Sciencemadness Discussion Board

High temperature pipe wrapping that is non conductive (electrically)

RogueRose - 16-7-2020 at 07:29

I need to wrap a small pipe (1/4" - 1/2" diam) so I can wrap nichrome wire around it so I can keep the temp high on the piping. The minimum operating temp will be 680F but will probably be operating at 1000F or so and ideally there would be some safety margin above that.

I've found some fiberglass sleeving that is suitable but it's only available in 50-100ft sections and is too expensive considering I need 1-2ft. I found suppliers in China (ebay listing) but with shipping times now, that is no where near ideal. I'm wondering if anyone knows of any businesses that would use this stuff in their daily business from electricians, HVAC, or automotive applications. I was hoping to I might be able to find a business that uses it and maybe buy a small piece.

Here are some sites that are bulk suppliers and it shows some of the applications. It looks like the sleeves are often used to insulate compressor or oil lines in vehicles or HVAC

https://www.techflex.com/high-temperature

https://www.cabletiesandmore.com/high-temperature-braided-sl...

If anyone is interested in ordering some smaller quantites, this seller has all different sizes and sells them in meter lots but it is shipped from china.

https://www.ebay.com/itm/1-40mm-White-600-C-HIGH-TEMP-Fiberg...

[Edited on 7-16-2020 by RogueRose]

mysteriusbhoice - 16-7-2020 at 09:41

try some KAO-WOOL pipe sleaves
https://www.morganthermalceramics.com/en-gb/products/high-te...
a bit fluffy but it should do the job!

Junk_Enginerd - 17-7-2020 at 02:07

This can't possibly be an issue to find. You can buy fibreglass mats used for composite plastics in almost any hardware store. Then just cut them to size. Same hardware stores are likely to also have strips of fibreglass which have seams on the edges, this is nice since you don't have to deal with all the fraying you get with cut edges. Seriously that fraying drives you nuts and suddenly everything looks like its been tarred and feathered unless you're careful.

It is also not too uncommon to wrap motorcycle or car exhausts with some form of fibreglass for heat retention, I assume many automotive/tuning shops will have these in stock.

Fibreglass sleeves of smaller dimension should also be available from electronics suppliers like digikey.

If necessary, the fibreglass could be fixated with sodium silicate, or a paste of sodium silicate and an inert ballast like clay, sand or something similar.

[Edited on 17-7-2020 by Junk_Enginerd]

wg48temp9 - 17-7-2020 at 03:27

The problem is the maximum operating temperature of most thermal insulation is not necessarily its operating temperature as an electrical insulation

Glasses in particular tend to have significant electrical conductivity at elevated temperature so most cannot be used for electrical insulation at 500C.

[Edited on 7/17/2020 by wg48temp9]

S.C. Wack - 17-7-2020 at 13:38

Ceramic fiber paper