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From: editor on 18 Feb 2010 19:28
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?
From: tony cooper on 18 Feb 2010 20:27
On Thu, 18 Feb 2010 16:28:33 -0800 (PST), "editor(a)netpath.net"
<editor(a)netpath.net> 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
From: Nervous Nick on 18 Feb 2010 21:05
On Feb 18, 6:28 pm, "edi...(a)netpath.net" <edi...(a)netpath.net> 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?

Sew it with heavy duty nylon button thread, then cover the suture with
a patch--maybe a patch like Tony suggests. I can almost guarantee that
this fix will outlast the bag.

--
YOP...
From: Better Info on 18 Feb 2010 21:18
On Thu, 18 Feb 2010 20:27:00 -0500, tony cooper
<tony_cooper213(a)earthlink.net> wrote:

>On Thu, 18 Feb 2010 16:28:33 -0800 (PST), "editor(a)netpath.net"
><editor(a)netpath.net> 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.



From: Bob Williams on 19 Feb 2010 05:16
editor(a)netpath.net 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?
As has been noted, polypropylene is almost impossible to glue with
conventional adhesives.
However, It can be repaired with a "Hot Glue Gun"
The molten adhesive is polyethylene, which is only one carbon atom away
from polypropylene. Make sure that the hot glue is very hot and flows
easily. It will probably help if you also warm the site of the tear to
soften the polypropylene to make it more receptive to the molten
polyethylene hot glue.
Good Luck.
Bob Williams
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