I need to repair loose fittings on the outside of my wife's pottery
kiln. An outer skin of stainless steel encloses very soft bricks that
can withstand 1300 degrees C. The outside gets too hot to touch; it
melts mains cable insulation. I need to replace loose screws that go
through the very thin SS into the bricks. I propose stainless steel self
tappers. Plastic rawlplugs won't do. Can you recommend a plug material:
how does Araldite behave at high temperature? Another resin? Polyfilla?

--
take the dog out to mail

How about these, expensive but will not melt

https://www.screwfix.com/p/rawlplug-...-50-pack/9584p

Richard

On Thursday, 14 March 2019 13:11:14 UTC, Mike wrote:
how does Araldite behave at high temperature? Another resin? Polyfilla?

Oh for the good old days of Rawlplastic (contains asbestos)

Owain

On 14/03/2019 13:36, Tricky Dicky wrote:
How about these, expensive but will not melt

https://www.screwfix.com/p/rawlplug-...-50-pack/9584p

Richard

That is the obvious route. Another, if the panels all come straight off
without sliding might be to set stainless steel studs into the bricks
with fire cement, then to support the sides with nuts fitted to the
studs. You could arrange an "air gap" between the panels and the bricks
by doing that.

On Thursday, 14 March 2019 13:11:14 UTC, Mike wrote:

I need to repair loose fittings on the outside of my wife's pottery
kiln. An outer skin of stainless steel encloses very soft bricks that
can withstand 1300 degrees C. The outside gets too hot to touch; it
melts mains cable insulation. I need to replace loose screws that go
through the very thin SS into the bricks. I propose stainless steel self
tappers. Plastic rawlplugs won't do. Can you recommend a plug material:
how does Araldite behave at high temperature? Another resin? Polyfilla?

Resins are mostly no use when hot.

Metal plugs, or if you cba to pay for them just bits of cut tin can. But any type of expanding plug requires some tensile strength in teh brick, and it sounds like you don't have that.

Fire cement is very weak IME, it might do though. Sand & cement is better if not too hot for it. Or an external wire band maybe.


NT

On 14/03/2019 14:42, Chris Hogg wrote:
On Thu, 14 Mar 2019 13:09:31 -0000, Mike
wrote:


I need to repair loose fittings on the outside of my wife's pottery
kiln. An outer skin of stainless steel encloses very soft bricks that
can withstand 1300 degrees C. The outside gets too hot to touch; it
melts mains cable insulation. I need to replace loose screws that go
through the very thin SS into the bricks. I propose stainless steel self
tappers. Plastic rawlplugs won't do. Can you recommend a plug material:
how does Araldite behave at high temperature? Another resin? Polyfilla?

There's often a layer of fibre insulation between the bricks and the
SS skin, but I agree, the skin does get very hot.

I would suggest not plugging the bricks at all if you can help it.
They are usually _very_ soft, and won't take any sort of stress such
as may be created by some sort of plug. For example, you can usually
push a nail into them by finger pressure alone. They're designed to
insulate, not to support stress. But if you really have to, then these
self drilling metal plasterboard plugs might be OK. Just make sure you
don't penetrate the bricks right through and make contact with the
Kanthal wire elements. That way leads to a shocking and possibly fatal
experience. https://tinyurl.com/y6dkulh6

But I'm not clear as to quite what you want to repair. Is the SS outer
skin becoming loose from the brickwork kiln lining, or is it an
external fitting (such as a hinge or closing clip) that's come lose
from the SS skin. If the latter, you could try pop riveting the
fitting to the SS skin.

You've reflected a lot of my thoughts here. The stainless steel skin
contains the bricks and if things have become loose, a gigantic jubilee
style clip would be a far better solution.

The bricks are very fragile, any force from a plug will crack a brick.
Keep the bricks in pure compression instead.

On Thu, 14 Mar 2019 13:09:31 -0000, Mike wrote:

I propose stainless steel self
tappers. Plastic rawlplugs won't do.

Brass "rawlplugs"?

https://www.fischer.de/de-de/produkte/standardbefestigungen/metallduebel/messingduebel-ms

Mandatory in Trenzal where heat would cause plastic plugs to melt and wehre it
would matter. Amazon has them at 10 for 6 EUR in M4.


Thomas Prufer

On Thu, 14 Mar 2019 14:42:18 +0000, Chris Hogg wrote:

If the latter, you could try pop riveting the
fitting to the SS skin.

Or even rent a stud welder... apply stud of thread and length of choice, press
button, done.

(I got to try a stud welder at a trade fair:-)


Thomas Prufer

In article ,
lid says...

Yes, there is a very thin layer of glass or ceramic fibre between the
bricks and the SS. I guessed at it being padding between the 16 sided
brick construction and the cylindrical outer skin.
It's a top loader, the 12 Kg lid lifts like a car bonnet and has two
swivel mounted stays. They each go through a jamming mechanism like a
glue / mastic gun plunger has. Those are swivel mounted onto the outside
of the kiln to support the lid open. On one of these swivel mounts the
screws, which look like steel, have rusted away. They are perpendicular
to the outer drum, straight int the brick. The failed screws were
probably about 4mm dia x 25mm long self tappers.

Gas struts like a car tailgate might seem better - there is no
counterbalance weight or spring. But the weight of the lid forms a seal
of sorts onto a rope (again ceramic or glass fibre I assume) giant 'o
ring' in the top face of the brickwork.