Hi all from Aussie

[Aussie Pete]

Re: Hi all from Aussie

well...i've taken all the sand out, looks pretty good inside, i forget to keep taking pics.
the hairline crack i mentioned along the top of the arch bricks, surely it wouldn't hurt to plaster up a little more along that edge, just to help keep it tight?.
I've decided i might do a damper similar to 'Brickies' oven, with a removal/slide brick to block off when needed. Question...would this brick have to be firebrick with maybe some calc. silic. board attached on top (to help insulate heat downward), or could i use an insulated brick?. Would the insulated brick cope with the fire & heat if i didnt take out the coals and the fire?.
If Brickies reads this...do you have any smoke or much heat loss around the edge of the removable brick, would it pay to wrap some insulated cloth around the edge maybe?.

Also whats an idea to slide the brick in & out on?, so it doesnt fall down inside the flue chamber. Maybe some smaller bricks set in a little for it to slide on.
cheers all

[brickie in oz]

Re: Hi all from Aussie

I've decided i might do a damper similar to 'Brickies' oven, with a removal/slide brick to block off when needed. Question...would this brick have to be firebrick with maybe some calc. silic. board attached on top (to help insulate heat downward), or could i use an insulated brick?.

You could use either, the insulating fire brick would be more durable as you slide it in and out.

Would the insulated brick cope with the fire & heat if i didnt take out the coals and the fire?.

Insulating fire bricks can be laid at the fire face of furnaces, so yes they will cope with the heat

If Brickies reads this...do you have any smoke or much heat loss around the edge of the removable brick, would it pay to wrap some insulated cloth around the edge maybe?.

I dont get any smoke coming out as the draw of the flue sucks in around the edges of the damper, there would be some heat lose as its not a tight fit.

Also whats an idea to slide the brick in & out on?, so it doesnt fall down inside the flue chamber. Maybe some smaller bricks set in a little for it to slide on.

I stuck my insulating fire bricks to a sheet of thin steel with silastic, my damper is long enough to not fall down plus when the leading edge falls into the flue the rear edge locks against the top of the slot.

[david s]

Re: Hi all from Aussie

A dense fire brick is heavy and awkward to handle especially when hot. An insulating fire brick is lighter and cooler to handle but it wears easily especially as you are frequently sliding it in and out. I think a piece of kiln shelf is a much better solution, you should be able to get some from a local potter. They often have broken shelves or some with glaze runs that can be ground off. The pic attached shows the damper on my kiln. You need to wrap the shelf neatly in a couple of layers of heavy plastic so it can be removed easily and leave you with a nice sliding fit.

[Gulf]

Re: Hi all from Aussie

well...i've taken all the sand out, looks pretty good inside, i forget to keep taking pics.

Please post some. My son and daughter-n-law are thinking about a cast. Would love to have the pics to help them decide.

[Aussie Pete]

Re: Hi all from Aussie

Gulf..i have some pics for u, i read your post, and reminded me to go take some..

Al...much appreciated for your responses, as always..

Oh yeh, i cleaned out the front arch bricks (the mortar between them), i used a grinder very gently, so i can grout them better later, would it be ok to use normal grout on the front of the arch brick, or should i continue to use the refractory cement?

I also layed another strip of refractory cement over the cracks where it meets the top of the arch bricks, i'm hoping is gotta help somehow...

heres some pics so far

[Aussie Pete]

Re: Hi all from Aussie

been a while, but i'm still here..
haven't done much, with life and all..
i have an idea with my flue/damper transition, it might be a bit hard to describe to ya all, but i'll give it a shot.

What i was going to do is make a channel out of steel on each side of the vent exit (on top of the dome), so it looks like a "C" channel, i'll mortar that in with more refractory cement to hold into place and i will make a slide plate out of 10mm steel that will slide inside each of the channels i've made...(you still with me..)
I will silicon or attach somehow some calc. silic board on top (25mm) of the 10mm plate steel, to help hold the heat in the oven. I will weld a handle on the front of the slide to slide in/out.
Once i've made the plate/slide i will then form more refractory over the top of the plate to let my flue sit in on.
So...what do you think of that idea, its about the best i can come up with, thats pretty easy and should be able to hold the heat in (as long as i make it a nice tight fit).
thoughts anyone??

I've tried to draw something like i'm planning...its only in paint, but its sort of the idea anyway

also..do you think it would be ok to grout/render between the bricks at the front of the arch in normal grout or refractory cement?.

[Aussie Pete]

Re: Hi all from Aussie

Does anyone see any problem with attaching my steel bracket for my damper out of the refractory cement?. What will or should i do to help stop it from cracking around the steel, i need it to sit in there nice and snug, so it really needs to be mortared in. Will the refractory cement expand and crack around the steel, would this even be a problem, as long as it doesnt fall out i suppose.
Also, is it possible to determine how much steel will expand, the thicker the steel, the less it will expand?. Just trying to work out how much gap i will need in the slide, so it doesnt get stuck.
thanks all.
build still going.....slow, but still going.

[cobblerdave]

Re: Hi all from Aussie

Gudday
Sorry have no experience with what your doing.... so can only watch at this point....I'm hoping though that "brickie" will come through for you, as he has the experience with dampers....

Regards Dave

[brickie in oz]

Re: Hi all from Aussie

Pete, do you have a rough drawing of what you are attempting with this, it would help.

I dont think mortaring in steel in an oven is a good idea BTW.

[david s]

Re: Hi all from Aussie

Steel will get hotter sooner than the surrounding refractory because it has higher thermal conductivity. This means greater thermal expansion and problems where it is in contact with any refractory. Personally I would prefer not to use any steel and have a sliding refractory piece (kiln shelf) against the refractory surrounding it.

[Aussie Pete]

Re: Hi all from Aussie

Al, post number #187 has a picture with a bit of an idea of what i'm thinking.
I'm aware of steel expanding, and honestly its probably not the ideal way to position a damper, but i have all the steel and am getting slots milled out the steel sides for my plate to run inside. I just wish there was a way or an idea that i could use this so that it could work.
i was thinking of maybe wrapping the steel with some kind of thermal material to help with expansion of the steel, honestly its probably not going to matter if it cracks a little, because i will be verm/perl. over the top and all around the flue, so that would cover any imperfections within the damper idea.
theres got to be something i could use, atleast just to help with expansion.Surely it wouldn't grow too much.

[brickie in oz]

Re: Hi all from Aussie

Personally I would prefer not to use any steel and have a sliding refractory piece (kiln shelf) against the refractory surrounding it.

What Dave said.

You could make a captive slide arrangement out of kiln shelving for the damper to slide in.

Have a look at the pic.

[Aussie Pete]

Re: Hi all from Aussie

G'day all, its been a while, but have slowly been working on the oven.
Firstly, i have solved my dilemna about the flue/damper. Many have said steel is not the preferred method of making a slide of sorts for a damper.....and i totally agree.
I have tried to solve the idea by making my slide out of 10mm thick stainless steel bar, sandwich on top of each other to form a slide for a plate. I then put fire proof sealant around the slide then wrapped it with fire-proof tape/ribbon, to allow for expansion with the heating cycles. It stuck really good to the steel and the ribbon. I cut out a square bit of the top of the dome, (the flue area) and placed my slide into it, i then surrounded the slide with refractory mortar to secure into place (held really well). I let that cure for a few days, then i made an upside down cone on top of the slide and mortared around that to a make a 6" diameter round hole for the flue to sit into. I made it a little smaller than the flue diameter, (so the actual flue pipe wouldn't fall into the oven). i placed a piece of round steel pipe ( the same size diameter of my flue) and mortared around that, so it would actually make a small ledge for the actual flue to sit on. It worked perfectly. Hope i explained that good enough.
I have added a few pics, let me know what you all think. Will it work???..time will tell.
Its the best i could do with what i had, i really wanted to do the damper out of fire bricks, like brickie had mentioned, but it ment another 2hr trip to the clay bricks yard to source more (and more money). I went with this idea, because i had everything, and i like to be different .
besides....if it works, i'll be a hero (well...in my eyes), and if it doesn't ....i'll be an idiot...either way, i'm ok with.
Its only mortar, i can always cut it out, and do it differently.

[brickie in oz]

Re: Hi all from Aussie

Steel is steel it will expand at a different rate to your refractories.

[Aussie Pete]

Re: Hi all from Aussie

i know Al, thats why i covered the slide with flexible sealant & fire-proof ribbon, plenty of room for expansion. (i think...)
Theres no steel what soever touching any refractory mortar.