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High temp epoxy

+1

In what application, please?

Yes, but still have this question as they generally require a specific high temperature post cure and are very tender and weak until fully cured. PTM&W does make a wide range of excellent products, Aeropoxy among them. The Tech line guys are outstanding.
 
words from an epoxy engineer

Yes, there are 'high temp resins', but according to an engineer I trust (he designs resin systems) they all catch on fire at about the same temp. I was looking for some FWF parts to be made from a 'High Temp' resin, but it turns out the high temp stuff will still burn when near a heat source like an exhaust manifold etc. He did mention the temp where they all will burn, but danged if I can remember what that was - maybe 450F or so?

If I am recalling the conversation well enough, the 'high temp resin' has a higher post cure temp, and that is about it.
 
Custom

In what application, please?

Custom plenum and air intake. Maybe not really required but I ordered my last air intake in high temp epoxy from Sam James and it worked great. Previous one scorched from the exhaust proximity.

Think I'll just make plenum out of West Systems but was curious. I get the high curing temp as well which would be difficult in my application.
 
DPL862 is a widely used base stock for most epoxies. The manufacturers add their herbs and spices to change various attributes. DPL 862 turns to apple sauce when cold but its easy to fix by keeping it in a metal can and putting it on low heat before use. The additives typically used to prevent crystallization also weaken the epoxy.

Nice thing about DPL862 is its about half the cost when you take out the middle men.

https://www.avtcomposites.com/product/dpl-862-epoxy-resin-gal/
 
Here's a data point. The EZ builders were making their engine baffles out of fiberglass 30+ years ago, and I doubt they were using exotic high temp epoxy back then.

I can barely *spell* 'layup', but if a fiberglass item was scorching from exposure to heat from the exhaust, wouldn't a radiant heat barrier would do more good than higher temp epoxy?

Charlie
 
wouldn't a radiant heat barrier would do more good than higher temp epoxy?
Exactly! On my cowling modifications, I used EZ-Poxy since the Safe-T-Poxy that came with my kit is no longer available. Where the exhaust came close, I applied Aluminized Heat Barrier. The stuff really works well and I haven't had any problem with it peeling off. I sealed the edges with red RTV.
 
Custom plenum and air intake. Maybe not really required but I ordered my last air intake in high temp epoxy from Sam James and it worked great. Previous one scorched from the exhaust proximity.

Think I'll just make plenum out of West Systems but was curious. I get the high curing temp as well which would be difficult in my application.

Steve, I cure plenums in a home oven with an extended "porch". Google "pregnant oven" and see pictures. If you integrate the inlets it won't fit.

I have read about people making the plenum cover from West 105 and said it did not slump. It must have a little higher capability than listed or changes slowly. In any case, it is reported to work.

I do suggest you use Lantor Soric XF 3mm core material for stiffness. It will get wet but not soak up resin and ~10 times stiffer.
 
You'll still need reflective material near the exhausts, preferably over an insulator.

For the plenum lid, the HTR I linked has a Tg about double that of West, higher than a lid will typically reach. It also cures at room temperature. Made a mod to my own plenum about two weeks ago.
 
I had to modify my lower cowling to accomodate a different exhaust system. The original cowling was vinyl-ester. The "cheeks" were EZ-Poxy. The aluminized heat barrier has protected the fiberglass and not come loose. If I were applying it again, I would use 3M #94 primer underneath.

HqeNeW.jpg
 
Good numbers for a room temperature cure epoxy. I have some exit parts running very close to a hot tailpipe without issue.

https://www.aircraftspruce.com/catalog/cmpages/htr212resin.php

West 105 has very low temperature ratings.

Wow! These are remarkable numbers for a room-temp cure epoxy. Prior to this, I considered MGS the gold standard, and Jeffco a close second, at half the price. I am testing a high T-g hardener from Jeffco now. But this HTR stuff looks amazing.

We worry about T_g on our speed-mod parts because some owners want to paint them dark colors (like black) and we are worried they will exceed T_g on a hot sunny day.
 
Wow! These are remarkable numbers for a room-temp cure epoxy. Prior to this, I considered MGS the gold standard, and Jeffco a close second, at half the price. I am testing a high T-g hardener from Jeffco now. But this HTR stuff looks amazing.

Steve, put your engineer eye to the mechanical specs. Not sure it is appropriate for primary structure, and I'm having trouble with the modulus unit conversions.
 
Looks like all the strengths are in psi, and the flex modulus is millions of psi.

With those strengths, I wonder about the elongation to failure and overall brittleness of the resin. Generally, in my own experience, the higher the strength and modulus, the lower the elongation to failure, and that's coupled with increasing brittleness.

Seems to be similar in metals, too, although there are broad exceptions.

Dave
 
For what it's worth, when I built my plenum, the owner of West sent me a gallon of their aerospace product. It is supposed to hold its shape to a very high temp but, you will need an oven to post cure it after the initial set. The higher the post cure temp and length of time, the better performance, up to a limit. I don't have the product sheet with me and they don't list this product on line. I do recall roasting it at 260 degrees for 48 hrs or something like that!
 
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