Are there any general rules of thumb for sizing the holes used
to stop cracks? As a guess, I'd imagine the material thickness
is the lower limit and anything bigger than five to ten times
the thickness would be a reasonable upper limit if there's room.
Does anybody know of a better approach? In my particular case
the material is molded ABS plastic, but I doubt that matters
very much.
On Wed, 3 Jan 2024 04:11:04 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Are there any general rules of thumb for sizing the holes used
to stop cracks? As a guess, I'd imagine the material thickness
is the lower limit and anything bigger than five to ten times
the thickness would be a reasonable upper limit if there's room.
Does anybody know of a better approach? In my particular case
the material is molded ABS plastic, but I doubt that matters
very much.
It's pretty loose - almost any small drill diameter will be far larger
than the tip of a growing crack.
If ABS (which is quite tough) is cracking, it may be that the bulk
plastic is degrading from age and/or chemical attack.
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 3 Jan 2024 04:11:04 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Are there any general rules of thumb for sizing the holes used
to stop cracks? As a guess, I'd imagine the material thickness
is the lower limit and anything bigger than five to ten times
the thickness would be a reasonable upper limit if there's room.
Does anybody know of a better approach? In my particular case
the material is molded ABS plastic, but I doubt that matters
very much.
It's pretty loose - almost any small drill diameter will be far larger
than the tip of a growing crack.
If ABS (which is quite tough) is cracking, it may be that the bulk
plastic is degrading from age and/or chemical attack.
There's not much opportunity for chemical attack, the part is a
Givi motorcycle topcase. It's stored in a garage and only exposed
to a bit of rain and occasional sun. Age is an issue, it was bought
by a previous ownerat least twenty five years ago. The cracking is
near two screwed-on metal lugs that form the static part of the
quick-release mounting system, so there's obvious stress concentration.
There's no other visible degradation, so I'm going to stop drill
the cracks and try to reinforce the case with fiberglass fabric
and ABS pipe cement. The cement is just a sort of lacquer, but it
sticks well and permeates the cloth readily.
If nobody recommends larger holes I'll use a handy small drill,
say less than one-eighth inch, to minimize leaks.
Thanks for writing!
bob prohaska
On 1/3/2024 9:50 AM, bob prohaska wrote:
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 3 Jan 2024 04:11:04 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Are there any general rules of thumb for sizing the holes used
to stop cracks? As a guess, I'd imagine the material thickness
is the lower limit and anything bigger than five to ten times
the thickness would be a reasonable upper limit if there's room.
Does anybody know of a better approach? In my particular case
the material is molded ABS plastic, but I doubt that matters
very much.
It's pretty loose - almost any small drill diameter will be far larger
than the tip of a growing crack.
If ABS (which is quite tough) is cracking, it may be that the bulk
plastic is degrading from age and/or chemical attack.
There's not much opportunity for chemical attack, the part is a
Givi motorcycle topcase. It's stored in a garage and only exposed
to a bit of rain and occasional sun. Age is an issue, it was bought
by a previous ownerat least twenty five years ago. The cracking is
near two screwed-on metal lugs that form the static part of the
quick-release mounting system, so there's obvious stress concentration.
There's no other visible degradation, so I'm going to stop drill
the cracks and try to reinforce the case with fiberglass fabric
and ABS pipe cement. The cement is just a sort of lacquer, but it
sticks well and permeates the cloth readily.
If nobody recommends larger holes I'll use a handy small drill,
say less than one-eighth inch, to minimize leaks.
Thanks for writing!
bob prohaska
ABS does seem to get hard with time and crack. I've seen it in a fair number of inexpensive ABS pond hoppers.
I don't know if modern plastic kayaks (the vogue these days for one
person "inexpensive" watercraft) are ABS or something else.
Use your Givi bags as a mold to make molds to make fiberglass bags. When
you are done you already have all the hardware.
I once got a bit of ridicule of ridicule in the RMHVB&G for asking if
anybody had ever put Givi bags on a Harley.
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 3 Jan 2024 04:11:04 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Are there any general rules of thumb for sizing the holes used
to stop cracks? As a guess, I'd imagine the material thickness
is the lower limit and anything bigger than five to ten times
the thickness would be a reasonable upper limit if there's room.
Does anybody know of a better approach? In my particular case
the material is molded ABS plastic, but I doubt that matters
very much.
It's pretty loose - almost any small drill diameter will be far larger
than the tip of a growing crack.
If ABS (which is quite tough) is cracking, it may be that the bulk
plastic is degrading from age and/or chemical attack.
There's not much opportunity for chemical attack, the part is a
Givi motorcycle topcase. It's stored in a garage and only exposed
to a bit of rain and occasional sun. Age is an issue, it was bought
by a previous ownerat least twenty five years ago. The cracking is
near two screwed-on metal lugs that form the static part of the
quick-release mounting system, so there's obvious stress concentration.
There's no other visible degradation, so I'm going to stop drill
the cracks and try to reinforce the case with fiberglass fabric
and ABS pipe cement. The cement is just a sort of lacquer, but it
sticks well and permeates the cloth readily.
If nobody recommends larger holes I'll use a handy small drill,
say less than one-eighth inch, to minimize leaks.
Good question...
Watching with interest.
On Wed, 3 Jan 2024 16:50:39 -0000 (UTC), bob prohaskaI agree - I'd use a 1/8" bit and then fill the hole with a flexible
<bp@www.zefox.net> wrote:
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 3 Jan 2024 04:11:04 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Are there any general rules of thumb for sizing the holes used
to stop cracks? As a guess, I'd imagine the material thickness
is the lower limit and anything bigger than five to ten times
the thickness would be a reasonable upper limit if there's room.
Does anybody know of a better approach? In my particular case
the material is molded ABS plastic, but I doubt that matters
very much.
It's pretty loose - almost any small drill diameter will be far larger
than the tip of a growing crack.
If ABS (which is quite tough) is cracking, it may be that the bulk
plastic is degrading from age and/or chemical attack.
There's not much opportunity for chemical attack, the part is a
Givi motorcycle topcase. It's stored in a garage and only exposed
to a bit of rain and occasional sun. Age is an issue, it was bought
by a previous ownerat least twenty five years ago. The cracking is
near two screwed-on metal lugs that form the static part of the >>quick-release mounting system, so there's obvious stress concentration.
There's no other visible degradation, so I'm going to stop drill
the cracks and try to reinforce the case with fiberglass fabric
and ABS pipe cement. The cement is just a sort of lacquer, but it
sticks well and permeates the cloth readily.
If nobody recommends larger holes I'll use a handy small drill,
say less than one-eighth inch, to minimize leaks.
There's no reason not to caulk those holes with a compatible rubbery >material.
Joe Gwinn
On 1/3/2024 9:50 AM, bob prohaska wrote:
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 3 Jan 2024 04:11:04 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Are there any general rules of thumb for sizing the holes used
to stop cracks? As a guess, I'd imagine the material thickness
is the lower limit and anything bigger than five to ten times
the thickness would be a reasonable upper limit if there's room.
Does anybody know of a better approach? In my particular case
the material is molded ABS plastic, but I doubt that matters
very much.
It's pretty loose - almost any small drill diameter will be far larger
than the tip of a growing crack.
If ABS (which is quite tough) is cracking, it may be that the bulk
plastic is degrading from age and/or chemical attack.
There's not much opportunity for chemical attack, the part is a
Givi motorcycle topcase. It's stored in a garage and only exposed
to a bit of rain and occasional sun. Age is an issue, it was bought
by a previous ownerat least twenty five years ago. The cracking is
near two screwed-on metal lugs that form the static part of the
quick-release mounting system, so there's obvious stress concentration.
There's no other visible degradation, so I'm going to stop drill
the cracks and try to reinforce the case with fiberglass fabric
and ABS pipe cement. The cement is just a sort of lacquer, but it
sticks well and permeates the cloth readily.
If nobody recommends larger holes I'll use a handy small drill,
say less than one-eighth inch, to minimize leaks.
Thanks for writing!
bob prohaska
ABS does seem to get hard with time and crack. I've seen it in a fair
number of inexpensive ABS pond hoppers.
I don't know if modern plastic kayaks (the vogue these days for one
person "inexpensive" watercraft) are ABS or something else.
Use your Givi bags as a mold to make molds to make fiberglass bags.
When you are done you already have all the hardware.
I once got a bit of ridicule of ridicule in the RMHVB&G for asking if
anybody had ever put Givi bags on a Harley.
--
Bob La Londe
CNC Molds N Stuff
On Wed, 03 Jan 2024 14:19:37 -0500, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Wed, 3 Jan 2024 16:50:39 -0000 (UTC), bob prohaskaI agree - I'd use a 1/8" bit and then fill the hole with a flexible
<bp@www.zefox.net> wrote:
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 3 Jan 2024 04:11:04 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Are there any general rules of thumb for sizing the holes used
to stop cracks? As a guess, I'd imagine the material thickness
is the lower limit and anything bigger than five to ten times
the thickness would be a reasonable upper limit if there's room.
Does anybody know of a better approach? In my particular case
the material is molded ABS plastic, but I doubt that matters
very much.
It's pretty loose - almost any small drill diameter will be far larger >>>> than the tip of a growing crack.
If ABS (which is quite tough) is cracking, it may be that the bulk
plastic is degrading from age and/or chemical attack.
There's not much opportunity for chemical attack, the part is a
Givi motorcycle topcase. It's stored in a garage and only exposed
to a bit of rain and occasional sun. Age is an issue, it was bought
by a previous ownerat least twenty five years ago. The cracking is
near two screwed-on metal lugs that form the static part of the >>>quick-release mounting system, so there's obvious stress concentration.
There's no other visible degradation, so I'm going to stop drill
the cracks and try to reinforce the case with fiberglass fabric
and ABS pipe cement. The cement is just a sort of lacquer, but it
sticks well and permeates the cloth readily.
If nobody recommends larger holes I'll use a handy small drill,
say less than one-eighth inch, to minimize leaks.
There's no reason not to caulk those holes with a compatible rubbery >>material.
Joe Gwinn
caulk. Also use a bit of acetone or MEK or Methylene Chloride drizzled
into the crack to "weld" the crack???
On Wed, 03 Jan 2024 17:25:08 -0500, Clare Snyder <clare@snyder.on.ca>Acetone won't harm the ABS and it won't stop the crack. It WILL help
wrote:
On Wed, 03 Jan 2024 14:19:37 -0500, Joe Gwinn <joegwinn@comcast.net>
wrote:
On Wed, 3 Jan 2024 16:50:39 -0000 (UTC), bob prohaskaI agree - I'd use a 1/8" bit and then fill the hole with a flexible
<bp@www.zefox.net> wrote:
Joe Gwinn <joegwinn@comcast.net> wrote:
On Wed, 3 Jan 2024 04:11:04 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Are there any general rules of thumb for sizing the holes used
to stop cracks? As a guess, I'd imagine the material thickness
is the lower limit and anything bigger than five to ten times
the thickness would be a reasonable upper limit if there's room.
Does anybody know of a better approach? In my particular case
the material is molded ABS plastic, but I doubt that matters
very much.
It's pretty loose - almost any small drill diameter will be far larger >>>>> than the tip of a growing crack.
If ABS (which is quite tough) is cracking, it may be that the bulk
plastic is degrading from age and/or chemical attack.
There's not much opportunity for chemical attack, the part is a
Givi motorcycle topcase. It's stored in a garage and only exposed
to a bit of rain and occasional sun. Age is an issue, it was bought
by a previous ownerat least twenty five years ago. The cracking is
near two screwed-on metal lugs that form the static part of the >>>>quick-release mounting system, so there's obvious stress concentration. >>>>
There's no other visible degradation, so I'm going to stop drill
the cracks and try to reinforce the case with fiberglass fabric
and ABS pipe cement. The cement is just a sort of lacquer, but it >>>>sticks well and permeates the cloth readily.
If nobody recommends larger holes I'll use a handy small drill,
say less than one-eighth inch, to minimize leaks.
There's no reason not to caulk those holes with a compatible rubbery >>>material.
Joe Gwinn
caulk. Also use a bit of acetone or MEK or Methylene Chloride drizzled
into the crack to "weld" the crack???
I'd verify that acetone exposure won't cause later cracking or stress >cracking.
But I don't think that acetone will stop the crack, because at least
in hard materials the crack is atomically sharp.
Joe Gwinn
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