What is the best way to clean rust before painting a cast iron stove?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

Big VA

New Member
May 4, 2011
16
Poconos, PA
I am trying to fix up a used defiant 1945 before it gets cold.
I ordered a CAT for $99 - hopefully it will work fine.
All the gaskets need to be replaced (will appreciate tips)
The stove looks very rusty, so I wanted to paint it. Does anyone have advice for what paint should be used? What is the best way to clean rust?

The flue collar has a gap of 1/8 of an inch (see photo.) Will Rutland furnace cement do the job filling it?
 

Attachments

  • 100_0720.jpg
    100_0720.jpg
    49.5 KB · Views: 430
  • 100_0722.jpg
    100_0722.jpg
    38.8 KB · Views: 515
  • 100_0723.jpg
    100_0723.jpg
    31.9 KB · Views: 439
Looks like a wire brushing will suffice, followed by a wiping with alcohol.

But it also looks like the connector pipe is installed upside down. The crimped end of the pipe is supposed to point toward the stove. That will cause dripping creosote to stay within the pipe instead of dripping down on the outside of it. Also the pipe is not fully inserted in the joint shown. It looks about 3/4" shy in length and I don't see any screws at the joints. Also suspect is the ceiling support or lack thereof. Can you post a better picture at the top of the pipe? How is the single wall connected to the class A pipe and where does this transition take place? It's hard to see from the pictures.
 
Big VA, welcome to the forum.

BeGreen is right on with his assessment. And before putting that stove pipe together we like to put furnace cement on the joints before they are put together. With the furnace cement, that also will stop any air leaks into the pipe which will cause more creosote because of cool air being mixed with the warmer flue air. The furnace cement goes on easy and is cleaned up easy with water and a rag. In addition, it is cheap so we aren't talking any big dollars here. Also at the joint to the stove. On changing the stove pipe to the other direction you can get an adapter which will allow the pipe to be put in right.

Remember, 3 screws per joint in the flue. #6 or #8 self tapping screws work nicely.
 
Big VA said:
...
The flue collar has a gap of 1/8 of an inch (see photo.) Will Rutland furnace cement do the job filling it?

I have filled a gap like that with a regular gasket rope topped off with furnace cement. If you can get the gasket to fit tightly all the way around the flue collar-pipe joint, then the furnace cement is not needed.
 
Before you go nuts trying to scrape off rust and paint the whole thing just try Rutland stove polish on it. You don't even need to scrape off the rust, just go over it with a rag and stove polish (unless it is really deep rust.) The rust on the pictures is not bad. It'll look brand new after you're done. You can buff it out for a polished look or leave it unpolished for the mat black look. Just make sure you fire it up one day and break it in with the windows open. It gives off a smell during the curing period. You'll have to do break in fires anyway, I'd recommend anyone with a cast iron stove should do them every year. The cement seams do absorb moisture and may suffer some thermal shock if you warm up the stove too fast in the first burn of the season. This could cause premature cracking of the cement.
 
BeGreen said:
Looks like a wire brushing will suffice, followed by a wiping with alcohol.

But it also looks like the connector pipe is installed upside down. The crimped end of the pipe is supposed to point toward the stove. That will cause dripping creosote to stay within the pipe instead of dripping down on the outside of it. Also the pipe is not fully inserted in the joint shown. It looks about 3/4" shy in length and I don't see any screws at the joints. Also suspect is the ceiling support or lack thereof. Can you post a better picture at the top of the pipe? How is the single wall connected to the class A pipe and where does this transition take place? It's hard to see from the pictures.

The pipes connect in that still box below the ceiling. Water drops come down from that box when it rains. I think I need a larger size pipe cap.
 

Attachments

  • 1.jpg
    1.jpg
    43.4 KB · Views: 423
  • 2.jpg
    2.jpg
    42.3 KB · Views: 430
  • 3.jpg
    3.jpg
    83 KB · Views: 447
  • 4.jpg
    4.jpg
    77.9 KB · Views: 418
  • 5.jpg
    5.jpg
    136.7 KB · Views: 437
This flue system was poorly installed. There should be no water or creosote dripping down the pipe. Lord knows what was done in the support box, but from the image it almost looks like someone ran single-wall up through the double-wall outdoor pipe. The water leaking looks like it may be because the storm collar is not siliconed to the main pipe. Though it is hard to tell if that is the only cause with the mess happening at the top. You can see they put a second storm collar up there.

It's a short run. I would pull it all out and redo it correctly and safely. If you can determine the mfg of the pipe and support box that would be great. It would be nice to keep the support box in place.

Each connector joint needs 3 screws 120 deg apart according to code. The "why" is because stuff happens and you don't want that pipe falling apart when there is a blazing fire in there, especially if you are not home or asleep. If that stove has one healthy puffback, it could blow those joints right apart. Same thing if someone accidentally hit them with something. For example, like using a step ladder indoors and turning around with it.
 
Big VA said:
Why does each joint need 3 screws?
The pipes were original to the house and there were no screws...

Listen to this man as he knows what he's talking about. He has corrected my set up more than once here! :red: But it's all in the name of safety. He has probably saved a lot of heart ache! Thanks BeGreen for all the advice you've given me in the past! The screws are easy to put in and will secure your pipes together. Just because they were like this when you moved in doesn't make them safe, or correctly done. When it comes to fire safety there is no room for skimping.
 
VCBurner said:
Big VA said:
Why does each joint need 3 screws?
The pipes were original to the house and there were no screws...

Listen to this man as he knows what he's talking about. He has corrected my set up more than once here! :red: But it's all in the name of safety. He has probably saved a lot of heart ache! Thanks BeGreen for all the advice you've given me in the past! The screws are easy to put in and will secure your pipes together. Just because they were like this when you moved in doesn't make them safe, or correctly done. When it comes to fire safety there is no room for skimping.

+1 BG gave solid advice with no gray areas.. There are too many things wrong in those pics and the install would not pass inspection.. For peace of mind I'd redo that entire chimney and make it safe and legal..

Ray
 
Thank you for advice everyone. It seems like I have some work to do.
Can any of the piping be reused?
What should be in the support box? It seemed like the pipe is just resting its weight on the stove...
 
It's possible that some of the piping like the interior black pipe can be reused. I'm less certain about the exterior pipe. That can be determined after seeing it's condition, size, brand and whether the support box can still be functionally and safely reused. One thing that concerns me is that the upper pipe would have to be pretty large to pass an 8" connector up through it. Also, the goobering of sealant around the base of the flashing it suspect if it is actually sealing holes in the flashing. But it could just be a misguided attempt to stop water entry.
 
BeGreen said:
This flue system was poorly installed. There should be no water or creosote dripping down the pipe. Lord knows what was done in the support box, but from the image it almost looks like someone ran single-wall up through the double-wall outdoor pipe. The water leaking looks like it may be because the storm collar is not siliconed to the main pipe. Though it is hard to tell if that is the only cause with the mess happening at the top. You can see they put a second storm collar up there.

It's a short run. I would pull it all out and redo it correctly and safely. If you can determine the mfg of the pipe and support box that would be great. It would be nice to keep the support box in place.

Each connector joint needs 3 screws 120 deg apart according to code. The "why" is because stuff happens and you don't want that pipe falling apart when there is a blazing fire in there, especially if you are not home or asleep. If that stove has one healthy puffback, it could blow those joints right apart. Same thing if someone accidentally hit them with something. For example, like using a step ladder indoors and turning around with it.

+1 . . . definitely time to fix it and do it right . . . and eliminate a lot of future issues now.
 
Big VA said:
Does support box have to support the weight of the pipe?

With this type of install, yes, Though the roof is what is actually supporting the weight. The top of the cathedral support box should be flanged under the roof flashing and nailed to the roof and hopefully also nailed to a brace behind the box.
 
I took apart the chimney and took some pictures.
The support box does not support the weight of class A pipe.
The weight of the chimney is on the stove.
Is that a serious problem?

Single wall pipe runs into the support box and is connected to class A by male-male connector inside of the box.
I reversed the direction of the interior pipe and put it together without adding more support.
I used furnace cement and 3 screws for each joint except the connection of the Class A to single wall pipe which takes place inside of the "support box"

I will appreciate any advice (I have never put a chimney together before.)
 

Attachments

  • 100_0736.jpg
    100_0736.jpg
    100.9 KB · Views: 243
  • 100_0737.jpg
    100_0737.jpg
    59.1 KB · Views: 247
  • 100_0741.jpg
    100_0741.jpg
    66.1 KB · Views: 238
  • 100_0743.jpg
    100_0743.jpg
    78.2 KB · Views: 222
  • 100_0745.jpg
    100_0745.jpg
    70.4 KB · Views: 233
I haven't installed Amerivent, but this looks like a predecessor to their TLC pipe. From what I can see it looks like it was installed incorrectly. If it installs the same, according to the manual, there should be clamping support band around the pipe that acts as a stop to limit the penetration of the class A pipe into the room. The support band also supports the weight of the pipe. The stove is not supposed to do this. The class A penetrates a certain distance into the room in order to maintain proper clearances when it transitions to single-wall pipe. There is a chart for this in the installation manual. Also, note that the male end of the class A pipe should be at the top, facing the chimney cap. The whole cap assembly looks like a cobbled aborti0n. Indoors, I would expect there to be a stove pipe adapter to handle the transition from the class A pipe to the single wall. But this is an old style pipe, so I don't know where you would find this piece. Maybe woodmanspartsplus?

Amerivent Catalog and Manuals:
http://www.americanmetalproducts.com/products/amerivent/chimney-systems/tlc-5-8.aspx

Here is a picture of the cathedral support box and the single-wall adapter:
http://www.woodmanspartsplus.com/49...merivent-All--Fuel-Roof-Support-Assembly.html
 

Attachments

  • amerivent cath support.jpg
    amerivent cath support.jpg
    23.5 KB · Views: 238
Status
Not open for further replies.