Tips & Tricks Blog
Notes, ideas and general comments on anything related to high-tech.

August 8, 2020

First hand experience with Samsung Galaxy S9 battery getting on fire…

Filed under: General — Tags: , , , ,

Wow, that was exciting…
My Samsung S9 battery bloated up popping the back cover open. I bought a replacement and was in the process of changing it when the old (bloated one) shorted somewhere inside in the bottom corner of the battery. It started by glowing in one small point then the whole thing started sizzling making lots of smoke. I tried to take it outside but made only a few steps before the whole thing got hot and scary to hold in hands, and I had to drop the phone. The battery remains popped out and started glowing red (I’m not exaggerating) then caught fire. Fortunately that main burning piece of the battery landed on the concrete part of the floor. The pieces that landed on the carpet were so hot that they melted it. Those were not thick big pieces that can absorb a lot of heat, pretty much just a copper foil.


Surprisingly, the phone still works, just the speaker board needs replacement…

December 15, 2018

Printing Alloy 910 from

Filed under: 3D Printing

For my first experimental print the nozzle temperature was 250C. That appeared to be the right temperature for printing, but a bit too high for the hotend. It looked like decreasing the temperature a little was possible. The further experiments proved that printing it at 245C works perfectly fine.

The bed was at 60C and covered by PVA. The attempts to print on clean glass at 75C and 90C were not successful.

The filament behavior appears to be similar to PLA. There’s leaking and fan is likely to be needed for printing small details. In the print pictured below the fan was always on at 30% (mostly because I was hoping it will help to keep the upper part of the hotend from overheating).


After making a few more prints the conclusion is that 50mm/s is too fast for this filament and my Makergear hotends. There was obvious insufficient extrusion of the filament in the infill  printed at 50mm/s regardless of fan being turned on or off and regardless of the printing temperature being increased or decreased 5C. Printing everything at the constant speed of 30mm/s immediately improved the results.

The print on the left picture is done at 50mm/s infill, the right at 30mm/s.

20181216_225311 20181216_232040

December 2, 2018

Printing T-glase clear filament

Filed under: 3D Printing

The material prints nicely. It flows and leaves strings like PLA though (perhaps increasing retraction a bit will help).

I used the same slicer settings as for their ( Nvent filament (didn’t play with any settings to make it more transparent). The extruder was at 245C although I think it could be at a bit lower (240-243 C) temperature to help with stringing. The bed was at 75. For small objects (20 x 20 x 10 mm calibration piece) it worked fine with Elmer’s glue, but the large pieces didn’t stick well enough till printed on the clear glass. I had no troubles removing those large pieces after cooling down (they pretty much got loose on their own).

t-glase-printing 20181202_011456

P.S. I forgot to note what was the fan setting and cannot remember it now (I think I kept it off).

October 4, 2018

How Much Lead Can You Get From a Car Battery

Filed under: General

Long story short, I needed to source about 20lb of lead cheaply and decided to take apart an old car-sized marine battery a friend gave me.

If you ever do that (and my advice don’t) just get the contact points and the big chunks that bridge the plates. You can see the latter on the picture inside the battery case.

Getting the lead mesh from the plates is not worth the efforts. There is more junk there than lead.

Baking soda and/or pool’s PH+ chemicals can be used to neutralize it. Borax can be used too. It converts it into boric acid and anhydrous sodium sulfate (neither of which is a nasty stuff, apparently). The process is simple. First, the water is added to dilute the acid (it’s not pure, so 50/50 mix is good enough). Then the neutralizing agent is added slowly (if doing it start with one spoon to see how it reacts). The baking soda and HTH PH+ bubble when added (borax doesn’t). As soon as it stops bubbling when the baking soda or HTH PH+ is added it should be good to dispose of.

It took quite a bit of the stuff to neutralize all the acid in the bucket and its remains in the battery case. I have scavenged and dumped in a pound or two all the above chemicals till it finally stopped bubbling.

20180915_160845 20180915_160854 20180916_3

The final result: 10lb


And after smelting there were only about 6lb left.

The conclusion: a lot of time, efforts and baking soda wasted (borax and PH+ did not count, didn’t need them anyway).

Water Purity Experiment

Filed under: Water

Just for the fun of it I decided to see how different is the residue after evaporating the water coming directly from the well, vs passed through the softener, vs passed through the reverse osmosis filter (iSpring under-the-sink system).

I have filled in 3 glasses, covered them with a napkin and left to evaporate slowly in a secluded corner in the basement.

To my surprise it took a while (about 2-3 months, probably due to high humidity in the basement in the summer).

Here are the results (left-to-right: well, softener, filter). The last row is under microscope (4x magnification):
20181003_231623 20181003_231630
20181003_231638 20181003_231642 20181003_231645
20181003_232125 20181003_23214420181003_232213
20181003_234106 20181003_234326 20181003_234424

The filter has (quote) “… Alkaline mineralization filter cartridge with Mineral Stone, Calcite, and Corosex …”. The content inside is of brown/yellow color, so I guess that’s where the brown crystals come from.

June 26, 2018

Printing with Taulman n-vent from LulzBot

Filed under: 3D Printing

The n-vent filament works well for the large items (like boxes). The 3mm blue roll I’ve got from LulzBot printed nicely at 237C hotend and 75C printing bed temperatures. The bed was a glass plate coated with Elmer’s glue. There’s only Slic3r profile for n-vent in


June 4, 2018

Microsoft OneNote Sign In Fix

Filed under: Web, Windows

After installing the OneNote 2016 PC client it asks you to sign in to the cloud.
If it decides that you have to use a business account (i.e. you are trying to set it up on a PC that is a part of a domain), but you need to use your personal account it is going to complain. It will either say that your email address’ domain isn’t known, your account does not exist/not found or it doesn’t look like work or school e-mail.

The following registry change will make it accept a personal account. First exit OneNote app, then change the value in the HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\OneNote\FirstBootStatus key to hexadecimal 2000202.

March 4, 2017

ESXi 6.5 and Ubuntu clipboard

Filed under: ESXi, Linux

Every time I have to set up new ESXi and add Ubuntu machine templates I’m getting into the same troubles, now writing it down to remember…
VmWare tools and clipboard are not working in Ubuntu desktop, so for the recent Ubuntu versions (14.xx, 16.xx):

1. In the ESXi host add the last 2 lines to the config and reboot:
[root@esxi1:~] cat /etc/vmware/config
libdir = “/usr/lib/vmware”
authd.proxy.nfc = “vmware-hostd:ha-nfc”
authd.proxy.nfcssl = “vmware-hostd:ha-nfcssl”
authd.proxy.vpxa-nfcssl = “vmware-vpxa:vpxa-nfcssl”
authd.proxy.vpxa-nfc = “vmware-vpxa:vpxa-nfc”
authd.fullpath = “/sbin/authd””FALSE””FALSE”

2. In the Ubuntu guest instead of installing the tools bundled with ESXi:
sudo apt-get install open-vm-tools-desktop

May 1, 2015

Sending WakeOnLan packet from VMWare ESXi

Filed under: ESXi

After a long unsuccessful search for something that would work for making available backup storage (WD Elements 4GB USB HDD) from my MS Windows desktop system to ESXi 6.0 server (as a datastore) ended up using old Dell laptop. It runs Linux, auto-mounts the USB HDD at the boot time and exports the mount point over NFS.

In order to avoid running it all the time, ESXi powers it up by sending wake-on-lan Ethernet packet and shuts down the laptop after backup is done. WD Elements powers on/off automatically when USB connection is up/down.
Attached is the ether-wake tool sources (with minor tweak for sendto() to work) and statically compiled binary runnable under ESXi.

The ESXi firewall has to be turned off for it to send the packet:

esxcli network firewall set --enabled false
./ether-wake 00:11:22:33:44:11
esxcli network firewall set --enabled true


January 25, 2014

RepRap X2V3 Simultaneous Printing from 2 Extruders

Filed under: 3D Printing — Tags: , ,

carriagesAlthough the main purpose of adding multiple extruder feature to the RepRap machines is to allow printing the dissoluble support material, the new RepRap X2V3 dual carriage design opens a few new interesting possibilities.

The machine supports driving each extruder hotend independently on the X axis (”Dual X Drive”, see video here  Its predecessor (RepRap X2) had both hotends fixed on the same carriage (similar to Makerbot’s dual extruder machines) and at relatively close distance of about 20mm. If printing simultaneously from both extruders the machine’s build volume on the X axis would be limited to the distance between the extruders (not quite useful). Because of that I’ve decided not to implement the “follow-me” mode while adding multiple extruder support to Marlin firmware.

Unlike it’s predecessor RepRap X2V3 is free to position the hotends at any distance the size of the machine allows. That makes it possible to  effectively use all the build space (i.e. the build envelope for simultaneous printing on RepRap X2V3 is about 100×200x130mm). Moreover, independent carriage driving allows simultaneous printing of mirrored copy of the object. That is often required when printing parts for the dual extruding machine or any object that has mirror symmetry. These hardware capabilities have convinced me to add the “follow-me” support to the latest (v1.1.0 X2 Beta 1 as of this writing) version of MarlinX2 firmware. The command for turning it on/off is M322. Its description is available in the file. The video below demonstrates the feature in action:

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