Rebuilt the f602n

[nola mike]

Had some warped side panels that I wanted to replace. After reading a bunch of threads by precaud, I decided to try to replace the cast panels with zircar. It ended up that replacing the side panels in this thing required a near complete disassembly. As it turned out, the secondary air chamber wasn't sealing well with the upper baffle, which is probably why my secondary burn was so lousy. Got everything put back together, just in time for temps in the 70's this past week. Here are the pics.

Pics are tough to upload...

 

[nola mike]

Maybe better

 

[begreen]

What's holding the zircar side panels in place? How thick are they?

 

[nola mike]

The whole rest of the damn stove is holding them in place. Secondary burn chamber and upper baffle specifically. 1/2" thick. I wonder how 1/4" would do. Certainly cheaper.

 

[begreen]

What's with the snappiness? No one has done this before that I can remember. Details help if someone else wants to try it.

 

[nola mike]

Wasn't meant to be snappy. The interwebs don't always convey the intended tone...
Precaud was the inspiration for the project (and the source of the zircar)
https://www.hearth.com/talk/threads/materials-used-to-line-fireboxes-a-test.31062/

You commented on the thread

 

[begreen]

I should clarify. No one has done this with a Jotul box stove and reported it here that I know of. As these stoves get older folks ask frequently about alternative solutions. Keep us posted on performance and how it stands up over the seasons.

I have the older 602 where the panels essentially hang off the side pegs. That's why I asked about how the zircar panels are held in. Are the side panels held captive between the secondary manifold and side ledges in the body casting?

 

[nola mike]

I should clarify. No one has done this with a Jotul box stove and reported it here that I know of. As these stoves get older folks ask frequently about alternative solutions. Keep us posted on performance and how it stands up over the seasons.

I have the older 602 where the panels essentially hang off the side pegs. That's why I asked about how the zircar panels are held in. Are the side panels held captive between the secondary manifold and side ledges in the body casting?

Yeah, much different then on the old model. The panels are held captive. Like I said, it requires a pretty thorough disassembly to remove the old ones, especially if warped--the new ones can probably fit with a bit of creative cutting. The parts are available still. It's $150 for the 2 new side plates, which is significantly less than the zircar. It's going to be hard to tell if any performance increase is due to the zircar or the rebuild, I think. Not sure about durability. I don't think they'll warp, and they seem fairly stout. I might take a small leftover piece and see how hard I need to whack it before it shatters.

 

[precaud]

A few comments:

No one has done this before that I can remember. Details help if someone else wants to try it.

BG, methinks there's a memory lapse here, look at the thread Mike referenced and you'll see you participated in it frequently.

Mike, the F602N side panels normally slide in and out, it's a snug fit. These were warped, that's why the stove had to be partially disassembled to remove them. The Zircar has much better dimensional stability, it will not warp like that.

A LOT of secondary air was being lost right up the chimney via the leaks around the edges. I'd clean and seal the baffle with stove cement before reinstalling.

This stove has to have been burned REALLY hard repeatedly to warp those side panels (which are pretty massive) and the secondary baffle like that. I always burned my 602's (both flavors) very hot and never had a warpage problem. Unless you have very poor draft, the so-called primary air control should not be open very much during normal operation. View it as "start-up air" and as a supplement to the constant stream of air being drawn in through the gap above the window and down over it. In high-draft conditions the primary control can even be shut, drawing plenty of air through the airwash "system". Check your window gasket to see that it seats the window properly to allow that air to flow. I believe they just doubled up the gasket up there to accomplish that. It's a cheesy system, it works until the gasket compresses, and then... not. Consider checking that that a part of your annual maintenance.

 

[nola mike]

The zircar i think is a bit more snug/thicker than the old panels. Hopefully won't need to try to remove them. Yeah, that stove was fired hard before I got it--everything was already warped, though I don't know if the side panels are worse since I had it. I straightened the air chamber right when I got it, but I don't think I did a good job. The pic up there is the "after" i straightened it out better. I did seal it up with cement. Best I can tell, the glass is gasketed on 3 sides. The primary air comes in through the top. I put some gasket on the top edge as well, cutting the air flow about in half. Still haven't had a chance to fire it up...

 

[precaud]

Best I can tell, the glass is gasketed on 3 sides. The primary air comes in through the top. I put some gasket on the top edge as well, cutting the air flow about in half. Still haven't had a chance to fire it up...

Yes, gasketed except at the top, where the air flows in. I don't think you want any gasket there, you want that airwash airflow unimpeded!

 

[begreen]

precaud you're right. I completely forgot you had this stove. Our side panels warped after a crack developed in the middle of each of them (and the baffle) after 20 yrs of use. We only put about 10 of those years on it so no knowledge of how it was run prior to us.

 

[nola mike]

Yes, gasketed except at the top, where the air flows in. I don't think you want any gasket there, you want that airwash airflow unimpeded!

Well, I was trying to cut down primary air, since sometimes even closed down all the way I was burning a bit hot if the stove was packed with bricks. Maybe not necessary now.

 

[precaud]

Wow, you must have a great chimney!

 

[nola mike]

Well, that didn't last long. Went to inspect the stove and found one new panel cracked in half, and one cracking. If I have enough zircar left over I might fashion a panel for that right side, if I don't have to disassemble completely. I don't know if the panels can be glued (doubt it)? @precaud, sounds like you had better luck with durability? Though I run hot, I didn't have any momentous over fires last season. Don't know if packing tight/direct blows might have done it. Nothing that I recall.

 

[precaud]

Mike, my Nestor Martin (pic in my avatar) has had a Zircar backplate for years now and there is no cracking. It runs hotter in the firebox than the F602 does. And I didn't see any cracking when I originally did my F602. In a woodstove firebox, you'll not come anywhere near the operating temperature rating of the Zircar material.

I suspect that the side panel isn't seating properly along the bottom; you can see in the pic, the cracked piece has settled down lower than the rest. i.e. the Zircar may be a bit thicker than the slot in places, or along the whole length, and is unsupported. If it is unseated along the bottom, then it isn't laying properly against the side either. I would suggest taking that panel out, chamfering the bottom edge (with a flat file) so that it seats fully into the slot, furnace cementing the two pieces together (held togeter with a wood clamp until it cures), and reinstall. Check the other panel while you're at it.

I may still have one of those side plates left from my project, I'll look for it over the weekend and see if I had to do something similar to it.

 

[nola mike]

I was actually thinking the opposite, that those panels were wedged in there so tight that the expansion/contraction of the stove may have done it. I moved that piece on the right for the picture so that the crack was more obvious; it hadn't separated at all when I found it. Believe me, those panels were tight up against the side. Even if a part of the panel was unsupported, it's not like it's carrying any load. Also, the left panel has crazing type cracks in every direction, not just vertically. Anyway, those panels were impossible to remove without a near complete disassembly, so I broke the side panel, removed, and made a new panel that wasn't so snug, And yeah, I f'd up that bottom cut, so now it definitely isn't supported equally. I realized after I took it out that probably just smearing it with cement would have done the job. No warping of the plenum when I removed it btw (the stove had been seriously overfired when I got it--when I disassembled last year nothing fit together correctly). We'll see how this does this season.

 

[precaud]

OK, well I can only attempt to diagnose from the armchair here, so go with your own analysis.

I cut the sidepanels for my F602 so they could easily be removed for maintenance. There was no pressure on them. You definitely want to size them allowing for the steel's expansion/contraction

The backplate of my X33 may have hairline surface cracks; I haven't looked, and frankly they don't bother me.

You've certainly put a lot of work into this. I hope you get the warmth reward soon.

EDIT: I should also mention, I NEVER stuff any stove so that wood wedges in under pressure against any surface. In response to heat, wood initially expands before it shrinks as moisture is driven out.

 

[nola mike]

EDIT: I should also mention, I NEVER stuff any stove so that wood wedges in under pressure against any surface. In response to heat, wood initially expands before it shrinks as moisture is driven out.

Ya know, you might be on to something there. I've been using bricks for about 1/3 of my loads, and they expand a good bit. This stove is so small that it's tough not to pack it tight. Could definitely be more of an issue with the zircar than the cast iron, and it would only take one time to crack it...
Looks like it might finally get cold enough to fire her up this weekend...