Materials Question: Looking for an insulator

How about kevlar? Or maybe some sort of ceramic composite if you want to get really fancy. You could always go old-school and use a very hard wood like mahogany.

 

Robert, There was a product I used a few years ago that I found at Griots Garage. It was a silcon paint that was fairly heavy in its consistancy ie;you could paint it on in layers and make as thick as you wanted. I painted the coolant tubes on a 308 that I had to see if I could lower the temp of the outside of the tube. I have also used it on an aluminum shield between header and alt. I was able to build the thickness to about a 1/4 inch. Supposedly the product was derived from technology from the space shuttle tiles which are silicone. Anyway so for the long story but you might check with Griots to see if thet still sell the stuff. Regards, Vern

 

Several materials come to mind quickly. Graphite foil as sold by UCAR/ Graftech under the product name Grafoil. A flexible graphite product produced in sheets/ rolls of various thicknesses. Excellent thermal insulating properties through the thickness. Used in many automotive applications with a metal reinforcement as head gaskets etc.
Ceramic fiber mat insulation as seen at:
http://www.ibiden.co.jp/eng/products/02/index_auto003.html
Used to insulate catalytic converters etc.
Good Luck!

 

If you really mean 450 deg F max, and not "450~500~550~something like that", you could use Vespel or Torlon (maybe at least for a quick test). The 450 is right at their upper bounds.

Another option for you might be Macor (a 1000 deg F ceramic that's machinable with conventional tools) if you're essential talking about making a ~1/8" thick sheet gasket sandwiched (i.e., compressively supported) between two flanges (and the flat area isn't too large).

What's the rough length x width x thickness of the needed piece? IME even these commercially-available tradename materials sometimes aren't that easy to source in a small retail way.

 

Zirconium Oxide doped with Yttrium looks like it might fit the bill:

http://www.aps-internl.com/html/ang/ang_isolation.htm

Don't know if the mechanical properties are compatible but worth asking.

And if you want to ask real experts, you could try here:

http://www.intota.com/multisearch.asp?strSearchType=all&strQuery=thermal+insulation+material

Or go to the local university and pick the brains of the material science professors. If they don't know what to use, they probably know who to ask.

I have done a bit of work in that general area myself, and if you want to IM me more details I can at least give you some ideas about what you're dealing with and the best ways to go about it.

 

Hi Robert, When you find the material you are looking for post you find would you. It seems I am always trying to insulate something for heat. TIA, vern

 

http://www.mcmaster.com/

In the products lists to the right go down near the bottom to raw materials, and click on plastics, scroll down to PBI and click on it.

PBI: Also known by the tradename Celazole, PBI provides excellent wear resistance at high temperatures. Common applications include ball valve seats and clamp rings.

Shape Rods and Discs
Rods and Discs Type Rod
Material PBI
Opaque Black
Backing Plain Back
Highest Temperature +601° to +700° F
Operating Temperature Range up to +650° F
Performance Characteristic High Tensile Strength and Electrical Insulator
Tensile Strength 23,000 psi
Tolerance Standard
Specifications Met Not Rated
Diameter
1" | 1.5" | 2.625"
Length
6" | 12"
These 4 products match your selections
Diameter /Length Each
1" 12" 8708K11 $328.17
1.5" 6" 8708K13 360.51
1.5" 12" 8708K12 721.03
2.625" 6" 8708K15 1161.77

Good luck!

 

Stay away from graphite / carbon fiber materials --- they will conduct some heat. Also, avoid silicones as they may not be tolerant to exposure to oil and gasoline. Here in the Aerospace world we use the following materials which are readily available, relatively inexpensive, come in a variety of pre-fabricated shapes (such as spacers / washers) and will meet your requirements:

Torlon
Vespel
Ultem
Kapton
G-10 (a type of fiberglass)


Look in the online catalog from "McMaster-Carr" out of Chicago ---- you will find exactly what you want ---- all these materials plus many ceramics that work well also. The caveat with ceramics is that they can be weak structurally in certain applications ---- I would stay with one of the "plastics" listed above. Given the contraints you listed, G-10 will be your best solution. The others are subject to some creep (deformation) at your operating temperatures.


Cheers,

 

millboard, fire resistant and has btu ratings up to 2. comes in thickness ranging from 1/16" up to 2+ inches. mcmaster-carr carries it. temp range is over 1500*F
and inexspensive!

 

I would recommend sheet phenolic. Ferrari used it for carb and fuel pump spacers on older cars. It is very easy to work with and machine.
Both McMaster Carr and Aircraft Spruce carry it.

Brian