Hearthstone Mansfield - How Hard to Rebuild?

[MDchanic]

Hello.

I am a brand-newbian on this forum, though not to forums in general, and not to wood burning.

I've heated various houses with wood and coal over the years, and in my current situation have essentially infinite wood ("just add muscle!"), so I've been hunting for the right cheap addition to the non-cat Vermont Castings Intrepid in our kitchen.

This house is a bit sprawling and added-on-to in design, so there's no way a single stove will be able to heat it, and my intention right now is basically to heat the (very large) master bedroom, and the "back" of the house, which was thoughtfully constructed without any ductwork for the propane condensing forced hot air furnace that heats the "front" of the house (it's also got a 5-ton whole house heat pump, 2 split units, and electric baseboard throughout the house - someone liked the "belt and suspender" philosophy...).

I've got a line on a well-used Hearthstone Mansfield, with a burned-through secondary manifold, secondary air tubes in a pile at the bottom of the firebox (which look rusty, but intact), wavy above-door ridge on the primary manifold, cracked glass, loose hinge pins, a missing ceramic baffle and blanket, and a whole lot of chips in the enamel, but no signs of bad overfiring (I've seen plenty of overfired coal stoves).

Having studied the exploded views, and read a few things, it looks like I would have to completely disassemble this stove in order to repair it.
Having looked at the parts price lists (and taken a few nitroglycerine pills to ease the chest pain), it looks like I need to be planning to do more repairing than replacing, though I have found reasonable prices for replacement glass, baffle, and blanket.
It looks like I should be able to MIG weld up a patch for the secondary manifold out of eighth-inch steel, heat and straighten the primary manifold with a torch, replicate the air tubes with steel pipe, provided I knew the proper diameters of the holes, should I need to do it, and machine new hinge pins, so those don't seem to be daunting prospects.

The price of this unit is low enough as to not be a barrier (that means CHEAP), but the 500 pound weight is high enough that I do not want to buy this thing, and drag it home, if I'm going to end up with a boat anchor, as I do not own a boat.

So, my question: How hard are these beasts to disassemble?
The advice I saw was to soak the stones for a few days, to loosen the cement, then remove nuts, bolts, and screws, and just lift out the stones one at a time, with assembly being the reverse, using some sort of good stove cement between stones, and new gasketing (obviously).
Is there more to it than this? Tricks? Pitfalls?
An added advantage of disassembly would be ease of moving it into the house, as I could carry it in "one piece at a time," as Johnny Cash would say.

Another question: How do you tell which air tube goes where? They seem to all be different part numbers, so I ASSume that there is some significant difference between them.

A final question: If the enamel is dinged up, how hard is it to strip the remaining enamel, for a repaint with regular stove paint? Can you sandblast it off? Is it better to just touch it up with a matched paint color (Hearthstone lists touch-up paint on their web site)?

Thanks in advance for any advice you may be able to give me,

- Eric

 

[begreen]

Asked many years back, removing the stones takes some skill.
https://www.hearth.com/talk/threads/hearthstone-mansfield-rebuild-questions.34981/
https://www.hearth.com/talk/threads/mansfield-creosote-complete-rebuild.45876/#560836

 

[MDchanic]

Thank you for the librarian services, Mr. Green.
I'm afraid that I was not diligent in going through all of the 19 pages of search results I obtained (I think I was up to 6 when the wife started giving me dirty looks and telling me it was late).

I'll see whether the gentleman will respond to a PM, and ask him a bit more about his personal experiences.
As I said, you can trip over and drag around a 200 pound stove quite a bit, but a 500 pound stove that needs work is just a whole other level of junk collecting.

Thanks again,

- Eric

 

[webby3650]

That stove should be free. It’s been terribly abused it’s whole life, and as you know needs a full rebuild. Considering it has no scrap value, and is not in working condition, it should free.

 

[MDchanic]

Hmmmmm...

I will take that thought in counsel.

The guy wants a couple hundred for it, which he claims (and I believe him) is what he paid (before he realized the mistake he'd made...).

I don't mind dropping a couple hundred bucks on something that will give me good service for a long time with a bit of work, but, of course, nobody wants to throw money away either.

Thanks,

- Eric

 

[Highbeam]

Don’t do it. The hearthstone stoves are great when new and very nice looking when left alone as art. For a guy wanting to use a stove for heat there are better performers and more durable designs. This particular stove was abused. Hinges worn out isn’t just a matter of buying new pins, the casting is softer than the steel pins so you need a new frame! The secondary manifold is cast iron so welding a patch on is not just buzzing on a scrap of steel.

 

[MDchanic]

Oh. The manifold's cast iron? Looked like mild steel.

I can weld cast iron, but I wouldn't have confidence in it inside a stove with frequent heat cycling.

That one fact actually changes the whole equation.

Thanks.

 

[begreen]

I think you're getting good advice, I wouldn't touch the stove even for free unless you want the stone for another project. @Kevlar_vw works for Hearthstone if you want another opinion.

 

[webby3650]

I’m pretty sure the manifold is Stainless steel. They use cast iron in the Manchester and the Clydesdale, but I’m pretty sure the others are steel.

 

[webby3650]

For what it’s worth, I sold my fully functioning Mansfield for $900 a few years back. And no, I wouldn’t not purchase another soapstone stove from Hearthstone...

 

[MDchanic]

The secondary manifold didn't look like stainless steel, and the hole burned through it didn't look typical of stainless steel damage, but if it were stainless steel, it would definitely make the project more possible.

As of now, assuming that the manifold is cast iron, I wouldn't mess with it, and I will avoid the stove.

I'll give it another day before I tell the guy I don't want it. He's go nobody else who's interested (surprise), so there's no real hurry.

If there's anyone who can absolutely confirm the material of the manifold, I'd appreciate it. I am a sucker for a unique restoration project.

- Eric

 

[webby3650]

The secondary manifold didn't look like stainless steel, and the hole burned through it didn't look typical of stainless steel damage, but if it were stainless steel, it would definitely make the project more possible.

As of now, assuming that the manifold is cast iron, I wouldn't mess with it, and I will avoid the stove.

I'll give it another day before I tell the guy I don't want it. He's go nobody else who's interested (surprise), so there's no real hurry.

If there's anyone who can absolutely confirm the material of the manifold, I'd appreciate it. I am a sucker for a unique restoration project.

- Eric

I deal with Hearthstones almost everyday. I have replaced stones and other components on many of them. None have been worthy of a complete rebuild... I can’t say for sure that they haven’t changed materials over the years, but I know my older Mansfield didn’t have a cast manifold, neither do current models. The tubes are SS for sure. I can find out if the manifold is as well.

 

[webby3650]

Unless you are talking about the vertical secondary air passage in the back of the stove that the manifold sets on? That part is cast iron.

 

[Highbeam]

In my hearthstone of similar vintage, a heritage, the secondary manifold was a cast iron clamshell that clamped onto the stainless air tubes and sat on a mild steel riser from below. I had to remove that manifold to grind on it so it would set down properly. Definitely a cast piece. Maybe the Mansfield is different. Unlike most stoves, the secondary manifold is not welded to the stove walls since they are stone. It kind of sets there on the riser, and two cast supports up front.

Usually when there is major melting like the photo shows, the whole top is caved in.

 

[MDchanic]

Nah, Webby, it's called the secondary manifold in the parts list.
It's the U-shaped part that goes around three sides of the top of the firebox, and attaches to the twin secondary air passages that rise vertically at the rear, and then holds the secondary air tubes between its arms, across the top.
The center of it (center of the U), in the middle top of the rear wall of the firebox, has a hole burned through it about ¾" by 2", kind of blossomed out, the way that stove parts tend to burn.
The whole part looks like a sort of an oval steel extrusion, with welded up ends and cut-out holes, which, combined with the hole burned in it when the rest of the interior (aside from the wavy eyebrow on the primary manifold) looked pretty good, made me think it was probably mild steel (and easily welded). I'll believe you if you tell me it's something else - I've got zero experience with these, and I'm happy to learn from those who know more.

I will admit I've become a bit fond of this stove because, 1. it fits perfectly into the "right" space in the bedroom, and could be fired up, left to idle, and would throw heat all night without further thought, and 2. it would also fit inside the living room fireplace (and match the stone), where it could be used to heat the front of the house, so it would be flexible.
Of course none of that matters if I've gone and picked an extremely heavy piece of garbage that I can't fix with a reasonable amount of work, and a small amount of money (remember, I'm cheap), which is why I'm focused on getting a realistic assessment of what I'd be in for if I got this thing.

I've got my ol' man's extra wood splitter all strapped down to the trailer now, so if I do want to get it, I'll have the trailer to go get it with.

I do appreciate the responses.

- Eric

 

[Highbeam]

Yep, that U-shaped secondary manifold thing was positively cast iron on my hearthstone heritage so just inspect the manny and know what you’re getting in to.

The actual owners of those goofy looking duck footed Mansfields seemed happy with the performance.

Soapstone sure looks nice.

 

[begreen]

I will admit I've become a bit fond of this stove because, 1. it fits perfectly into the "right" space in the bedroom, and could be fired up, left to idle, and would throw heat all night without further thought

Scotch that scenario. Stoves in bedrooms are not approved except in special circumstances.

Also, outside of paint touchup, there is only one solution to restoring the enamel in that condition.That is sandblasting it down to metal and having it re-enameled, which is not an inexpensive option. However once the old enamel is off the parts could be painted instead of re-enameled.

 

[MDchanic]

Highbeam, the piece in question, as described above, is lozenge-shaped in section, and overall is shaped like three sides of a square (following the three sides of the firebox), with the two 90° angles being curves with about a 1" radius it's #40 in the image below:

​

- Eric

 

[MDchanic]

Scotch that scenario. Stoves in bedrooms are not approved except in special circumstances.

Then I guess you really wouldn't like the fireplaces in the other bedrooms...

- Eric

 

[begreen]

Yes, some old houses had one in every bedroom. It's not me that doesn't like them as long as they are safe, but I guess there have been enough issues that fire code said no more.

 

[MDchanic]

Interesting. I hadn't heard that being the case around here. In general, there's not much that bothers them here.
I'll look into it when I have a chance.

- Eric

 

[begreen]

Interesting. I hadn't heard that being the case around here. In general, there's not much that bothers them here.
I'll look into it when I have a chance.

- Eric

My understanding is that it has to do with the amount of air the stove draws from the room. Bedrooms tend to be a small space often with a closed door while people are sleeping. Many inserts explicitly warn against bedroom installation for this reason. The exception being a large bedroom with no doors.

 

[MDchanic]

This one's about 25' square, with 2 inside doors and a pair of non-sealed french doors to the outside - it's kind of an air leak extravaganza.

Of course, there is also such a thing as "outside combustion air supply"...

- Eric

 

[webby3650]

I just looked at the current models. The Mansfield is welded steel, the heritage is cast iron. The current model looks exactly like the exploded view from above.

 

[Kevlar_vw]

The secondary manifold didn't look like stainless steel, and the hole burned through it didn't look typical of stainless steel damage, but if it were stainless steel, it would definitely make the project more possible.

As of now, assuming that the manifold is cast iron, I wouldn't mess with it, and I will avoid the stove.

I'll give it another day before I tell the guy I don't want it. He's go nobody else who's interested (surprise), so there's no real hurry.

If there's anyone who can absolutely confirm the material of the manifold, I'd appreciate it. I am a sucker for a unique restoration project.

- Eric

The primary air manifold, and secondary air manifold in the Mansfield are steel, not cast iron as other people are claiming. The warped section in the front of the stove is the “air wash”. It is welded to the primary, and forces hot air at the glass, keeping it clean.