I need help with casting carbon fiber

[PSU1980]

This is my first attempt at casting. I slid the carbon fiber sleeve over the tube and dripped Stickfast CA on the carbon fiber. Let the tube dry for two days and then I casted it.

Below are pictures of my mold how a caste tube came out and the one I turned.

I used Aluminite Water Clear, pressurized the castings for 2 hours at 40psi. Removed the mold and took inside for the night.

Came home from work, took the blanks out of the mold and then turned the one blank. I didn't notice the area that appears that the resin didn't adhere to the carbon fiber.

The resin cured for around 21 hours before I turned it.

Any help as to what I did wrong would be greatly appreciated.

Thanks,
Tim

 

[Kenny Durrant]

Tim I've only used Alumilite a few times so I'm limited on the tips I can give. I agree that it's separation so I would guess the resin wasn't mixed or weighed precisely or trapped air was the cause. Rather than me guess I'll tell you what I do and maybe you can pick up a few ideas to add to your method. First I paint the tube black then I use Epoxy Glue to glue the fiber to the tube. This is the messy part for me because I literally put an excessive amount of glue on the tube. I like to see the glue ooze through the fiber when I stretch it to tighten it on the tube. I take the excess that oozes out and smear it all over to help seal any voids in the fiber. I let set for a couple of days then cast. I hope this helps.

 

[JohnU]

I've cast lots of carbon fiber but only with polyresin and never alumilite. I get very little failures with Polyresin Silmar 41.

 

[jttheclockman]

I do the same as John. I too always use silmar but I also glue the fiber to the tube using the resin. No glues.

 

[MarkD]

Been there, found that Alumilite does not work well for that application. As the others have said, use polyester resin is better for application.