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!

 

Im sure one of the staff will be along in a bit to answer in full.

answers to your questions as i would do it:

1. yes you could use a foam to make a "plug" and mould directly from that. However it would be far easier to use an existing case of the right size to mould from. You would know the shape is right to start with.   I would suggest that if you go down the plug route, you then make a proper mould from the plug as it means you can repeat the process if it goes wrong, and the visible side is the "shiney" side to start with.

2. kevlar does offer some good heat resistance and is sometimes used for that purpose. However for the kind of temperatures you are asking, you may be better off using some foam to provide a decent insulation to the case.

4. Buying a case to mould from solves a lot of the issues in this question as you can strip down the old case for parts or copy them. There are online suppliers of hinges and catches so they shouldnt be a problem.  Also you can buy rubber edging trim and seals in a variety of sizes for automotive or other uses.

Hi,

Thanks for your detailed post and sorry for the delay in getting back to you. Warren has given some good advice.

I'll try to answer all your points:

1. I agree entirely with Warren. If you can 'copy' an existing case (and you're happy with its size/shape/design) then do that - use the case as a 'pattern' and make a mould using that pattern. This will leave you with a female mould that's the right shape for your instrument and with a good finish on the inside (which will become the outside of your part).

If you can't find a case like this then you should certainly look at making a 'pattern' for the case. I would imagine this pattern would be a simpler, smoother shape than the exact shape of the instrument and also be larger (maybe considerably larger) in order to accomodate the foam lining that you will use inside the case. For this reason, applying anything to your instrument itself is not neccessary and would not really help, far better to start from scratch making a foam or MDF pattern and then make moulds from this pattern (like you would if you were copying an existing case).

2. Again, Warren is spot-on. Kevlar is a reasonable insulator and because of its VERY high tempertaure tollerance it does get used in some insulation applications but this is always for protection from very hgih heat, not because Kevlar has a particuarly high U-Value. At the thickness you would be using the Kevlar its thermal insulation performance would be pretty insignificant. For thermal insulation (and shock protection) foam would be a very good idea.

Don't worry about the compatibility of the foam with epoxy because you'll be making the case first and then bonding the foam into the case, which you can use any contact adhesive to do.

3. As above, I think foam is a good idea. Profiled polyether foam ('eggbox foam') is great for lining cases and suchlike. You could also consider 'memory' foams. We don't supply these materials and they're quite bulky so I would suggest just checking with some local suppliers.

4. This one's more of a question of what system you can find. If you've got two surfaces that come together pefectly then you should be able to find an off-the-shelf sealing system somewhere (although I can't recommend anything myself). Try checking with seals suppliers or silicone extruders to see if they have a section that would suit. My guess would be a silicone or rubber section that's bonded to one side fo the case and then accepts and seals with the other side of the case shell.

I hope this helps and look forward to working with you.

Best regards, Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Hello to everybody,

sorry for my late reply, but I have been quite busy.

Thank you very much for all your advices, I will keep in mind all the great info you gave to me!

About getting a case and copy it, I didn't mention that this case doesn't exist, I was looking for it for buying it for my instrument but I couldn't find it, so I decided to make one.

My first step will be to get the foam, so I will keep you informed about how is the process of the case going!

Thanks again!

You're welcome. I look forward to seeing how the project progresses. Be sure to post some pics in the 'project showcase'.

All the best, Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Dear friends,

I have started now with my project and couple of questions have comen to my mind. Hope you can help a bit with your valuable knowledge as usual.

I have made a pattern of Foam, and I think is quite ok, but about the nexts steps:

1. I don't know if I had a mistake, but the Foam supplier recommended me to use a polyester putty, because the foam is hard but porous. I bought and applied one layer of polyester putty, but in the can is written that this putty is also porous, and another layer of a complementary putty should be applied on the top of that.
Do you think is necessary? Did I make a mistake already in the process?

2. I was planning to add a logo to the case. I have contacted with a serigraphy supplier for making a PVC plate. My idea is to make a hole in square shape in the foam's surface, so that when I try to get the case, there is the same squared-hole on it. The question is: Once the case is fully cured, can I add the PVC plate in the squared-hole and add some extra epoxy resin for holding it to the case inside the case surface, and then sand paper the area and polish it for leaving a very smooth surface with the logo inside? The idea is that the PVC plate remains inside the surface of the case, not on the top of the case, sorry if I don't explain myself properly. 

Hope you can help me with these questions.

Thanks, hope you are spending a great summer!

Hi,

1. I don't know if I had a mistake, but the Foam supplier recommended me to use a polyester putty, because the foam is hard but porous. I bought and applied one layer of polyester putty, but in the can is written that this putty is also porous, and another layer of a complementary putty should be applied on the top of that.
Do you think is necessary? Did I make a mistake already in the process?

I'm not familiar with the filler/putty that you're using to coat your foam pattern so I honestly don't know if it's right or not. Remember that you'll now have a polyester surface on your part and so you need to be very careful about what you make the mould from in order to ensure that it will release OK from the pattern. Our Uni-Mould system would be OK because it used a vinylester gelcoat and so it will release fine but epoxy tooling gelcoat would not.

Regarding your logo I'm afraid I can't quite understand what it is that you want to do so I'm not sure what advice I can give you. Maybe try re-phrasing?

All the best, Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Hi again,

1. Ok, I understand, I am going to use the Uni-Mould System, so then hope will be Ok.

2. I try to rephrase:

I want to add a logo to the case, so instead of attaching the PVC plate with the logo to the case throught adhesive application, my idea is:

To make a hollow where the plate could be accomodated in the pattern so, that I will get the same hollow in the final carbon fiber case. When the case is cured and finished, can I then put the PVC plate inside the hollow and then fill again with epoxy resin? I would like the logo remains not over the case in the surface, I would like to have inside the proper case.

I hope you can understand what I mean. The orders of materials from inside the case would be: carbon fiber layer, epoxy resin, PVC plate and epoxy resin. After that, I would sand paper the last small part of epoxy resin and polish it to make an even surface. I attach an image for better understanding.



Thanks again for your attention, and waiting for your advices.

Best Regards!

Hi,

OK, I understand now. Well, it's possible but you're certainly making a lot of work (and causing a lot of problems) for yourself! - We get a lot of questions on the forum and in emails about embedding logos, signitures and the like, often in very adventurous ways and if I could give one piece of advice to aspiring composities manufacturers (particuarly those with little experience) it would be to hold-off with the fancy logos until you've got your product coming out spot-on; particlarly if there's a good chance that the inclusion of said logo might cause production problems or actually end up being its downfall.

In your idea here you're creating quite a detailed area of the moulding with right angled corners where fibre bridging or bag bridging is likely to be a problem. If that doesn't end up being a problem then it still may well cause a re-lease problem unless the sides of the recess are sufficiently tapered. Finally, if that all goes to plan and it doesn't bridge and it release OK from that section without taking a chunk out of your mould or part then you are left with the task of 'embedding' the logo and then blending that embedding resin into the surrounding resin without it looking a mess. I think for this last part if you plan on lacquering the whole case afterwards then this might be feasible but if you just want to blend nicely into the surrounding flat material then it might look messy.

I never want to stop people from having a go at something they want to do but my advice would certainly be to concentrate on getting the case right, where you've got enough to think about, and worry about embedding logos when your carbon fibre cases are the hottest ticket in music!

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Hi there,

Completely understood, and of course you are completely right. I just try to have the project as planned as possible and to know which of the ideal ideas in my mind are possible in the practical part of the project.

Thanks again very much for your attention and I will inform how is the project going.

Best Regards!