I recently purchased a Nathan K horn from a local Antique shop in New Westminster. It came from a 1919 100 ft fishing vessel, clearly it was added on later than 1919. It is made out of brass. I could not get any sound from it when purchased, so I dismantled it. Cleaned the plates. The rubber gaskets were almost rock solid so I had them in rubber solvent solution for several days, still quite hard. I had the entire horn chromed. Then I found the stamp saying 300PSI. I have tried the horn with 100PSI and only 1/4 inch lines and the sound is clear but volume not loud. She will go on my boat were I have 135 PSI and half inch lines. Few questions. Should I replace the rubber seals with softer ones? Is it really possible this horn would require 300PSI. Did Nathan ever make brass horns for boats? Probably need to take some internal pictures when I dismantle it again.
Hey that’s a nice find and horn looks great. Hope you didn’t chrome the inside however since the nozzle/seat needs to mate perfectly with the diaphragm disc. Make sure you have a good seal (i.e. not being able to use lung pressure to blow any air through the horn). You can probably get new seals from Microprecision but it could be a tad old; try the Horn and Whistle board in case you have trouble sourcing parts.
Well yes I did chrome the inside as well as I will really need it to protect from Salt water corrosion. Still the plates move freely as the layer is very thin and all the airholes are open. I can blow through it with lung power, suspect the seal in the center that is hard as a rock.
I don’t think I would have chromed the horn(s), I would have had someone powder coat it for me… just as good protection without the shiny…
HornBlasters does sell replacements for that:
https://hornblasters.com/products/details.php?i=nathan-airchime-k-diaphragm-kit
-Kris