Nathan,
It is just a matter of observation and timing. I always use hot hide glue for bushings, never PVC-E. I watch while applying steam, seeing how much the felt is swelling, and at the first sign of pulling away, I stop steaming. I then immediately insert a heat controlled brass caul (in a soldering iron), placing a corner of the caul into the middle of the bushing, so as to avoid pushing the bushing out of place.
The simplest way to explain more details is to refer you to a couple videos I posted a few years back. I also discussed this method on the CAUT list several times since I first started using it, probably close to 20 years ago.
You can, of course, use Profelt if steam worries you. But steam is much faster to do.
BTW, here is a detailed thread on leather versus felt key bushings.
And here is what I think is the first thread on the topic of steaming key bushings, 1998. It was the old caut, and the thread is a bit broken, so you can only see a partial quote of my initial post in Avery Todd's post. Unfortunately, the current search function of MyPTG SUCKS, so I can't just search the date and find the actual post. The only choices are times "within one year" or "older." Oh, well.
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Fred Sturm
University of New Mexico
fssturm@unm.eduhttp://fredsturm.nethttp://www.artoftuning.com"We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
Original Message:
Sent: 09-22-2016 10:50
From: Nathan Monteleone
Subject: leather key bushing
Fred,
How are you able to steam them without causing them to come unglued? Does the glue choice have something to do with it (pvc-e for example)?