High temperature sheet material

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ateallthepies

Native
Aug 11, 2011
1,558
0
hertfordshire
The copper washers didn't work although the cause may have been that the inside diameter was slightly larger than the thread diameter so not sealing as much as it could?

I think I will have to buy some thin copper sheet and make some myself and give that a try. If that does not work I thought about getting some stove silicone and in a tube and squashing it down between two boards to make a sheet? In a tube the silicones go well over 1000 degrees c!

On looking at a lamp at turnoff in the dark I noticed the brass glowing dull red so my guess of needing resistance of 500 degrees C is about right.

I looked at the silicone flue stuff again and see it's rated at up to 500 degrees F :(
 

Dave Budd

Gold Trader
Staff member
Jan 8, 2006
2,818
234
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Dartmoor (Devon)
www.davebudd.com
Shame the copper didn't work. I take it that you used a spanner to tighten it properly and thus compress the metal?

How about using a fibre taken from a ceramic rope such as oven doors. Wrap it around the thread like you would ptfe tape?
 

ateallthepies

Native
Aug 11, 2011
1,558
0
hertfordshire
The copper washers I had were 1mm thick and leaked badly so I bashed some sheet copper to less than .5mm and made some washers and tried one and then two together and still no good.
Yes I tightened as much as I thought the 5mm of M6 brass thread into a standard M6 steel nut would take.

Things tried so far...

Viton rubber
Gasket fibre
Copper
Aluminium
Silicone tube
Ptfe sheet


I had some success with exhaust assembly paste but this too failed after a few hours and several heat/cold cycles.

I have ordered some stove door ceramic sheet and still to try the stove Silicone bit after that I'm all out of ideas?

The problem is I need a fool proof way of sealing this joint if I'm to offer these for sale at some point. I have all the other problems worked out but this one. It only takes a tiny amount of leaked gasified Paraffin to make it not work so some sort of flexible sealer required.
 

ateallthepies

Native
Aug 11, 2011
1,558
0
hertfordshire
Well I tried using lead washers but they pretty much melted straight away. Also tried some ceramic fibre sheet but it just crumbled. Also tried wrapping the thread with glass fibre thread but it instantly leaked.

I was about to give up but thought I would try Copper washers again. I ordered some 0.3mm sheet and punched out some washers and annealed them. Well would you believe it they seem to work!! My bashed Copper attempt must have had some unevenness to it hence the leaking or maybe they weren't thin enough?

Today I have had a lamp running for about 5 hours using the replaceable nipple vapouriser and all seems well although I have noticed a slight halo around the Mantle and a little flame budding out the bottom of it that I haven't noticed before? It seems to be at full brightness though.

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With lights on...

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With lights off...

b76bea759f454f8470be560bc95aab11_zps2f048d21.jpg
 

Macaroon

A bemused & bewildered
Jan 5, 2013
7,123
278
71
SE Wales
It sounds as if you've got it with the annealed copper................I must say I was surprised when copper didn't work at the start; keep us up to date please :)
 

ateallthepies

Native
Aug 11, 2011
1,558
0
hertfordshire
Will do, I reckon it was the thinness of the washers that made the difference?

I'm also thinking that any micro fissures that do occur in the seal the carbon buildup will seal them so it will get better with use?

I will now run this set up for several tanks worth to make sure it holds before continuing this project.
 

The Cumbrian

Full Member
Nov 10, 2007
2,040
30
49
The Rainy Side of the Lakes.
Try using a brass washer on top of the copper washer to make sure that it's evenly compressed.

When I used to inspect Ex electrical fittings I would condemn any glands with IP washers that were directly compressed by the gland; unless there was a washer compressing it ( or an earthing "banjo" ), it would more than likely leak.
 

KIMBOKO

Nomad
Nov 26, 2003
379
1
Suffolk
Graphite tape is used in my stove to seal the gland/control valve. I don't think it will wick. I have necer used it myself but have seen it discussed on various forums.
Like "Classic pressure lamps"
Details

"Graphite foil is manufactured from expanded natural graphite which means it can be compressed to form an excellent seal. It comes in sheet form, is flexible, clean and can be cut with normal scissors. You just cut off a strip, wrap it around the spindle and compress with the stuffing box. It will compress about 50%.

The technical specs are:
Made in the UK
No binders or adhesives
Standard Carbon content 99% minimum.
Standard density 1.0 g /cc.
Temp range from - 200°C to + 2800°C in inert conditions.
High thermal shock resistance & high electrical conductivity.
Very low friction.
Tensile strength > 5.2Mpa
Leachable Chloride & Fluoride - 50ppm maximum.
Compressibility - 47%
Recovery - 9%
Electrical Resistivity - 900 x 10-6 ohm cm parallel to surface, 250,000 x 10-6 ohm cm perpendicular to surface.
Ash Content < 1.0%
Sulphur content < 1300ppm
Chloride content 50 ppm maximum.
 

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