How to crack your cast iron stove?

[STJP]

Hello Vermont Castings woodstove users,

I bought my Defiant II in the late 1980s or early 1990s. After little to moderate use I stored it in 1994. Getting ready to fire it up again here in 2017. There are lots of questions on this forum regarding cracks in various VC stoves. My stove is not cracked and I want my stove to last.

Would like to once again tap into the vast amount of experienced wood heater users here. What are the primary causes of cracked stoves? What would I need to do, or not do, that would increase the chance of cracking my Defiant?

Appreciate your help and info. Keep warm.

STJP

 

[peakbagger]

IMHO cracks can come from several places. Poor design of the casting and poor castings can be a source. VC went for fairly thin wall castings and the thinner the wall the better the design should be. VC went through many ownership changes and it possible bad castings may have made it out the door. Not much you can do about it except hope you didnt get a bad one.

You cant do much about a manufacturing defect but you definitely can help by doing some initial burn in fires and treating inside of the stove as somewhat fragile. I see folks on occasion not being able to get a round in the firebox so they knock it in with another round, it should be obvious but dont do that.

There used to be knock off Taiwanese stoves on the market, one brand was Scandia. They were well known to have cracking issues and more than few ended up with major casting failures. The castings were poor and full of porosity from crap in the molten iron or bad patterns. I have older Harbor Freight tools where its obvious that the castings came out poor so someone filled the holes in with filler and painted the casting. Probably not a good thing on woodstove but I bet there are some out there that have this.

 

[kybishop]

Our Defiant is over 40 years old. My father bought it new.

As he understood it and was personally told the first stoves were made by melting engine blocks down and recasting them into the stove panels. That was very early on. He believes ours was well after they stopped using engine blocks.

We have not had any issues with cracks other than the central area of the fireback(s). We are on our third fireback in 40 years. First one he replaced and it went from the single back to the newer two piece fireback. I recently replaced it due to a crack.

As I understand it from reading on this forum it is believed that ash buildup behind the fireback causes excessive heat on the fireback. It can not ventilate properly and causes it to crack. Ours was indeed dirty, had ash buildup behind it when I took it all apart and rebuilt it. It is important to keep that area clean. It is difficult to get to and to see to clean it out.

I have not really heard of too many other issues with cracks in these stoves. They seem to be extremely well built and designed in my opinion. Seems I did see mention of a crack in the top of one of these recently.

We always brought our up to heat gradually. Not build a big hot fire right off the bat. Let the stove come up to temp gradually and we always have run it at about 300 degrees measuring the temp at the stove pipe about 6' up from the floor.

 

[peakbagger]

The single price rear fireback was a design flaw. Even the two piece has limited life as I and many long term defiant users have had to change out the upper section.

Realistically a good foundry can clean up almost any feedstock, it just takes time and money. If someone is going for quick and cheap they just take shortcuts.

 

[STJP]

As usual on this forum I learned alot from your responses peak and ky.

Thank you both for the information.

STJP

 

[defiant3]

PUT A COUPLE INCHES OF SAND IN THE BOTTOM BEFORE YOU FIRE IT!!

 

[STJP]

PUT A COUPLE INCHES OF SAND IN THE BOTTOM BEFORE YOU FIRE IT!!

defiant3,

Thank you for the reminder. It was in the plans for sure. I'm going to Lowes tomorrow for a bag of sand. My sand is wet.

Cheers,

STJP