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Gallery / Re: New Office Clock
« Last post by Brass_Machine on Today at 08:02:49 AM »That is cool!
Recent Posts
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How do I?? / Re: Make an Interval Timer for my Harbor Freight 220 Volt Spot Welder?
« Last post by vtsteam on June 28, 2025, 06:08:50 PM »I haven't tried mine yet.
Do you have specifics for what kind of spot welder it was and what the SSR's and the MOVs ratings were?
Do you have specifics for what kind of spot welder it was and what the SSR's and the MOVs ratings were?
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How do I?? / Re: Make an Interval Timer for my Harbor Freight 220 Volt Spot Welder?
« Last post by bhowden on June 28, 2025, 02:02:20 PM »For what it is worth, I made a timer for my spot welder a few months ago. I used an arduino nano, 7 seg display and an SSR with MOV. Very first time it turned on the inductive kick killed the SSR. I ended up going to a couple of relays in parallel which seems fine. I have not used it extensively so not sure how well they will hold up. The relay had a rating for inductive load which I followed.
Brian
Brian
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Metal Stuff / Re: What Happens If You Add 99.0 Silicon to an Iron Melt?
« Last post by vtsteam on June 28, 2025, 11:02:47 AM »That was excellent, Joules. 
I'm not casting steel, of course, just iron (lower temp, higher carbon) but it was very interesting anyway. More information than I have found on my own.
My guess is that pure silicon is pretty ephemeral in a melt, and more so than ferro-silicon. Generally in home foundry work, the effect of ferro-silicon addition is said to last no more than 5 minutes after addition, so you don't add it until the very end, before pouring the mold.
I do use ferro-silicon to prevent chill (hardening -- carbide formation) in melts for thinner castings. Or if a scrap type seems to chill easily, by experience.
I originally bought the pure silicon in hopes of adding it to aluminum to try to make aluminum extrusion scrap a better sand-casting material. But shortly after receiving it (EBay purchase) I read that others had tried to add it to an aluminum melt, and hadn't succeeded because of its high melting temperature (1414C). So then I thought about using it for iron, and wondered why ferro-silicon was normally used, and I'd seen no mention of pure silicon.
I've since heard of one person who said they were successful in adding pure silicon to aluminum, but no explanation (so far) of how that was achieved.
I have personally dissolved copper in aluminum at much lower than copper's melting temperature, so I don't discount that it may be possible with silicon. That's dissolution, not melting. I would like to know about that if it's been done.
I've also seen one video on YouTube where a very amateur melter, with poor stock (beverage cans?) did seem to combine silicon and aluminum in a covered electrical muffle furnace at very high (for aluminum) melt temperature. Maybe he got it to silicon melt temp? If so, and somehow he kept oxygen out, I guess it's possible. But in a normal aluminum melt, gross overheating is asking for a big loss in quality, and wholesale production of dross. Considering what he started with the metal quality of the final castings looked poor, with the Si/Al example slightly better than without, to my eye.
Anyway, thanks Joules, and nope not a fab lab, just EBay, and at a price for a small quantity not much different that the ferro-silicon I purchased in the past.
I'm not casting steel, of course, just iron (lower temp, higher carbon) but it was very interesting anyway. More information than I have found on my own.
My guess is that pure silicon is pretty ephemeral in a melt, and more so than ferro-silicon. Generally in home foundry work, the effect of ferro-silicon addition is said to last no more than 5 minutes after addition, so you don't add it until the very end, before pouring the mold.
I do use ferro-silicon to prevent chill (hardening -- carbide formation) in melts for thinner castings. Or if a scrap type seems to chill easily, by experience.
I originally bought the pure silicon in hopes of adding it to aluminum to try to make aluminum extrusion scrap a better sand-casting material. But shortly after receiving it (EBay purchase) I read that others had tried to add it to an aluminum melt, and hadn't succeeded because of its high melting temperature (1414C). So then I thought about using it for iron, and wondered why ferro-silicon was normally used, and I'd seen no mention of pure silicon.
I've since heard of one person who said they were successful in adding pure silicon to aluminum, but no explanation (so far) of how that was achieved.
I have personally dissolved copper in aluminum at much lower than copper's melting temperature, so I don't discount that it may be possible with silicon. That's dissolution, not melting. I would like to know about that if it's been done.
I've also seen one video on YouTube where a very amateur melter, with poor stock (beverage cans?) did seem to combine silicon and aluminum in a covered electrical muffle furnace at very high (for aluminum) melt temperature. Maybe he got it to silicon melt temp? If so, and somehow he kept oxygen out, I guess it's possible. But in a normal aluminum melt, gross overheating is asking for a big loss in quality, and wholesale production of dross. Considering what he started with the metal quality of the final castings looked poor, with the Si/Al example slightly better than without, to my eye.
Anyway, thanks Joules, and nope not a fab lab, just EBay, and at a price for a small quantity not much different that the ferro-silicon I purchased in the past.
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Metal Stuff / Re: What Happens If You Add 99.0 Silicon to an Iron Melt?
« Last post by Joules on June 28, 2025, 08:39:16 AM »I found this, the most I learned about adding silicon is it oxidising. Kind of hints at keeping oxygen away from the melt.
https://www.ispatguru.com/silicon-in-steels/
Apologies if you have already seen this page, the lower part references effects on steel. You raided a fab lab VT ?
https://www.ispatguru.com/silicon-in-steels/
Apologies if you have already seen this page, the lower part references effects on steel. You raided a fab lab VT ?
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Metal Stuff / Re: What Happens If You Add 99.0 Silicon to an Iron Melt?
« Last post by vtsteam on June 27, 2025, 06:17:53 PM »Tried that, Tom, but no reply -- at least through the forum.
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Software Tools / Re: Playing with Blender For Artists (Bforartists) - Easier way to learn Blender?
« Last post by sorveltaja on June 27, 2025, 06:13:08 PM »Some of mesh editing tools in blender have weird ways of working.
So far, most annoying is mirroring an object. The tool itself works as one might expect, but the mirrored object always has a negative scale on mirror axis:
[ You are not allowed to view attachments ]
It can be fixed by using 'apply scale' command to reset X, Y and Z scales to positive 1.000.
If the object's scaling is not uniform, it affects modifiers like beveling (which isn't that great in Blender, though). Anyway, I wonder where negative or non-uniform scale can be used without messing things out?
So, once the scale is reset, perhaps because of negative scale value, mirrored object's normals or faces are inverted, which also affects modifiers (such as Boolean operations won't work):
[ You are not allowed to view attachments ]
Next thing to do is to select all faces in edit mode, and apply ‘flip’ or ‘recalculate outside’ command.
Same steps have to be repeated over and over every time. It makes otherwise simple operation rather tedious, so I started to look if there are ways to automate previous steps.
One way is to use output of Blender's info window, which shows history of previous actions:
[ You are not allowed to view attachments ]
Commands can then be copied to Blender's text editor and executed there as a script. Seems to work quite well, with just one click. But to make a button for it to 3D window instead, I asked ChatGPT - that glorified oracle - how that can be done.
It added some python code to make it happen. Commands included are:
- Duplicate object
- Mirror (in this case in x axis)
- Apply scale
- Enter edit mode
- Selection mode face
- Select all (faces)
- Flip normals
- Enter object mode
Although I'm not much of a programmer, I was able to figure out, what kind of code snippet to add to make a script to an installable add-on:
[ You are not allowed to view attachments ]
There are also some other command sequences, that I guess can be handled or 'buttonized' with similar python scripts as well. The script that ChatGPT provided, has comments on what different parts of code does, so it's fairly clear where certain list of commands should be placed.
So far, most annoying is mirroring an object. The tool itself works as one might expect, but the mirrored object always has a negative scale on mirror axis:
[ You are not allowed to view attachments ]
It can be fixed by using 'apply scale' command to reset X, Y and Z scales to positive 1.000.
If the object's scaling is not uniform, it affects modifiers like beveling (which isn't that great in Blender, though). Anyway, I wonder where negative or non-uniform scale can be used without messing things out?
So, once the scale is reset, perhaps because of negative scale value, mirrored object's normals or faces are inverted, which also affects modifiers (such as Boolean operations won't work):
[ You are not allowed to view attachments ]
Next thing to do is to select all faces in edit mode, and apply ‘flip’ or ‘recalculate outside’ command.
Same steps have to be repeated over and over every time. It makes otherwise simple operation rather tedious, so I started to look if there are ways to automate previous steps.
One way is to use output of Blender's info window, which shows history of previous actions:
[ You are not allowed to view attachments ]
Commands can then be copied to Blender's text editor and executed there as a script. Seems to work quite well, with just one click. But to make a button for it to 3D window instead, I asked ChatGPT - that glorified oracle - how that can be done.
It added some python code to make it happen. Commands included are:
- Duplicate object
- Mirror (in this case in x axis)
- Apply scale
- Enter edit mode
- Selection mode face
- Select all (faces)
- Flip normals
- Enter object mode
Although I'm not much of a programmer, I was able to figure out, what kind of code snippet to add to make a script to an installable add-on:
[ You are not allowed to view attachments ]
There are also some other command sequences, that I guess can be handled or 'buttonized' with similar python scripts as well. The script that ChatGPT provided, has comments on what different parts of code does, so it's fairly clear where certain list of commands should be placed.
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Metal Stuff / Re: What Happens If You Add 99.0 Silicon to an Iron Melt?
« Last post by tom osselton on June 21, 2025, 05:18:44 PM »Is Ironman ( luckygen1001 ) still around I’d probably shoot him a email.
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Metal Stuff / What Happens If You Add 99.0 Silicon to an Iron Melt?
« Last post by vtsteam on June 21, 2025, 09:57:17 AM »I've added ferrosilicon routinely to iron melts for the usual reasons. I recently got ahold of some elemental (99.0+ pure) silicon metal, and wondered if that could be used in an iron melt to similar effect.
Melting point is 1414 C , which seems do-able (unlike in a normal aluminum melt). I do realize that the S.G. is much lower than iron, so it will tend to float, and oxidize, and that the silicon effect is transitory, so needs to happen at the very end of the melt.
Other than that, is there a reason why it isn't generally talked about? I mean I just did a search online and after 3 pages of pointless results repeating that (ferro)silicon is used in iron melting, there was nothing to say yay or nay about pure silicon metal addition.
Anybody know -- or even better, have actual experience?
Melting point is 1414 C , which seems do-able (unlike in a normal aluminum melt). I do realize that the S.G. is much lower than iron, so it will tend to float, and oxidize, and that the silicon effect is transitory, so needs to happen at the very end of the melt.
Other than that, is there a reason why it isn't generally talked about? I mean I just did a search online and after 3 pages of pointless results repeating that (ferro)silicon is used in iron melting, there was nothing to say yay or nay about pure silicon metal addition.
Anybody know -- or even better, have actual experience?
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Project Logs / Re: The Return of No. 83, a Hot Air Engine
« Last post by vtsteam on June 20, 2025, 06:55:41 PM »I cleaned the engine, and did a quick test again with the displacer this time.
With the brake applying pressure at 900 RPM at the fifteen minute mark, the displacer version was putting out 0.370 watts.
That compares with the 15 minute regenerator run at 935 RPM of 0.134 watts.
With the brake applying pressure at 900 RPM at the fifteen minute mark, the displacer version was putting out 0.370 watts.
That compares with the 15 minute regenerator run at 935 RPM of 0.134 watts.