Question about getting a clean break on a 24 inch tube

I was working on a big vase yesterday and needed to cut a 24 inch tube of cobalt blue glass. Figured I'd score it and tap it like normal, right? Wrong. Spent almost three hours trying to get a clean break without it running or chipping. Tried heating the score line with a small torch, cooling it, everything. Finally got it after my fifth try by using a really light touch on the initial score and warming the whole tube in the garage for an hour first. Anyone have a better method for thick color tubes?

3 comments

3 Comments

palmer.val1mo ago

Honestly that whole warm up method sounds like way too much work... I just run cold water over the score line for a minute and snap it fast. Heating the whole tube is just asking for thermal shock problems later. A light score is good, but the real trick is a firm, quick break, not babying it. All that pre-heating is just making the glass more likely to run wild on you.

anthony_fox29d ago

That warm up method you found is actually pretty smart for thick color glass. Cobalt blue can be a real pain with its different cooling rates. Palmer.val has a point about quick breaks with water, but on a tube that big, I've had the score run on me every time with the cold snap method. What finally worked for me was a diamond band saw, but that's a whole other tool. For hand breaking, your light score and even heat seems like the right call to avoid those chips.

willow24429d ago

Totally get the struggle with thick cobalt. Watched a score run halfway down a tube once trying the cold snap. Your even heat method sounds way more controlled for that size.