Re: [bolger] Re: Big Dig epoxy
I've been wondering if the epoxy around the bolts is really acting as an adhesive, or whether it's just a really well fitted wedge. Using wedged bolts has been the standard for lifting blocks of stone in quarries for thousands of years. Compressive strength, yes! Bonding, no. Unless the bolt is perfectly smooth and straight, you'd see resistance to torque in either case.
From "The Epoxy Book:"
TYPICAL PHYSICAL PROPERTIES*
SYSTEM THREE EPOXY RESIN
Test Method
ASTM D 638 Tensile Strength, psi 7,500
ASTM D 638 Tensile Elongation, % 11
ASTM D 638 Tensile Modulus, psi 325,000
ASTM D 790 Flexural Strength, psi 12,500
ASTM D 790 Flexural Modulus, psi 350,000
ASTM D 695 Compressive Strength, psi
at Yield: 12,000
at Failure 26,000
Of course this is for the cured epoxy alone and doesn't include any modifications made by such fillers as milled glass fibers, silica thickener, or ...
Roger
derbyrm@...
http://home.insightbb.com/~derbyrm
From "The Epoxy Book:"
TYPICAL PHYSICAL PROPERTIES*
SYSTEM THREE EPOXY RESIN
Test Method
ASTM D 638 Tensile Strength, psi 7,500
ASTM D 638 Tensile Elongation, % 11
ASTM D 638 Tensile Modulus, psi 325,000
ASTM D 790 Flexural Strength, psi 12,500
ASTM D 790 Flexural Modulus, psi 350,000
ASTM D 695 Compressive Strength, psi
at Yield: 12,000
at Failure 26,000
Of course this is for the cured epoxy alone and doesn't include any modifications made by such fillers as milled glass fibers, silica thickener, or ...
Roger
derbyrm@...
http://home.insightbb.com/~derbyrm
----- Original Message -----
From: Jon & Wanda(Tink)
To:bolger@yahoogroups.com
Sent: Saturday, August 11, 2007 1:53 AM
Subject: [bolger] Re: Big Dig epoxy
But the problem may be the addatives that controle the speed and make it harden more flexable or brittle. Different formulations have
different properties. I use a 1-1 for glueing and a 2-1 for coating
and glassing. The 1-1 will blush and flex more. The 2-1 will not is
harder to sand and mire abrasion resistant as well as soakes in
better. The gray epoxy we use for ancher bolts in foundations can be
really cranked on in a few days winter or summer.
Jon
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But the problem may be the addatives that controle the speed and make
it harden more flexable or brittle. Different formulations have
different properties. I use a 1-1 for glueing and a 2-1 for coating
and glassing. The 1-1 will blush and flex more. The 2-1 will not is
harder to sand and mire abrasion resistant as well as soakes in
better. The gray epoxy we use for ancher bolts in foundations can be
realy cranked on in a few days winter or summer.
Jon
it harden more flexable or brittle. Different formulations have
different properties. I use a 1-1 for glueing and a 2-1 for coating
and glassing. The 1-1 will blush and flex more. The 2-1 will not is
harder to sand and mire abrasion resistant as well as soakes in
better. The gray epoxy we use for ancher bolts in foundations can be
realy cranked on in a few days winter or summer.
Jon
--- Inbolger@yahoogroups.com, "dnjost" <davidjost@...> wrote:
>
> As a Bostonian I have been following this one closely for several
> years (I actually drove right through the repaired tunnel last
week).
>
> According to this mornings Boston Globe,there was a similar issue
in
> Singapore where a similar problem with the same fast setting epoxy
> was discovered, and they had informed Powers Fasteners of the
problem
> prior to the use in the Boston tunnel. The amazing thing is that
it
> is a small dollar amount, I think $2000 total that caused the
issue.
>
> Other issues being looked at:
> 1. Did the contractor insist on using the fast set epoxy to stay
on
> a time schedule.
>
> 2. Was the epoxy cured at the right temperature?
> 3. Was the epoxy mixed to the correct ratio?
>
> This was a tragedy that did not have to happen and many, many,
hands
> were involved in the catastrophe. I am sure that the D.A. is not
> done with indictments here.
>
> this being said...I will stick with WEST System for Birdwatcher II,
I
> am used to the mixes and have a system in place for metering it out
> in useable batches. Just repaired the rail on my old Diablo last
> week while working on a frame for the BW. Nothing ever wasted.
>
>
>
> David Jost
> Boston, MA
>
As a Bostonian I have been following this one closely for several
years (I actually drove right through the repaired tunnel last week).
According to this mornings Boston Globe,there was a similar issue in
Singapore where a similar problem with the same fast setting epoxy
was discovered, and they had informed Powers Fasteners of the problem
prior to the use in the Boston tunnel. The amazing thing is that it
is a small dollar amount, I think $2000 total that caused the issue.
Other issues being looked at:
1. Did the contractor insist on using the fast set epoxy to stay on
a time schedule.
2. Was the epoxy cured at the right temperature?
3. Was the epoxy mixed to the correct ratio?
This was a tragedy that did not have to happen and many, many, hands
were involved in the catastrophe. I am sure that the D.A. is not
done with indictments here.
this being said...I will stick with WEST System for Birdwatcher II, I
am used to the mixes and have a system in place for metering it out
in useable batches. Just repaired the rail on my old Diablo last
week while working on a frame for the BW. Nothing ever wasted.
David Jost
Boston, MA
years (I actually drove right through the repaired tunnel last week).
According to this mornings Boston Globe,there was a similar issue in
Singapore where a similar problem with the same fast setting epoxy
was discovered, and they had informed Powers Fasteners of the problem
prior to the use in the Boston tunnel. The amazing thing is that it
is a small dollar amount, I think $2000 total that caused the issue.
Other issues being looked at:
1. Did the contractor insist on using the fast set epoxy to stay on
a time schedule.
2. Was the epoxy cured at the right temperature?
3. Was the epoxy mixed to the correct ratio?
This was a tragedy that did not have to happen and many, many, hands
were involved in the catastrophe. I am sure that the D.A. is not
done with indictments here.
this being said...I will stick with WEST System for Birdwatcher II, I
am used to the mixes and have a system in place for metering it out
in useable batches. Just repaired the rail on my old Diablo last
week while working on a frame for the BW. Nothing ever wasted.
David Jost
Boston, MA
> For joints in compression, no adhesive is needed.The tricky thing is that boats move and flex, so that most joints
cycle between compression and tension. Simplistically, I believe that
is why joints, like the standard 'taped' seam joint of a tack and tape
plywood panel need to be taped both sides. That way, one side is
acting in compression (or shear) all the time and you never rely
solely on tensile strength. I think, also, that the weakness of epoxy
in a tension joint is why George Buehler (and some other
conservatives) insist that all joints have mechanical fasteners like
bolts or nails.
Spoken like a consultant!
Maximum area means minimum unit stress so that even the poorest adhesive will work.
For joints in compression, no adhesive is needed.
Roger (sorry, couldn't resist)
derbyrm@...
http://home.insightbb.com/~derbyrm
Maximum area means minimum unit stress so that even the poorest adhesive will work.
For joints in compression, no adhesive is needed.
Roger (sorry, couldn't resist)
derbyrm@...
http://home.insightbb.com/~derbyrm
----- Original Message -----
From: Bruce Hallman
To:bolger@yahoogroups.com
Sent: Friday, August 10, 2007 11:35 AM
Subject: Re: [bolger] Re: Big Dig epoxy
<snip>
Telling me that for strong joints in wood you want:
1) lots of surface area and
2) compression joints not tension joints.
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[Non-text portions of this message have been removed]
>Leave it to the lawyers to sort out the settlement here, but having
> Picking a "glue" for a tunnel roof? That's a tough one.
done some tunneling professionally... I am guessing that they used
epoxy to glue steel dowels into holes drilled in the rock. One common
problem is that it is hard to ensure that you got epoxy injected all
the way into the hole, it is very easy to have a trapped air bubble
and/or dust layer in the drilled hole that impedes epoxy bonding.
Also, very often you are working with poor or uneven quality rock, and
the rock can crumble. I have heard that, theoretically, epoxy can
creep, so I guess that is a possibility too, but I have never seen it.
In the case of our boats, epoxy is applied differently, covering large
surface areas, and wood is much less dense than even the softest rock.
I have looked at several broken epoxy|wood glue joints, and I always
have found that the wood fails before the epoxy, typically with a thin
layer of wood fibers pulling loose just next to the plane of the glue.
Telling me that for strong joints in wood you want:
1) lots of surface area and 2) compression joints not tension joints.
IMHO there's a whole bunch of characteristics, mostly determined by the hardener and additives, and "strength" is only one of them.
The dime store stuff that fixes porcelain tea cups is RIGID and will shatter, just like the baked clay it bonds with. The System Three material is designed to work with wood. The wood breaks first, but only by a little. I like the idea of buying from boat builders that are also chemists working for boat builders.
Picking a "glue" for a tunnel roof? That's a tough one.
Roger
derbyrm@...
http://home.insightbb.com/~derbyrm
The dime store stuff that fixes porcelain tea cups is RIGID and will shatter, just like the baked clay it bonds with. The System Three material is designed to work with wood. The wood breaks first, but only by a little. I like the idea of buying from boat builders that are also chemists working for boat builders.
Picking a "glue" for a tunnel roof? That's a tough one.
Roger
derbyrm@...
http://home.insightbb.com/~derbyrm
----- Original Message -----
From: michaelmickjoseph
To:bolger@yahoogroups.com
Sent: Thursday, August 09, 2007 2:56 PM
Subject: [bolger] Re: Big Dig epoxy
--- Inbolger@yahoogroups.com, adnyb@... wrote:
>There are many forms of epoxy. Actually, epoxy one buys for boat
building is pretty much the lowest grade if I have read some
manufactures websites correctly. That it works as well as it does,
(and it does work very, very well) makes one wonder what the "good
stuff" would be like...
> I'm sure there are differences in strengths depending on the
chemical mix - but I also don't think that boats have very many 6000
pound panels suspended by glue. Of course, if someone merely glued
a ballast keel on they might have a surprise waiting them <G>
>
>
> -----Original Message-----
> From: GarthAB <garth@...>
> To:bolger@yahoogroups.com
> Sent: Thu, 9 Aug 2007 9:09 am
> Subject: [bolger] Big Dig epoxy
>
>
>
>
>
>
> Just saw this in the NY Times, concerning the epoxy used in Boston's
> Big Dig tunnel. Makes me wonder about strength differences in the
> epoxies we use for boatbuilding -- do they vary depending on the
speed
> of the hardener?
>
> ----------------------------------------------------------
>
> The supplier of the epoxy that federal officials have blamed for the
> collapse of a Big Dig tunnel was indicted Wednesday in the death of
a
> woman crushed by falling ceiling panels.
>
> The company, Powers Fasteners Inc., was charged with one count of
> involuntary manslaughter. It is the first criminal charge in the
> tunnel collapse, which killed Milena Del Valle, 38, in July 2006 as
> she was on her way to the airport. Her death ignited an uproar over
> the safety of the $15 billion Big Dig.
>
> Martha Coakley, the Massachusetts attorney general, said the charges
> stem from the fact that Powers, based in Brewster, N.Y., produced
two
> kinds of epoxy â?" standard set and fast set. The standard-set one
would
> have been adequate for the ceiling, she said, but fast-set epoxy was
> incapable of suspending such heavy panels for a long time.
>
> Ms. Coakley said that Powers "blurred the distinction" between the
two
> epoxies, and that the fast-set one was used for that section of the
> tunnel, even though the company's testing indicated it was
> inappropriate for such a job.
>
> Paul Ware, a special assistant attorney general, said that in 1999,
> when bolts were seen to be pulling out within months after the
ceiling
> had been installed, a Powers representative called to the tunnel
> failed to disclose that fast-setting epoxy could cause "creep" that
> could weaken the hold of the bolts.
>
> ...
>
>
>
>
>
>
__________________________________________________________
__
> AOL now offers free email to everyone. Find out more about what's
free from AOL at AOL.com.
>
>
> [Non-text portions of this message have been removed]
>
[Non-text portions of this message have been removed]
--- Inbolger@yahoogroups.com, adnyb@... wrote:
manufactures websites correctly. That it works as well as it does,
(and it does work very, very well) makes one wonder what the "good
stuff" would be like...
pound panels suspended by glue. Of course, if someone merely glued
a ballast keel on they might have a surprise waiting them <G>
__
>There are many forms of epoxy. Actually, epoxy one buys for boatbuilding is pretty much the lowest grade if I have read some
manufactures websites correctly. That it works as well as it does,
(and it does work very, very well) makes one wonder what the "good
stuff" would be like...
> I'm sure there are differences in strengths depending on thechemical mix - but I also don't think that boats have very many 6000
pound panels suspended by glue. Of course, if someone merely glued
a ballast keel on they might have a surprise waiting them <G>
>speed
>
> -----Original Message-----
> From: GarthAB <garth@...>
> To:bolger@yahoogroups.com
> Sent: Thu, 9 Aug 2007 9:09 am
> Subject: [bolger] Big Dig epoxy
>
>
>
>
>
>
> Just saw this in the NY Times, concerning the epoxy used in Boston's
> Big Dig tunnel. Makes me wonder about strength differences in the
> epoxies we use for boatbuilding -- do they vary depending on the
> of the hardener?a
>
> ----------------------------------------------------------
>
> The supplier of the epoxy that federal officials have blamed for the
> collapse of a Big Dig tunnel was indicted Wednesday in the death of
> woman crushed by falling ceiling panels.two
>
> The company, Powers Fasteners Inc., was charged with one count of
> involuntary manslaughter. It is the first criminal charge in the
> tunnel collapse, which killed Milena Del Valle, 38, in July 2006 as
> she was on her way to the airport. Her death ignited an uproar over
> the safety of the $15 billion Big Dig.
>
> Martha Coakley, the Massachusetts attorney general, said the charges
> stem from the fact that Powers, based in Brewster, N.Y., produced
> kinds of epoxy â" standard set and fast set. The standard-set onewould
> have been adequate for the ceiling, she said, but fast-set epoxy wastwo
> incapable of suspending such heavy panels for a long time.
>
> Ms. Coakley said that Powers "blurred the distinction" between the
> epoxies, and that the fast-set one was used for that section of theceiling
> tunnel, even though the company's testing indicated it was
> inappropriate for such a job.
>
> Paul Ware, a special assistant attorney general, said that in 1999,
> when bolts were seen to be pulling out within months after the
> had been installed, a Powers representative called to the tunnel______________________________________________________________________
> failed to disclose that fast-setting epoxy could cause "creep" that
> could weaken the hold of the bolts.
>
> ...
>
>
>
>
>
>
__
> AOL now offers free email to everyone. Find out more about what'sfree from AOL at AOL.com.
>
>
> [Non-text portions of this message have been removed]
>
I'm sure there are differences in strengths depending on the chemical mix - but I also don't think that boats have very many 6000 pound panels suspended by glue. Of course, if someone merely glued a ballast keel on they might have a surprise waiting them <G>
-----Original Message-----
From: GarthAB <garth@...>
To:bolger@yahoogroups.com
Sent: Thu, 9 Aug 2007 9:09 am
Subject: [bolger] Big Dig epoxy
Just saw this in the NY Times, concerning the epoxy used in Boston's
Big Dig tunnel. Makes me wonder about strength differences in the
epoxies we use for boatbuilding -- do they vary depending on the speed
of the hardener?
----------------------------------------------------------
The supplier of the epoxy that federal officials have blamed for the
collapse of a Big Dig tunnel was indicted Wednesday in the death of a
woman crushed by falling ceiling panels.
The company, Powers Fasteners Inc., was charged with one count of
involuntary manslaughter. It is the first criminal charge in the
tunnel collapse, which killed Milena Del Valle, 38, in July 2006 as
she was on her way to the airport. Her death ignited an uproar over
the safety of the $15 billion Big Dig.
Martha Coakley, the Massachusetts attorney general, said the charges
stem from the fact that Powers, based in Brewster, N.Y., produced two
kinds of epoxy — standard set and fast set. The standard-set one would
have been adequate for the ceiling, she said, but fast-set epoxy was
incapable of suspending such heavy panels for a long time.
Ms. Coakley said that Powers "blurred the distinction" between the two
epoxies, and that the fast-set one was used for that section of the
tunnel, even though the company's testing indicated it was
inappropriate for such a job.
Paul Ware, a special assistant attorney general, said that in 1999,
when bolts were seen to be pulling out within months after the ceiling
had been installed, a Powers representative called to the tunnel
failed to disclose that fast-setting epoxy could cause "creep" that
could weaken the hold of the bolts.
...
________________________________________________________________________
AOL now offers free email to everyone. Find out more about what's free from AOL at AOL.com.
[Non-text portions of this message have been removed]
-----Original Message-----
From: GarthAB <garth@...>
To:bolger@yahoogroups.com
Sent: Thu, 9 Aug 2007 9:09 am
Subject: [bolger] Big Dig epoxy
Just saw this in the NY Times, concerning the epoxy used in Boston's
Big Dig tunnel. Makes me wonder about strength differences in the
epoxies we use for boatbuilding -- do they vary depending on the speed
of the hardener?
----------------------------------------------------------
The supplier of the epoxy that federal officials have blamed for the
collapse of a Big Dig tunnel was indicted Wednesday in the death of a
woman crushed by falling ceiling panels.
The company, Powers Fasteners Inc., was charged with one count of
involuntary manslaughter. It is the first criminal charge in the
tunnel collapse, which killed Milena Del Valle, 38, in July 2006 as
she was on her way to the airport. Her death ignited an uproar over
the safety of the $15 billion Big Dig.
Martha Coakley, the Massachusetts attorney general, said the charges
stem from the fact that Powers, based in Brewster, N.Y., produced two
kinds of epoxy — standard set and fast set. The standard-set one would
have been adequate for the ceiling, she said, but fast-set epoxy was
incapable of suspending such heavy panels for a long time.
Ms. Coakley said that Powers "blurred the distinction" between the two
epoxies, and that the fast-set one was used for that section of the
tunnel, even though the company's testing indicated it was
inappropriate for such a job.
Paul Ware, a special assistant attorney general, said that in 1999,
when bolts were seen to be pulling out within months after the ceiling
had been installed, a Powers representative called to the tunnel
failed to disclose that fast-setting epoxy could cause "creep" that
could weaken the hold of the bolts.
...
________________________________________________________________________
AOL now offers free email to everyone. Find out more about what's free from AOL at AOL.com.
[Non-text portions of this message have been removed]
Just saw this in the NY Times, concerning the epoxy used in Boston's
Big Dig tunnel. Makes me wonder about strength differences in the
epoxies we use for boatbuilding -- do they vary depending on the speed
of the hardener?
--------------------------------------------------------------
The supplier of the epoxy that federal officials have blamed for the
collapse of a Big Dig tunnel was indicted Wednesday in the death of a
woman crushed by falling ceiling panels.
The company, Powers Fasteners Inc., was charged with one count of
involuntary manslaughter. It is the first criminal charge in the
tunnel collapse, which killed Milena Del Valle, 38, in July 2006 as
she was on her way to the airport. Her death ignited an uproar over
the safety of the $15 billion Big Dig.
Martha Coakley, the Massachusetts attorney general, said the charges
stem from the fact that Powers, based in Brewster, N.Y., produced two
kinds of epoxy standard set and fast set. The standard-set one would
have been adequate for the ceiling, she said, but fast-set epoxy was
incapable of suspending such heavy panels for a long time.
Ms. Coakley said that Powers "blurred the distinction" between the two
epoxies, and that the fast-set one was used for that section of the
tunnel, even though the company's testing indicated it was
inappropriate for such a job.
Paul Ware, a special assistant attorney general, said that in 1999,
when bolts were seen to be pulling out within months after the ceiling
had been installed, a Powers representative called to the tunnel
failed to disclose that fast-setting epoxy could cause "creep" that
could weaken the hold of the bolts.
...
Big Dig tunnel. Makes me wonder about strength differences in the
epoxies we use for boatbuilding -- do they vary depending on the speed
of the hardener?
--------------------------------------------------------------
The supplier of the epoxy that federal officials have blamed for the
collapse of a Big Dig tunnel was indicted Wednesday in the death of a
woman crushed by falling ceiling panels.
The company, Powers Fasteners Inc., was charged with one count of
involuntary manslaughter. It is the first criminal charge in the
tunnel collapse, which killed Milena Del Valle, 38, in July 2006 as
she was on her way to the airport. Her death ignited an uproar over
the safety of the $15 billion Big Dig.
Martha Coakley, the Massachusetts attorney general, said the charges
stem from the fact that Powers, based in Brewster, N.Y., produced two
kinds of epoxy standard set and fast set. The standard-set one would
have been adequate for the ceiling, she said, but fast-set epoxy was
incapable of suspending such heavy panels for a long time.
Ms. Coakley said that Powers "blurred the distinction" between the two
epoxies, and that the fast-set one was used for that section of the
tunnel, even though the company's testing indicated it was
inappropriate for such a job.
Paul Ware, a special assistant attorney general, said that in 1999,
when bolts were seen to be pulling out within months after the ceiling
had been installed, a Powers representative called to the tunnel
failed to disclose that fast-setting epoxy could cause "creep" that
could weaken the hold of the bolts.
...