How to fix a broken Bose headset?

Discussion in 'Workshop Tips and Secrets / Tools' started by etterre, Oct 31, 2007.

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  1. Oct 31, 2007 #1

    etterre

    etterre

    etterre

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    It's probably not exactly the right forum, but since I'm considering a fix with composites and a fix with metal...

    Sigh. I've got a Bose X that I bought used and it's now been broken (I blame my kid :) ) The u-shaped stirrup that holds the left earcup has snapped near one of the attachment points. I called Bose and was told that they don't sell replacement parts... but I could send it to them and they would fix "anything" for $175. Not a bad deal if the ANR was getting futzy, but I only need a $5-10 plastic part. Since the stirrup is made of plastic, my first try was to clean it, glue it back together with 5-minute epoxy, and add some fiberglass for extra support. Maybe it's because I used the cheap stuff (Devcon from a hobby store), but the epoxy didn't stick. I think my problem is that the plastic is of a type that just doesn't chemically bond to epoxy, so I actually need to do rough it up with sandpaper so that I get more of a mechanical bond.

    But now I'm wondering if that is actually the best way to fix it - so I'm fishing for other ideas. Here's a few that I've considered:

    1. Create a new stirrup out of fiberglass and epoxy. The only way I can think of doing this entails making a female mold from the broken part and then essentially filling the mold with flox. The I'd have to finish it off with sanding and some machining so that the attach points line up. While I'd be more likely to get a reasonably light part that looks like the original Bose piece this is probably a fair amount of work. I'd learn a lot, but...

    2. Make some measurements, do some drawings, and have a machine shop make a "more rectangular" version out of aluminum or steel. Easier for me to do... but I'm a little afraid of the $$$ I'd spend at the machine shop and if it might make the $175 charge from Bose look cheap.

    3. A slight spin on #2 where I do my own machining work. I don't have a milling machine (or access to one), but the part all in one plane so a rough copy could be made from a piece of flat plate. I do remember reading about one guy's technique that involved using a normal wood router and templates to create the part out of aluminum stock.

    4. Modify a steel stirrup from a different headset. I did a could of rough measurements and I can get a replacement steel stirrup from David Clark for $10. It doesn't have the same connection between the stirrup and the headband, but it would be fairly easy to make an "adapter" by boring a couple of holes in a cube of aluminum and screwing the adapter onto the steel stirrup at the appropriate point.

    Anybody got a better idea or a reason to pick one method over another? I'm currently leaning towards #4 since it should provide a fairly durable fix without a "lot" of work. It won't be "pretty," but I could still buy "pretty" at a later date for $175 if it really bugs me. Since there's a nick at the same point on the right stirrup, I'm also figuring that I might as well fix both sides.

    The big picture shows the left stirrup in it's current condition. Note that there isn't much material missing at the break - I've just moved the pieces apart to show the break better. They fit back together pretty cleanly, but I can't instantly align the pieces together due to the curvature of the pieces and the break itself - so using an instant bond cyanocrylate (Superglue) wouldn't work. The smaller picture is an "end-on" view showing the relative "smoothness" of the break.
     

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  2. Oct 31, 2007 #2

    orion

    orion

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    You're right, some plastics just don't bond worth beans. Using a better epoxy however may be one possibility. Looking at your options though, I wonder if by the time you're done with all that whether the $175 would be a more cost effective way to go. But just in case, let me try to give you some alternatives.

    First, you might try a better adhesive. There are several made specifically for plastics, most of which you could probably get from your local hobby shop. Plastic-Weld comes to mind but I'm sure there are others.

    The part may however be made from something that's a bit more chemically resistive so epoxy may be your best bet. There are of course many that may be better than Devcon but do stay away from the 5-minute stuff. Generally, the longer the cure the better the final bond quality. I've had pretty good luck with Hysol EA9460, even on plastics.

    For a better chance of success, I might suggest that you take a small drill (something like a #40)and bore one or two small holes in both parts. Of course make sure the holes line up. To do this you may have to clamp the two pieces together and then drill from the outside. As you go to bond the two pieces together, insert "music wire" into the holes, making sure to get a bit of the epoxy onto the wires also. Make sure the wire and the holes are a snug fit. In this way the music wire will reinforce the joint in bending and the epoxy at the break will just hold it together.

    If you want to cast your own, you might want to join the two pieces with a low cost epoxy and then create a part mold using a casting silicone. A friend of mine uses this process for creating various model parts from master components and it works beautifully. Given the strength of some of the better epoxies, I would guess you wouldn't have to fill the resin with flox or any other additives, just pour or inject the epoxy into the cavity and let it set. Keep in mind however that although you can probably de-mold the part over night, most epoxies require a lot of time (up to three months) or an elevated temperature to reach full cure.
     
  3. Nov 1, 2007 #3

    etterre

    etterre

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    Thanks - after a small search, I found a supplier for a 2 part silicone mold-making kit ( the "mold-max" product from www.smooth-on.com ) that's only $22. I'll probably go that route for the "long-term" fix, but I'll give the music wire trick a try with some of the "extra" Aeropoxy from the Rutan practice kit that I have.
     
  4. Nov 10, 2007 #4

    Dana

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    Roy, here's how I have made similar repairs:

    Get some very thin cyanoacrylate (the "wicking" kind, not the "gap filling" gel). Hardware stores may not have it, but hobby shops catering to the R/C crowd sell it. With the wicking CA, you can put the broken pieces together first, and then apply the glue... it will wick in and bond it. That won't be strong enough by itself, but it should hold the parts together for the next step. Before you glue it, though, lightly sand the outside of the parts adjacent to the break, to break the gloss and scuff up the surface. Then after it's glued, for maximum adhesion, clean the surface with laquer thinner and don't touch that area again (the oils from your skin will prevent a good bond).

    Get the thinnest glass cloth you can find (again from the R/C shop, or nylon or dacron fabric will also work) and lay strips along the part. Drip the thin CA onto it and press it into place with a pin or knife blade; it's easy to see when it's properly wet out and laying on the surface. After fully encapsulating the broken area with the glass/CA, you can coat it with a thin layer of epoxy for a harder, smoother surface.

    I've used this technique numerous times... two years later the plastic turn signal stalk in my car (broken right at the base where the stress is greatest) is still holding up fine.

    -Dana

    Mary had a little lamb. The doctor was very surprised.
     
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  5. Nov 13, 2007 #5

    Sticky1

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    don't you think it would be easier to send them back to bose......I did.....they fixed for free.....
     
  6. Nov 13, 2007 #6

    etterre

    etterre

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    Sure, it would be easier - but not free. How long ago did you get your set fixed? In talking it over with my flight instructor, he had a friend that also had to pay to get his Bose X fixed - so the repair charge isn't a new thing.

    Don't get me wrong - I'm not knocking Bose's support. My headset is a secondhand one that I bought off E-bay years ago (they had the original 9V battery box) that I later upgraded to the current AA battery box. So they're easily years outside of any sane warranty period. I did call Bose's customer service number - and that's where I got the $175 "fix anything" quote. Not an unreasonable price if there was something more substantial wrong with them... but well beyond what I want to pay so that they'll swap out a $5 part.
     
  7. Nov 14, 2007 #7

    Sticky1

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    I sat on and broke mine a year ago. I called bose and asked what I should do......They said send them back....I did.....Freebeeeeeeeeee.....

    No Questions asked.....other than name and address, no warrenty card was sent in..
     
  8. Nov 14, 2007 #8

    Tony F.

    Tony F.

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    I'm not sure if it will work, but the cement used by plumbers for plastic piping might work. It's based on methyl ethyl ketone, which dissolves the surface layer of the pipe and ensures a very good bond. If your plastic is softened by MEK this should work. The music wire idea would be good in conjunction with the cement bond. Be aware that MEK is nasty stuff, so don't get in on your skin. The cured cement is OK, as the MEK has evaporated.
     
  9. Oct 12, 2015 #9

    wadedunbar

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    Hi, I have been trying to find parts for my two Bose head sets!! I have sent them back twice and only one time the warranty paid! Now two brackets are broken on one and one on another one! I called and they said it would cost $275.00 for each one to fix !!! I think like Volkswagen they need to have a recall on their crap!
     
  10. Oct 12, 2015 #10

    don january

    don january

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    Try these it may make it work again....... hammer.jpg
     
  11. Oct 13, 2015 #11

    Turd Ferguson

    Turd Ferguson

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    Correct. Just switch to a different type of adhesive. Not all epoxy sticks to plastic. For example, epoxy won't stick to SMC used for many jetski hulls. But I found some purpose blended epoxy that not only sticks, it is amazingly strong.
     
  12. Oct 14, 2015 #12

    12notes

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