Altec 311-90 Restoration

[TPK]

I have finally obtained a suitable horn for my latest Altec project. Well actually this will be my final build after about 15 or so, and I want this to be my greatest and end game system. Anyway these are nice condition horns but need perhaps some cleanup and hopefully painting.

Per the pics, the coating has a slight greenish hue - is this normal, perhaps algae or just painted? My initial thought was to clean with mild soap and water and just paint over everything the original grey color. But I thought I'd ask if anyone has encountered this. Also, there is one chip in the coating - what have experienced folks used to fill any chips? I thought I would just use epoxy but thought I would ask what others have done.

I hope the experienced Altec folks still check into this site ...

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[Altec Best]

If i were you I would be very careful NOT to knock off that coating on the horns.. Altec used Aquaplas back in the day to keep them diecast aluminum horns from ringing which they will do without it. I see some of it is missing by the throats. You could try an automotive undercoating to dampen them. But the coating is probably very brittle being 40-50 years old now.You could try to dust them off with a small amount of compressed air. But also do NOT get to close to them with the air as you could blow it right off. If you have a very soft sponge ? The softest you can find while damp you could try to tamp them to get clean. After you try to fix the missing dampening material I would let them dry and mask off the mounting plate and just paint them gray to try and encase the Aquaplas into the paint to prevent them from flaking off even more.. Diecast Aluminum horns ring like a bell without dampening material.. I don't think they sell dampening material like Aquaplas in 1 qt. containers. 5 gal buckets is the smallest size IIRC..And the 5 gal buckets were like $200 decades ago... So it is expensive. Your best bet would probably be the automotive undercoating or dampening material as you don't need that much from your pictures. Just take your time and be careful with the coating. I found this. It is only 4 oz. but that looks like all you will need. Apply it the same thickness of what is already there . Apply with a putty knife them tap in a bunch of times to create the same texture that is already on the horns. I would use the whole container. You can never have too much dampening on those horns.. And then just paint them after it has dried.. Best of Luck !

Aquaplas 4oz.

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However this maybe a better overall solution..

Acoust-X Sound Damping Coating 1 Gallon - Acry-Tech Coatings


And here is another one...

Antivibe™ DL - Blachford Acoustics

[TPK]

Thanks for the response and especially for the links. Yes there is only one small patch where the coating is missing but the rest of the coating on both horns seems very well bonded. But can't really know for sure so I will heed your warnings. Would the aquaplast normally be soft and pliable or hard?

Think I will try the Acoust X - the OEM aquaplast would normally be what I would use, but I may need more that 4 oz perhaps. I'll just need to do some tests to ensure the Acoust X is compatible. Surface prep for both the coating and paint is a bit of an unknown - guess I'll just need to experiment gently...