Fwd: Stripped agraffe and JB weld

[Douglas Gregg]

---------- Forwarded message ----------
From: Douglas Gregg <class...@gmail.com>
Date: Sat, 14 Sep 2013 22:18:20 -0400
Subject: Stripped agraffe and JB weld


About a month ago there was a discussion about repairing a stripped
agraffe. Clearly an oversized agraffe is best but I suggested putting
it back in with JB Weld epoxy because it has exceptional strength in
repairing iron. It also has very little creep under tension because of
the iron dust filler in the epoxy. I was shot down by Joe and Isaac
who thought the JB Weld would not take the stress. So I designed an
experiment. I drilled a hole in the iron collar of a barbell weight
set, slightly larger than the threads of an agraffe, and epoxied the
agraffe into the hole with JB Weld original slow set. I let it set for
4 hours and then heated it for another 4 hours with a lamp to about
250 F. (It has been tested to 400F for engine repairs). After 24
hours, I tied a bass string to the agraffe and added 100 lbs of
weights on the bass string and hung it from the ceiling of my shop for
a month while I went to California to help my son. When I came back,
it was still hanging there as I had left it. The attached photos show
the epoxy just as it looked when I left but after a month with 100 lbs
hanging on it.

Was 100 lbs enough? Yes. If you take the worst case scenario and there
is 200 lbs of tension on a bass string and in the worst case, there is
a 45 degree angle going down the curve of the plate to the agraffe,
then the upward force on the agraffe will be 100 lbs. I had my son,
the mechanical engineer, check my vector analysis. Most plates don't
have that much angle from the tuning pin to the agraffe and to the
speaking length, so there is still more safety margin. The lower the
angle, the less upward force. My simple experiment supports my
suggestion that JB Weld will hold an agraffe. I also would not
hesitate to put it behind flagpoled bridge pins either. It is very
resistant to compression as well as tension.

I saw a repair of a Model T crankcase a couple days ago that had a
rod thrown through it. JB Weld did a nice job of repairing the hole in
the iron casting. It also machines like steel.

Be sure to cure it well before putting stress on the epoxy.

Doug Gregg
Classic Piano Doc

[Joseph Garrett]

Doug,
I use J-B Weld. Just not in this application. I think that the things missing in this "experiment" are the shock factor of the hammer hitting the string. Also, it seems apparent that you've never done a scale evaluation, since most bass string tension are far more than 100 lbs. Vector smector dude. It will hold for a while, but I suspect that the "aging" (degradation), that occurs in all epoxies would be a determining factor. If this were to be used to fix a definite POS/PSO, yeah, go for it. If it were me, I'd definitely have the client sign a disclaimer. Just my take on it.<G>
Best,
Joe

Captain of the Tool Police
Squares R I
gpianoworks.com

[Douglas Gregg]

Joe,
You definitely have to take into account the direction of forces in
this situation. I did take into account actual bass string tension.
Few bass strings could take more than 200 lbs tension without
straining and stretching. 100 lbs of upward force at the agaffe is
more than realistic. Vector forces must be calculated in this case.
String vibration adds minimal upward force to the system.

My point is that the JB Weld can take the force without creep. Period.

Doug Gregg

[Douglas Gregg]

[Joseph Garrett]

Doug,
Ah..."...without creep".??? I don't recall seeing anything in your original post in that regard, either calculated/percieved or even mentioned.<G> However, I would pretty much agree with that on a short term situation. Nothing as to sheer, with the exception of the "vector" thing, which alludes to it. Overall longevity would be my concern however. Let's face it chemicals like epoxy are, in terms of the object we work on, pretty short term in their lifespan of effectiveness. I just don't want some neophytes to jump on that bandwagon to quickly.
Epoxy is something that has a learning curve attached to it. DAMHIK!<G> Then, we must be fairly certain of it's age. i.e. the darned stuff has a Shelf Life, albeit a rather short one! Then we have to learn all of the specific applications of each TYPE of epoxy. Of the various "Steel Epoxies" out there J-B Weld is not my first choice.
If I were to go into my local Ace Hardware Store, there would be at least 3 different Steel Epoxies available at any given time. (Sometimes more). Of those, one would be the "house brand". I can say that I would NEVER use the house brand, through several bad experience with it. My choice would be DEVCON over J-B Weld. It has a more consistent curing time and is easier to work, if shaping/carving is needed in any application. That is my experience with Steel Epoxy. Of course there are many more available that I have not had the opportunity to use. So, I can't speak to them.
Finally, IF I ran into a decent grand piano with that sort of repair on it, I would not think much of the tech that did it, even though it may or may not hold. It just smatters of "quick and dirty" in my book. Sorry. A helicoil or insert would be something that would give me pause, but would show me that the tech did the best under difficult circumstances.<G> That's my take on that.
Regards,

[Ron Nossaman]

On 9/15/2013 8:12 PM, Douglas Gregg wrote:

> Few bass strings could take more than 200 lbs tension without
> straining and stretching.

Doug,
When you don't know what you're talking about, it's best just not to
talk rather than trying to fake it.

>
> My point is that the JB Weld can take the force without creep. Period.

What's wrong with making an attempt to fix something right instead,
where future maintenance or repair won't be affected?

Ron N

[Ron Nossaman]

On 9/15/2013 8:38 PM, Joseph Garrett wrote:

> A helicoil or insert would be something that would give me
> pause, but would show me that the tech did the best under difficult
> circumstances.

One more time. There is no Helicoil insert available that will work on
an agraffe, though Pianotek sells an insert that I would have no
reservations about using.

By the way, how is it possible to strip an agraffe thread? I question
that it is.
Ron N

[Joseph Garrett]

Ron,
Sorry about the "helicoil" comment. I knew that, but my olde mechanics mentality popped in there by accident. Of course you are right about the helicoil. The insert from Pianotek or one that you can make yourself, if you have the proper taps and dies.
I too, have wondered about how an agraffe hole gets "stripped". I've only had one incident where it was necessary to do the insert. That was a tech, in a drunken stupor tried to extract broken agraffe stem and REALLY screwed it up! Not a pretty picture with broken stem, broken easy-out, broken drill bits (2) and major screwdriver gouges in the cast iron! (Big OUCH!) Piano belonged to another tech, (not to be named on this list<G>) All of which shows that even qualified techs can screw things up if not working with all brain cells at all times.<G>

Best,
Joe


-----Original Message-----
>From: Ron Nossaman <rnos...@cox.net>
>Sent: Sep 15, 2013 6:47 PM
>To: pian...@googlegroups.com
>Subject: Re: [pianotech] Fwd: Stripped agraffe and JB weld
>

[Ron Nossaman]

On 9/15/2013 8:57 PM, Joseph Garrett wrote:
> I too, have
> wondered about how an agraffe hole gets "stripped". I've only had one
> incident where it was necessary to do the insert. That was a tech, in
> a drunken stupor tried to extract broken agraffe stem and REALLY
> screwed it up! Not a pretty picture with broken stem, broken
> easy-out, broken drill bits (2) and major screwdriver gouges in the
> cast iron! (Big OUCH!) Piano belonged to another tech, (not to be
> named on this list<G>)

That's not stripped though. That's attacked by a herd of idiots all in
one. Have you ever actually seen a stripped agraffe? I haven't. Ed Foote
has complained about undersize agraffe shanks in the past. Ed, have you
ever had one strip, or seen a stripped one?

Ron N

[Douglas Gregg]

Ron,
I think your smart alec remark about faking it applies to you.
If you would like a good reference book to read, try going back to the
masters like Chickering and WG Schaff and FE Morton in the proceedings
of of the Conference of Piano Technicians, New York 1919. Pages 19-28
has a long discussion about bass string strength. Breaking points can
go to 450 lbs but elastic limit (strain) is reached at a little over
200 lbs tension. After that, the string will continue to stretch. Most
bass sections were kept to around 175 lbs tension to allow for some
overpull by the chippers. Also, there was considered no real advantage
to exceeding that tension. So I think I am on pretty solid ground on
those numbers. I recommend this book published by the American Steel
and Wire Co. 1919. Since they published it without a rebuttal, I
presume they agree with the information in it. Reprinted, but no date
given for some reason.

This was a follow up about the JB Weld adhesive strength-PERIOD. As I
said, my point is simple. JB Weld can take the stress. I did not say
that it was the preferred way to repair the agraffe. In fact I said it
was not.

As for Joe's recommendation of using Devcon epoxy steel because it can
be carved, I would not say that JB Weld can be carved. It can be
machined. It gets very hard when fully heat cured. Does it last
forever, I don't know. Do they use epoxies to build bridges,- YES- all
the time. So stay home if you are worried.

Also, just for the record, the JB Weld tubes that I used were over two
years old when I glued that agraffe. I would not recommend using any
adhesive over 1 year old, but I had it on hand and wanted to start the
test before I left for a month. It worked despite its age. That speaks
well for the product.

Doug Gregg



On 9/15/13, Joseph Garrett <joega...@earthlink.net> wrote:

[Ron Nossaman]

I recommend working on actual pianos, recording and improving scales for
a while instead of, or at least in addition to reading old books. In
measuring these old scales, you'll learn (maybe) the difference between
what people write in books and what exists in real world pianos.

Ron N

[Douglas Gregg]

Ron wrote:
I recommend working on actual pianos, recording and improving scales
for a while instead of, or at least in addition to reading old books.
In measuring these old scales, you'll learn (maybe) the difference
between what people write in books and what exists in real world
pianos.

Oh, excuse me, I didn't know you worked on more pianos than Mr. Chickering.


One of my veterinary pathology professors had a saying in his office:
"Never wrestle with a pig. You will both get very dirty but the pig likes it."

[Joseph Garrett]

Hmmm? I know this was not aimed at me, but ..Doug, that was so juvenile and demeaning. What's the deal here?
Both Ron and I attempted to set you straight with current knowledge and you seem to be satisfied with archaic textbook b.s. that is not relevant! Admit that you were wrong on some points of your argument and get on with it. And YES, Ron knows a helluva lot more that Mr. Chickering imo!

Joe


-----Original Message-----
>From: Douglas Gregg <class...@gmail.com>

>Sent: Sep 16, 2013 10:35 AM
>To: pian...@googlegroups.com
>Subject: Re: [pianotech] Fwd: Stripped agraffe and JB weld
>

[Ron Nossaman]

On 9/16/2013 12:44 PM, Joseph Garrett wrote:
> Hmmm? I know this was not aimed at me, but ..Doug, that was so
> juvenile and demeaning. What's the deal here? Both Ron and I
> attempted to set you straight with current knowledge and you seem to
> be satisfied with archaic textbook b.s. that is not relevant! Admit
> that you were wrong on some points of your argument and get on with
> it. And YES, Ron knows a helluva lot more that Mr. Chickering imo!

I make no such claims, but the message is that anyone who's interested
in learning something can easily demonstrate Doug doesn't know what he's
talking about by measuring scales from a number of production pianos,
new and old, and calculating tensions. It doesn't seem to me to be too
bright insisting on something that's so easily disproved. I'd think that
anyone who is actually interested in knowing anything would show some
honest curiosity and be willing to make an attempt instead of just
getting loud and irrational. But then I think that every time I run into it.

Ron N

[Douglas Gregg]

You guys seem to not get it.

You said that JB weld would fail to hold an agaffe. I proved you
wrong. I accept that it is not the preferred way to replace an
agraffe. I said that several times. Now you go every possible
direction to try to say that I am wrong. Go figure.
How do you feel about Climate Change???

Doug Gregg

[Ron Nossaman]

On 9/16/2013 1:24 PM, Douglas Gregg wrote:
> You guys seem to not get it.
>
> You said that JB weld would fail to hold an agaffe.

I said no such thing, and couldn't care less. It would be a schlock fix.

And you still don't know what you're talking about with bass string
tensions.
Ron N

[Joseph Garrett]

Greg,
I don't recall saying it wouldn't work, (for a while), I told you all of the negatives to that kind of a repair. You, sir, "seem to not get it.". I'd suggest rebooting your machine, since you seem to be stuck on stupid at the moment. (which is not your normal imo.)

Joe


-----Original Message-----
>From: Douglas Gregg <class...@gmail.com>
>Sent: Sep 16, 2013 11:24 AM
>To: pian...@googlegroups.com
>Subject: Re: [pianotech] Fwd: Stripped agraffe and JB weld
>

>You guys seem to not get it.
>

[johnp...@piano88.com]

Nice experiment, Doug.

It looks like you glued it in permanently, or did you put a release
agent on the threads to create a JB Weld threaded repair for the test
agraffe? A threaded repair would be the preferred repair verses
installing an agraffe that can never be removed.

-John Parham

[lcl...@yahoo.com]

Nice suggestion, John, But I'd be afraid that any sort of thread release might impair the curing of the J.B. Weld. (Unless it was applied to the threads of the agraffe and allowed to fully cure, first - just trying to ponder all eventualities here, for the sake of discussion. Might be best to contact J.B. about a compatible thread compound.) Don't expect a reply from Doug, though --- he may have abandoned this list for one where the participants are more civilized. Thumpe Sent from Yahoo! Mail for iPad

---

From: johnp...@piano88.com <johnp...@piano88.com>;
To: <pian...@googlegroups.com>;
Subject: RE: [pianotech] Fwd: Stripped agraffe and JB weld
Sent: Wed, Sep 18, 2013 12:02:03 PM

[paul bruesch]

Or maybe, as most everyone (including Doug) agrees, don't do a schlock JB Weld repair on agraffe threads to begin with. Sheesh! 

[Ron Nossaman]

On 9/18/2013 8:44 AM, paul bruesch wrote:
> Or maybe, as most everyone (including Doug) agrees, don't do a schlock
> JB Weld repair on agraffe threads to begin with. Sheesh!

Well, Doug didn't give much indication that he agreed, unless I missed
it, but just kept pounding it. Also, it's odd that all those other
people agreed it's a schlock fix but didn't say a thing, and left the
two who were trying to point that out to take the brunt.
Ron N

[paul bruesch]

«My simple experiment  supports my

suggestion that JB Weld will hold an agraffe. I also would not

hesitate to put it behind flagpoled bridge pins either.»

«My point is that the JB Weld can take the force without creep. Period.»

«This was a follow up about the JB Weld adhesive strength-PERIOD.  As I

said, my point is simple. JB Weld can take the stress. I did not say

that it was the preferred way to repair the agraffe. In fact I said it

was not.»

«You said that JB weld would fail to hold an agaffe. I proved you

wrong. I accept that it is not the preferred way to replace an

agraffe. I said that several times.»

Given that, it baffles me why someone of his apparent skills, abilities, and knowledge would waste his time doing this is beyond me.

[Ron Nossaman]

On 9/18/2013 10:41 AM, paul bruesch wrote:

> «This was a follow up about the JB Weld adhesive strength-PERIOD. As I
> said, my point is simple. JB Weld can take the stress. I did not say
> that it was the preferred way to repair the agraffe. In fact I said it
> was not.»

Ah, he did say so. My apologies. I missed it.

> Given that, it baffles me why someone of his apparent skills, abilities,
> and knowledge would waste his time doing this is beyond me.

I've never understood him.
Ron N

[lcl...@yahoo.com]

Ron --- sometimes all a customer is willing to pay for is a "schlock fix", which leaves the technician with a choice: A) Walk out indignantly because it is beneath you. B) Do it, but tell the customer that it is not the preferred way to address the situation. As long as you are totally "up front", both are ethical. But if you live in a region where such customers prevail, and you walk out a lot, you will not eat unless you find another line of work.

Thumpe Sent from Yahoo! Mail for iPad

---

From: paul bruesch <pa...@bruesch.net>;
To: pianotech <pian...@googlegroups.com>;
Subject: Re: [pianotech] Fwd: Stripped agraffe and JB weld
Sent: Wed, Sep 18, 2013 3:41:24 PM

[Ron Nossaman]

On 9/18/2013 1:27 PM, lcl...@yahoo.com wrote:
> Ron --- sometimes all a customer is willing to pay for is a "schlock
> fix", which leaves the technician with a choice: A) Walk out
> indignantly because it is beneath you. B) Do it, but tell the
> customer that it is not the preferred way to address the situation.
> As long as you are totally "up front", both are ethical. But if you
> live in a region where such customers prevail, and you walk out a
> lot, you will not eat unless you find another line of work.

Do whatever you're willing to justify. I'll do likewise.
Ron N