Miraphone 186 Bottom Bow Repair

(or "how to remove the dents from a bottom bow without removing it from the horn")


Above are a couple of pictures of what this bottom bow looked like before I started the cosmetic surgery.  One would think that the magnets and dent balls would work for this kind of damage, but I'll assure you that even if you have magnets powerful enough to move Mount Everest, it is virtually impossible to take these dents out.  The reason is that Miraphone does not normally finish the portion of the bottom bow that is under the guard and the magnets and balls simply won't work.  You'll see exactly why in some of the later pictures.


First, the keel is taken off...  then, the bow guard reinforcement plate has to be removed.  Getting the keel off is pretty minor, but removing the plate can be very tricky.  Starting at one end of the plate, it is heated to melt the solder.  As the plate becomes loose, it has to be pried up ever so little as it is heated further and further toward the opposite end.  Much care has to be taken to insure the the plate is not bent or stretched as it is removed.  Once the plate is off, all of the solder must be removed from the bow and from the backside of the plate.  Everything has to be clean before any dent removal can be done.  Now, you can begin to see why the magnetics won't work as long as the keel and guard plate are in place.  Miraphone did not do a very good job of smoothing the seams on this bottom bow.  Any attempt to use the magnetics would have resulted in lots of bumps in the finish due to the seam and the blobs of solder that were underneath the guard plate.


Above, I've removed the solder and used the magnetics to remove the majority of the dents.  The next step is to give the bow a little polish to reveal if further dent removal is required.  When the bow is finish well enough that it looks good WITHOUT the guard, it is ready to install the guard.


Here we go straightening the bow guard.  This one was salvagable because the dents did not have any sharp creases of tears.  Much care has to be exercised to keep from stretching the guard or it will not fit properly when it is reinstalled to the bow.


Above, the guard has been soldered back onto the bow.  The guard is wired to the bow to hold it in place while soldering.  This is an easy task as long as all of the old solder has been removed and the parts are fit properly.  In order to get a good solder bond between the guard and the bow, the edges must be fit within a few thousanths of an inch.  Once the guard is back in place on the bow, all of the residual solder is removed from the joint by scraping...  and then it is buffed.  Looks pretty good, doesn't it?


All that hard work to make sure everything was properly prepared for assembly has paid off!  The finished job looks GREAT!  Now...  all that's left to do is touch up the lacquer and put the horn back into the hands of a happy customer!


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