Epoxy experience?

[rturbett]

Has anyone tried Progressive polymers epoxy? They have a pretty involved website that has taught me quite a bit, and lured me with their cost savings.
I would love to hear if anyone has used their epoxy before I commit to them.

Rob

[rturbett]

http://www.epoxyproducts.com/noblush.html

[rasorinc]

Here is some testing results of various known epoxies. Raka seems the best buy here. Compare prices to this brand.http://www.oneoceankayaks.com/Epoxresl.htm

[ahender]

That Progressive Polymers website has got to be the worse designed website I have seen in years.

Gives me a headache just looking at it.

Of course back in 1995 it would have been state-of-the-art.

For an even cheaper price, go to www.uscomposites.com -- $65 for a 1-1/2 gallon kit.

I use the above for non-fabric jobs like cores, bulking, etc.

For fabrics I am using MGS Epoxy, expensive but extremely long working times and low viscosity.

alan

[rturbett]

You are right about the website- but it seemed full of good information. I couldn't read the green font!

What is your decision for switching resins for cloth work?

My biggest concern is long term durability

[ahender]

The MGS epoxy I use (335) is aerospace approved in Germany and is one of the epoxy systems sold at www.aircraftspruce.com -- a homebuilt aircraft site.

I use it because it has a mixed viscosity of around 350-400 and a pot life of 4-6 hours -- which translates to about 1 to 1-1/2 hours for a 500+ gram tub of resin.

It also will allow for a 50 degree F temperature increase before the pot life halves. Most resin systems are in the 18 degree range before the pot life halves.

I heat it up to about 100-110 degrees and it probably has the viscosity of Pro-Set epoxy, at about $50 per gallon cheaper (resin plus hardener).

It is expensive but the extra working time keeps me from freaking out to much when things are not going as planned (by all definitions I am a novice boat builder).

As for the U.S. Composites epoxy, I first started using it about 8 years ago.

Do a forum search for this resin -- not a lot of info but all the users seem happy with it.

alan

Take care to temper these slow EP / Hardeners proper! That is sometimes a real task if it comes to 140°C ! But if you can manage that, you have usually the best of the best. Especially in terms of fatigue resistance (durability), for that reason the aircraft approval is given!
Regards
Richard

[ahender]

Apex1:

Could you elaborate on your comment.

Are you referring to post-curing?

thanks...alan

Originally Posted by ahender

Apex1:
Are you referring to post-curing?
thanks...alan

Yes, sorry if that was´nt clear, tempering IS post curing.
Regards
Richard

[rturbett]

Thanks for asking - i was trying to figure that out too!

My work will not be vacuum bagged. The biggest challenge i have is keeping the epoxy from sagging/ running down the vertical sides of the hull.
using some thickener with a faster cure glue has helped

[ahender]

Apex1:

Thanks for your comments.

For the MGS 335 epoxy, the post cure schedule recommends a temperature of 140 degrees F, not 140 degrees C.

With a small part (12' canoe), that is easily doable.

For those who might be interested, here's the data sheet for the epoxy (www.newsrx.com/temp/MGS_Epoxy_Data_Sheet.pdf).



alan

Originally Posted by ahender

Apex1:
Thanks for your comments.
For the MGS 335 epoxy, the post cure schedule recommends a temperature of 140 degrees F, not 140 degrees C.
With a small part (12' canoe), that is easily doable.
For those who might be interested, here's the data sheet for the epoxy (www.newsrx.com/temp/MGS_Epoxy_Data_Sheet.pdf).
alan

Hi Alan, rturbett,
do´nt know that resin, but in general the aircraft resin (it is better to say hardener, cos, notice, the same resin with another hardener has no approval), has a loong pot life and allways needs to be post cured at relatevily high temperatures. Usually in two post cure steps. Most of these Resin / Hardener need a first cycle at around 70 to 80° Celsius and a second one at 120 to 145° Celsius, each cycle about 12 to 30 hrs. (the longer the better, you cannot "cook" the stuff to death).
Having that in mind I gave my comment.
And are you shure, only one cycle at 140°F is manufacturers specification? (for Aircraft application) If so it´s a bit uncommon, but nice.
Regards
Richard

[rturbett]

I'm glad i am not building airplanes-yet!

I haven't needed to post cure my epoxy work- I just made sure the the basement was warm enough.

Rob

Yeah, but what they did´nt tell you, IF you temper, you can get a better product.
Read: even the "normal temperature" curing matrix can gain in strength if you raise the the temperature (slow and even) to approx. 60 - 70°C, stay there for about two hours and reduce to ambient (again very slow and even). Although there are some formulations that do not get substantially better by tempering, in general the matrix improves.

Regards
Richard

[rturbett]

I'll crank up the furnace for a day - It will be a treat after the winter we've had