Spinet Foam

[theseacowexists]

Looking for some experts to weigh in on question I have that I haven't been able to get a definitive answer on...

Is the foam ever an issue in Hammond spinets?

All of the research that I've done regarding foam always seems to be in relation to the console models. However, it seems that the consensus is that the Hammond switched to foam in ALL organs by 1964. I think I read somewhere that the spinets have thinner strips of foam than consoles, and this might be the reason why there's virtually no discussions out there on foam in spinets.

[bourniplus]

Hi,
I can say that my M100 had it. It was a thin strip about 1/2 inch wide. I had removed it from the lower manual when I did the lower foldback many years ago, and a few days ago I removed it from the upper, when I opened it only to find out that the poorman foldback such as performed on an M3 -for the 1' drawbar- can't be done on an M100.

[muckelroy]

It is a much thinner adhesive strip than that used on full sized consoles. I haven’t heard of it causing problems but if you are ever doing cleanup work on the manuals, it should be removed while you’re in there.

[kziss]

Looking for some experts to weigh in on question I have that I haven't been able to get a definitive answer on...

Is the foam ever an issue in Hammond spinets?

All of the research that I've done regarding foam always seems to be in relation to the console models. However, it seems that the consensus is that the Hammond switched to foam in ALL organs by 1964. I think I read somewhere that the spinets have thinner strips of foam than consoles, and this might be the reason why there's virtually no discussions out there on foam in spinets.

Hi Theseacowexists.
All five spinet organs that I have defoamed all had the thin ( approximately 4 millimeters thick) foam strips whilst the two 1965 C3 organs that I defoamed had the full thickness 1 centimeter thick foam strips.

I have not yet defoamed the manuals of my two H-100 series organs, but by looking inside the manuals through the narrow openings on the underside of the manuals where the wiring harnesses with the TG note terminal strips are, it appears that the H-100 organs have the thinner foam, strips similar to that of the spinet organs.

The two 1965 C3 organs had severe foam caused damage to hundreds of the manual resistance wires, and both manuals of one of the 1965 C3 organs were so badly damaged that I had to replace the manuals with a set of manuals salvaged from a 1960 RT3 organ.

With the spinet organs that I defoamed, the only foam caused damage was only on one or two resistance wires in a 1968 L-142 organ thus making this an easy repair.

Because the foam strips on the spinet organs are thinner, this means that there is less likelihood of the foam to come into contact with the manual resistance wires except for the situation where the foam has significantly swollen in size or if the self adhesive backing behind foam strip has deteriorated and the foam strip has then come loose and landed on to the manual resistance wires, or if the foam strip has crumbled and some of it has fallen on to the manual resistance wires.

Even if there is no apparent foam damage, I would strongly recommend removing the foam strips both in the console organs and in the spinet organs because the foam strips are a dangerous destructive time bomb waiting to go off.
All the best.
Kon.

[andyg]

In the UK, I've never come across a problem with foam in a Hammond spinet - in 48 years. I don't personally know anyone who has. But I think there was one UK report of it being an issue on the forum a few years back. Maybe it's our more temperate, even climate, but the spinets all seem to be fine over here. I'd visually check but if I found nothing out of order, or likely to become a problem, I'd leave it.

But if the climate's different, maybe Kon's advice is best followed.

[theseacowexists]

Thanks for the input, everyone!

As far as I can tell, my M-100 dates from late 1963, and has spent it's whole life here in upstate NY (real upstate, like on Lake Ontario). What is the method for visually checking for foam without taking the manuals apart? I've heard something about rivets indicating felt and holes indicating foam. From what I can see without taking anything apart, I don't see any rivets or holes - just screws (which of course go into holes).

If there is foam, I am concerned with it becoming a problem when the organ starts to be gigged with. I believe that I read somewhere that moving the organ can loosen the foam.

[bourniplus]

My M100 has no rivets and had the foam. You might be able to see by looking with a small mirror in the area where the drawbar wires enter for the upper manual.

[snacks]

I seem to remember reading here that all M100s were built with foam. They have the diving board keys; it sounded like those style spinet manuals always had foam. I have not looked inside either of mine for rivets vs foam, though.

[theseacowexists]

I seem to remember reading here that all M100s were built with foam. They have the diving board keys; it sounded like those style spinet manuals always had foam. I have not looked inside either of mine for rivets vs foam, though.

Interesting - I haven't read that about all M-100s before.

Before I decided to start tearing mine apart, I remembered the spare set of spinet manuals that I have (dad bought them long ago and they've been used for replacement keys on the T-200). Just like the manuals in the M-100, there were no rivets. When I opened up the spare upper manual, sure enough there was a thin strip of deteriorated foam. Only about 1/2" wide and probably less than 1/8" thick. As far as I could tell, only one resistance wire had touched the foam, but the tiny bit that was on the wire came right off and did not appear to be corroding the wire. Most of the foam crumbled as I pulled it off with my fingers. The adhesive was a bit trickier though. But after 20 minutes with some iso alcohol, a razor blade, and a wire brush, I had a foam-free spare manual! Good practice for when I do the M-100. While I was brushing the adhesive and foam off, I covered the rest of the manual in saran wrap so none of the crap sprayed into the resistance wires. If the foam isn't any worse than this manual, the hardest part is probably going to be getting the manuals accessible.

- - - Updated - - -

A couple more pictures:

[snacks]

Hi,
I can say that my M100 had it. It was a thin strip about 1/2 inch wide. I had removed it from the lower manual when I did the lower foldback many years ago, and a few days ago I removed it from the upper, when I opened it only to find out that the poorman foldback such as performed on an M3 -for the 1' drawbar- can't be done on an M100.

I hadn't heard this - what is it that prevents the 1' foldback mod from being done? Were the upper notes built without the necessary contacts?

[bourniplus]

- what is it that prevents the 1' foldback mod from being done? Were the upper notes built without the necessary contacts?

The extra contacts in the M100 are for the second-to-last (last black) drawbar, and there are only 12 of them. After I had unsoldered them, percussion wouldn't decay on these 12 notes, so I resoldered them to ground. (I really wanted the 1' foldback for that 888000008 sound). There is a bit of misinformation on the net about this, although there is an old thread on the forum that kind of says the same thing.

[theseacowexists]

Just to follow up...

Feeling emboldened by the successful removal of the foam from the spare manual, I decided to tackle the manuals in my M-100. The hardest part truly was accessing the manuals. Fortunately a buddy of mine stopped by while I was working and was able to act as an extra set of hands to hold the manuals so that I didn't have to completely disconnect them from the organ while getting the foam. The good news is that, between the two manuals, the foam had only leeched onto three resistance wires, and was easily removed with a bit of alcohol and left no damage. Also, what was left of both foam strips easily peeled off - no scraping or scrubbing required.

This was a great education in getting to know the internals of the M-100, especially for when I finally decide to add some foldback to the upper manual. The only disappointment was when we turned the organ on after all that work disassembling and reassembling and it, it didn't sound any better!

Side note - I don't know if anyone is familiar with the old Hohner Pianets and their "sticky pads." For those of you who aren't familiar, the sticky pads, which plucked the reed for each note, contained a layer of foam and completely disintegrated over the years, rendering the Pianets useless until replacements were produced. Now after having had first hand experience with both a Pianet and a foamy Hammond, it appears to me that the foam in both might be the same material. Any thoughts on this? It certainly doesn't seem too far fetched, given that they were both manufactured in the same era.

Now back to getting my poor old T-200 up and running again...