Wood Stove Pipe Longevity

GA lyn,

Goose you can also get the same stainless in a B vent style that is double wall so it will run a bit cooler on the elbow. Not sure of the configuration you have (probably a 90 out the back wall from the stove) but if the 90 is in an area that is not too visible you could double 45 it allowing the flue to vent much more efficiently and not hitting the 90 wall before the exit.

Are you sure it is not a problem with your stove or the fuel you are burning?

It sounds like you are loosing a lot of heat up the chimney, which is not heating your house.

Creosote is a danger if the fuel you are burning is rich in it. Having elbows compounds the problems and if the creosote starts to burn it will increase the pipe temperature dramatically.

If you can replace the 90° elbows with two 45° elbows and a diagonal pipe in between you will reduce the load on the chimney.

Lyn's suggestions are very valid, but it would be in your interest to first make sure your stove is working correctly and the fuel you are burning are not contributing unduly to the problem.

I'm with AH here. I grew up in a house heated by coal stoves. It had 90 degree elbows, and none were replaced in the 18 years that I lived there.

I have to agree with the last two posters. There may be a reason you are replacing these elbows, other than poor quality steel.

Now that I think about it, I don't recall having this problem "back on the farm".

It depends how the elbows were made, if the metal was simply "stretched", that would make it very thin, you need an elbow with "ribs" that maintains the thickness far better.....it is also more flexible with heating and cooling without stress and breaking.....especially if the elbow is held very (too) firmly and forced to flex where it is thin and weak.....

The thinning on a badly made piece might be as thin as only 10% of the original metal thickness.

If you have access to stainless steel sheet, its easy to get it rolled and seam welded, then you only need to cut out a 90° wedge out and weld it again. That will last forever!

You should check out malliable castiron piping, it should last for years.

I had to buy coupple times stoves feeded with old used oil,querosene,gasoil or any liquid that burns:those were three sections,one or two stainless steel(more or less cheaper) black steel the third one,then very ordinary 90 galvanized steel elbow,same next ones straight to the wall: first two sections got red and rivets jumped out when air inlet was completely open what was never needed.Worked for years until we got modern stuff.I don't know what happened to you.Course you could think in a engine exhaust system: cast iron first,a good thick,and then thin black steel.How couldn't work?.-

Do you have a good rain hood, ie water running down the pipe, especially with no fire, combined with residue, make rust rust rust. (2) 45's are fare superior to one 90.

PFR

I heated with the same Sears circulating wood stove for 27 years. It had a rear exhaust which took a 90* elbow up, then another one back into the chimney. The first five or six years, I found myself replacing the elbows every other year. Finally, an elderly neighbor told me that the problem was a combination of running the stove too low for too long and not giving the pipe a thorough cleaning in the spring. He said if the fire is kept low the creosote builds up, even with very clean fuel. Letting the pipe get caked risks chimney fires, plus, a creosoted pipe pulls moisture out of the air in the warm weather, then the creosote gets gooey and runs down the pipe, building up in the elbows - a perfect set-up for quick rust.

Once I took his advice, those pipes lasted seven-to-ten years.

I found the chromed pipe to outlast black or galvanized about 3x longer on an Ashley airtight using wood ( lots of creosote leaking back into stove).

Dick

Several good posts here, just a little to add though.

Try to get the thickest wall that you can, which means the metal gauge number is going to be lower, (for example 20 ga is thicker than 28 ga in sheet metal). Much of what is sold in the big box stores is ok for A/C ducts but not stove use. The thicker the wall the longer it will last at the same rate of corrosion.

Have you discussed your problem with a good sheet metal shop? They may have some advise from others who have had the same problem in your vicinity. Stainless certainly would be the way to go. See if you could obtain sweep elbow, larger radius, which would keep the number of joints down as compared to multiple 45deg elbows. While at the sheet metal shop ask them how much it would cost for them to supply the elbow and also to fabricate an "elbow to last all elbows" out of Stainless Steel. A good shop can solve many problems!

Good Luck, Old Salt

I have found much good info. in all of your comments and appreciate the help. It sounds like a sheet metal shop with a "sweep" elbow may be the way to go. I'll check their prices first. It could be that the non-insulated stainless pipe, from the first comment, may also be worth looking into, also.

Pipes inside the house need to be uninsulated to allow the heat from the exhaust smoke to be reclaimed, in Sweden, Norway and Finland (probably Russia too), they often place the stove as far away from the chimney, on the other side of the room sometimes.

They then lead the pipe around the room, climbing slowly, to get as much heat from the wood as possible. Nowadays the wives will not allow that!!!

If there is a possibility of creosote distilling out (any wood burning stove, but not pellets), you should run the stove at full whack from time to time to clean it out. Also, at least once a year get it properly swept......remember running at a low heat produces more creosote and burns less of it.

It (creosote) also is the possible cause of small explosions when opening the door to refuel.....remember to always run at full whack for a minute or two (open damper) to get rid of any built up gases......or you can get a quick visit to a hospital and a complete redecoration of the room - at best!!!

What ever you do, don't burn Cottonwood. That will foul up your wood stove pipes, stainless steel or not.