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Thread: pyrex softer than simax?

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    Default pyrex softer than simax?

    well i have been playing with my lathe for the last week and blowing thorugh tube at a rate i have never come close to while doing handwork. holyshit the lathe is fun but man its expensive to get her going and learn......

    anyway since i still suck at the lathe and i was using up my simax that i love and use in my daily...i decided to use up the rest of a case of 38.1 heavy wall pyrex that is several years old.

    it was part of a package deal i got and i kinda forgot about it until recently.

    so here is the weird part. after making several tubes out of simax i feel i am starting to get the groove as well as figuring out my heatbase.

    well fuck me if the pyrex isnt just an entirely different animal.

    this stuff seems very soft and takes considerably less heat to get the glass hot (too hot if your not careful) i dont like it...

    what gives? i have heard of issues with clarity between brands but the hardness factor is weird to me. they are the exact same size and thickness.

    i also noticed the pyrex is nowhere near as straight as the simax which leads to a fun time on the lathe.

    i wanted to use it as practice but since i really use simax exclusively, it may hurt me to work this stuff if it is so different.

    anyone have this experience?
    Quote Originally Posted by mer View Post
    life>fiction

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    Default Re: pyrex softer than simax?

    I recently switched to Pyrex because I can get a really good price on it at a local scientific shop compared to driving two hours for Schott or paying shipping for Simax. I`m not on a lathe but I am fairly new to glass and I will say when I first switched I had trouble. I ended up going back to just silver fume and clear so I could get used to how it flows. I had been using Schott and the Pyrex is way stiffer it seems.
    After a few I got used to it. But it was kinda like learning all over again.

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    Default Re: pyrex softer than simax?

    Quote Originally Posted by GWS View Post
    well i have been playing with my lathe for the last week and blowing thorugh tube at a rate i have never come close to while doing handwork. holyshit the lathe is fun but man its expensive to get her going and learn......

    anyway since i still suck at the lathe and i was using up my simax that i love and use in my daily...i decided to use up the rest of a case of 38.1 heavy wall pyrex that is several years old.

    it was part of a package deal i got and i kinda forgot about it until recently.

    so here is the weird part. after making several tubes out of simax i feel i am starting to get the groove as well as figuring out my heatbase.

    well fuck me if the pyrex isnt just an entirely different animal.

    this stuff seems very soft and takes considerably less heat to get the glass hot (too hot if your not careful) i dont like it...

    what gives? i have heard of issues with clarity between brands but the hardness factor is weird to me. they are the exact same size and thickness.

    i also noticed the pyrex is nowhere near as straight as the simax which leads to a fun time on the lathe.

    i wanted to use it as practice but since i really use simax exclusively, it may hurt me to work this stuff if it is so different.

    anyone have this experience?
    Are you sure it's boro 33. Corning made several types of
    Pyrex glass. I work it all (brands of boro 33) and never felt a significant difference as you say. One thing is obvious if you working small tube on the lathe as opposed to large it will heat and work expadentioly faster.

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    Default Re: pyrex softer than simax?

    ^^^yeah its boro and for sure is a different animal. its from 2002 i think. ill take a pic of label on box.
    Quote Originally Posted by mer View Post
    life>fiction

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    Default Re: pyrex softer than simax?

    I used some pyrex out of a batch a friend got recently. I could feel ribs in the tube when I was spinning it, and noticed that it had a different glow than other glass. It looks more orange. Can't say it's any softer/stiffer than simax(I usually use simax), but schott seems stiffer than both. At least from what I've seen.

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    Default Re: pyrex softer than simax?

    I noticed the differnce between pyrex and china clear when pulling points.The china tube gets softer and pulls longer,Where pyrex gets stiff faster with a shorter pull.
    I thought it could be that the lead content is higher in china glass?

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    Default Re: pyrex softer than simax?

    I started on ppyrex and I would say the opposite after working some simax heavy wa;ll and profileed tuube, the simax seems more fluid and softer when hot.

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    Default Re: pyrex softer than simax?

    Quote Originally Posted by somewhere View Post
    Are you sure it's boro 33. Corning made several types of
    Pyrex glass. I work it all (brands of boro 33) and never felt a significant difference as you say. One thing is obvious if you working small tube on the lathe as opposed to large it will heat and work expadentioly faster.
    expadentioly faster huh?

    Wow.

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    Default Re: pyrex softer than simax?

    The standard Corning Pyrex is #7740, so if it says that it should be normal.

    Duran seemed a lot more fluid when I first tried it, after using Pyrex and Kimble a lot. Simax is more like Duran than either of those two, as far as how it flows.

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    Default Re: pyrex softer than simax?

    Quote Originally Posted by GarageGlass View Post
    I started on ppyrex and I would say the opposite after working some simax heavy wa;ll and profileed tuube, the simax seems more fluid and softer when hot.

    that's what i've always noticed (i use simax exclusively). scientific workers are known to never mix brands, because there's different cooling rates (as you're noticing). some complex seals need to be spot on.

    all clear boro is made to COE 33, but will have drastically different cooling curves. think star white vs turbo cobalt- close in COE but incompatible due to opposite cooling curves. apparently simax has more potassium in it which is not good for some pharmaceutical applications because there's more background radiation (not to be worried, this is on the beyond microscopic level) and that interferes with some readings. maybe this is what makes it softer

    on a side note....

    i found that the chinese clear boro is super soft, but prone to alot of devit and crappy silver colors. when i made pipes, i could definitely make them faster on chinex, but they might look like balls and not sell as well. good luck getting purples from silver colors!

    once you decide on a brand you like, you can usually make a deal/contract with a distributor, order in bulk, and get a hefty discount that makes good glass way cheaper. speaking of cheap glass, don't forget to add in product loss from "cheap tube detonation" in your figures. that chinese garbage blows up all the time, and from what i remember of it, easy ate up the discount in wasted gas, oxy, time, and glass

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    Default Re: pyrex softer than simax?

    Kimble seems to be a little softer than SImax as well
    @B.RY_glass

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    Default Re: pyrex softer than simax?

    [QUOTE=julian;657276]The standard Corning Pyrex is #7740, so if it says that it should be normal.

    QUOTE]

    well julian those numbers are on the box i got. its from 2003

    jason, thanks for the breakdown. you are always a wealth of info.

    i put a tube of simax in one chuck and a tube of the pyrex in the other and lined them up within a half inch of each other and put a flame right between them while they were both cold so i could heat them at the same exact time with the same flame.
    the pyrex tube for sure got fluid quicker and also was much soupier when it did get hot. im not a fan.

    its weird that some of yall are reporting exact oposite of this?

    i just ordered a few cases of 50x5 simax and i think i will stick to what i have always worked and the heatbase i understand more.
    Quote Originally Posted by mer View Post
    life>fiction

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    Default Re: pyrex softer than simax?

    i use pyrex, and i third the idea that it is way stiffer, and i love that about it.

    I feel everything blows out nicer, and it is easier to keep the glass even with a slightly stiffer glass.

    worked for someone elde for a minute, and they used SBA, i think, i did not like how floppy it got for a the simple prodo i was doing. i like the resistance of pyrex.

    my pyrex is fresh!
    monkey grippin'

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    Default Re: pyrex softer than simax?

    ^^^this makes no sense unless the formula changed or i got a whacked case.

    the pyrex i have is noticeably softer.
    Quote Originally Posted by mer View Post
    life>fiction

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    Default Re: pyrex softer than simax?

    Different formulas glow differently than others at different temps. If we are judging temp by glow, we could misjudge temp out of familiarity with a different brand. Not saying this is happening to you, but it's possible.

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    Default Re: pyrex softer than simax?

    We get to work with Kimbles donated reject glass at salem, and use schott and pyrex at work, don't know about simax but i dont see a lot of difference either way. but pyrex is "gooeyer" than most other boros i've noticed.

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    Default Re: pyrex softer than simax?

    Quote Originally Posted by brian falls View Post
    expadentioly faster huh?

    Wow.
    exponentially. wow is right I should use a spell checker

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    Default Re: pyrex softer than simax?

    Weird, I just got a case of pyrex 25x4 and it is by the far the straightest roundest most even tubing I have ever worked with..

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    Default Re: pyrex softer than simax?

    Pyrex changed post-2000. The older stuff was definitely more stiff than Simax or Schott... no idea about newer Pyrex.

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    Default Re: pyrex softer than simax?

    I have to say that I've not noticed a dramatic difference in the two, although if anything the Simax I've used has been almost unnoticably softer than either Duran or Pyrex. Yes, the glow of Pyrex can be different, but I've found all the glasses to have a slightly different visual in the flame. I've used Pyrex, Schott, Simax, Jobling, the Chinese stuff and an Australian made pyrex from the 70s (now that was a completely different ball of wax, deeper red/orange glow and as soft, if not softer, in the flame as the chinese stuff, but completely compatible with all the others in general applications. The Australian stuff is the closest I got to achieving invisible joins.).
    And, yes, Jason is right about mixing brands, when I was making scientific apparatus, I didn't like to mix brands because there could be issues in more complex items, unless I was doing a repair job and didn't know the base glass.

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