Slime rubber cement, let dry or not?

On 2020-05-01 18:01, John B. wrote:
On Fri, 01 May 2020 08:52:28 -0500, AMuzi wrote:

On 5/1/2020 12:07 AM, John B. wrote:
On Thu, 30 Apr 2020 22:26:40 -0500, AMuzi wrote:

On 4/30/2020 10:02 PM, John B. wrote:
On Thu, 30 Apr 2020 20:11:58 -0400, Frank Krygowski
wrote:

On 4/30/2020 4:35 PM, AMuzi wrote:
On 4/30/2020 3:07 PM, Joerg wrote:
Got a tear in a thick tube, possibly a production defect.
Upon hints from this NG I bought Slime Rubber Cement a
couple years ago:

https://shop.slime.com/products/rubb...nt=47493356552


The instructions say:


PROPER USE:
• Buff area around puncture lightly, removing loose
particles and making sure
entire area within 1/2" of puncture has roughened appearance.
• Brush on a moderate amount of rubber cement onto roughened
surface and
spread evenly. Work into material and scrape off excess.
• Remove backing from patch without touching exposed surface.
• Apply repair material directly over puncture and press
firmly, especially
around the edges.


No mention of the usual "Let dry for 5min". Do I have to put
the patch into the wet rubber cement?

What does "work into material" and "scrape off excess" mean?

Main reason I ask is that a similar repair attempted with
letting it dry first resulted in the patch literally falling
off. So it does not seem to be the same stuff that's in the
little patch kit tubes.


I don't know if their product is different, better, worse than other
rubber patching products.

That said, some old guys in the motorcycle/auto tire business would do
that- scuff, blow clean with compressed air and then wet the area
liberally with rubber cement. After a couple of minutes' wait, he would
draw a blade across the surface, removing a thick black smear of
cement/crud and leaving a prepped, clean, tacky surface. Slap patch on
and press well with a patch stitcher[1] and you're golden.

When I was young, patching tubes was all day every day (labor was cheap,
tubes were expensive) and we used the Tech brand patching system. Scrub
area clean with Tech Buffer (mostly trichlorethylene) on a clean cloth
which removes a striking amount of black scum. Then just wet an area
slightly larger than the patch- not drippy or gloppy, just enough to wet
the area. It will look dry in well under a minute. Press down patch and
stitch it home. I had a failure or two in a year doing a couple dozen a
day every day.

Your directions seem to be a mix of both methods.

IME #1 cause of patch failure is lack of cleanliness. Get the area clean
and you're well on your way to a successful patch.
#2 by frequency is slapping a patch over wet cement. That makes the
patch deform with wrinkles, which leak. Customers bring those in (I
bought this patch kit- it's no good) still.

[1] looks much like a pizza cutter but with a blunt 5mm wide outer rim:
https://www.picclickimg.com/d/l400/p...Dia-Roller.jpg

The patch stitcher looks remarkably similar to a window screen spline
roller:
https://www.lowes.com/pd/Saint-Gobai...g-Tool/3094501

... which I have around here somewhere, but I don't use on patches.
Instead, I use two wooden dowels, about 3/4" = 19mm diameter. One is
held horizontally in the bench vise and forms the work surface for the
careful cleaning, scrubbing, cement application etc. Once the patch is
applied I "stitch" it by using two hands to roll the other dowel
perpendicular to the first, much like a baker's rolling pin. This
applies lots of pressure.

I agree with #1 = cleanliness. I've never done mistake #2, wet cement.
But for me, tip #3 is taking my time and being careful to get it exactly
right.

One of my first tours ended with a badly patched tube that leaked slowly
and couldn't be improved. The rest of the day was spent pumping it up,
riding a couple miles, and repeating, all the way home.

That burned in my brain to first, change to a spare tube; next, patch
the original at home, carefully, in comfort.

:-) Anyone that rode in the days of tubular tires would be
accustomed to the change it here and fix it at home routine :-)
--
cheers,

John B.


Yes, seems like so long ago. 20 March, 2020 was my most recent.

I came across a set of tubular wheels at a swap meet a while back and
thought about converting (regressing?). And than I remembered those
evenings sewing up tires with dental floss ( I seem to remember was
recommended ) and decided that just maybe I could get along with
conventional tires and tubes a bit longer :-)

The wife is the seamstress in the family but somehow I never could
interest her is sewing tires :-)
--
cheers,

John B.


When a cheap tubular was $5 and a silk racing tubular was
$12, my $1.20 per hour wage led me to patch and sew
everything and anything, even other riders' castoff tires.

Today a good tubular is under $20 and I just toss out 3 or 4
a year. Hell, a set of Michelin Pro with Michelin tubes and
a rim liners is $200. I leave the arithmetic to the reader.

Ah Ha! You left out your per hour wage :-)


Sometimes that doesn't matter. Like when you find a flat rear tire on
April-30, you want to ride on May-1 and the bike shops around are closed.

--
Regards, Joerg

http://www.analogconsultants.com/