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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Gary Weller on April 13, 2011, 02:04:12 pm

Title: Cracked jbl 2380 horn - any good fixes till replacement arrives?
Post by: Gary Weller on April 13, 2011, 02:04:12 pm
A friend of mine had a mishap (cab fell off dolly) and discovered a crack and a small piece came out of his jbl 2380 horn near the flange where the driver mounts.

Is there a way to fix this somewhat till his replacement arrives? He's got the piece and it fits tightly. What would you suggest to "glue" it back in place for the time being?
Title: Re: Cracked jbl 2380 horn - any good fixes till replacement arrives?
Post by: Dave Neale on April 13, 2011, 09:31:33 pm
A friend of mine had a mishap (cab fell off dolly) and discovered a crack and a small piece came out of his jbl 2380 horn near the flange where the driver mounts.

Is there a way to fix this somewhat till his replacement arrives? He's got the piece and it fits tightly. What would you suggest to "glue" it back in place for the time being?

JB Weld.
Title: Re: Cracked jbl 2380 horn - any good fixes till replacement arrives?
Post by: Matthew Knischewsky on April 13, 2011, 11:58:16 pm
A friend of mine had a mishap (cab fell off dolly) and discovered a crack and a small piece came out of his jbl 2380 horn near the flange where the driver mounts.

Is there a way to fix this somewhat till his replacement arrives? He's got the piece and it fits tightly. What would you suggest to "glue" it back in place for the time being?

Epoxy.
Title: Re: Cracked jbl 2380 horn - any good fixes till replacement arrives?
Post by: Tim McCulloch on April 14, 2011, 03:25:39 am
A friend of mine had a mishap (cab fell off dolly) and discovered a crack and a small piece came out of his jbl 2380 horn near the flange where the driver mounts.

Is there a way to fix this somewhat till his replacement arrives? He's got the piece and it fits tightly. What would you suggest to "glue" it back in place for the time being?

Your adhesive repair should not introduce and seams, puddles, or flashing inside the throat or walls of the horn.  It must be smooth and follow the original contours or it will sound different (and probably sound inferior) when compared to undamaged horns.

Have fun, good luck.

Tim Mc

p.s. JBL's plastic horns are not robust.  You should find a way to support the driver independently of the horn.  Look at JBL 2509A for inspiration.  You can see it in use in the JBL Cinema Series 4670D.
Title: Re: Cracked jbl 2380 horn - any good fixes till replacement arrives?
Post by: Grant Anderson on April 19, 2011, 04:07:12 pm
A friend of mine had a mishap (cab fell off dolly) and discovered a crack and a small piece came out of his jbl 2380 horn near the flange where the driver mounts.

Is there a way to fix this somewhat till his replacement arrives? He's got the piece and it fits tightly. What would you suggest to "glue" it back in place for the time being?

Epoxy or JB Weld may result in a mechanical bond only, which is unreliable. What you're looking for is a chemical bond. When gluing plastic, make sure to use the proper solvent-based glue for the type of plastic being glued.  When done properly, the pieces will be essentially "melted" together, and be roughly as strong as the original part.

I don't know what the JBL horns are made of (ABS is likely), but you can probably find out with a little research.  It's easy to test a particular glue by putting a small amount on a hidden part, and see if it softens the plastic. If it does, then you're on your way. By the way, Methyl Ethyl Ketone makes a fine glue for ABS plastic.  Or just buy the stuff for ABS pipe in the plumbing department of your local hardware store.

Good luck!
Title: Re: Cracked jbl 2380 horn - any good fixes till replacement arrives?
Post by: Gary Weller on April 19, 2011, 10:35:11 pm
From the jbl pdf, it says it's made of "molded structural foam".
Title: Re: Cracked jbl 2380 horn - any good fixes till replacement arrives?
Post by: Chris Gruber on April 19, 2011, 11:21:35 pm
From the jbl pdf, it says it's made of "molded structural foam".

http://www.amazon.com/b?ie=UTF8&node=979130011