Making as SS "heat exchanger" for my VC Encore

[slindo]

With VC parts supply in question, I am starting to think about a plan B. While my stove really ought to have both the refracatory assembly and the "heat exhanger" - basically just a sheet of SS with a few bends in it - replace, I can get by for a few more years by just replacing the heat exchanger, which which I ought to be able to make or have made for a lot less than VC wants for it.

Only thing is, I don't know if a special grade of SS is required to stand up to the heat. Anyone know if there is any particular grade of SS I should be using? The stuff VC used last time seems to have been not up to the job seeing is how it completely pretzeled itself, destroying the cat in the process.

Oh, if anyone has a usuable used heat exchanger left over from a rebuild they'd part with, I'd be glad to buy it. It's for an early 0028 Encore.

Odd thing is, I actually had one myself at one time, left over from my first rebuild, but can't seem to find it. Odd, it isn't like me to throw out a good piece of SS!

 

[webbie]

The temp rating of ss is not all that different for the grades - it is the resistance to corrosion that is the big difference. Keep in mind that many 300 and 400 grades easily pass the HT chimney specs, which means they can take 1700 degrees constantly and bursts of 2100.

I doubt, however, that you will be able to use a grade better than what they would use at the factory.. although you may be able to use a thicker sheet or put a lip or bends in it. I am not familiar with the exact part, as I don't remember ss in there other than to "can" the catalytic element.

For stainless, you might want to look on ebay - some left over sheets quite cheap. Do an ebay search on 24 ga stainless steel or something like that.

 

[drizler]

http://forum.iburncorn.com/viewtopic.php?t=7833 Take a look here for some pix of how a guy made a burn pot for his corn stove. Thats pretty typical and you can see there isn't much specialized knowledge required. That goes double if you have the part in your hand so you can simply duplicate it as best you can. Big question is "Can you weld". If so it no great shake to make one up if its all simple straight angles. If not you might farm it out to a local pro or beer drinking buddy who does. Stainless is hard to work with as it is so hard to drill and cut compared to mild steel. You can usually get nice stainless sheet at a scrap yard for a pretty good price. Think panel off old commercial coffee machine or restaruant work table ect, its all over the place at a scrap yard just go ask if they have any or if you can go scrounging. Steel at hardware stores is insanely priced so I can honestly say I have never bought one piece from one for that single reason. From what I see with corn 304 Stainless is the best for holding up to heat and corrosion and corn is way more corrosive than wood but most any grade of stainless will do if you are making one up yourself I would think. The thing to remember is that if it is easy to make then you can just punch out a new one at will which means a heavier constructed thicker piece made of regular steel might fill the bill as well and be a whole lot easier to fab up. That is why I try to use as little stainless as possible around the house and I have a chop saw, torch, mig and arc welder. Regular mild steel is so much easier to deal with especially if you are drilling holes or trying to form it some way. If you are drilling the stuff make sure you have a very high quality bit and use cutting oil and the right speed on the drill . A few holes not so bad , a lot and you aren't going to be having fun anymore.
Whatever you do make sure you get or make one before you completely trash the existing one and save yourself lots of headaches and expense if you have to pay a pro. I have to make one soon identical to the one in the pictures in that thread this season. It should save me at least a hundred bucks and shipping.

 

[slindo]

The "heat exchanger" I need is just about as simple as it could get - literally, a rectangular sheet with two or three bends. No tricky cutting, just shearing to size, and no welding. holes or fasteners.

Which may be why they distort so badly - flat sheets have little resistance to warping. I have a vague recollection of being shown in 7th grade shop class to always put a flat piece in the brake and put a very slight "X" across it, to stress it a little so it wouldn't warp or oilcan.