Composite Materials

Discussion in 'Community' started by Butler Trumpet, Apr 6, 2005.

  1. Butler Trumpet macrumors 6502

    Butler Trumpet

    Joined:
    May 26, 2004
    Location:
    Dekalb IL
    #1
    Hey, so I am looking into making my own, and possibly marketing, trumpet cases. (weird for this website I know) So what I want to do, is have a shell for the case made out of some kind of composite material that is very strong, but also flexible (about as flexible as tupper wear) Then I would cover with foam and fabric... and make a case.
    So there's that... any suggestions on what kind of material I could use for the shell? I was thinking either fiberglass, though Im not sure if it is flexible enough, or I was thinking of Kevlar, though Im not sure if it is solid enough.
    So what are you thoughts on this?
    Thanks lots! :D

    Edit... I have done research on this around the web... and haven't really come up with anything that is useful to me. But I did learn how to make a subwoofer box, however that is to rigid for what Im looking for.
     
  2. pseudobrit macrumors 68040

    pseudobrit

    Joined:
    Jul 23, 2002
    Location:
    Jobs' Spare Liver Jar
    #2
    Check Aircraft Spruce & Specialty. www.aircraftspruce.com/ Order a free catalog. Buy a grab bag of composite stuff and practice. The thing with composites is that you can use them as composites -- you're not locked into one fibre type -- a carbon/kevlar blend is common.

    Kevlar would be a good choice from an economics standpoint. If you get serious, prepreg is the way to go.
     
  3. mcadam macrumors 6502a

    mcadam

    Joined:
    Apr 3, 2004
    Location:
    københavn
    #3
    Hello - that sounds like a great project...
    Hmmm... I'm thinking... fiberglass is really stiff and not flexible, at least not any kinds I know of. And I believe that's how most composites work (though I'm not an expert).
    If you want it flexible I think you should be looking more into some kind of plastic or rubber material. This could come as sheets that could be vacuum-sucked over a positive mold - really nice process that gives a great finish and is very practical if you wanna start a little production of them. You'll have to find someone with a machine for doing it though. My school has one, but it's in Denmark...
    It could also come as a 2-component (fx silicone which comes in many different qualities) rubber thing, with a big bottle of thick liquid rubber and a small bottle of hardener. This process is quite a bit more messy and toxic (not worse than fiberglass though) and the (negative)mold is more complicated to make.


    Why do you want the outer shell to be flexible? I would assume it needed to be hard to protect the trumpet inside.
    But I can see that it could become real nice and flashy untraditional with a slightly soft material. And protective enough as long as you don't sit on it I guess?


    A very untraditional material could be beewax - which is much harder than you'd expect, very plastic-like. But probably not soo durable, especially in the summer, hehe (melts at ca 62ºC, gets soft before that)... but it smells really nice, is absolutely non toxic, really nice to touch and look at. Perhaps you could first shape the inner foam and then melt the wax into it's surface. Add more layers and smooth it in the end with a heatgun. I think it could work in a normal temperate climate...

    Hope to hear about your progress

    A
     
  4. Butler Trumpet thread starter macrumors 6502

    Butler Trumpet

    Joined:
    May 26, 2004
    Location:
    Dekalb IL
    #4
    Wow thats pretty cool about the vacum thing... I will have to check that out somehow... hmm....
    Anyway, the reason I wanted it to be flixable, is because having trumpets in it, if it is just a little bit flexible, it will take impact better, rather than being more rigid. Kinda like how racecars break apart to absorb impact and all.
    So do you know where I could find some info on this vacum thing? Cause that really sounds the most like what I want.
    Thanks so much!

    edit: do you know of any companys that would be able to make something like this? really it isnt complicated, and if I could just have a company make them for me, then that would really be ideal.
    Thanks!
     
  5. mcadam macrumors 6502a

    mcadam

    Joined:
    Apr 3, 2004
    Location:
    københavn
    #5
    Hi there - I'm afraid I'm not in the best position to help you find a vacuum machine (don't even know the proper name in english hehe). The ones I've been using have been in the workshops at my school of architecture and at the school of fine arts in Copenhagen. So I would perhaps start by asking at the department of dance or media arts at your college - if there is some scenografy or prop-guys. They might know. The machines I've been using have been really really old, 30 years at least - so I wonder which proffesionals still have them around...

    A
     
  6. Butler Trumpet thread starter macrumors 6502

    Butler Trumpet

    Joined:
    May 26, 2004
    Location:
    Dekalb IL
    #6
    So I am now looking into nylon... and some other materials... still having some troubles. Though one of my trumpet student's dad is the head of a company that makes prosthetic arms and such, as well as shoe inserts... and these are made of a plastic like material, not sure what yet, that is very tough, but also flexible enough to make a shell out of... so Im hoping to talk to him soon about all of this.
    :)
     
  7. mcadam macrumors 6502a

    mcadam

    Joined:
    Apr 3, 2004
    Location:
    københavn
    #7
    Ah, that seems like a nice connection. Sounds like he could be full of know how, ideas and perhaps even acces to machines and tools :D Prosthetics are amazing, my professsor at arch school is really into it - claims the technology, and medical technology in general, is far more sofisticated that space technology. And the materials used for prosthetics could be perfect - soft and extremely durable I would imagine...

    Hope to hear more about how it's going

    A
     
  8. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #8
    Yeah, I don't think you are going to find a composite that has the kind of flexibility you want. Most composites are not flexible, by the nature of the binder material, and by the fact that the addition of the filler makes it less flexible yet. Thermoplastic carbon composites might be flexible, but I'd doubt you'd have a lot of advantage over plastic for this kind of application. What are you worried about in terms of damage-resistance that you need the composite for?

    If you want to be very protective of a musical instrument, I'd think that the critical thing is what isolates it from shock -- whether the outside is plastic, steel, titanium, carbon fiber, or whatever, if the path betwen the exterior surface and the instrument can support a fast impulse load directly onto the instrument, then that's a bad thing. If it damps it out, then that's a good thing, right?

    In terms of manufacturing, high density polyethylene (HDPE) might work fine for you. While this is the material that many soda-type bottles are made from, it is flexible and also fairly strong, especially if you make it with several layers. (most automotive fuel tanks are made out of multi-layer, and are designed not to leak in almost any collision!). Also it has the virtue of being light, and it can be manufactured in complex shapes. If you do a good job with the wrapper you put around it, it could be a very nice product! :)

    EDIT: One problem with plastics like HDPE and nylon is possibly going to be that a mold to make the shell pieces in is going to be a large investment. There might be some way around this, though, if you will not be making very many cases, by using a mold that was made through some kind of rapid-prototyping or with soft steel.
     
  9. Butler Trumpet thread starter macrumors 6502

    Butler Trumpet

    Joined:
    May 26, 2004
    Location:
    Dekalb IL
    #9
    Yeah you are right about that... the shell doesnt really matter to much as long as the padding I put in the shell is good... but the reason Im so interested in it is because thats where I have to start. Once I have the shell... the rest will be incredibly easy (covering the inside with foam, and then covering everything with cloth or leather...)

    anyway yeah, HDPE sounds really cool, because the other materials that I have been advised arent really good I have found for complex shapes, and not that this shell is going to be THAT complex, it is however going to be more so than just a simple box you know... so thats pretty cool.

    As far as cost for the mold goes... what I am really looking for, is a company or something that I can team up with to make my shells for me, sell them to me, and then let me do what I want with them. And in the long run, I would really like this to be a full production kind of thing, making not just me and my friends a case, but hundreds of cases hopefully... really making my business grow. (realistic? i hope....)

    so any ideas of some companies that could do this?
    Thanks lots!!
     
  10. pseudobrit macrumors 68040

    pseudobrit

    Joined:
    Jul 23, 2002
    Location:
    Jobs' Spare Liver Jar
    #10
    I hate to rain on your parade, but unless you have serious capital available, plastic moulding is not the way for you. In order for a company to make these for you, you would need to purchase hundreds if not thousands in advance to cover the costs (I'm imagining at least five figure numbers, possibly six).

    If you're thinking more along the lines of selling a few here and there with the hopes of expanding, I'd look into composites. A top layer of CF on a fiberglass case would be really whiz-bang.

    Anything CF is selling like hotcakes these days, and the economies of scale for niche items are still favourable, unlike plastics, due to the inevitability of labour overhead.
     
  11. Butler Trumpet thread starter macrumors 6502

    Butler Trumpet

    Joined:
    May 26, 2004
    Location:
    Dekalb IL
    #11
    So, is fiberglass able to be fabricated at home? Like, if I went to my garage, would I be able to make the shell for this thing myself? From what I have seen on TV and such, they way I take it, it comes in cloth material, then you paint it with some stuff that sets it up and it hardens... is that right? because if it is then that is exaclty what Im looking for... and just need to know where to get it.

    Alright thanks so much! :)

    Edit. I just read this http://www.ffcobra.com/FAQ/cf/page3.jpg
    and after reading, I think that carbon fiber is the way to go... as long as it is easy, and cheap to work with. So just re-read that last paragraph, and instead of saying fiberglass say carbon fiber :)
     
  12. James Philp macrumors 65816

    James Philp

    Joined:
    Mar 5, 2005
    Location:
    Oxford/London
    #12
    Well the shell is kinda important - it shouldnt crack on impact! (tough)
     
  13. Butler Trumpet thread starter macrumors 6502

    Butler Trumpet

    Joined:
    May 26, 2004
    Location:
    Dekalb IL
    #13
    Right... that would be the worst thing if it cracked... if I did make a case, and someone was using it, even if it did protect the trumpet, if it cracked then the case would be kinda useless.... so thats no good. Which is why I think I want to stay away from fiberglass because it just isnt as sstrong ( I think ) as what I would like.
     
  14. dvdh macrumors 6502

    dvdh

    Joined:
    Apr 6, 2004
    #14
    In terms of materials, your production run is going to have a lot to do with what you can use. If you are looking at an injection molded material you have to do at least 500,000 units before it become feasible. With roto-molding, your feasible run is down to about 50,000 and tooling costs are significantly lower for something the size of a trumpet case. The next options use sheet materials. Vacuum forming can be done using low-end forms made of medium density fibre board (machined to form either by hand or using CAM / 3d routers.). With vacuum forming a few hundred (or even less) products is very economically possible. In a similar vein, fibre glass, and other hand-laid fibre reinforced composites can be done on a low production run.

    In terms of what you are trying to do, I wouldn't discount fibreglass quite yet. If it is reinforced correctly, it would be stronger and more durable in a variety of temperatures than most of the plastics that you could have either vacuum formed or injection / roto molded.
     
  15. Butler Trumpet thread starter macrumors 6502

    Butler Trumpet

    Joined:
    May 26, 2004
    Location:
    Dekalb IL
    #15
    I just found this website
    http://www.fibreglast.com
    looks like a good place to get some stuff to make both fiberglass and carbon fiber...
    what do you think? still, is this something that can do what I want it to, make one at a time, for cheap?

    when all is said and done I will probably be wanting to sell each case for about $150-$200... so as long as my production per unit isnt above 100 then I should be okay as far as profit goes.
    thanks!
     
  16. pseudobrit macrumors 68040

    pseudobrit

    Joined:
    Jul 23, 2002
    Location:
    Jobs' Spare Liver Jar
    #16
    I'll repeat the above advice again. Aircraft Spruce's catalogue is as big as a phone book and is 100% free last time I checked. The catalogue has an overview of the composite selections and the properties of different materials. They have a selection of different weaves and weights of all different type of materials. It also tells you which epoxy systems work best with which type of fabric.

    I would use a few layers of E Glass fabric to keep costs down with an outer layer of carbon fibre for looks. E Glass has a lot of flex to it (compared to other composites), but holds up to a beating very well. I have a friend who made an old style goalie mask out of it (and he wears it!).
    Carbon fibre is about four times as expensive per yard as E Glass and much harder to work with. Many people doing layups have trouble getting the epoxy impregnated into the weave.

    In my 2002-03 catalogue, AS have a practice kit for sale that includes a manual, some fiberglass and epoxy with a few tools for $60.

    I would start with that, work my way up to confidence with Glass, then try CF.
     
  17. pseudobrit macrumors 68040

    pseudobrit

    Joined:
    Jul 23, 2002
    Location:
    Jobs' Spare Liver Jar
    #17
    Don't set your pricing based on what your costs are. Set your pricing based on what the market will bear. What does the current market for these cases look like? What are competing cases (even if they're not composite) selling for?
     
  18. Butler Trumpet thread starter macrumors 6502

    Butler Trumpet

    Joined:
    May 26, 2004
    Location:
    Dekalb IL
    #18
    Cool... my catalog actually just came today. I ordered last week when you said that before. I am looking at the composite material practice kit right now... it costs $49.95 with the manual because I live in the states. So yeah I will order that, it looks cool.

    I am only saying that price because that would be a very competitive price. The case I have right now... which isnt made any more because the guy who made them passed away a few years ago, cost about $300. Now the best case you can buy (which is similar to mine) costs about $250(ish)
    If you go here and look at WK-TP25BP (should be the 3rd one down) this holds two trumpets and a piccolo trumpet, which is what I want mine to do. http://www.stusmusic.com/wolfpak.htm you can see what these cases look like... not bad, but mine will be better :) So that is why I want to make mine for under $200, and hopefully closer to $150.... better product and cheaper I hope.
    Thanks!
     

Share This Page