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Subject: 
Re: Variations in dark blue color.
Newsgroups: 
lugnet.color
Date: 
Fri, 15 Feb 2008 18:14:36 GMT
Viewed: 
8928 times
  
In lugnet.color, Scott Lyttle wrote:
In lugnet.color, John Patterson wrote:
It is true that where LEGO used to receive color-molded pellets for
molding, and now the ABS is clear/uncolored and colors are injected during
molding.

Scott, a question, why is it more difficult to control the color with clear
plastic than it was to control the color in the older method of using colored
plastic?  Is it not the same problem to insure that the colored pellets are the
same color?  They probably made countless runs of the same color pellets without
changing color.  Its hard to believe that they had quality control in the 60s,
70s, 80s, 90s, but can't contol it now.  Is it possible that Lego has reduced
each brick run and they have the problem when making a second brick run?
Your post on the making of the bricks and injection molding was most helpful and
useful.  It was like watching the Discovery Channel's How Its Made.  Thank you.
One personal question.  I have a model of the White House that was on display in
Lego's corporate office in Denmark.  It is glued together.  At some point in its
history it was outside.  It is all white bricks and there is yellowing.  What I
don't understand in that the yellow bricks are not consistent.  They are 1x8,
one next to another and one maybe yellow and the other is pure white.  About
every fifth brick is yellowed in random patterns all over the piece.  Any reason
that you can think of?  This has puzzeled me for some time now.
Thanks
John P

John,
Adding color dye to clear ABS is like taking a bowl of flour, and adding food
coloring to it.  You will find that as you mix the flour, some of the flour will
wind up being tinted a little darker than other areas.  It depends on your
mixing technique, and all the relative aspects (i.e. how fast your mixing, the
way you are mixing, what you are mixing with, etc).


Now, if it were possible to buy a bag of flour with the flour colored the way
you wanted it, you could have a better guarantee of the consistiency, as the
company (i.e. vendor) producing the flour that you purchased would be doing
their own quality checks.

Now, if you needed a lot of different colored flour, would you be better off
buying several different bags of flour each with a specific color, knowing you
wouldn't be using the entire bag each time, or would you be better off buying a
huge amount of flour, then only taking what you needed from the large portion
(which is probably cheaper per use due to size and economies of scale), and
mixing your own colors?

I figure this is pretty close to how things are happening now.  Using your own
color, you are now taking color consistency QC into your own hands, and not
using the vendors QC in addition to your own.

Transitions from the "norm" of 30 years, to newer methods are never seamless.
There's always going to be bumps.  Any consultant that guarantees "seamless
transition" doesn't fully know the process.

As for the yellowing--on top of other posts in the thread about yellowing,
another thing to consider is the display was probably static, and you should
consider the position of the sun in relation to how much sun bricks are getting.
I'd dare say that bricks exposed to sunlight for a longer period of time are
bound to yellow faster.

Scott

Thanks for the explanitation.  I still would think that if the supplier of the
pellets starts off with a clear plastic and then adds color, it would be the
same for Flextronics starting with a clear plastic and adding color to make the
pellets.  Perhaps I am a little dense, but when the pellet supplier added the
color they were the same as Lego or Flexrtonics adding color.  They all start
with clear plastic and add color.
As for the yellowing on the bricks, perhaps i didn't explain it well enough.
There is a row with every fifth brick yellowed and a row below it with every
fifth colored but spread in a different pattern.  There is no way that one brick
yellowed next to on that did not to get more sun.  They all would have gotten
the same amount of light.  One yellower right next to one that did not, no
bricks are half yellow and half white.  This is from the builders in Denmark and
I would think that they all had the same bricks while building this.
     I was emailed by a former employee of Legoland and she said that the
bricks are sprayed with a chemical that what blocks UV light.  At this point I
guess that they were using bricks that were presprayed and some that were not.
She did make sence, except that the models were sprayed after it is built.
Perhaps they sprayed the bricks before the early models were built and used
bricks that were sprayed and not sprayed for an inside creation, and now at
Legoland spray the bricks after the model is built.
John P



Message has 2 Replies:
  Re: Variations in dark blue color.
 
(...) I believe that although the chemical coating prolongs the life of the model, it doesn't mean it will last indefinitely or will never yellow. It just means it takes longer to do so. I wish I remembered the stats, but I think it's something like (...) (16 years ago, 15-Feb-08, to lugnet.color)
  Re: Variations in dark blue color.
 
(...) John: Not quite. Flextronics is a molder, while the suppliers they would buy precolored pellets from are compounders. The difference is all in the method and intensity of mixing. When a compounder colors a resin like ABS, they do start with a (...) (16 years ago, 16-Feb-08, to lugnet.color, FTX)  

Message is in Reply To:
  Re: Variations in dark blue color.
 
(...) John, Adding color dye to clear ABS is like taking a bowl of flour, and adding food coloring to it. You will find that as you mix the flour, some of the flour will wind up being tinted a little darker than other areas. It depends on your (...) (16 years ago, 15-Feb-08, to lugnet.color)

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