First test with Pyrex filament

Thanks again @bradley & @Tricia.Suess :grin:

Printed a mini beer mug with the “beta” filament that was sent to me to test out. Anyone interested can check out the vids I have so far.

It’s in the kiln right now so I’ll post an update when it’s done (success or failure).

Not using refractory because I didn’t want to have any weird discoloration or it sticking, and no carbon. I did some research on some glassworking to pick a firing schedule, but I imagine it’ll need some tweaking depending on the results.


Longer result :slightly_smiling_face::

I am really enjoying the knife bit, Highball.

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As I said on YT, you are BRAVE! That is one big beer glass to do for your first part! Hope you got some success!

Also, can you remind me how big your nozzle is? My current setup would get about 1/50th through that part before clogging.

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Hah it’s smaller than it looked in the video (but I probably should’ve tried something smaller…)

I’m using a .6 brass nozzle but the key for me is printing at a higher temp of 225 for the Pyrex (I print at 234 for the copper). This last one failed and I’ll post my result and thoughts on getting it to succeed in a bit

(brass… hmm…)

Ah, dang, sorry to hear that. I am kind of guessing it’s because of the lack of refractory material? I’ve done some debinding experiments and the whole thing just falls absolutely apart into the glass beads, not like the copper which holds its shape a little bit.

Yeah I wanted to see if it would hold and I didn’t want to use my normal refractory since I thought it would mix or cause weird discoloration.
I have successfully confirmed I need it though lol.

I bought some small steel shavings and will try that next to see if it holds up and am thinking a peak temp of 1400 or more at a longer hold time

What are the steel shavings for?

The most I’ve tried so far is 1100 C. 1400 C sounds terrifying, lol.

1400 freedom units hah
Steel shavings as a refractory since I didn’t want to use the castable stuff. :man_shrugging: we’ll see if it works

Oh and one thing on the brass nozzles. They’re so cheap that it’s easier for to to just buy a bulk pack and if they clog beyond repair ditch it for a new one. They also seem to print much better than the steel one I tried a while back.

I also think I’ll actually go for 1600f since it’s higher in the"softening point" range for Pyrex at a longer hold time

So… closer inspection and my brass nozzle is toast. Didn’t have the issue with the copper filament but Pyrex wrecked the brass nozzle after a single print. Ponied up and bought a better steel nozzle, so will have some more tests when that comes in

Got this interesting blue tinge to this small piece I used to test my fire cycle. Any idea what it might be @WayneWayneHello / @bradley ? This is the first piece of pyrex that came out feeling solid (still cowboy’n it to figure my own process out)

Just wait until your competitors are adding blue food coloring to copycat your product :wink:

I have actually noticed blue streaks in my parts but nowhere to that degree. Much more subtle:

Of course yours appears to be a much more dense part as well (nice) and I’m assuming hotter as well. The densest I’ve gotten them was running at 1300 C with the problem being that my refractory material (aluminum oxide) bonds/sticks to it, whereas the other material I tried (magnesium sulfate) starts to break down/act funky. What is the stuff you’re using again?

So yeah, I don’t know about blue, but mine has turned yellow (in the magnesium sulfate), as well as swelling up like a potato chip:

My guess is it must be some kind of impurity reacting… A glass maker might know more, though.

I was thinking some impurity as well getting “sucked” up or reacting strangely to the surface. The blue was from my mixture of the tabcast refractory and the silicon stuff (I put a comment somewhere on here so I’ll have to find it and link)

Part feels pretty good (even for a failed print) so I’m going to try a bigger scale soon, but for the science, here’s my tests so far on refractory (video will show more when I’m happy with a result)

  • no refractory = part collapse
  • my blend = blue part (peak at 1800f)
  • steel shavings = outer coating of steel inner white Pyrex (looks sort of like an oreo cookie)
    • although this didn’t work it was interesting and I wonder if a second fire at hotter Temps to fuse the steel as an outer shell and Pyrex inside (I cant really think of any practical use for this just thought… what if…?)
  • graphite power - not sure yet going to try it after getting this nozzle unclogged
    • and I found out I don’t have the powder yet… soooo may be a bit since it was delayed
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It’s interesting that you are getting this blue part at just 1800f (a bit less than 1000 C). 1000C is at the tail end of porosity for me, with parts at 1100 and 1300 starting to be fused. Yours looks really solid though.

is it watertight? Have you tried to make coffee with it yet?

I took a second look at it (it’s been a few days) and it did look pretty solid but I was able to snap it pretty easily. I did this before I saw your reply… so to answer your question it is now currently not water tight :sweat_smile: (no coffee for me)

I just changed up my firing schedule too with a higher temp (2050f) but I won’t know how it does for at least another day or two

Fought with clogs, cura settings, nozzle changes, new ptfe tube and with delayed Amazon orders…

And I think I may have things dialed in (for printing). I ended up changing to a .8mm hardened steel, dropping the temp to 215C and disabling retraction. Print isn’t finished yet, but it’s looking way more promising than the past several tries have been.

My graphite powder came in too so I’m excited to give that a go and will probably also throw a failed print in as well with my refractory blend to test how it compares.

Also tweaked the firing schedule several times and hoping this new one will give some better results :pray:

I’m using a 0.4 mm nozzle. The one thing that dramatically, dramatically helped with glass was lowering temp from 220 to 200 c. Retraction had less of an impact if at all. Worth trying if clogs are still frequent, at least!

I think you shared it already, but do you think you could send me a link to the refractory you are using?

Found that comment:

Okay so assuming this is what you are using:

…it’s also alumina? It just makes no sense to me. First because it looks really different (more like plaster, or flour, as opposed to the fine white sand-like alumina that TVF sells?) but also because it seems to behave differently around glass and metal. With the alumina from TVF, it always seems to be stuck to the outside of the part afterwards — with copper there’s an oxide “skin” that then peels off so it’s not a problem. But with glass it’s totally fused.

Can you confirm if the TABCAST stuff looks similar to the aluminum oxide TVF sells? Because from what I see in your videos, the stuff just falls off of your parts, including the glass, right afterwards. ( it also looks more like plaster than sand to me in this picture: image

maybe the grit size, or the addition of the calcium oxide or something…

Yeah that’s the tabcast refractory I bought but I also mixed it with this

#80 Aluminum Oxide - 8 LBS - Medium to Fine Sand Blasting Abrasive Media for Blasting Cabinet or Blasting Guns.

I’ve got some parts in the kiln tonight that’ll be done in the morning so I’ll post an update soon. I’m comparing how my blend does against graphite powder.

As far as if it looks like what tvf supplies… I wouldn’t be able to give a 100% accurate answer since I never purchased it, but the one Pic on the site looks similar

But I do remember a rather “plastery” feel to it. The Blasting medium was jet black and I mixed it pretty thoroughly with the entire container of tabcast