[bkmont]

Originally Posted by 68ragtop

They are tuned & epoxy primed. No dixie, but they do sound strong. I tested them without a new gasket or sealant. makes a big difference having them sealed up. very loud & clear!

Now the question is what sheen? I have been searching google images & it looks like most NOS horns are more of a satin, low gloss finish. But restoration shops are painting them semi/medium gloss.

Any thoughts?

here are a couple examples I found:

http://www.ebay.com/itm/NOS-GM-Delco...BW5vm0&vxp=mtr

http://www.ebay.com/itm/55-64-CHEVY-...ZXFOpv&vxp=mtr

Woow! Those look great. So tell me the steps you took to rebuild the horns.
Is it that easy? Where did you get the rivets?
Thanks,
Bryan

[68ragtop]

Originally Posted by bkmont

Woow! Those look great. So tell me the steps you took to rebuild the horns.
Is it that easy? Where did you get the rivets?
Thanks,
Bryan

Thanks! Really wasn't bad. I had 4 horns & upon testing them, none of them worked. All showed open circuit with my meter. So I drilled out the rivets & found the points/contacts were the culprit. My feeling is they corrode & go bad from lack of use. But thats just a guess. I slid i piece of folded over 400 grit paper between the contacts, sanded until I could open the gap & see they were cleaned up. then passed 800 grit through to smoothen them out. That alone was the culprit of why they didn't work.

They do have a gasket between the diaphragm & the mechanical side of the horn, buts not a good seal. moisture no doubt leaked past the gasket & into two of the horns I took a apart. I re-assbembled them to test & then bead blasted. took them back apart, made new gaskets & sealed all mating surfaces with ultra black RTV.

I took the rivets to my local hardware store & found a small allen headed threaded fastened that was the same head size as the rivets. On the nut side I put standard nuts in the lathe & cut them down to the same od size as the rivets. so I basically had threaded sleeves. so, they are not like the original rivets, but they will trick the eye when you first look at them. IF you put seam sealer in the heads of the bolts, they would look really good imo. I decided not to do that because it looks so close to the original & if for some crazy reason they ever need to come apart again its still an option.

Now I really need to decide how much gloss these should have. my window for top coating the epoxy primer is going to be closing soon

[bkmont]

Originally Posted by 68ragtop

Thanks! Really wasn't bad. I had 4 horns & upon testing them, none of them worked. All showed open circuit with my meter. So I drilled out the rivets & found the points/contacts were the culprit. My feeling is they corrode & go bad from lack of use. But thats just a guess. I slid i piece of folded over 400 grit paper between the contacts, sanded until I could open the gap & see they were cleaned up. then passed 800 grit through to smoothen them out. That alone was the culprit of why they didn't work.

They do have a gasket between the diaphragm & the mechanical side of the horn, buts not a good seal. moisture no doubt leaked past the gasket & into two of the horns I took a apart. I re-assbembled them to test & then bead blasted. took them back apart, made new gaskets & sealed all mating surfaces with ultra black RTV.

I took the rivets to my local hardware store & found a small allen headed threaded fastened that was the same head size as the rivets. On the nut side I put standard nuts in the lathe & cut them down to the same od size as the rivets. so I basically had threaded sleeves. so, they are not like the original rivets, but they will trick the eye when you first look at them. IF you put seam sealer in the heads of the bolts, they would look really good imo. I decided not to do that because it looks so close to the original & if for some crazy reason they ever need to come apart again its still an option.

Now I really need to decide how much gloss these should have. my window for top coating the epoxy primer is going to be closing soon

Thanks for the lowdown on the horn rebuild. I have a set of 68s and 70s that need a rebuild. I think I'll try your method.

[68ragtop]

Originally Posted by bkmont

Thanks for the lowdown on the horn rebuild. I have a set of 68s and 70s that need a rebuild. I think I'll try your method.

The one thing I learned was you have to drive the rivets out with a center punch. they are pressed in. With exception to the rivet that is in the "bell" of the horn. take a smaller drill bit & drill that one all the way through after removing enough of it to separate the halves. Then drill & tap that hole so you can just thread a new bolt into the alloy side. I ruined the the first horn before realizing that rivet is different than the others. you'll have to shorten that bolt if you don't want it sticking out into the bell. the other bolts I used were an off the shelf length. I can measure them if you need that info.