I've got some problem bottles.Looks like calcium or lime.Thick and gritty.They are three piece molds,so I don't want to screw them up. Any suggestions?
Any commercial lime-remover (such as Lime-Away) can be used from the bottle to remove lime. There are many acids useful for this purpose, from vinegar (acetic acid) to hydrochloric acid. It is always smart to read the warning label on these products.
The only commercially available acid which will damage glass is hydroflouric acid, which is used a few spot-removers. Those product labels usually brag about removing rust stains, rather than removing lime scale.
Harry's right, there are very few chemicals that will damage bottle glass, other than hydrofluoric acid and some Alkali Fluorides the only other one's I can think of are high purity Aluminium powder and Lithium Hydroxide, I don't think most have to worry about them [] .
I didn't know hydrofluoric acid was still available retail anywhere, I think it's been stopped here due to it's potential use for chemical weapons, it's a pity as it's the only practical way I know to etch Quartz and dip bottles [&o] .
Thanks guys, Here's what it looks like after 24 hrs. in a 3 to 1 mix of muratic acid. I love the way this stuff smokes when exposed to the air. Really mean stuff! Sure took care of this. Have a great day! Jim