Sciencemadness Discussion Board - Can common soda glass bottles be reshaped?

Can common soda glass bottles be reshaped?

Junk_Enginerd - 17-7-2020 at 02:17

I do my chemistry on a shoe string budget and I also enjoy making apparatus myself. I've done a whole lot of modification on borosilicate and that's usually no problem except for the intense heat it takes, meaning I have to use an oxygen/fuel torch. This gets surprisingly expensive since I haven't yet invested in a large oxygen tank, and the small disposable ones last for 15 minutes and cost $25...

It'd be really cool if I could make for example round bottom flasks from old beer bottles, but I have not once managed to heat one to workability without cracking it or even exploding it.

Does anyone here have experience lampworking soda glass? Can it be done at all?

Fyndium - 17-7-2020 at 03:15

Soda glass? Yes, it's very workable, much more so than borosilicate.

Glass bottles, like beer and soda? Based on the tutorials I've watched they need to be melted very slowly, over several hours, I'm not sure if this is due to thickness variations or if the glass is hardened or tempered in some way that needs to be softened.

Problem with soda glass is though that even if you were able to make flasks out of it, they will still be very prone to cracking under heat variations. Carboy flasks are sold on the other hand in beer and wine making shops, 50 liter one costs only something like 20 euros.

draculic acid69 - 17-7-2020 at 03:49

As a general rule anything with the textured ridge around the bottom is a definite no-go for heating.the only way you'll get something out of them is crush them into powder,add 10% boric oxide,melt the mix and completely reblow a new vessel out of it If u can find a glass vessel without the textured ridge around the bottom then there's a possibility of it surviving a heating/reblowing cycle not a guarantee but a good chance. I have been able to use beer bottles for very small amounts of liquid by sitting them in a coke can with the top 1/3rd of the can cut off but that's about it. A spaghetti sauce jar or a beer bottle might also work if u sit them in a tomato tin with fine sand in it.bcoz sand takes a while to heat up it will ease the stress on the glass heating to quick but I haven't tried it yet.below is a pic of the textured ridge I'm talking about

[Edited on 17-7-2020 by draculic acid69]

images.jpeg - 15kB

Junk_Enginerd - 17-7-2020 at 03:58

Quote: Originally posted by Fyndium

Soda glass? Yes, it's very workable, much more so than borosilicate.

Glass bottles, like beer and soda? Based on the tutorials I've watched they need to be melted very slowly, over several hours, I'm not sure if this is due to thickness variations or if the glass is hardened or tempered in some way that needs to be softened.

Problem with soda glass is though that even if you were able to make flasks out of it, they will still be very prone to cracking under heat variations. Carboy flasks are sold on the other hand in beer and wine making shops, 50 liter one costs only something like 20 euros.

Yes, I know it's very workable, that's part of the appeal. I have done some basic glassblowing with soda glass, but always from a total melt rather than reshaping something existant. It's trying to heat an existing piece that I can't solve...

I assume it is because it just has a high COE, as all soda glass does...

Yeah sure, but I think I've mostly worked my way around the issue of cracking when used. I recently tried making nitric acid from sodium bisulfate and sodium nitrate with a few different soda glass reaction vessels. I heat it to ~200-250°C and had zero failures. What I did was using a heating bath made of iron silicate blasting media, and I also applied aluminium tape to most of the bottles to ensure even spreading of heat.

I had one container that was a spherical small vase with a neck. I taped it with aluminium and even heated it with a flame directly and it did just fine actually. I think as long as heating is performed carefully, and the shape is as spherical as possible, soda glass can perform well enough. This is what I want to explore, and it'd be a ton easier if I could experiment with the shapes easily...

draculic acid69 - 17-7-2020 at 03:59

Quote: Originally posted by Fyndium

Trying to evenly heat one of those would be extremely difficult.

Junk_Enginerd - 17-7-2020 at 04:05

Quote: Originally posted by draculic acid69

As a general rule anything with the textured ridge around the bottom is a definite no-go for heating.the only way you'll get something out of them is crush them into powder,add 10% boric oxide,melt the mix and completely reblow a new vessel out of it If u can find a glass vessel without the textured ridge around the bottom then there's a possibility of it surviving a heating/reblowing cycle not a guarantee but a good chance. I have been able to use beer bottles for very small amounts of liquid by sitting them in a coke can with the top 1/3rd of the can cut off but that's about it. A spaghetti sauce jar or a beer bottle might also work if u sit them in a tomato tin with fine sand in it.bcoz sand takes a while to heat up it will ease the stress on the glass heating to quick but I haven't tried it yet.below is a pic of the textured ridge I'm talking about

[Edited on 17-7-2020 by draculic acid69]

I don't know about that. I used a 1.0 L glass bottle (vinegar bottle) for heating NaNO3 + NaHSO4 to ~150°C and it held fine. Typical beer bottle bottom on that, ridges and all. The trick I used was taping the lower half with aluminum tape taking care not to have any crinkles or bubbles in it. This seems to spread the heat well enough to not induce much thermal stress. I also used an iron silicate(sand blasting media) heating bath.

The heating bath does make temp regulation sluggish and it'd be nice to not have to use it. I think I would need a spherical bottom for this though, hence my question.

Dr.Bob - 17-7-2020 at 17:35

I understand the desire to make things, I have tried all my life. But commercial bottles are made for strength, and very thick, so heating them to use as reactors, or worse yet, to work them, will break most. I used home bottles and jars when I was young to store chemicals, and that works well for most things, especially dry solids/powders, and non volatile/corrosive liquids. But for doing chemistry, just buy some beakers, flasks, or any borosilicate you can find, used or new. Even a chipped or scratched borosilicate flask will handle lab use heating better than most soda glass. And sadly, used labware is readily available in most places, due to the number of closed labs.

Chemetix - 17-7-2020 at 22:29

Soda glass is easily worked, in fact a hot brazing torch with propane air is the best for this sort of work. Making your own labware is probably going to look very cool in the end but it will be not very functional.
But, if the glass blowing side of things is something you want to investigate you need to know a few things about bottle glass. For one, some glass bottles are prestressed to cope with pressure, beer bottles are one example, and will shatter when exposed to any flame. They need annealing first if you want to use them, or just break them up and melt them back into a gather. Second thing, glass bottles are formulated to freeze quickly after being in a mold. This isn't ideal for a glass worker on a torch, the glass just fights you on so many little annoying levels, but it can be done.

draculic acid69 - 18-7-2020 at 06:16

I reckon if the bottles were annealed slowly they would stand up to heat cycles better without cracking

Brightthermite - 1-8-2020 at 10:16

You are going to need some type of furnace to work these bottles. Like others have said they need to be heated slowly and evenly. I had some luck using my coal forage. Placing a fire grate down above my flame bed and sealing everything up with fire brick. It reminded me of a sort of pizza oven. All I did to my bottle was squash down the neck, but it didn't crack!!

S.C. Wack - 1-8-2020 at 14:30

In the late 70's-early 80's I saw Coke bottles with stretched out necks sold as curios, nicely done and not as sketchy-looking as today's Mexican Coke bottles.

CharlieA - 1-8-2020 at 16:07

I wonder if those started out as regular soda bottles, or if they were cast that way?

S.C. Wack - 1-8-2020 at 18:09

They seemed to be normal bottles reheated enough in the neck to pull quite a ways.

I want to say Spencer Gifts (coolest mall store ever, kids) but I'm not 100% sure.

Distillation glassware has probably been borosilicate for 100 years for good reasons.

[Edited on 2-8-2020 by S.C. Wack]

wg48temp9 - 2-8-2020 at 02:26

See the tutorial http://harrachglass.blogspot.com/2013/01/bending-neck-of-gla...

PS: Your empty small disposable O2 bottles will be useful for serious P production or the lower half makes a robust crucible less likely to fail than a tin can.

CharlieA - 2-8-2020 at 18:08

Quote: Originally posted by S.C. Wack

They seemed to be normal bottles reheated enough in the neck to pull quite a ways....
Edited on 2-8-2020 by S.C. Wack]

Thanks, I suspected that.

CharlieA - 2-8-2020 at 18:11

Quote: Originally posted by wg48temp9

See the tutorial http://harrachglass.blogspot.com/2013/01/bending-neck-of-gla...

Now all I need is a kiln!

But I think I'll just buy a bottle if I really want one.

But that link is informative, thanks for posting it.

macckone - 2-8-2020 at 21:49

For small thin glass apparatus soda glass has been used for a few centuries.
borosilicate is superior but wasn't really widespread until 'pyrex' was developed in 1915.
Ceramics are superior to borosilicate for some applications requiring high heat (over 300C)
Pottery is probably going to be a better way than glass working if you are on a serious budget.

Cheap chinese distillation sets are available on ebay, both new and used.
Probably cheaper than a glass working set up.
I buy quartz flasks for three of those oxygen cylinders.

Fluorite - 8-11-2020 at 09:19

Can drill a hole in glass bottle using a sodium hydroxide crystal and melting it using a lighter without breaking the glass?

unionised - 8-11-2020 at 09:57

Quote: Originally posted by Fluorite

Can drill a hole in glass bottle using a sodium hydroxide crystal and melting it using a lighter without breaking the glass?

Probably not, but you can do it with a proper drill.

Chemetix - 8-11-2020 at 15:24

A piece of copper pipe in a drill and some fine sand made into a paste with oil and water will cut a hole in soda glass. Modern diamond coated hole saws are much quicker but I think you are looking for a fairly low tech approach.

Clear_horizons_glass - 9-11-2020 at 11:17

Beer bottles and soda bottles are not annealed. They are tempered glass. That is why you have to heat them up very slowly. (Like Chemetix was mentioning).
Which basically means it can withstand a lot of physical force, but when it breaks it shatters. Like a wind shield. To remedy this, you either have to crush it and melt it in some kind of furnace (Like Draculic acid69 was saying), or ya have to very slowly raise it up to annealing temperature to release the 'stress' (thermal differences created from manufacturing and different thicknesses), and then some how attach it to a blow pipe and heat it with some kind of glory hole. Also, a kiln would really help it survive. I'm not sure what the annealing temperature is for various bottles. Maybe that information is out there if ya dig enough.
If ya don't have a lot of this equipment on hand, I would say it would be way cheaper to order some flasks.

It is definitely possible to work though. I've made a lot of swans while vending at festivals. Less sodium flare and they are pretty easy to get at the festival. Gonna make a ton out of coke bottles for xmas gifts this year.

What size tank are you using that goes out in 15 minutes? Is there possibly a welding shop around you can rent a bigger tank from?
I know around here you can rent a tank for like $15 a month, get a $40 fill and it should last ya at least 6-8 hours going pretty hard.

Junk_Enginerd - 12-11-2020 at 04:32

Quote: Originally posted by Clear_horizons_glass

Beer bottles and soda bottles are not annealed. They are tempered glass. That is why you have to heat them up very slowly. (Like Chemetix was mentioning).
Which basically means it can withstand a lot of physical force, but when it breaks it shatters. Like a wind shield. To remedy this, you either have to crush it and melt it in some kind of furnace (Like Draculic acid69 was saying), or ya have to very slowly raise it up to annealing temperature to release the 'stress' (thermal differences created from manufacturing and different thicknesses), and then some how attach it to a blow pipe and heat it with some kind of glory hole. Also, a kiln would really help it survive. I'm not sure what the annealing temperature is for various bottles. Maybe that information is out there if ya dig enough.
If ya don't have a lot of this equipment on hand, I would say it would be way cheaper to order some flasks.

It is definitely possible to work though. I've made a lot of swans while vending at festivals. Less sodium flare and they are pretty easy to get at the festival. Gonna make a ton out of coke bottles for xmas gifts this year.

What size tank are you using that goes out in 15 minutes? Is there possibly a welding shop around you can rent a bigger tank from?
I know around here you can rent a tank for like $15 a month, get a $40 fill and it should last ya at least 6-8 hours going pretty hard.

Ah. The tempering does explain why they don't behave like I expect, i.e. they fucking explode when heated...

I do have a whole bunch of suitable equipment in varying stages of decomposition... Since I do some metal casting I have most of the high temperature stuff, although maybe not temperature regulated to the degree one might want in glass working vs metal melting. It's 50-100 kW of roaring diesel and gasoline, on or off lol.

Eh this isn't about cheap, it's about because I(maybe) can and I want to. I have enough borosilicate glassware to do most of the things I need, including round bottom flasks etc.

800 ml tank. Mini welding torch thingy. Nowadays I've solved it and my oxygen costs me about 30 cents per 1000 liters, built myself an oxygen concentrator setup and store it in a 20 L tank.

Fyndium - 12-11-2020 at 04:39

Sounds like you could first melt the glass stock in your metal burner furnace, and then process it into new shapes and learn some glassblowing on the way. No wonder round bottom flasks were the most common shape, because you can just literally blow them.

zed - 13-11-2020 at 04:35

I don't know what kind of equipment you are using, but Oxygen tanks are expensive. Can you utilize compressed air? I have friends that have built heating systems based on that. They worked fine.

A one-time expenditure, to acquire a decent compressor, might save you a fortune, in the long run.