Topic: What's going on with this dump weight?

[uphoosier]

Sorry, but this is my first dump weight.  What is going on at the bottom with the red?  Notice it trails up into some of the bubbles a slight way.  Thanks for looking. 

http://glassgallery.yobunny.org.uk/displayimage.php?pos=-9015
http://glassgallery.yobunny.org.uk/displayimage.php?pos=-9014
http://glassgallery.yobunny.org.uk/displayimage.php?pos=-9013

[KevinH]

That's a good question - and one which I am not sure has been fully answered in the general literature. However, it is a fairly common feature of the base of these bottle-gflass Dumps (or doortsops). Perhaps it is some form of "rusting"?? How it gets there is not known to me. The colour and extent of this feature varies.

Here's another example. This shows overall rough "crystalisation" with a small central area that has "rust" inside it.

[uphoosier]

Well, it looked like rust to me, but I felt kind of stupid to use glass and rust in the same sentence,  Thanks, Kev.

[Leni]

Isn't it where 'bits' (and that's a technical term, I'll have you know!  ) come off the end of the pontil rod and contaminate the glass? 

[aa]

Hot glass is corrosive,like acid and it attacks the metal surface of the glassmaker's iron. Depending on the method of cutting in and detaching the piece from the iron, some metal can be detached from the iron and if the base is not ground away remain on the base of the glass. At the time this piece was made, I believe irons were made of mild steel.. and after a time, mild steel rusts.

[uphoosier]

Thanks for responding and making that clear to me.
Ken