How to repair a broken weld on a 805b horn

I just bought a pair of 805b horns. One of them came with known damage. The bottom middle cells are slightly pushed together, and the weld in the middle is broken.

Were these just tack welded together? How can I repair that section, and then match the original paint?

Here are two pics. Hopefully they are big enough. I think if you click on the pics they get bigger


Attachment 3671
Attachment 3674

I got a decent deal on the horns. 500$ for the pair, including factory 1"-1.4" reducers.

I can't believe how dead they are. They ring as much as a bag of sand. Lol

epoxy maybe? it would avoid heating the horn and melting the coating.

Take this with a grain of salt as I have never even seen a pair of these in real life.
I suspect that the strips running along all the cells is sweated on with solder, top, middle and bottom and than the shorter strips are added on top of them connecting both rows. If that is the case you may need to remove the vertical upright, carefully cut a 1" section from both cells on the bottom and replace that with a new section. Afterwards replace the vertical section.
Do you know any good radiator repair guys? They are good with working with this kind of stuff.
Done properly and repainted it should look like nothing ever happened.

BillWojo

Good info guys. I didn't think about not melting the coating off. Also I had just assumed they were welded together.

There is a pair of multicells listed on ebay that says the horns have been "repaired" and welds are "tight". Wonder how they repaired those?
Shit, that pair just sold for 895$ plus freight charges

If you look at the joints in the pictures you can see spots were the solder is showing under the paint.
Somebody help me out here, wasn't there photo's of the Altec horn shop posted showing horns being built? Not the cast horns but the built up steel horns. Might get some clues there.
How you decide to repair them is up to you, epoxy, rivet in a steel patch or resoldering them with a new patch. No matter what, they will sound great.
If you decide to do any soldering on them, find someone with experience in soldering sheet metal. If you ever saw a radiator repair guy replace a brass tank, they make it look so easy. It probably is with 20 or 30 years of experience doing it. I know I'd wind up with a big mess on my hands, and I've been using torches for most of my life.
Keep us posted on how you proceed, I don't think this has been discussed before.

BillWojo

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Originally Posted by BillWojo

If you look at the joints in the pictures you can see spots were the solder is showing under the paint.
Somebody help me out here, wasn't there photo's of the Altec horn shop posted showing horns being built? Not the cast horns but the built up steel horns. Might get some clues there.
How you decide to repair them is up to you, epoxy, rivet in a steel patch or resoldering them with a new patch. No matter what, they will sound great.
If you decide to do any soldering on them, find someone with experience in soldering sheet metal. If you ever saw a radiator repair guy replace a brass tank, they make it look so easy. It probably is with 20 or 30 years of experience doing it. I know I'd wind up with a big mess on my hands, and I've been using torches for most of my life.
Keep us posted on how you proceed, I don't think this has been discussed before.

BillWojo

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I agree they look soldered to me, a common manufacturing technique during the the era of multi cell horns. I would look for a metal working shop that that still utilizes those skill, such as a radiators shop, or possibly a motor cycle shop that builds oil tanks and fuel tanks. Looks like a simple fix of aligning thing correctly and soldering using the proper solder, and soldering techniques.

I like the professional solder method.

If that is not available then this may be an option: SteelStik Epoxy Putty Stick


| J-B Weld

Thanks guys. Very good info. I might just know someone who is an old school tradesman that can do this.

I will probably use them as-is for now until I can get the one horn fixed. The damage is on the bottom, and cannot be seen unless one gets within a few feet. I think this is mostly a cosmetic issue but it still bugs me.

Now I just need to get GPA diaphragms for my 291C drivers, and get another 515b for my 828 cabs. A7 to A5 conversion will be complete! :)

Original construction is hand knocked and sweat tin.

Mah is spot on.

Hammer out the body work, structurally repair with JBWeld(epoxy) and clamp if necessary.

Restore original smoothness with fiber free body filler or spot putty.

To re-sweat them, the area needs to be totally free of paint and damping compound. IMO, this creates a more daunting challenge.

Note the irons hanging on the end of the bench and a couple "in the fire" (not RoHS compliant ;) )

http://www.hostboard.com/forums/hbmc.../2017/09/6.jpg

Thanks for the info (and pic) bowtie! I think I can do that repair;)

I want to disturb these as little as possible. I don't think I can replicate the coating very easily.

Do you have any idea of the date these were manufactured? They came from the Market Square Arena in Indy. I'll have to research the venue and maybe I can get an idea when they were installed.

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Attachment 3680

Think they were part of the hanging system. I read the arena completed in 1974, and closed in 1999

Bowtie, what photo hosting site do you use now?

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Bowtie, what photo hosting site do you use now?

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I haven't found a good one. i miss the old photobucket, kodak film, real coca cola, when "std" meant standard, and most of all my mind. :)

That pic is hosted at the lansing heritage site, i just let the hostboard software embed the link.

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http://www.audioheritage.org/images/.../multicell.jpg

I used some of my hurricane prep time to fix the one horn. I was able to pop the section back into place. It stays where I want it to without any glue.

Once the stores open again I will get some JB Weld put some on the broken joint.

Its so easy to manipulate the pieces where I want them. Very easy material to work with. I doubt I can get them 100% perfect, but they will be good enough for my garage HiFi.

Thanks

Am I better off getting the JB weld epoxy stick (like mah linked), or some of their regular 2 part epoxy mix? I want the strongest fix I can get

Then silver solder it ;). JB Weld is the strongest epoxy I've used and according to specs has a > 4x psi rating Vs SteelStik. I've patched holes in blocks from thrown rods, built up damaged cylinder heads, etc., filled holes in concrete where multi-ton equipment rolls over it, etc..

That said, the SteelStik is plenty strong enough for your app.

GM