I'm looking for a substitute for asbestos cement based insulation boards that are used structurally as well as thermally. Googling provides a few names such as 'Duraboard' and 'Isofrax' and 'NAD500' but technical information is sparse. Has anyone experiance of these or other products that will take the odd brief duration splash of molten iron, can be machined, drilled, bolted to, and are available up to
25mm thick without sacrificing all legs and arms?AWEM
IIRC, many of the modern asbestos replacement boards are based on calcium silicate. Googling on that brings up several possibilities; a visit to your local builder's merchants would probably give you a fair sample of what's on offer. Vanilla CS board didn't cost many extremities last time I bought some (it was going to be used as the outer cladding of a pottery kiln); however, you may need one of the reinforced variants if you want it to have any significant structural properties - the stuff I bought was fairly friable.
The other material that may be worth a look is glass fibre reinforced cement board - again, should be available from builders merchants. Not sure it is available in 25mm thicknesses though...
Regards, Tony
--Look for stuff called Fiberfrax. Trouble is you usually have to buy it by the box, which was enough to wrap my 4hp Yarrow boiler *twice*.
I believe the substitute for 'Asbestolux' board was/is called 'Mineralux', & its mechanical properties seemed very similar. I'm pretty sure that mica is/was one of the constituents. I haven't used any for years, though. I did buy some much softer insulation board, probably the Calcium Silicate to which Tony referred. Not expensive, but not very strong.
HTH
Tim
Neither will survive contact with molten iron :-(
A number of places do alumina based ceramic fibre boards, but I don't know what surgery is needed in exchange for the products. I'm a year or two away from that point.
examples are :-
I used to work with some wood-fibre cement board that was routable, even took a thread. And fire-proof.
Pyrok?
Wilfrid Underwood
Can't help from direct experience, though I have heard of VFB (vacuum formed board) and also ceraboard, used by kiln makers. I don't know how strong it is though, and it isn't cheap.
What I am really writing about though is a tip from the fireworks community, who treat to cardboard mortar tubes for longevity (cardboard is safer than metal in the rare event that a shell detonates in the tube, the shrapnel is softer).
They soak the cardboard in 200-350 g/l calcium chloride solution (the stuff used in cheap chemical dehumidifears will do) for between twenty minutes and an hour, then pour out the solution and add sodium silicate (waterglass) solution and leave for a minute or two. This forms calcium silicate, with a melting point that should be high enough to withstand molten iron.
'NAD500'
these or
(vacuum formed
safer than
shrapnel is
(waterglass)
Neat trick, I like that , thanks!
AWEM
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.