CF/FG fillets?

[The Rocket Kid]

How does one do Carbon Fiber and/or Fiber Glass fillets?

A video, you tube or otherwise would be much appreciated!

 

[powderskierman]

Do a search for this tread. Tons of great info. CJ's "HOW TO BUILD IT STOCK 3IN DARKSTAR into "redux" build starts now!!

 

[GregGleason]

I am going to hazard a guess and assume that you are wanting to do structural fillets. You may also want them to be "finished" fillets or "aero" fillets, so an "all-in-one" fillet. That is harder to do with CF. Most chopped CF will make the epoxy a bit lumpy and harder to control, but will result in a strong fillet. On the other hand, milled fiber will work better as it is essentially a powder and is much easier to mix in to make a more homogenized fillet. Not as strong as a CF fillet, but stronger than epoxy by itself (which is pretty brittle).

Last night I was reading some information from Jim Jarvis (a great composite rocket craftsman) regarding fillets, who mixes milled fiber and a bit of fumed silica (Cab-o-sil) to create what is called a non-Newtonian fluid, so that once you get the shape desired for your fillet it will maintain that shape until the epoxy sets.

Greg

 

[The Rocket Kid]

I am going to hazard a guess and assume that you are wanting to do structural fillets. You may also want them to be "finished" fillets or "aero" fillets, so an "all-in-one" fillet. That is harder to do with CF. Most chopped CF will make the epoxy a bit lumpy and harder to control, but will result in a strong fillet. On the other hand, milled fiber will work better as it is essentially a powder and is much easier to mix in to make a more homogenized fillet. Not as strong as a CF fillet, but stronger than epoxy by itself (which is pretty brittle).

Last night I was reading some information from Jim Jarvis (a great composite rocket craftsman) regarding fillets, who mixes milled fiber and a bit of fumed silica (Cab-o-sil) to create what is called a non-Newtonian fluid, so that once you get the shape desired for your fillet it will maintain that shape until the epoxy sets.

Greg

yes I am looking to do structural fillets.
were would I buy chopped/milled CF or do I just buy CF like normal and somehow "chop" it myself(or FG assuming it is the same procedure for both)?
Sounds like a very interesting article.Could you post or pm me a link to it?

Do a search for this tread. Tons of great info. CJ's "HOW TO BUILD IT STOCK 3IN DARKSTAR into "redux" build starts now!!

thanks I've already been following it and your right its full of valuable info.

 

[blackjack2564]

were would I buy chopped/milled CF or do I just buy CF like normal and somehow "chop" it myself(or FG assuming it is the same procedure for both)?

I get mine here, one order is darn near a lifetime supply. https://www.wildmanrocketry.com/ShowProducts.aspx?Class=830&Sub=831

 

[cherokeej]

Make chopped carbon or glass by taking little 1/16" snips from a scrap. Make a good measure of them.

Measure out some thin laminating type epoxy in a cup, mix well. Pour half a teaspoon off onto a paper plate, and set aside. To the remaining epoxy, add the chopped carbon or glass. Then add enough colloidal silica (Cab-o-sil) to the mix until it is thick as peanut butter.

Use a small brush to wet the areas to be bonded with the thin epoxy you set aside, then add in the thickened material to form the fillets. Smooth with a gloved finger and isopropanol. Strong fillets. :wink:

 

[Aksrockets]

https://www.youtube.com/watch?v=aFMdtHKWhZk

ones I made a few weeks ago. This just shows the fillets forming. Finishing is a whole different thing.

Alex