US Composites

Hey guys,

Who here has experience with US Composites 3:1 epoxy resin? Also have any of you used Rexco Partall mold release?
Any advice or tips are appreciated.

Thanks

Us composites works well. I have used both think and thin. Think works for non laminating applications.

Great stuff.. Good folks to do business with... Come to think about it, I need to order some of their laminating blend.

Good service I placed my order on Sunday, got shipping notification on Tuesday, my half gallon kit of 635 3:1 arrive on the following Tuesday (Florida to Washington State). Have yet to use my epoxy though

I particularly enjoy the 3:1 and 4:1 laminating epoxy blends. I've also gotten some various fillers such as faring compound, 3M microbubbles, fumed silica.... from them. Fast shipping!
-Ken

littlemisterbig said:

Hey guys,

Who here has experience with US Composites 3:1 epoxy resin? Also have any of you used Rexco Partall mold release?
Any advice or tips are appreciated.

Thanks

Click to expand...

I'm using the 3:1 thick on BBT right now...

Assuming you are referring to the 635 resin and medium (3:1) hardener, yes, have been a vocal advocate for many years. If though you are referring to the 150 (thick) resin, then no. I have found the later to be far too brittle for most high-power rocketry applications. If you need a thick structural epoxy I would lean toward System Three's T-88--simply fabulous product!

I've also used the 3:1 medium #635 resin system. Works a peach and is less viscous than West, which makes it better for laminating. If you are looking for something slower, just know that the slow hardener requires a heated cure.

We have used 635 extensively in building radio control models. It is an excellent product.

I am looking at 635 3-1 for laminating. The consensus seems to be it is very good for laminating (cheaper than West). Does it also work well for fillets? With or without fillers? Would this be a great (cheaper) "all purpose" resin.

This is my all purpose resin. I use it for bonding (add chopped carbon and some colloidal silica), fillets (lots of colloidal silica), laminating (add nothing).

I love it.

Laminating resins are usually pretty thin... in order to have good "wet-out" properties.
Aeropoxy makes 2 different epoxies; one just for lamination, the other for general bonding.

JD

CZ Brat said:

I am looking at 635 3-1 for laminating. The consensus seems to be it is very good for laminating (cheaper than West). Does it also work well for fillets? With or without fillers? Would this be a great (cheaper) "all purpose" resin.

Click to expand...

I just finished up some fillets on a 3" Darkstar using the USComposites 3:1 epoxy. I had some small diameter biaxial weave carbon fiber "tubing" that I saturated with epoxy and laid into the fillet area. I thickened the remainder just past the point of gravity flow using chopped CF. WOW. Seems stronger than anything I've done before!
-Ken

CZ Brat said:

I am looking at 635 3-1 for laminating. The consensus seems to be it is very good for laminating (cheaper than West). Does it also work well for fillets? With or without fillers? Would this be a great (cheaper) "all purpose" resin.

Click to expand...

I use 635 3:1 for laminating, and just started using 4:1 (the fast one, not too sure if I remember the ratio correctly) for adhesive and fillets. For adhesive I mix in US composites fumed silica to thicken it up, and for fillets their q-cells (sandable). Great stuff!

Two thumbs up for 3:1, both thick and thin........
Started using it 15 years ago and never stopped. Chopped CF or Chopped FG for added strength....:wink:

I'm about to place my 3rd US composites order! I have so far only used the thin for laminating but decided to try injecting it - what a mess! Any recommendations on which fillers (sold by USComposties) to use with the thin epoxy to make it injectable? What about for making fillets?

Would it be better to get some thick for injecting & fillets?

Kevin

I injected fillets using 635 4:1 thickened with their fumed silica. I went a little thinner than mayo and taped off the openings I could see. Went reasonably well, but if you're using natural fiberglass tubes, adding some colorant a la Wildman will help see the distribution. Lab at work was tossing out some nanosphere carbon, thinking of trying that.

Ive also used the 1/32" milled FG similar to CJ's chopped CF, just enough Milled fiber that the epoxy will self level. Usually I seoerate my mixed epoxy into two parts a larger into which I mixed the fibers, and a smaller amount in case I thicken it too much I have a little to thin it down.

I also use 1/32" milled fiber and put some black pigment in it for natural FG tubes. The black pigment is also useful for fillets on black FG rockets.