Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 13, 2014 18:02:41 GMT -8
Hmmm... In my view, you do need (warm) air injection the full width of the burn tunnel ceiling. I've tried one in each corner but this layout didn't work as well as the full width gap. The corner layout happened to be slightly larger as a whole. And if I remember correctly the P channel works best just after the trip wire?
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 13, 2014 15:38:23 GMT -8
Cool, thanks Matt! Do you know what they are called? I mean, is there a name like refractory insulation tubing or something of the sort I should ask for (you know, so I don't sound completely in the dark about what I need)?
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 13, 2014 3:22:34 GMT -8
I did a burn in the prototype again yesterday. Similar results to the first burn but the wood was even wetter than before. It still drafted well with just a quick blow on a bunch of pine straw and continued to burn well for about an hour. The perlite had gotten wet and did not afford as much insulation value so it didn't rocket as well and took much longer for the smoke to clear up. Even with a slight breeze down the riser tube I got very little smoke back even under the less than optimum conditions.
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 13, 2014 3:15:15 GMT -8
Thanks Matt! Can you tell me where I might get one?
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 12, 2014 16:03:35 GMT -8
Okay, I have pretty much figured out what I am going to do with the top thanks to all of the input. Now one last thing. I said I was working backwards now to the riser. I don't know where those nifty pre-made insulated risers came from that I have seen on Peter's builds and I think Matt might also have one. Would they support themselves if they were recessed into a cast burner (at an angle) without any support? as soon as I can arrange some time off I will be picking up castable refractory cement for the burner. Before making the mold for the casting though I need to know what I am going to do about a riser.
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 12, 2014 15:10:13 GMT -8
Ok Griz, I see it clearly now! That is a really nice looking unit you have there!
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 12, 2014 7:05:16 GMT -8
Thanks griz! I saw this build, quite impressive by the way! I don't think the attached picture is the one you meant to attach here though, it is of the bench portion of your build. Did you mean to post the top, where the heat from the riser impacts the top of the "drum" (for lack of a better term for it)? In the picture you cannot see the burn ring you are speaking of.
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 10, 2014 17:26:25 GMT -8
Wow Max! Thanks for going through all that trouble and all the calculations! Math was never a strong point of mine (I actually loved math, it just didn't love me back, didn't like English much but it had some affinity for me. Strange things happen in life). I know what a corbel is but in the manner you speak of it I am construing it to mean a recess in the top of the bell to hold the RSJ? Or would one affix a corbel of some kind on the inside of the bell to support the joist? I have been mulling over shortening the bell lengthwise and using firebrick pillars in the center of the bell to support the plates at their midpoint, thus having all four sides of any one plate with support under them at their edges. The pillars would add to the ISA of the bell (9 inches by bell height times 4) of course and that is the reason to shorten it by (at least) one brick length (9in or ~22.9cm). EDIT: Just thinking, how would I seal between the two plates then? ... back to RSJ.
Having trouble with this... what do you mean 2.5in slabs? 2.5in thick? That would be one very hefty piece of steel! I fairly followed all the rest and I agree wholeheartedly about building in safety factors in the calculations. Much better to over rather than under engineer. Which is why this particular part of the build is so important. EDIT: Disregard, I read and reread what you were saying an now understand you meant the weight of the fire brick on top of the RSJ. But now I am still wondering what thickness and type of metal to use on top of the RSJ now that I know the RSJ will be good to go. Leaning toward four plates of 1/2 inch steel since 3/8 for Patamos have done well without signs of warping. I found a steel provider near me with a search. It may be a good idea to go consult with them. I will probably purchase materials rather than try to collect them. I am not much good at scavenging.
Vortex, wow, I would have thought the thicker metal would have caused fewer problems not more!
Patamos, well I was thinking of 1/2 inch so that is good information to have for sure, thanks for the correction! Matt, those look very nice. I wish dimensions had been given for these but I could find none. Dimensional data was given for some of the others but not these specifically. I will have to do a search for some of the right size for my application if I do not use just plain old steel plate (mostly covered in fire brick for heat retention purposes! Thanks!
ALL: I had no idea the top of the bell would turn out to be so complex! Maybe I will just throw a piece of high temperature plywood over the whole thing and be done with it! (Tongue planted firmly in cheek guys, don't take that comment seriously!)
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 9, 2014 16:38:22 GMT -8
Thanks for the input Vortex! That surely would not do! Would you think, if I can source some 1/2 inch steel plates (12.7mm) that the problem might not be so severe? I know that would be mighty heavy but if I could make only one (of I am thinking 4) of them removable I could make that one into the cook top/radiator and brick over the others? That would make the plates around 1ft by 2ft (.3 X .6m) but if only one would be removable (then only occasionally) that might give enough heft to not warp? That picture IS worth a thousand words!
Max, How might you go about the structural bearing for such a design? I am thinking RSJ again. You said failure temperature is around 400C (approx 700f). How much heat might be expected to accumulate within the bell? Enough to reach this failure temperature? Perhaps a temperature probe/gauge set in a probe well could be useful to see that a burn could be stopped before reaching the failure temperature?
Patamos, no warping of the plate experienced at 1/4" thickness (6.35mm)? That size is about the size I am talking about. Half thick (insulating i.e. lighter) fire brick might not be too much for it to bear to cover 3 of 4 plates along the top of the bell?
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 9, 2014 3:29:40 GMT -8
Thoughts are such an ever changing thing. As long as I have enough space to place an industrial sized stew pot that would be enough cooking space (to be able to cook some burgers on the surface would be nice too). Otherwise if the rest of the top of the bell could be brought to a simmering temperature and held there for as long as possible would be fine. With these parameters what would be a good way to accomplish?
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 8, 2014 19:06:08 GMT -8
Maybe something like 2 RSJ and brick over two thick steel plates and one (preferably stainless) plate for the cooktop? Really cooking is not the main function at all so I might just brick over all three plates. How then would I do a clean out? Maybe a low door or two at floor level? Cleanout needs to be as little a chore as possible so that it is not so difficult as to be one of those put it off forever things.
Hey, maybe a door just big enough to put one of those robotic vacuum cleaners in once a year! After all, it should be only fly ash in there right?
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 7, 2014 14:59:21 GMT -8
Spoken by a woodworker I am guessing!
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 6, 2014 18:25:44 GMT -8
Oh yeah, until you said something about that I didn't even think of those! Now to find someone in the State or County for a hook up! Thanks man! Good idea!
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 6, 2014 15:05:04 GMT -8
The rule is not broken at all Robert! It is just angled a little. The proportions are still correct, the riser is just not vertical. We might say a convention was broken but not a rule as such.
|
|
Cramer
Junior Member
Posts: 129
|
Post by Cramer on Jan 5, 2014 16:03:54 GMT -8
Robert, maybe you didn't read the post and just looked at the video. The video shows only the beginning of the burn. The smoke cleared up a short time after the video was shot and I put my face in it several times and there was only the slightest hint of a smoke odor after it began burning well. You also don't see flame at the riser because it was at the very beginning of the burn but it was clearly visible a bit later in time as things began heating up.
|
|