How to fix tiny tear in camera bag before it widens?

On Thu, 18 Feb 2010 16:28:33 -0800 (PST), "
wrote:

Cutting bottom straps off camera bag today, I accidentally made a tiny
cut about 1/4" long in "second bottom" layer of bag. Bag apparently
is polypropylene.
Any ideas on how to fix it - so it doesn't spread?

Bicycle tire patch kits are sold at auto supply stores for under $2.00
Ugly, but if it's in the bottom of the bag no one will notice. Test
the glue on a small spot, though.

--
Tony Cooper - Orlando, Florida

On Thu, 18 Feb 2010 20:27:00 -0500, tony cooper
wrote:

On Thu, 18 Feb 2010 16:28:33 -0800 (PST), "
wrote:

Cutting bottom straps off camera bag today, I accidentally made a tiny
cut about 1/4" long in "second bottom" layer of bag. Bag apparently
is polypropylene.
Any ideas on how to fix it - so it doesn't spread?

Bicycle tire patch kits are sold at auto supply stores for under $2.00
Ugly, but if it's in the bottom of the bag no one will notice. Test
the glue on a small spot, though.

Polypropylene is one of the more difficult plastics to glue. The adhesive
for rubberized compounds (as in a bike-tire repair kit) will have no effect
on poly plastics. Not even super-glue will stick to poly plastics. That's
why the cap for super-glue tubes is made of poly.

One of the very few adhesives I've found that works is a product made by
LocTite, called "Stik 'n Seal" in the USA. A water-glass clear silicone
type of compound. Though I doubt it would work real well for a tear or cut,
but it does adhere glass, metal and other substances to poly plastics when
given fuller layer contact. You could try applying this glue to a small
patch of similar or clear poly and giving the two more surface contact
across the cut, patch-style.

The only other solution for poly mending is using a patch and adhering it
with light pressure and heat, very very very carefully, so you don't do
even greater damage. This is rarely possible on an already assembled
product due to curvatures and existing seams. But does work when you have
flat sheets that can be seamed this way. Many a beach-toy is constructed in
this manner. If you can find a water-bed repair kit, that might also be
effective.

On TV many years ago they used to sell a vinyl repair-kit for car
upholstery cuts and rips that might work. It used to come packaged with
various colors to mix together for color-matching. With texture swatches
that you apply over the "glue" while it sets up to match the original
upholstery texture. Where you can find that today I have no idea. Advice
for mixing upholstery-vinyl compounds (a type of poly) with other types of
poly and having it work would have to come from someone that's ever tried
it. I doubt it would work, but it's possible.

"Better Info" wrote in message
...

Polypropylene is one of the more difficult plastics to glue. The adhesive
for rubberized compounds (as in a bike-tire repair kit) will have no
effect
on poly plastics. Not even super-glue will stick to poly plastics. That's
why the cap for super-glue tubes is made of poly.

One of the very few adhesives I've found that works is a product made by
LocTite, called "Stik 'n Seal" in the USA. A water-glass clear silicone
type of compound. Though I doubt it would work real well for a tear or
cut,
but it does adhere glass, metal and other substances to poly plastics when
given fuller layer contact. You could try applying this glue to a small
patch of similar or clear poly and giving the two more surface contact
across the cut, patch-style.

The only other solution for poly mending is using a patch and adhering it
with light pressure and heat, very very very carefully, so you don't do
even greater damage. This is rarely possible on an already assembled
product due to curvatures and existing seams. But does work when you have
flat sheets that can be seamed this way. Many a beach-toy is constructed
in
this manner. If you can find a water-bed repair kit, that might also be
effective.

On TV many years ago they used to sell a vinyl repair-kit for car
upholstery cuts and rips that might work. It used to come packaged with
various colors to mix together for color-matching. With texture swatches
that you apply over the "glue" while it sets up to match the original
upholstery texture. Where you can find that today I have no idea. Advice
for mixing upholstery-vinyl compounds (a type of poly) with other types of
poly and having it work would have to come from someone that's ever tried
it. I doubt it would work, but it's possible.




Given that information, I wonder if the glue that's used for patching above
ground swimming pool liners might work.

Better Info wrote:

Polypropylene is one of the more difficult plastics to glue. The adhesive
for rubberized compounds (as in a bike-tire repair kit) will have no effect
on poly plastics. Not even super-glue will stick to poly plastics. That's
why the cap for super-glue tubes is made of poly.
I've had good success bonding poly plastics with
cyano-acrylate glues (eg superglue), by giving the materials
to be bonded a wipe with xylene first, and then applying the
CA glue just as the the last smear of xylene evaporates.

--
What is the difference between a duck?

On Sat, 20 Feb 2010 18:19:41 +1000, Doug Jewell
wrote:

Better Info wrote:

Polypropylene is one of the more difficult plastics to glue. The adhesive
for rubberized compounds (as in a bike-tire repair kit) will have no effect
on poly plastics. Not even super-glue will stick to poly plastics. That's
why the cap for super-glue tubes is made of poly.

I've had good success bonding poly plastics with
cyano-acrylate glues (eg superglue), by giving the materials
to be bonded a wipe with xylene first, and then applying the
CA glue just as the the last smear of xylene evaporates.

Thanks for the tip. It'll give a new use for my container of xylene. I
hadn't thought of mixing/using solvents as a catalyst for unrelated
adhesives+plastics before. I wonder if methyl ethyl ketone might be an even
better intermediary, as that seems even more reactive to a wider variety of
plastics than xylene.

__________________________________________________ ___

My plastics and paints solvents-reaction list, from least reactive to most.
Rated by experience only, from life-experience random fix-it projects:

Kerosene : Dissolves waxes, to make a penetrable liquid lubricant. Another
usage, draw a few lines of a candle-wax over a scratched CD/DVD then add a
drop or two of kerosene, rub it all in and then buff with a soft dry cloth
to fill up the smallest of scratches. Makes the CD/DVDs readable again. For
quicker evaporation use Naphtha instead. Kerosene dissolves waxes much more
slowly than naphtha. The same method can be used on scratched or scuffed-up
reading/sun glasses, naphtha method preferred.

White gasoline

Isopropyl alcohol : Dissolves powdered rosin to make an easy to apply
friction enhancer, great for small belt-drive systems that are slipping due
to belt-fatigue or oils on the belt. I've had many a throw-away VCR in the
past that was fixed instantly with a couple drops of this liquid-rosin on
the one or two rubberized drive belts. It will also dissolve many ink and
pigment vehicles more safely than any of the following solvents, but will
require more elbow-grease. A slower but safer way of removing them.

Naphtha : Dissolves/penetrates most gum and rubber compounds, the best
label-adhesive and tape-adhesive remover which will not harm the underlying
plastic. It is also the same combustible sold as Ronsonol, Zippo
flint-lighter refill. You can buy it at 1/10th the price from a hardware
store under the label of Naphtha. It also rejuvenates the paper-feed grip
on printers where the feed rollers have hardened and glazed themselves too
much, without harming the printer's plastic case.

Pine Oil : I've only used it to "disappear" special-effects plastics in
novelty items and special-effects projection systems. As its index of
refraction perfectly matches most clear-sheet plastics when immersed in
this compound. The sheet of plastic perfectly disappearing (visually,
without harm to the plastic) but any dichroic or other surface-effect
application on that plastic remains. Hmmm... I guess it's not technically a
plastics-solvent then. Nonetheless it's a fun optical-experimenter's
liquid.

Orange Oil : Not much experience with this, but I know it will ruin some
plastics, permanently.

Toluene

Methyl cellulose : ? I think it is called. It's the solvent used in the
original "Magic-Markers", not Sharpies, an unmistakable aroma. A few
centiliters beneath the felt nib rejuvenates any dried-out Magic-Marker. It
is also the solvent used to produce the child's "Permanent Plastic-Bubbles"
toy. I'm guessing the name of it, the bottle is back on my lab-shelves
somewhere. If you've ever smelled a Magic-Marker you are knowledgeable of
this liquid compound.

DEET insect repellent [N,N-Diethyl-meta-toluamide], worth mentioning. : The
most annoying of plastics solvents in the world; as it seems to melt most
of the commonly used plastics for watch-bands and watch-faces,
fishing-lures, plastic compass housings, sunglass lenses and frames, etc.,
etc. And you don't know about it until a day to a week later when your
hard-plastic compass-case or sunglass frames are now a smeary black melted
mess and the compass or sunglasses are totally ruined. Most annoying is if
you get a DEET covered finger-print on your new plastic-lensed sunglasses
and that's the only thing it managed to melt. There is no cure. These
melted and smeary qualities of the DEET afflicted plastics never changing
afterward, into perpetuity. Other than a way to get your body and clothes
to be repellent to insects, DEET serves no other useful purpose in anyone's
life anywhere on the planet. IMHO.

Xylene : This and the following two will dissolve the most stubborn of
silk-screened or baked-paint labels, use this and the next two with caution
or you may destroy the plastic that a label is printed on. It can also be
used to safely remove most cements used for glass-optics without harming
the housing or the baked pigments on the metals. Is also used to un-cement
permanently prepared microscope slides that have been fixed (made
permanent) with Canada Balsam.

Methyl ethyl ketone : Don't huff it you damn kids! You have enough
brain-damage already. And ... GET OFF MY DAMN LAWN, you lousy kids!

Acetone : Seems to dissolve, or ruin, most anything if applied long enough,
will even un-cement cemented achromats if the achromat is immersed in
acetone for an appreciable amount of time. This is the same solvent as in
nail-polish remover and superglue (cyano-acrylate-glue) remover. Buy 4 oz.
at the nailpolish counter for $5, or a quart of it for $2.50 at the
hardware store.


Though the last two seem interchangeable in reactiveness at times depending
on the plastic or pigment vehicle. Most of them easily available and
inexpensive from any hardware-store in the paints and solvents dept.

There was one fantastic solvent that someone gave a pint of it to me once,
it is used to bond plexiglas to plexiglas. Just place plexiglas parts edge
to edge and flood the meeting surfaces with a drop or two; instant,
permanent, water-tight bond; as if the parts were originally a solid unit.
But the vapor-pressure of it is so high that it evaporated through the thin
seal under the metal cap in less than 2 months. Before losing it all from
the metal container to the atmosphere I managed to construct a full set of
plexiglas shelves for all my chemical supplies. And even made a giant
water-prism to place on a windowsill to project a wide and bright rainbow
across the ceiling every morning. The plexiglas water-prism being 4x4x4x12
inches. I never did find out what that solvent is called. I imagine I can
find out by surfing the net or calling any custom plexiglas design
companies. It had already served its purpose so it's just a mild curiosity
now. It was nonetheless an interesting plastics solvent I had not used nor
known of before.

It would be interesting to see a household and inventor's usage-list of
commonly found solvents. There's my contribution.


Bonus points for reading: What's the most reactive solvent in the world?
And no, it's not sulphuric, nitric, phosphoric, nor hydrochloric acid. Nor
is it lye, to cover the bases. (pun intentional)

Hint: The astute might guess correctly.

Better Info wrote:
On Sat, 20 Feb 2010 18:19:41 +1000, Doug Jewell
wrote:

Better Info wrote:

Polypropylene is one of the more difficult plastics to glue. The adhesive
for rubberized compounds (as in a bike-tire repair kit) will have no effect
on poly plastics. Not even super-glue will stick to poly plastics. That's
why the cap for super-glue tubes is made of poly.
I've had good success bonding poly plastics with
cyano-acrylate glues (eg superglue), by giving the materials
to be bonded a wipe with xylene first, and then applying the
CA glue just as the the last smear of xylene evaporates.

Thanks for the tip. It'll give a new use for my container of xylene. I
hadn't thought of mixing/using solvents as a catalyst for unrelated
adhesives+plastics before. I wonder if methyl ethyl ketone might be an even
better intermediary, as that seems even more reactive to a wider variety of
plastics than xylene.

Snipped bits out

Excellent compendium.

My experience with orange oil is that it's a good solvent for removing
sticker gums from bottles, or metal, but as you say, some plastics react.

And that there are lots of things that are cheaper by a big margin at
the hardware store vs. the drugstore, or depending on what it's called.

Isn't toluene a major ingredient in a number of glues?

And I too cannot recall the name of the solvent for plexi- used it 20
years ago, and it does do the job, especially if you've done a dry run
to make sure the pieces fit together well....

--
john mcwilliams

Better Info wrote:

snip lots of useful stuff
Bonus points for reading: What's the most reactive solvent in the world?
And no, it's not sulphuric, nitric, phosphoric, nor hydrochloric acid. Nor
is it lye, to cover the bases. (pun intentional)

Hint: The astute might guess correctly.
I would have to say Dihydrogen Monoxide by a long shot.
Although it is useless on most plastics, and needs an
additional reagent for most metals, it is a very effective
solvent indeed. In many cases, even if it won't dissolve the
substance directly, it can act as a carrier for other
chemicals to dissolve a huge range of substances.

Gotta be careful with it tho - it is a powerful inhibitor of
lung function, and thousands die every year due to it's
lung-inhibiting properties. There's also a great body of
evidence that indicates it's vapours are a powerful
greenhouse gas. Even so, I find it so useful that I keep
copious quantities on hand at all times.


--
What is the difference between a duck?

On Sun, 21 Feb 2010 06:28:35 +1000, Doug Jewell
wrote:

Better Info wrote:

snip lots of useful stuff
Bonus points for reading: What's the most reactive solvent in the world?
And no, it's not sulphuric, nitric, phosphoric, nor hydrochloric acid. Nor
is it lye, to cover the bases. (pun intentional)

Hint: The astute might guess correctly.

I would have to say Dihydrogen Monoxide by a long shot.
Although it is useless on most plastics, and needs an
additional reagent for most metals, it is a very effective
solvent indeed. In many cases, even if it won't dissolve the
substance directly, it can act as a carrier for other
chemicals to dissolve a huge range of substances.

Gotta be careful with it tho - it is a powerful inhibitor of
lung function, and thousands die every year due to it's
lung-inhibiting properties. There's also a great body of
evidence that indicates it's vapours are a powerful
greenhouse gas. Even so, I find it so useful that I keep
copious quantities on hand at all times.

And we have a winner!

Nasty stuff that dihydrogen monoxide. I always have to dilute it with high
percentages of ethyl alcohol or something to make it safer to handle. I've
heard about a few special-interest groups that are trying to get the
production of it banned world-wide.


An even more OT p.s. Does anyone know what you get when you mix plexiglas
with nitric acid? Knowing how many explosives are formed from organic
compounds and nitric acid, I've been avoiding putting or dropping anything
on top of the splotches and stains of the plexiglas cover on my lab table
where some nitric acid spilled. The deeply frosted regions seem stable, but
I'm wary. I was using the nitric to refine some sterling silver to pure
silver at the time.

In rec.photo.digital Better Info wrote:
On Sun, 21 Feb 2010 06:28:35 +1000, Doug Jewell
wrote:

Better Info wrote:

snip lots of useful stuff
Bonus points for reading: What's the most reactive solvent in the world?
And no, it's not sulphuric, nitric, phosphoric, nor hydrochloric acid. Nor
is it lye, to cover the bases. (pun intentional)

Hint: The astute might guess correctly.

I would have to say Dihydrogen Monoxide by a long shot.
Although it is useless on most plastics, and needs an
additional reagent for most metals, it is a very effective
solvent indeed. In many cases, even if it won't dissolve the
substance directly, it can act as a carrier for other
chemicals to dissolve a huge range of substances.

Gotta be careful with it tho - it is a powerful inhibitor of
lung function, and thousands die every year due to it's
lung-inhibiting properties. There's also a great body of
evidence that indicates it's vapours are a powerful
greenhouse gas. Even so, I find it so useful that I keep
copious quantities on hand at all times.

And we have a winner!

Nasty stuff that dihydrogen monoxide. I always have to dilute it with high
percentages of ethyl alcohol or something to make it safer to handle. I've
heard about a few special-interest groups that are trying to get the
production of it banned world-wide.

If you need it pure it's such a good solvent that it's difficult to
keep it pure for long. Fortunately the dehydrated version stores well
indefinitely.

--
Chris Malcolm

On 2010-03-29 01:22:34 -0700, John Turco said:

Chris Malcolm wrote:

In rec.photo.digital Better Info wrote:

heavily edited for brevity

Nasty stuff that dihydrogen monoxide. I always have to dilute it with high
percentages of ethyl alcohol or something to make it safer to handle. I've
heard about a few special-interest groups that are trying to get the
production of it banned world-wide.

If you need it pure it's such a good solvent that it's difficult to
keep it pure for long. Fortunately the dehydrated version stores well
indefinitely.


Which makes me wonder: How did the medieval alchemists intend to store
their long-sought "universal solvent," eh?

In a container made from the universal insoluble.


I guess it's fortunate that they never made it!




--
Regards,

Savageduck