Talk Composites - The Forum for Advanced Composites

Cover 10mm carbon fiber tube inside evenly with epoxy resin?

http://www.talkcomposites.com/Topic22039.aspx

By valzine - 9/28/2016 10:55:28 AM

Hello everyone,

I've been searching the forum but couldn't find the answer to my question. I'm trying to cover the inside of a 10mm carbon fiber tube with inner diameter of 8mm in thin layer of high temp food safe epoxy resin. The inner aperture is very important to me (precision I'm looking for is up to hundreds of mm). I achieve needed inner diameter by drilling with precise drill bits. The tube is approximately 50mm in length. My questions are:

1. Can I somehow spay the epoxy inside or do I have to apply it by hand? If applied by hand, what would be the best tool to use?
2. Would 3k rolled carbon fiber tube absorb the thin layer of epoxy resin and leave the inner aperture the same? Or do I have to polish it somehow (drill again?) after I apply it?

Here is the resin I'm intending to use: 
By valzine - 9/29/2016 12:47:50 PM

ChrisR (29/09/2016)
What sort of service temperatures and why must the inner aperture be 1/100th mm accurate? (how you achieve or even measure this is beyond my comprehension unless you have state of the art facilities)

The only practical way would be to make your own tube using a mandrel of just under the size you want, allowing for expansion of the mandrel during a heated cure cycle. 

Use the "food safe" resin as the main matrix & bobs your uncle









ChrisR, thanks for your reply. I was able to measure 135C the highest. Obviously, during the winter it can get as low as -20 - 30C when the device is not operating. This will cause huge fluctuations with any metal, the only exception would probably be Invar but where to even get it lol? 

As far as about measurements I measure another tube that goes inside of that cb tube with a micrometer that has .01mm accuracy, which allows me to select the right tube for the aperture and achieve the desired coefficient of friction.. It's actually easier than you think. And the drill bits are pretty precise when sharp ;-)