Door Autoclaved airated cement block

[cobblerdave]

Gudday
Got invited to a mates place in the break Great pizza for lunch. best roast lamb and veg for evening meal......Shame about his door

Mate... pretty ugly but I have got to admit the thing worked a treat...can't believe a piece of aluminum foil could stop that ply from burning!
Anyway I have made this one for him which is little tidier than my own.
[ATTACH][/ATTACH]
Its basically 75mm... 3in Hebel block bolted to a 10mm ply front (non gal bolts) another piece of 10mm ply screwed to the first covering the bolt heads which do get hot. The handles scewed to this so they two remain cool.
A revel is then cut into the hebel ..the stuff cuts like butter you can saw, chisel or rasp to shape. The door can then be used to seal all that heat when the fires out for some slow cooking. My original one has survived about a year quite well handles the heat alright. It has a crack in the hebel block (from a fall).... now I better build myself new one with the extra prettier wood to cover the boltheads.

Regards dave

[cobblerdave]

Re: Door Autoclaved airated cement block





Sorry stuffed that ......

[brickie in oz]

Re: Door Autoclaved airated cement block

Ditch the bolts and use silastic to glue it all together, the bolts will transfer heat.

[cobblerdave]

Re: Door Autoclaved airated cement block

Gudday Al
What silasic? what sort of silastic is this,wait a min didn't you use silastic in your chimney damper?......what and were did ya get it


Regards dave

[brickie in oz]

Re: Door Autoclaved airated cement block

Most silastic is good to 600c, I used roof and gutter silastic from Bunnies.

[TropicalCoasting]

Re: Door Autoclaved airated cement block

Ive put a blow torch to roof and gutter silicone to try and get rid of it to solder a join on a gutter.It didnt burn after a few minutes I gave up

[david s]

Re: Door Autoclaved airated cement block

When I tried a Hebel panel screwed to a wooden door it cracked in half after a couple of months. The problem is that it is made from Portland cement. If you could get an aerated concrete slab that used calcium aluminate cement that would be a better solution.
Al, can't see any silastic withstanding 600 C The stuff I use is good for 220 C I use it around my flue. It gets a bit soft when firing, but hardens on cooling and doesn't affect its sealing capacity. There are high temp silastics that will withstand higher temps, but they contain carcinogens and are way more expensive.

[brickie in oz]

Re: Door Autoclaved airated cement block

When I tried a Hebel panel screwed to a wooden door it cracked in half after a couple of months.

Did it crack where the screw holes were?

The silastic holding the skid plate to my damper is still holding and Ive clocked the flue gasses at around 600c.

[cobblerdave]

Re: Door Autoclaved airated cement block

Gudday All
Sorry for the late reply...
Davids thanks for your input....the crack I have in my temp. door is from dropping it ...ages ago... hebel is brittle. 10mm ply is flexible, drop the door and thats what happens. The bolts held it together so I kept on using it and yes the Hebel surface has stood up to the heat....I tend to use it also placed in front of the chimney as a heat sheld as well ...no probs. Its been a year now to so much for a temp. door.
So I think I will build Mod 111 for myself using silastic as the glue (thanks brickie) It should give me a flexible union between the ply and the hebel and stop the tendancy to crack. The hebel insulation properties should stop the worst of the heat from the silastic (thanks fornoa)
And if it fails .....the hebel used is worth $5 the other materials scrap and the effort involved....nothing.

Thanks all
regards Dave

[david s]

Re: Door Autoclaved airated cement block

Brickie, my Hebel cracked right down the middle not where the screws were. The panel was only 1" thick. wouldn't use screws again, they get so hot they tend to char the the wood where they make the threads. I now use 3/16" 316 SS , much better. I prefer solid timber to ply as the glue holding the ply together does not like t he heat cycling, I think solid timber is better, I use Quilla.
Brickie, if your refractory was 600C it would be glowing red (doubtful), perhaps you were reading F

PS Tokyo is awesome. Saw an Italian fish restaurant with a WFO, will take a pic if I get back there again. There is EVERYTHING here.

[cobblerdave]

Re: Door Autoclaved airated cement block

Gudday all
Problem wih building a temperary anything and it works... you keep on using it and never build a "proper" one.
So I've made my mind up the door has to get pulled apart or I'll never build another


Pulling it apart was interesting the hebel surface was basically a bit smoke stained and chipped but still in good condition not deteriated at all from the heat. The ply that it was bolted to was also still good I 1/2 expected to find some heat damage around the bolt holes but there was none. Did however showed charring on the bottom edge where it was in contact with the hearth bricks at the entrance no scorching anywhere else so the hebel did its job.
So I started Mk 111 door this time using silastic instead of bolts

[Aussie Pete]

Re: Door Autoclaved airated cement block

hey Dave, i think i have read somewhere that you could also use calcium silicate board as a door...is that right?. I think it may have to be covered with steel sheeting of some sort to help protect from the initial fire/heat.
this is what i was going to use, i dont think its too expensive either, about $25 a sheet.
interestingly..which would be lighter...hebel or cal. sil. board?

[cobblerdave]

Re: Door Autoclaved airated cement block

Gudday
Using silastic I glued the hebel to a face made of two pieces of 10mm ply screwed together.

2 pieces so if the silastic didn't work out I can unscrew them bolt the hebel on them rescrew the secound over the top to cover the hot bolt heads. I used 3 in ( 75mm)hebel as i did in the first and cut a 1 in (25 mm) revel
Too bloody heavy I was sure mark 1 didn't weigh this much so I weighed it ....12.6 KG.....Decieded that was getting too much so I set about reducing the weight

Cut 25 mm off the whole thing and recut the revel weighed the door again.....9.4 KG thats better and the thing even though still quite heafty is usable. as you can see I used hand tools to do this it real dusty stuff and power tools would just make a big mess. Its real easy to saw and rasp Ive carved things with it before

Final door also has a the ply cut higher than the hebel on the bottom and a piece of alum angle to protect it from the hot bricks. I be testing this one to see that it works and I'm on the lookout for some interesting hardwood to replace the outer piece of ply with.
Sorry some of the photo got mixed up but thats all to date

Regards Dave

[cobblerdave]

Re: Door Autoclaved airated cement block

hey Dave, i think i have read somewhere that you could also use calcium silicate board as a door...is that right?. interestingly..which would be lighter...hebel or cal. sil. board?

Gudday Pete
Have some cal sil board and its real light... lighter than hebel. Real soft to. My problem with it it is that it really needs to be covered with a metal skin. My metal working skills are not that advanced and the door that I did see "proffesionally" made was worth $300. Bloody beautiful job looked great And you can just guess what ....gets real hot.... not what you need from an insulated door. Definitly need to separate the outer and inner parts!
I'll keep the cal sil board and this can be on ongoing project.
Meanwhile the hebel door has proven to work well ....is easy to make...cheap and the parts easy to obtain.
Now that Ive written this out I have a thought... perhaps a composite could work an outer wood door with a metal protective layer on the inside to protect the cal sil.... could work

Thanks Dave

[Aussie Pete]

Re: Door Autoclaved airated cement block

that sounds like a plan Dave, show us some pics when your done. I'm still yet to make my door, yours will be interesting to see how it comes up.