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Post 28 Aug 2023, 04:10 • #1 
Joined: 07/30/23
Posts: 33
The paint characteristics is one the of important aspects of the
rod. It has the biggest viewing surface on the rod. I am going to
list some of the characteristics we tested for in the paint:
Consistency in the pigment color
Hardness and Flexibility
Adherence (won't Chip)
Able to endure harsh environments
Mar resistance
UV resistance
Alcohol resistance

On the glass rods we used 2 component epoxy paint except for
rods and outriggers that are painted white. For them we used a
1 component Valspar paint.
On the graphite and Boron rods we used a 2 component urethane.

Whenever a new batch of paint came in, a small batch was mixed up and
we painted some scrape blanks and ran them through the oven.
A color draw down is made to check the color consistency
against our standard draw down. We wiped the painted blanks with alcohol
to check their resistance because a lot of alcohol is used
in the production line. Below is a draw down process image:

After the blank came out of the oven we would rub them together
to check their mar resistance and hardness. Mar resistance
and hardness is very important because when they go through the
production line they are bundled together maybe 30 at a time
and continually rub against each other.

When a new paint color or paint supplier submits a paint, the
sample paint is put into the salt spray, humidity, and UV chambers
for about 30 days. Our standard blank for testing fatigue was
coated and is put on our fatigue testing machine and flexed
until the blank breaks. We then look carefully under a microscope
to see if the paint had good flexibility and adherence.
Below is the fatigue testing machine:

So how do we paint the rods?
Just about all our rods were dipped into a little apparatus we called a
dipping pot that I am not going to draw for you. I used to have one of those
pots but can not locate it at this time. It had a number of rubber pieces stacked
on the top with some with slots and some with holes in them. There were
similar rubber pieces stacked on the bottom and in between the rubber was
a chamber that held the paint. Protruding from the chamber was a fixture
to hold a removable reservoir that held about 16 ounces of paint. The
whole apparatus was approximately 8" wide, 7" tall and 4" in depth.
There was a deep pit down below the floor ( about 9 feet) where under each
pot a thick polyethylene bag would collect the excess paint. The oven had a wide
plate to rest the pin plates that had the painted blanks on them. Because my memory
is failing I am guessing that the oven ran at about 140 degrees and the time the
painted blanks were in the over was about 40 minutes. The paint was catalyzed
so the oven was only to speed up the curing process. The paint mixer had to be
very careful because if the paint was mixed improperly we would not know about it
until they come out of the oven and hundreds of blanks could be involved in the
mishap. The viscosity of the paint also played a big part in the
mixing paint. If the paint was to thick it would sag on the blank and if it
was too thin it wouldn't cover well. A Zahn cup was used to measure the viscosity.
A large clock with a second hand had to be right where the mixing was being
done in plain view. After the solvent was added to the mixed paint the Zahn
cup was lowered and filled with the paint. When the second was on
12 o'clock the paint mixer would pulled the Zahn cup out and timed how many
seconds it took for the Zahn cup to empty. The primer since it was a thicker paint used
a different holed Zahn cup than the finish paint. Solvent amount was adjusted for the
correct time to be acquired. Below is an image of a Zahn Cup:

There were about 16-18 dipping stations. Each station had a bin that the rods
were put in tips down and an overhead adjustable height pin plate holder
for the pin plates that held the painted blank. The pins in the pin plates varied
according to the butt diameter of the blank. An average pin plate would hold
approximately 30 painted blanks.
The pin plate holder could also rotate 360 degrees. The plate size of the aluminum
pin plates was approximately 5" wide X 30" thick and a 1/4" thick. The pins were
approximately 5" long. They were made of steel and the clip that held the blank
against the pin were heat treated spring steel. There were tall paint racks that would
hold about 8 or so pin plates upside down. Also there was a large support group in
the paint room so the dippers would not have to stop dipping for anything reason.
After the painted blanks filled the pin plate, the pin plate was then put on to the
large racks that could hold approximately 8 pin plates. Then a oven loader would
push the rack over to the oven and load the conveyor with the pin plates.

The dippers could take a blank from the bin that was beside them, dip it and shove
it on to the pin plate in about 5-6 seconds on the average. This of course would
vary depending on the blank size etc.. There was a crows nest for the very long blanks.
A girl down below would start the dipping process and at the top of her reach
hand it to the girl in the crows nest in a continuous motion or otherwise a ring
of paint would be seen on the painted blank if the dip was stopped momentarily.
All the outriggers were done this way and also longer blanks.

A perfect scenario would be to apply one coat of primer and one coat of finish.
However most of the time 2 coats of primer had to be applied.
Every coat of primer has to be sanded by a centerless wet sanding machine before
the next coat could be applied to the blank, similar to the one below:

The paint operation was in an uncontrolled environment and occasionally we had
problems with paint separation, orange peel, pin holing and blistering etc..
For an example, the paint mixer, mixed some Burgundy finish using the solvent
supplied by the paint's supplier for 2 girls to dip at 7AM in the morning. It was cool
and humid at the time. They started dipping and the paint started to separate. I was immediately
notified. I had the paint mixer make a small batch of the paint using Methyl Ethyl Ketone
as the solvent to adjust the paint viscosity instead of the paint supplier's solvent.
It almost solved all the separation but not completely. I then had the paint mixer use Acetone
instead and it solved the separation completely. At about 1PM that same day it was now hot
and dry. The girls had continued using the same mixture with the Acetone and the rods
were now blistering coming out of the oven. So now, I had the paint mixer make a batch
of paint using Butyl Cellosolve to slow down the paint surface from drying to fast and to
let the other solvents in the paint bleed out before the surface dried, thus eliminating the
blistering. Solvents were a very important tool to have when you had to paint in an
uncontrolled environment.

The rods all went through a paint inspection that did a very thorough and steadfast job in
checking the painted blanks. There was no negotiation. When the rods come out of
the oven with surface problems they all have to be re-sanded and re-coated again.

There were so many man hours and so much material wasted in that
department because it was in an uncontrolled environment.

You might ask how can it be that a large company like Conolon
did not have a controlled environment for that operation.
Well, there are things better left unsaid.

When I set up the Kunnan factory I made sure the paint department
along with the blank department were in a controlled environment
over there in Taiwan.

Post 28 Aug 2023, 04:13 • #2 
Glass Fanatic
Joined: 12/05/06
Posts: 2080
Location: US-PA
Good stuff! Thanks for posting!

Post 28 Aug 2023, 06:00 • #3 
Master Guide
Joined: 07/21/21
Posts: 446
Location: Florida
Thanks! Had no idea it was so complicated.

Post 28 Aug 2023, 08:04 • #4 
Joined: 07/30/23
Posts: 33
This paint room set up was done years before I got there. Maybe the type
of paint they were using back then was not affected by swings in temperature
and humidity changes. As for the conditions staying the way they were while I was there,
"some things are better left unsaid"

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