Posted by: gingercreekstoves | September 27, 2017

Rust jacking! What’s that? ?

Or:  Why Should I restore my antique stove?

You like how it looks.  It looks pretty good the way it is, and it’s supposed to look old, like an antique, right?  Well, some antique stoves have been kept so well, and used so little, that they really are in very good condition. That would be more the exception than the rule, though.

RO_baseburner

Most antique stoves have not been kept in a dry, indoor environment for the past hundred years or so. They usually have been stored in a shed or barn, or worse, outside on the porch or somewhere out in back of the house. Or in the garden.

Grand_Glenwood_No_103

When the new stove came in, the old stove went out. Probably just a matter of space in the house, and limited number of chimneys to hook up to.

So, back to rust jacking.  Antique stoves were made of cast iron and sheet iron, or sheet steel. Cast iron is unique among metals because although it is very dense and durable, it is also porous. So, it tends to soak up moisture and water and even humidity from the atmosphere and that starts oxidation, namely: rust.

Ok, but it’s just a thin coating of rust, and can be sandblasted off. That’s correct.

However, in terms of an antique stove, it’s when rust builds up on the surface and over time starts to migrate down and settle in the seams where the stove parts join together. There is already dried sealant in the seams, competing for space there.

rust_jacking1

Gradually, the rust continues to build up and expand within the seams, along with the old sealant.  Eventually it creates enough pressure to crack the cast iron, which is held together with steel bolts. The bolts are probably ‘frozen’ in rust as well, so the more brittle cast iron succumbs to the pressure before the bolts do, and cracks to relieve the pressure.  That is known as ‘rust jacking’.

 

rust_jacking_crack

Cracks in an antique stove will decrease the value because it will take more work to restore. Also, some cracks can be welded, or recast more successfully than other parts.  Cracks can also happen for other reasons than rust jacking, such as overheating, and over tightening a bolt or screw, or simple damage from moving or shipping the stove incorrectly.  Cast iron is dense and strong, but it is also brittle.

Notably, the cast iron from a hundred or more years ago was of much higher quality, higher carbon content, than the cast iron of today. So, once the rust is off and the cast is protected, it can easily last another hundred years. Can’t say that for the cast iron in new wood stoves.

Grand_Glenwood_103 (1)

Also if you want to use the stove again ….it needs to be restored to clean the rust and old sealant out of the seams. Then painted with high heat stove paint, and reassembled with new stove mortar in each seam, and  appropriate new screws or bolts.  Otherwise it will continue to collect rust in the seams and spring new cracks. Also, without new sealant, the stove could leak smoke through the seams into the house, also draw in air through the seams and burn too hot.

coal fire glow

While a quick sandblast or wire-brushing of the exterior, along with a coat of stove paint can make a stove look somewhat new again, it doesn’t make it safe to use . To be safe to use again, it needs to be re-sealed. And, that means a full restoration. There is a lot going on under the surface, in places you can’t even see, that need attention for a stove to work safely, as it was intended.

So, how to protect your antique stove for many years to come?  Get it properly restored!

Then, keep it  and use it in a dry,  indoor environment. An antique stove cannot be used in a screened room, or patio, or outside, unless you want to ruin it within a year or two.  So, use it in your house, and  use a magnetic thermostat on it so you don’t overheat it, and you will be set for at least another 50 years.

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