High Temperature Epoxy Resin

Hello Krishnan!

I do not have a great experience with High Temp. Epoxies, but can you disclose a little more of the intended part function? The "glass fiber" suggests to me that the part must have a certain strength, either to withstand a structural, or pressure loading. What reasons would prevent the use of a machined metal part?

The temperature does seem to be high enough to warrant the use of a specialized epoxy, i.e. not store brand-off the shelf. And in my limited experience a 10mm wall thickness would probably require both vacuum to eliminate air bubbles (can this even be accomplished with glass fiber loading?), and I would think depending on the process of curing some warpage issues may arise. Can the epoxy part be machined after curing? What tolerances are required? What will the finished part be exposed to besides heat? Any volatiles? Water? Air alone?

I have surely asked more questions than provided any answers, but I am intrigued as to the use of this part.

I have personally used www.matweb.com for finding a wide array of materials for different projects. They have a very useful database of materials which can be searched by material type as well as many differing material properties.

Hopefully this can be of some help. My advice would be to find a material which appears to be close to your needs and then contact the supplier directly, it takes time to discuss all needs with a compounder/supplier but in the end in my experience it saves far more time to have the assistance to do the task correctly the first time.

Excellent guidance!

I have attempted to provide the following clarity.

What reasons would prevent the use of a machined metal part?

The tube need to be micro wave radiation opaque and hence use of metal is ruled out.

. Can the epoxy part be machined after curing? What tolerances are required? What will the finished part be exposed to besides heat? Any volatiles? Water? Air alone?

FRP is only a support layer over PTFE tube for reinforcement. Dimensions and operating environments are not exactly critical.

I surely respect your advice. The component will be outsourced to a company well versed in glass tape winding techniques and once the suitable resin system is identified the project can be progressed with confidence.

I am thinking of PTFE as core knowing fully that I will be touching the upper temperature limit of the material.

Due to the reasons of confidentiality of the project I am unable to reveal more details.

Thanks for indicating the material selection web site.

Quote:What reasons would prevent the use of a machined metal part?

The tube need to be micro wave radiation opaque and hence use of metal is ruled out.

Unquote

Metal IS microwave opaque. Epoxy is not. Or do you want a radioparent tube?

Anabond have some single component epoxies for high temperature use. However, I have used it only up to 175ºC.

http://www.anabond.com/

Thanks.

I stand corrected.

I just checked the definition of "radioparent" and this is exactly the property I have been looking for and learn a new terminology in the bargain!.

Yes! I will check with Anabond range.

Possibly Hysol range from Loctite-Henkel will offer suitable resin for application in excess of 250 deg C.

Thanks again.

Have you considered some of the new high temperature high strength polymers. Solvay has some products which may suit your purpose. Peek may be suitable. You can check it out.

Solvay Specialities India Pvt. Limited
401, Suraj Prakash, 86 Shankar Ghanekar Marg,
Prabhadevi, Mumbai 400025 India
Phone: +91-22-2437-2646
Fax: +91-22-2436-1488

Email: Inquiries

Contact person: Ravindra Marudhar

http://catalog.ides.com/Results.aspx?RSCOLS=&

Dear Mr. Ramani,

Thanks to you i have sent inquiries to the firm.

I appreciate your help.

Search for an epoxy company that offers products for aerospace and/or fly-away use. Seek a filled epoxy (for opacity) and one based upon an epoxy novolac resin (for higher cross-linking and often very high temperature resistance - the curing agent is also important in providing heat-resistance to 260C˚. For the best high temperature resistance, ask for the an aromatic type curing agent. Best: seek an epoxy product that has at least 10% aluminum filler (or other metal), along with other fillers, and the above. Joe M.

Thanks!

But metallic filler is ruled out as the component is used in RF radiation environment.

Not enough information.

Epoxy novolac resin might work, but not with glass. You're in the carbon fiber temperature range, if there's any requirement other than self support.

End use/surface finish/pressure/vacuum/underwater/outer space?

There is a resin used for pc board mnf, I have had some at one time but have lost the details. it is heat cured, in the case of pc boards between heated platens.

It is high temp rated so possibly ok for your application, have a google around.

Take a look at some of the Araldite systems from Huntsman. They have some elevated temp curing systems that have appropriate viscosity and gel time for filament winding and will get you a Tg of ~140-150 deg C. That should get you a service temp of 120 deg C or so. Araldite XB 3585 with Aradur 22962 looks like a decent candidate.

Good luck!

Krishnan,

Another thought occured to me, I understand you cannot tell us exactly all the operating parameters of the project, but if the piece is not going to be subjected to massive loadings or in danger of impact damage have you considered a glass construction? Or as well I know there are ceramic-glass composites available as well. I have no experience with these but I know some are "machinable grade", and as well I would assume if you need visible spectrum opacity but radioparency that could be accomplished.

If not oh well, it just popped in my head.

-T

Edit: To avoid any vagueness I meant a solid glass construction, i.e. epoxy-less. From my quick research most glass products have a Tg of around 300° C or greater.

Dear friend,

Of I meant glass fiber in epoxy matrix resin system and not solid glass.

Of the concern expressed about impact failure etc due to mechanical loading, I have consciously opted to filament winding technology for a sound structure.

To quote from: http://engineershandbook.com/MfgMethods/filamentwinding.htm

"Filament winding consists of winding resin impregnated fibers or roving of glass, aramid, or carbon on a rotating mandrel in predetermined patterns. The method provides the greatest control over fiber placement and uniformity of structure. In the wet method, the fiber picks up the low viscosity resin either by passing through a trough or from a metered application system. In the dry method, the reinforcement is in the pre impregnated form. After the layers are wound, the component is cured and removed from the mandrel. Traditionally used to produce pressure vessels, rocket motor cases, tanks, ducting, golf club shafts and fishing rods, filament winding technology has been expanded, and non cylindrical, non spherical composite parts are now commonplace. Typical thermo set resins used in filament wound parts include polyesters, vinyl esters, epoxies, and phenolics".

Thanks for sharing your concern.

Dear mr Krishna,

I aminfoming you 280 deg C in Epoxe is very dificult

to withstant . you have not tell it is a direct temp or indirect.

any way you can go to filament winding . you will use Phinolic resin

it can durable , machinable, not in Alkali or Acid

CHERIAN.A

Dear Cherian,

Thanks for your input.

I am keeping all the options open.

Most ideal solution suggested by Bioramani in his kind post #6 make tremendous technical sense offering permanent solution.

Perhaps look at polyimides rather than epoxies?

try www.masterbond.com/

good luck

JB weld says it resists heat up to 250 C but I put it in boiling water and it came apart. I do use it in place of solder on copper water pipes, which transport low temp steam, and it stays together good. Maybe you'll want to try Ultra Grey gasket maker, it sticks better and is harder then other gasket makers I've tried, and it's temp rating is up to 260 C. Or Ultra copper which is 300 C something, but it doesn't stick as good.

Hi Krishnan,

Please have a look at http://www.cotronics.com/vo/cotr/cm_potting.htm

They have ceremic adhesives and potting compunds working upto 3000 degree F.

Rajnish Vaish