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Quick and easy MPC chip repair!

#1
While putting in some sax pads with a hot glue gun(worked well), I decided to attemt to fix my Clarinet MPC which has had a chip since I got it. I filled the chip with hot glue, chilled it in some ice water then shaped it with the sides of the still hot hot glue gun nozzle. Worked perfect, and may have quieted some odd harmonics and difficulty in achieving proper emouchure. And, it can always be reversed and more permanently repaired, but this repair required no major sanding which could have damaged the facing.




 
#3
pretty good. With a chip like that normally black epoxy is used. Though takes extra time to solidify and harden but at least it looks like the rubber itself.

As you mention, the hard part is sanding the material and not affecting the surrounding material .
Yup, not much sanding here. Most of the shaping was done with the hot glue gun nozzle. As I said, just quick and easy. If you need a MPC working in a couple minutes, this will do. I will have to get some black epoxy and fix it right in the future.
 
#4
pretty good. With a chip like that normally black epoxy is used. Though takes extra time to solidify and harden but at least it looks like the rubber itself.

As you mention, the hard part is sanding the material and not affecting the surrounding material .
What epoxy do you recomend? I was looking at Loctite Epoxy Repair Putty Stick Basically, a two part putty. Should work.
 
#5
My second attempt is probably permenant, and much better looking. Didn't take much more time but did require some sanding and polishing in some sensitive areas.

I used this. The metal putty was the logical choice, for the color if nothing else.


Worked well, and total cost of the three putty sticks was $7 at the hardware store.


On the facing, the repair is more or less indistinguishable from the rest of the MPC.


For a strength test, I made an odd shaped piece from the leftovers. I am unable to break this piece even using considerable hand force. I am sure I could break it with pliers, just as I could metal.
 
#6
I found the best tools to use for sanding and polishing were cheap nail files(sand paper type), and a nail polish/buff stick. Both were available for under a buck at the dollar store.

Most important thing to remember is to use as little as possible to fill the void. Any excess will be difficult to sand off cleanly. Sanding is mainly to create a smooth transition from the MPC to the epoxy. If you have to sand excessively, you are more likely to end up sanding the MPC it's self, which you should not have to do at all.

Total cost of the repair was negligible, as I have the vast majority of the putty and tools unused. It is likely a permanent repair as well, and took about an hour with time allotted for the putty to harden enough to sand.
 
#7
is the putty non-toxic?

I recently repaired a cracked shank, and discovered that there were concerns about the toxicity of epoxies. Recommendation from others was to use something approved for drinking water systems, such as JB Waterweld. This did an excellent job, but leaves a white/blue porous surface. Not so good in some places.
 

Steve

Clarinet CE/Moderator
Staff member
CE/Moderator
#8
Oops, just saw the posts on this thread.

I use 2 epoxies.
One, the one that you have found in the 2 sticks that you combine.
THe other is a liquid epoxy from Ferrees. I don't have the specifics of it off the top of my head but it comes in two little jars and you mix the two to activate it. It may take a while to cure though, which gives you plenty of time to smooth it out.

My first main item I look for is to make sure it is safe to be put in the mouth, ie, toxic in any means. Of course in the area it is you want to make sure it is marine approved lol
 

jbtsax

Distinguished Member
Distinguished Member
#9
I found the best tools to use for sanding and polishing were cheap nail files(sand paper type), and a nail polish/buff stick. Both were available for under a buck at the dollar store.
These are also great for finishing brass---especially if you don't have a buffing wheel. Pictured below are the ones from Walmart that I use a lot for shaping and finishing brass keys.

 
#11
is the putty non-toxic?

I recently repaired a cracked shank, and discovered that there were concerns about the toxicity of epoxies. Recommendation from others was to use something approved for drinking water systems, such as JB Waterweld. This did an excellent job, but leaves a white/blue porous surface. Not so good in some places.
Not sure, but from my experience most epoxies(including the JB product) have some level of toxicity before/while curing. After curing most are just as non-toxic as any plastic. FWIW, the warnings for the JB waterweld are exactly the same as the Devcon product. Almost to the letter. I'd be surprised if there is much difference between their chemical structure at all. You can read the JB list of ingredients on their web site. Nasty stuff in there. But once cured, it is just a resin, like Bakelite, PVC, ABS, resonite, ebonite, ebolin etc. All of these compounds are toxic to some level before they are in their cured state.
 

Steve

Clarinet CE/Moderator
Staff member
CE/Moderator
#12
Not sure, but from my experience most epoxies(including the JB product) have some level of toxicity before/while curing. After curing most are just as non-toxic as any plastic. FWIW, the warnings for the JB waterweld are exactly the same as the Devcon product. Almost to the letter. I'd be surprised if there is much difference between their chemical structure at all. You can read the JB list of ingredients on their web site. Nasty stuff in there. But once cured, it is just a resin, like Bakelite, PVC, ABS, resonite, ebonite, ebolin etc. All of these compounds are toxic to some level before they are in their cured state.
Thus don't mistaken it for a tootsie roll while it's sitting around. :)
 
#13
Thus don't mistaken it for a tootsie roll while it's sitting around. :)
Lol. Very true! Not to be taken internally...well...at any stage.
 

pete

Brassica Oleracea
Staff member
Administrator
#14
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