Cracked Plastic Side Molding On Ti'books: Material and Repair

[Jerry Krinock]

on 04/05/21 18:51, Dan K at macdan at comcast.net wrote:

> Just an FYI for anyone interested, the 'trim' ring around the edge of
> TiBooks is made of ABS plastic, not carbon fiber. It _is_ black ABS
> however. :-)
> 
> Figured this is a good spot to mention this - since the trim is made of
> ABS, cracks can be permanantly repaired using a solvent-type plastic
> weld. I've repaired several badly cracked TiBook 'trim rings' (isn't that
> _every_ TiBook? :-) using Ambroid ProWeld, though other similar products
> should work as well. Local hobby shop is a likely source, as are such
> online retailers as Tower Hobbies.

I'm not sure I agree that this is ABS.  I agree it looks like ABS, but:

1.  I tried to weld a crack yesterday using Oatey ABS drain pipe cement and
clamping it together.  It did not work at all and showed no sign of
dissolving the plastic.  If it was ABS, it would have worked.

2.  ABS can have color molded in:

http://www.dow.com/automotive/materials/products/magnum/product.htm

We all know that painting this molding was one of the worst decisions Apple
engineers ever made, but why would they have specified painting if the color
could have been molded in?  (Possible bad answer: Metal in paint provides
electromagnetic shielding needed for product to pass FCC and ETSI testing).

3.  I read somewhere else that it was carbon fiber.

4.  Ambroid Proweld (near the bottom of the following link) is listed as
dissolving other types of plastic other than ABS:

http://www.ambroid.com/Ambroid.html

******

Regarding repair, after scraping off the failed ABS cement, I repaired it
with 2-part epoxy, and it seemed to work, but I don't want to stress it.  If
I wanted to do a good job, I would try the Ambroid Proweld since Dan says it
has worked for him more than once.