|
|
Post by jliebler on Jan 25, 2015 9:01:23 GMT -8
Here is my thought on how I might build a riser for an 8" batch box. I'd like to know of any pitfalls. I've found a source for ceramic fiber boards, rigidiser and appropriate glue, www.ceramaterials.com/ceramicfiberboards.html. My plan is to use the 2" thick high density 2300f boards and rip them, on my table saw, into trapezoidal cross section strips with the saw set at 22.5 degrees making the cross section 5 3/16" x 2 x 3 1/2" (8 of these sections make an 8 1/2" octagon) . I'll use a smaller angle to cut the ends for mitered joints between the 'tube' segments. I'll coat all surfaces with colloidal silica and let it dry, then use fiberboard glue to assemble the octagonal sections tiying them together with stainless wire. Then, after cutting the port opening assemble the sections using the fiberboard glue. About $250 in materials for a "state of the art" riser. |
|
|
|
Post by Robert on Jan 27, 2015 4:17:31 GMT -8
I am not so sure about ceramic fiber boards... if so then better would be to use the round ones... vacuum formed ceramic fibre...no need to cut anything. anyway from my research and after asking lots of questions to the technicians, here is what i think: ceramic fibres are not ment for direct contact with the flames... it is just an insulation and sooner or later it will erode and it will need to be changed. Peter was using for some time the riser made of that stuff and maybe he could add something on this subject... Last time i remeber we spoke about it he told me that his riser got soft... Joris Pouls from Belgium is using a lot of that round ones in his builds... Since 3-4 years he do not see any problems with his riser... the question is for how long? Recently i used special isolative firebrick that can have direct contact with the flame... it was our first riser... so we need soem more time to check that stuff, but it is very promising. torun.all.biz/ksztaltki-i-cegly-mulitowe-mulit-materialy-g233649we paid less then 2$ for a piece... used 50 for making a riser... than seems to have a super state of art riser for 100$  |
|
|
|
Post by patamos on Feb 19, 2015 9:38:06 GMT -8
Does anybody know how well the pressed vermiculite board holds up in direct contact with high temperature flames?
|
|
|
|
Post by satamax on Feb 19, 2015 14:20:26 GMT -8
Does anybody know how well the pressed vermiculite board holds up in direct contact with high temperature flames? Ask Peter! |
|
|
|
Post by satamax on Feb 19, 2015 14:24:23 GMT -8
|
|
|
|
Post by peterberg on Feb 20, 2015 2:01:31 GMT -8
Does anybody know how well the pressed vermiculite board holds up in direct contact with high temperature flames? Depends on the binder. The kind of vermiculite board which is sold here is specified for 1000 C (1830 F). This wouldn't be adequate for the firebox and lower part of the riser. Until now, it's holding fine in my 4" prototype J-tube which is in daily use as the main heater of our house. When you want to build the whole riser out of this board, you'll need a higher specified board, say 1200 C (2190 F). Don't use it inside the firebox, this material can't take abrasion. |
|
|
|
Post by woodburner on Feb 21, 2015 16:28:59 GMT -8
Can I see a picture of your prototype? Is it approved for local building control?
|
|
|
|
Post by patamos on Feb 21, 2015 21:43:49 GMT -8
Thanks Satamax and Peter, I'm thinking of applying the board as the top plate/wall of a horizontal heat riser on a modified vortex stove. It may not reach 1000c, but then again, it might… So I am looking at other options I'm getting ready to experiment with casting clay-vermiculite plates 4" x 12"(across) x 1.25" with fiberglass mesh on the upper (less heat) side. The idea being that 4 in a row will make a 16" long riser wall. maybe work some kick-tail and back-sweep features into some of their edges. Maybe slight gaps between them will evoke similar disruptions of laminar flow and also help to modulate heat arriving under the griddle above... The pucks and risers i have made in the past have hardened off and held up well under less extreme loads. Will see what happens...  |
|
|
|
Post by satamax on Feb 21, 2015 23:31:37 GMT -8
|
|
