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mason contractors
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Rosin experiments on fierplaces and fuel

http://heatkit.com/docs/rosin.PDF

multiple reads needed.

This is a very in depth group of tests done with water/dye and salt.
It was to done in a upside down model F.P. of that bedroom slant that Rumford depicted in his footnote.

It shows two kinds of eddys that plague FPs.,the breast and the smoke shelf type. They attribute The Rumford success with the 4'' throat and the rounded breast.They also say that Rumford had a hard time with down drafts coming down the rear of those big chimneys and overcame it with the narrow throat....and in the process he ended up with a shelf at the back which he stressed keeping it flat and not trumpet like as to accept downdrafts.They also give merit to a FP getting air from those stratified currents coning down the back and into the throat when the room is tight....which will enter the room if the throat is too big and not positioned right.

They explain that although this test was not done with thermo dynamics it was proper and similar enough in physics to be right.

It was designed to show air currents effects on fuel consumption
but had to address all the FP mechanics.

I looked at Buckleys sight [as I remembered reading some of this before]
and he has this listed and wrote it off as a fluke experiment tha falsely credits Rumford with the slant variation [although he said a Rosin isn't a bad FP] an labeled "competitive propaganda" the assumption that Rumford believed in bi directional air flow in a chimney...and the use of the smoke shelf in defending against it.
He also said a Rosin FP is shorter....which is moot as I'm concerned.

I noticed only, that the throat didn't go 3 to 6 '' past the verticle part of the inner breast. I believe this model was after the bedroom fp which was small and only 13'' deep....so Buckley is out of line again saying it was only 27'' tall...which was about what thATbedroom FP was.

Buckley; http://www.rumford.com/Rosin.html

This bi directional air "weather constant or intermittent is a reality in my book and plays havoc on weaker chimneys with large flues. The strong ones recycle it along with heat coming in from the fire.

Personally I think these new FPs with no shelf will fail unless constant makeup air and a strong draft is the norm...good luck.

The past 4 nights I pushed the envelope a bit and closed my damper to 1-3/4'' which is now 1/30 the opening.....raining now windy the other night...works great still!....video next Sat. with my son and maybe the little one?..lol

JB you might be getting to me.. I now am starting my fires Ti Pi style!
 

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You are a wealth of knowledge Francis. How does the saying go, what is old becomes new again. - and there is nothing new under the sun. I am intrigued at the size of your damper opening. It must have quite the draw to it!

I used to only start the fire as a tee pee, once it burned down i would just add a log or 2. I do remember often a log or the end of one would be out on the actual hearth, the depth of the firebox was 18" with nothing in the front. The smoke would be pulled in and go right up the clay throat.
 

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Vendor
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The Orton fireplace book led me to "The forgotten art of building and using a Brick bake oven". I just got it and haven't had time to do more than look at the pictures, but it looks interesting.
 

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By the way Tscar....I don't suppose you have any plans on building a brick smoker, with indirect firebox?
 

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Mooman Master Mason or 3M
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So, all in all, was this particular section of Thompsons/Buckleys text, the most intriguing part for you FC?.....

"Thus, for example, supposing the wall of the chimney in front, from the upper part of the breast of the chimney to the front of the mantle, to be only 4 inches (which is sometimes the case, particularly in rooms situated near the top of a house), in this case, if we take 4 inches for the width of the throat, this will give 8 inches only for the depth of the fireplace, which would be too little, even were coals to be burned instead of wood. - In this case I should increase the depth of the fireplace at the hearth to 12 or 13 inches, and should build the back perpendicular to the height of the top of the burning fuel (whether it be wood burned upon the hearth, or coals in a grate), and then, sloping the back by a gentle inclination forward, bring it to its proper place, that is to say, perpendicularly under the back part of the throat of the chimney. This slope (which will bring the back forward 4 or 5 inches, or just as much as the depth of the fireplace is increased), though it ought not to be too abrupt, yet it ought to be quite finished at the height of eight or ten inches above the fire, otherwise it may perhaps cause the chimney to smoke; but when it is very near the fire, the heat of the fire will enable the current of rising smoke to over-
come the obstacle which this slope will oppose to its ascent, which it could not do so easily were the slope situated at a greater distance from the burning fuel*.

* Having been obliged to carry backward the fireplace in the manner here described, in order to accommodate it to a chimney whose walls in front were remarkably thin, I was surprised to find, upon lighting the fire, that it appeared to give out more heat into the room than any fireplace I had ever constructed. This effect was quite unexpected; but the cause of it was too obvious not to be immediately discovered. The flame rising from the fire broke against the part of the back which sloped forward over the fire, and this part of the back being soon very much heated, and in consequence of its being very hot, (and when the fire burned bright it was frequently quite red-hot,) it threw off into the room a great deal of radiant heat. It is not possible that this oblique surface (the slope of the back of the fireplace) could have been heated red-hot merely by the radiant heat projected by the burning fuel; for other parts of the fireplace nearer the fire, and better situated for receiving radiant heat, were never found to be so much heated; and hence it appears that the combined heat in the current of smoke and hot vapour which rises from an open fire may be, at least in part, stopped in its passage up the chimney, changed into radiant heat, and afterwards thrown into the room. This opens a new and very interesting field for experiment, and bids fair to lead to important improvements in the construction of fireplaces."

Because it certainly was for me!
 

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mason contractors
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that's the footnote / welcome to the Orton Wells "War of the Rumfords''

Buckley is in denial that this slant experiment is where Rumford was headed.....he writes it off as a "nice try" but a failure due to smoke and large throats!

The Rosin and the Orton are derrived from Rumford's little bedroom
slant.

Read my last post ...the experiment model was basically his bedroom.They substituted different dimentions foe each experiment to see different results.

Rumford's bedroom fp is fig.7 and the Rosin invention was;38 The Rosin has no shelf as he believed they caused eddys but they are slanted and have rouded breast just. Personally I don't like Rosins.I think if he had a shelf theyed smoke because of the low throat being so close to the opening.I could just imaging a wind change causing a draft pause
.....the smoke would have to go out in the room, I would bet.
Also I think they are all low around 27''......it's no wonder a insurance to keep from smoking without having the throat up 14'' or so above the opening. They would through heat out at that lintel height throat though!....but forget choking them!. I wonder what the throat to opening ratio is? I think it's a 4'' throat.
 

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Mooman Master Mason or 3M
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Isn't the point here...that Ben figured out through experimentation- pretty much all that is needed to know? And that everyone that has screwed with these designs since, has not improved upon them? I mean, if even Ben himself thought that there was some improvement in creating a "slight" slant, but not to much, shouldn't we be moving away from the straight backs anyway? I mean, code doesn't really help us when it comes to "Rumford" design anyway! I don't mean building slants like they are now, just a variation between the two. Also, if one should be able to drop a plum-bob down the center of the flue and hit the center of the box, (and modern code really doesn't provide a means of easily achieving that), shouldn't we be combining the two designs to find a happy medium that works? Bens findings on angles and dimensions, seem concrete. 135 on covings, 3.5"-4" wide throat @ 12", backs @ 1/3 the openings and so on....They all work! Simple.
 

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mason contractors
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Ben?

By saying Ben You mean Count Rumford ? not Franklin

Both Ortons and straights work well..I really don't like mixing though, and with using the sectioned clay breasts that are 10'' deep and 8'' for the throat and face that's 18''. A 6'' slant added will get you 24''deep but it'll smoke because the throat is short of the opening by being 14'' back 4''face and 10 precast. So the burden is on the rear positioned short throat to keep the smoke from collecting along the inner breast wall . Especially at each end.

The plumb bob from the center of the throat to the center of the box floor is basically a governor for controlling too deep a box.

8'' face and rough = 2'' to throat center = 10''....= 1/2 of a 20'' deep box. [I never realized my throat is only 7'' in from the face.]

I find 20'' is a bit too deep unless one has to cook on it...16 to 18'' is good all around . The flue inside wall is even to the throat's inside edge at 8 to 9'' back from the face.
Try not to place a flue where it has two shelfs, in front and behind the throat...turbulence causing....Buckley says not so, but I say yes, esp on sluggish chimneys.

Start the slant at 8'' from the floor.....it helps lessen the pitch and eliminates low box turbulence....smoke and heat will then follow that rear wall with ease.........as long as you keep the fire against it new logs at the back then on top.

I have mine going now in the rain and fog at 1-1/2'' =1/30 face to throat ratio...no smoke gotta be about 40 hours of burning so far.

I keep thinking of that footnote and the part where he says it will be able to sit on any hearth unattached! He certainly was inspired by Franklin..even with fireplaces!
 

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You sound bitter. I'm just working on my own place ..relax. Good thing your going to get your $2000 check in the mail..sounds like you're probably out of work
 

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Capra Aegagrus
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Joe, as a new kid on the block, you're not really entitled to a lot of leeway with a first post like that. We're easier with folks who've established themselves here and then ask a question outside of their field (essentially a DIY question). You can probably get a pretty good feel for what you want to do simply by going to Rumford Fireplaces and looking at the info there.
 

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Joe, as a new kid on the block, you're not really entitled to a lot of leeway with a first post like that. We're easier with folks who've established themselves here and then ask a question outside of their field (essentially a DIY question). You can probably get a pretty good feel for what you want to do simply by going to Rumford Fireplaces and looking at the info there.
I get it ..thanks. wrong place.
 
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