat it up. Let it cool down a little, and put the pipe wrench to it again.

Cap wrote:

coal berner wrote:

Cap wrote:Was that a hollow cast plug or a solid forged plug?

But I like the approach in the absence of blasting the external area around the threads with a blue flame. Sometimes the square head becomes so rounded or buggered, you may not be able to use the Rigid.

The torch works 99.9% of the time see it done on a weekly basis Cast plug on the return some of the older ones used forged plugs either way the torch works .

What size welding tip do you use on your torch? Oxy/Mapp or Oxy Acetylene

You use the torch to heat it up not to cut it out once it is heated to red used the pipe wrench to turn it out
what is a welding torch I am talking about a cutting torch OXY & Acetylene you do not weld with a torch you heat & cut
with one You use a welder to weld with. I would hope you would know the differents between the two .

Excellent description for fixing a situation!

But I like the approach in the absence of blasting the external area around the threads with a blue flame. Sometimes the square head becomes so rounded or buggered, you may not be able to use the Rigid.[/quote]
The torch works 99.9% of the time see it done on a weekly basis Cast plug on the return some of the older ones used forged plugs either way the torch works .[/quote]
What size welding tip do you use on your torch? Oxy/Mapp or Oxy Acetylene[/quote]
You use the torch to heat it up not to cut it out once it is heated to red used the pipe wrench to turn it out
what is a welding torch I am talking about a cutting torch OXY & Acetylene you do not weld with a torch you heat & cut
with one You use a welder to weld with. I would hope you would know the differents between the two .[/quote]

JC, i got you!.. The heating tips on a torch are actually welding tips. Used in the old days before electric welding become so popular! I would use a #7 tip to heat the plug of that size.

Also you may not know, Mapp gas is a hotter fuel on the secondary flame. But Acetylene is hotter on the primary side of the flame which is what you use to cut.

The plugs were the solid cast type with the square end on them. They wouldn't budge and with the extender on the pipe wrench, the ends broke right off.

I also have a torch set, but probably most homeowners do not.

Nice tutorial. Thank you!

Cap wrote:But I like the approach in the absence of blasting the external area around the threads with a blue flame. Sometimes the square head becomes so rounded or buggered, you may not be able to use the Rigid.

The torch works 99.9% of the time see it done on a weekly basis Cast plug on the return some of the older ones used forged plugs either way the torch works .[/quote]
What size welding tip do you use on your torch? Oxy/Mapp or Oxy Acetylene[/quote]
You use the torch to heat it up not to cut it out once it is heated to red used the pipe wrench to turn it out
what is a welding torch I am talking about a cutting torch OXY & Acetylene you do not weld with a torch you heat & cut
with one You use a welder to weld with. I would hope you would know the differents between the two .[/quote]

JC, i got you!.. The heating tips on a torch are actually welding tips. Used in the old days before electric welding become so popular! I would use a #7 tip to heat the plug of that size.

Also you may not know, Mapp gas is a hotter fuel on the secondary flame. But Acetylene is hotter on the primary side of the flame which is what you use to cut.[/quote]

Yes I Know The Differents in Mapp & Acetylene Gas . Maybe they where called welding tips in the old days But Today in 2009 there called torch tips http://www.nationaltorch.com/tips.html

stoker-man wrote:The plugs were the solid cast type with the square end on them. They wouldn't budge and with the extender on the pipe wrench, the ends broke right off.

I also have a torch set, but probably most homeowners do not.

Yes you are probably right that most homeowners do not have a torch .
But on the other hand most home owners should not try this in there basement or anywhere else either .
They should get someone that knows what there doing to fix it .
Cutting into them threads with a saw blade or hitting them with a chisel or a punch is not a good thing either
alot more work & time to fix them.

I have always used "the Fire Wrench" FIRST! If you bugger the square cap, it will be a long day with drill bit sharpening, breakage, sawzall time.....perhaps a screw-up. Heat it uniformly, have the pipe wrench adjusted properly and a couple of pipe extentions at hand. This sure saves some skin, and leaves time for other projects. Same is true on the nuts for hot water coils....don't even think that they will just spin off without soaking or heat. You only get one chance with them, and you don't need to play "Gorilla" with a 1/2" stud and nut. PS: chase the studs, and add some anti-seize before you reassemble anything on solid fuel appliances.

38 outside at 6AM......days getting shorter......fire them up boys!!! (and young ladies, sorry Lisa, forgot my manners)