Talk Composites - The Forum for Advanced Composites

Musical Instrument Case

http://www.talkcomposites.com/Topic1681.aspx

By fibercase - 5/15/2012 9:58:18 PM

Dear friends of Easy Composites,

 

First of all, I would like to congratulate youfor your complete web site (also carbonmods) and your very well explainedvideos.

I write you because I plan to start a projectwith carbon fiber very soon and even though I have been reading a lot about howcomposites function and also watching all your videos in youtube, still I havesome unanswered questions related to my project. Hope you can help me a littlebit with that.

My project consists in making a transport casefor my musical instrument. But I have several problems mostly in how to makethe first steps and also in which way I can get the best possible results.


1. I am planning to make a mould, but I wouldn’tlike to put any wax or release agent, gel coat etc. over my expensiveinstrument. So I thought about making a copy of the structure with metal plateor with foam. Which material do you think works better for making round edgesin several directions?

Then I am thinking about two possibilities: oneis to use the structure made with the new material as a mould and apply thecarbon fiber layers over that structure following a kind of skinning process inorder to make the case around of it. Is it possible? How should I proceed foravoiding the metal or foam to get stuck to the carbon fiber? The best qualityresult should be in that case the outer layer, is it possible to get nice resultsin the last applied layer with this system? Should I sand paper it and polishit later for getting the good results?

The second possibility is to do the opposite:create a mould from the copied structure of the instrument and then work likewith a normal mould, applying the carbon layers inside the mould.

 

2. Then, my instrument is very sensitive totemperature changes, and is very common that it’s damaged going from -20ºC instreet to +22ºC in a room. I was thinking in putting a layer of carbon fibre,layer of Kevlar and layer of carbon fiber, because I don’t want to be too thickcase. What do you think? Is Kevlar good thermic isolator? Do you recommend someother material for this purpose compatible with epoxy resin?

 

3. I was thinking about placing a special foamhigh resistance to impacts and also thermic isolator. Do you know some foam suitablefor this purpose? Which is the best way of attaching the foam to the compositecase? Do I need special glue for that or what do you recommend?

 

4. And the last question, I would need also toseal the two parts of the case when they close. Would be perfect to find amaterial which could seal air-tightly and isolates temperature. I have readthat PVC is quite good on that. Do you recommend some material for this? Is PVCcompatible with epoxy resin? How can I attach it to the composite?


I am sorry about asking so many questions, but I amtrying to figure out by myself taking out a lot of sleeping hours and I can’tfind the answers.

Thank you very much in advance for your patienceand attention, and hope to read soon from you.

Best Regards!

 

By Matt (Staff) - 8/6/2012 12:41:35 PM

Hi,

You'll certainly need to 'surface' the foam with something to seal it, harden it and allow it to be polished up to a high standard. On its own the foam is not a suitable release surface.

For coating the foam pattern I would suggest epoxy coating resin and a layer of lightwight 163g glass coth and then additional applications of the epoxy coating resin with microballoons and fumed silica to make it thicker and more sandable. You should then be able to flat and polish this to a high standard ready to take your moulds off.

-- Matt