Matthew Goheen

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since Jan 08, 2017
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Recent posts by Matthew Goheen

Containing water, and having enough of it with efficient enough heat exchange, to store the amount of heat the stove delivers without turning much of the water to steam, are the real challenges of using water.

 Masonry/cob on parts of the interior surfaces of ducting or a bell might be 3-600F by the end of a burn, but the diffisuon of that heat into connected mass, toward the outer oayer of cob, make it so our butts never see 300-600F...

 Water can convect heat away, and allow it to stratify toward the top of a container being heated...  and can be pumped through insulated piping, to deliver that heat to remote areas...  and with apparently about 5x the heat capacity by weight of cob, has it’s advantages for certain types of installations.

Reina LLC has some interesting videos about their solar heated tanks that along with super insulation, and use of solar heat gain in the sunny season, allow them to make net zero homes in Alaska.   The key is that they install solar thermal panels, and charge 5-15 thousand gallon insulated stratification tanks built into the home.

In my mild climate, I could probably do well with 300-500 gallons of water as solar thermal storage.

Their video “Mythbusting Solar Thermal” on youtube is quite excellent.
6 months ago
If you are thinking of the plate glass from fireplace inserts or the door sets that can be installed on the front of an open hearth fireplace, I believe those are normally borosilicate rather than the ceramic glass, because that much ceramic glass would cost well more than I see those “fireplace door” sets selling for.
6 months ago

Phil Stevens wrote:I will prowl the secondhand dealers and see if I can find a small window from an old wood fire. All the modern ones are big and I can't imagine trying to take a wet saw to one. Anybody done this?



 I believe the clear ceramic glass used in wood stoves can be cut with standard “score and snap” techniques used in traditional glass cutting/window glazing...  just errors are significantly more costly.  A belt sander or diamond file can then be used to round off sharp edges for safer handling, if needed...

 I think the belts used in sanding the edges of plate glass are different from your normal “wood shop” sanding belts, but not sure.

 The one i’ve seen had a 4” wide belt in a bandsaw like setup that must have been 8-10 feet of belt total.  I didn’t get to inquire about the type of grit.

 It might be the same as high quality wood sanding belts and just longer to allow the belt to have a reasonable life.  Looked like the purple 3M “SandBlaster” belt material.
6 months ago
 I think what is used in windows on wood stoves is actually a ceramic glass and not pyrex/borosilicate.

Neoceram, robax, and another brand name exist but I can’t remember the last one.

 Another high heat option would be corning ware cook ware, but that tends to be thick and amber/oramge brownish colored.

 Ceramic glass would probably only be required in the hottest zones... Areas where you could not leave a camera directly exposed very long to the radiating heat through the window anyway... but i’m not sure what temperature range and differential capabilities of borosilicate are.

 I do know that when a college roommate tried to use a pyrex pie pan like corningware, placing it on the stove top with water in it, and turning the stove on to high, it made a godawful explosion of hot glass shards all over the kitchen when it gave up to the overwhelming heat induced internal stresses...  Thankfully no one was in the kitchen, as he had started it and walked away to let it get boiling, and none of the glass was hot enough to start a fire... may have been some damage to vinyl flooring and seat cushions, I can’t remember that part specifically, just our other roommate losing his S#!T because it was his prized pie pan, the noise was totally jarring even in the other room, and he was already less than thrilled with the roommate in question...

 Good luck, and I look forward to seeing the results of such observation windows!





 
6 months ago
I would be inclined to use rockwool, or fiberglass before bubble wrap insulation on a single walled flue pipe for insulation.  If either of those two melt or catch fire, you've got much bigger problems than than a "too hot" chimney pipe or barrel.

 That bubble wrap is made for attics and applications that don't normally exceed much higher than 200F.

 
11 months ago
It may be working fine, but let me mention that that “aluminum insulation” is basically plastic bubble wrap with an aluminzed layer or two of plastic in there.

 About as fire resistant as plastic shopping bags.  If either of you ever has someone run your rocket continuously to where the mass gets really hot, that stuff will melt onto the pipe in the 300F-350F range, and begin to really smoke and combust in the 400-500F range.

 Easier to install, but makes me think of burning plastic army men as a kid, watching flaming drops of plastic fall off and make a flitting sound as the tiny drop of “kiddie napalm” fell from the army man to the ground.

There may not be enough mass of plastic for a real fire there, but certainly a toxic, stinky mess of plastic combustion products.

 I would be inclined to keep a close eye on that any time the stove is running, especially while you are troubleshooting and not operating in a static and “fully dried out” state.

11 months ago
The formula for diameter to circumference is pi*diameter... 3.14159  times diameter, so for 8" pipe
3.14159 • 8 =  ~25.133 inches

So 25-1/4" should be enough....  25-1/2" may leave you wanting to trim it.

I realized I trimmed mine to just a tiny bit more than the circumference if my pipe, and it was compression of the inner diameter of my blanket when rolled up in the pipe, that holds it in place.

 The inner diameter of the cfb wants to be pi*6, and is cut at pi•8, so no significant overage is necessary.

It may have "ripples" running up the inside from that 25" of blanket being compressed to the less than 19" at the inner 6" circumference... Mine did.  Works fine.
11 months ago

Loretta Stuber wrote:Matthew, my name is Loretta not Claudia.



 Yes, sorry Loretta, I think I fat fingered your name and my phone autocorrected that to a name that's in my contacts.

And yes, you roll it a bit smaller, and press it outward once slid into postion vertically (easier done with the metal pipe laying down tho) working up the length of it from each end, and should wind up with no gap at the vertical seam of the blanket liner, and enough pressure that the thing holds it's self in place... (doesn't take much pressure, but the blanket can't be short on that width for the circumference)

11 months ago
Claudia,

  I have seen others using this method report that if you cut the blanket so it is a bit more than the circumference of the outer pipe, it will hold it’s self in against the side, so add an inch to the circumference on your initial cut width and trim it down from there until you have a good fit.  I have a test bed j-tube that has this type of riser and have run it for 10 hours or so full out with no issues or deterioration, and did not use any “fiber-rigidizer” sodium silicate solution.  (I believe the silicate solution also lowers the insulating value of the CF blanket as well)

 Better a half inch or inch wide than starting a little too narrow and having it loose and not self suspending.

 

11 months ago
All of those do seem rather expensive.  
11 months ago