TIG welding (by alaric)

Back in 2008, I took a welding course, in which I fixed the mistake I was making with my stick welding, and had a go at MIG and TIG.

Now, although I learnt to make nice beads with stick welding on flat surfaces, I still struggle with various things. Much of the welding I want to do is on thin metal, so I need to run the welder at a very low current, creating a feeble arc and with a tendency to stick, and still burning through if I'm not quick. I still can't do inside joint welds (the arc sticks to one side, or the other, and rarely both).

Is it my poor technique, or am I being limited by the fact I'm using a ten-year-old arc welder that cost £50 from B&Q? When I borrow a friend's MIG welder, I do much better work, and tinkering with my technique over the past decade has failed to make a huge improvement...

Whether it's me or the welder, I know that stick welding isn't perfect for what I want to do. As well as the issue with thin materials, it can't weld aluminium. I had a stick welder because it was all I could afford at the time, and living in a small flat, I didn't want to be storing compressed gas cylinders!

TIG is widely regarded as hard to learn, because there's so many variables to control - those ten complicated-looking knobs on the welder, the movement of the torch, the fine control of current with a foot pedal, the way you feed the filler metal in. However, when I tried it, I found that I liked all that control. With a MIG, you set the power level and the wire feed speed on the machine, and then pull the trigger to weld - which is great if the settings are all correct and you're doing a long straight uniform bead. But if you're having to change position as you weld, or dealing with varying thickness of metal so the rate of conduction away from the weld varies, it's trickier to have those settings correct. And to get them right, you need to do test welds, adjust, and do more test welds.

With a TIG welder, you can vary the speed at which you move the torch (and the current, with a pedal) and the rate you dab filler metal as you work, based on feedback from how the weld looks. Although there's more to vary, there's less need for trial and error. That suits me better! Back when I did the welding course, I'd really enjoyed TIG, and found it easy to do great welds, but a MIG machine looked a lot more likely to be affordable. So I was slowly saving up for a MIG machine.

And then I found that R-Tech, a local company on the outskirts of Gloucester that make welders and are widely lauded for their quality and good customer service, offered twelve months' interest free credit.

Suddenly, rather than saving up for many months for a MIG welder, I could afford a TIG welder (and quite a good one, too), with the money I'd saved as a deposit and then sixty pounds a month for the next year. THIS CHANGES THINGS...

So, today, my new TIG welder arrived. It can go up to 160 amps, it can do AC or DC (so it can be used for aluminium), it can do pulsed power control, and it has a foot pedal for precise work. So it'll be great for thin stuff. Also, it can do stick welding, but "nicely"; DC, with good current regulation, as opposed to my old AC transformer. That should make it produce much more steady arcs, so I'm looking forward to seeing if I can also improve my stick welding with it - stick welding is worse than TIG in most respects, except that it's faster and doesn't use up shielding gas. I still have a lot of stick welding electrodes to use up, so when I'm doing work on heavier bits of metal, it'd be nice to use them if I can do so and still produce good welds!

This evening, I unpacked it, ground a tungsten, put everything together, and rearranged some shelves in the workshop to set it up. I made a hook to hang the torch on by my welding bench, checked that the right things appear on the display when I turn it on, and then sadly bade it goodnight, as I'm not getting the shielding gas cylinder for it until tomorrow.

My plan is to start running test beads along a bit of scrap steel until I seem to have got the hang of it, then do a few easy jobs - such as re-doing some of the shoddy welds I messed up with the stick welder, and adding a steering stop to the festival trolley, and fixing a bit of my welding bench that snapped off after the bottom rusted.

Once I'm confident, I'm going to finish my current big project - a custom server case for love.warhead.org.uk, which hosts this site and many others! I've been taking it to my friend's workshop to use his MIG on it, which only happens when we're both free (less than once a month), and involves folding all the seats down in the car and lugging a significant weight of steel through the house. Did I mention that this thing's 1.2 meters high, and made of 1.6mm thick steel plate?

But I'm so incredibly stoked I'm going to have a TIG welder. I'd all but given up on the dream!

What a morning! (by alaric)

Ok. My days are usually pretty stressful. I'm supposed to work from 9am to 5:30pm with an hour's lunch break, but most days, I can't; with the school run I rarely get into work before 9am, and with picking Mary up from nursery (Mon+Fri), or getting Jean to Cubs (Wed), or getting Jean to Ju Jutsu (Tue), I tend to have to leave at 5pm at the latest. So I eat at my desk and work through the "lunch hour" to fit my working day into 9:30am to 5:00pm. Except on Tuesdays, I need to leave at 4pm to get Jean to Ju Jutsu for 4:30pm, so I make up for that by also skipping lunch on Thursday, despite staying until 5:30pm then (I manage to get in for 9am on Thursdays, as I can drop off at school slightly earlier on that day, and Tuesdays too). So it all balances out and I fit my contracted hours in each week, but with zero leeway and no lunch breaks.

But that is merely the backdrop to today's story.

Read more »

DNS issues today (by alaric)

Gah! This morning, my alerting system texted me to say that love (the primary server) can't talk to ihibehu (the backup server in the USA). A quick looked confirmed that we seemed to have some kind of routing loop in level3's network, which was therefore returning "TTL exceeded" to pings. I could connect to ihibehu OK from another network, confirming that it was just a local routing spat of some kind. I shrugged and moved on with life.

However, people started complaining they couldn't resolve DNS for stuff I host, so I had another look. love and ihibehu are both DNS servers (they go by the name of ns0.warhead.org.uk and ns1.warhead.org.uk in that role), and if one is unreachable, then the other should be contacted, so all should have been fine. However, it turned out that the IP address for ns0.warhead.org.uk was still pointing to its old location (and love don't live there anymore), so ns0.warhead.org.uk wasn't "working"; and so for the people whose route to ihibehu went via the routing problem, ns1.warhead.org.uk wasn't working as well.

Oops! One tricky aspect of distributed fault-tolerant systems is that sometimes part of them fails and you don't realise because all the user-visible stuff silently fails over. Therefore, you need to test things below the failover layer to make sure they work individually. Although I check both DNS servers are up, I wasn't checking that the "glue records" mapping the nameserver names to IPs pointed to the right place...

But I clearly remembered sending in the request to the registrar to change the glue record for ns0.warhead.org.uk when I moved it, didn't I? I checked my emails and, yes, I'd send that request, but with all the other stuff I was dealing with in the migration, I never chased it up. And lo, nestled among my spam emails was a response from the registrar, reminding me that I still had access to the interface to do it myself (The registrar used to be me, but I passed that mantle on to somebody else), and suggesting I do so. So it had never gotten done.

"No time like the present, then," I thought, and set out to send in the request, only to find that I don't still have access to the interface, because it also needs a password which I removed from my password databases when I passed control of the registry interface over. Doh!

So I've re-requested that the registrar does it for me. Thankfully, the routing loop has healed up and all is working again while I wait for that to happen. And I'm going to write a test for my glue records being correct into my monitoring system, because that was just sloppy!

Ugarit 2.0 released (by alaric)

Unless I messed up the release process, Ugarit version 2.0 is now available from the Chicken Scheme egg repository.

What does this mean to you, dear reader? Not a huge amount; you can go and read the release notes at the bottom of the Ugarit documentation page for the fine detail. But, to summarise:

• The beginnings of archival mode! As well as storing chains of snapshots of a filesystem, as Ugarit has always done (generally to be used as a versioned backup system), Ugarit vaults can now also store "archives", which are groups of files or directory trees identified by arbitary metadata, such as "This is the song 'Ooofarno' by 'Bobby and the Beaters', which is track 11 out of 12 from the 'Fishes In The Sea' album", or "This is a photo of Aunt Mavis taken at 13:58 on the 3rd of August, 2020, at Uncle Bob's 100th birthday party", or "This is a PDF of a paper by Donald Knuth on ternary numbers, called 'Simplified Arithmetic in Base Three'". You can then find things by searching on this metadata, which is much, much, nicer than creating trees of directories to organise all your stuff into. The user interface for getting things in and out of archives is still a bit minimal - but I have plans to fix that.

• The way tags are stored has changed. Ugarit 2.0 will read vaults created by prior versions happily, but when it writes to a vault, it'll write new-format tags (which have type information as well as a pointer to something), which old versions of Ugarit won't be very pleased to find.

• We now store a "metadata block" in every vault, pointed to by a hidden tag (we didn't used to be able to hide tags, so old versions of Ugarit will show you a funny tag, and complain if you try and do anything with it, as it's a new-format tag). This stores a vault format version number, so we can better handle incompatible changes to the vault format going forward; and as it's hashed and encrypted like any other block, it means you'll get an instant error if you try and connect to a vault using the wrong hashing and encryption settings, rather than bizarre errors further down the line.

• We've made it possible to store large logs in the vault. When we do a snapshot or an archive import or something, we keep a log of warnings and recoverable errors that cropped up while doing so. This is stored as a file attached directly to the snapshot or import object, so it can be arbitrarily large.

• Added log.sexpr and properties.sexpr files in the explore-mode interface, inside every snapshot or archive import object, which let you access the log and the metadata. These are files you can extract, or you can look at them with the new cat command.

• Added a cat command in the explore-mode user interface to dump a file to the screen for viewing.

• Added a client-side cache of snapshots and imports, which significantly speeds up the exploration of backup histories and archive metadata. Optionally, you can make the cache persist between sessions, otherwise it's made afresh for every explore session.

• As well as the existing ability to fork a tag into two tags that share the same history (applicable both to snapshot tags and archive tags), added the ability to merge two tags into one, melding the two histories into one. This includes some exciting logic to combine those histories for display in explore mode!

• Added a new sqlite backend, which provides a storage inside a single file, managed by sqlite. I wrote it to make testing easier, but it's a useful storage backend in its own right!

• Tidied up the Ugarit internals, splitting the core up into a load of separate modules. This makes development easier for me, and means nothing to users.

So what's next? I want to improve the usability of archive mode - right now, it's quite easy to import a bunch of files, but you have to hand-edit a text file to provide metadata beyond what it can automatically extract (currently just basic file information, plus whatever it can extract from ID3 tags and Ogg metadata); and then you can explore the history of the archive (as a series of imports) through the explore interface, or use a command-line tool to search for files, and then extract them or stream them to standard output.

What I want is:

• A shiny (web-based?) UI for searching the archive, seeing thumbnails of images, and the ability to download files with a single click or to perform bulk editing operations on metadata with ease and panache.

• A music player, that lets me pick music from an archive to queue, or to be given an arbitrary search criteria to find music to random-play, playing direct from the archive.

• A way to pick photos and assemble them into galleries, which are then publicly visible through a Web interface. Sarah wants to be able to put sequences of photos together, as well as individual photos that don't form parts of sequences, into multiple albums, for her blog publishing stuff (which is often quite image-heavy). The current image publishing framework I threw together for her years ago is a bit limiting now, and quite clunky to use.

• A mountable filesystem that lets me access archives, either in a generic manner (with auto-generated directories for every property, and every value of that property, containing all files with that value of that property) or with customised directory layouts (such as presenting my music collection as /music/ARTIST/ALBUM/NUMBER:TITLE.EXTENSION, with all the capitalised bits generated from the metadata). I'd like to do this by adding this to the explore mode virtual filesystem, and then having that mountable.

Concussion (by alaric)

For all of the time I've known her, Sarah has been poorly. When we first met, she was being investigated for a bowel problem, and she also suffered shoulder pain from a bike accident when she was a teenager. When she was pregnant with our first child, she had an exciting array of complications, and took many years to recover from the experience; she had mobility issues and pain due to a separated pelvis, lacked energy, had reduced sensation in her legs, and so on. The second pregnancy was nowhere near as bad, but Sarah still bled for months afterwards due to problems with her womb lining.

However, some months ago, while trying to lose weight, she cut wheat from her diet; and a load of niggling health problems she had reduced significantly, while her energy levels rose. She suddenly found it easier to lose weight, and things were looking pretty rosy.

However, this meant that she wasn't certain of her limits any more. Last Sunday, she was dancing, and found that she could now dance hard, and didn't need to keep stopping and resting; until she was suddenly dizzy, and stumbled backwards off of the nice soft grass and onto a concrete path, where she fell over backwards and hit her head hard on the ground.

I didn't see it happen; I was looking the other way, but Jean called out to me, and I saw Sarah lying on her back. She was instantly surrounded by people, and a paramedic was at hand almost immediately, so other than providing my cloak as a blanket, my role was reduced to holding her hand and helping Jean to pack up our things so we could leave.

This led to a thrilling trip in an ambulance with her neck immobilised, and several hours in A&E being examined and X-rayed.

Thankfully, this revealed that she had no structural damage to her spine or skull, so she could be released from the collar and head restraints, and sent home.

Jean was a star throughout; she rode in the ambulance, with Sarah's glasses and phone and medication, while I followed in the car, and helped the ambulance staff by verifying the truth of questions they asked Sarah to check her memory function. She didn't panic, even though it was clearly stressful for her, and did all the right things.

On Monday, Sarah mainly slept. On Tuesday, my father and stepmother visited, and we had a day out; Sarah was still speaking slowly and having short-term memory problems (forgetting where she put things, mainly). But on Wednesday she was struggling, with her speech slurring and often struggling to remember words for things, so she spoke haltingly. So we took her back to A&E, where she was given a CT scan, which thankfully confirmed that she didn't have any bleeding inside her skull (which would have been bad news). So she was let out again, and told to come back if she wasn't better in another week and a half.

At the time of writing, a week after the accident, she still has difficulty concentrating for long conversations, and can't concentrate on reading or watching TV or anything like that for more than a few minutes at a time. If she tries, she starts to struggle to think clearly at all, and her speech worsens. I've not kept track, but she sleeps through the night and probably spends at least a quarter of the day napping, and has to restrict her waking hours to mentally non-taxing tasks. Loud noises cause her pain, and I've been having to work from home to keep an eye on her and to keep Mary from bothering her.

So, it looks like she has Post-concussion Syndrome; this means she may be better in a few weeks - or may well be like this for years. Apparently about one in ten people still have symptoms after a year.

Her personality is intact, and her memories all seem to still exist; she just has to take her time to find them, which makes conversation difficult at times. But she can't do any of the things she loves to do, because sustained concentration renders her zombie-like within minutes. Unless that clears up, her career in writing, crafts workshops, and science communication will be over. I feel reasonably confident I can leave her looking after herself at home now, but she won't cope on days when Mary is not at nursery, so if things don't improve my job may become awkward until Mary starts at school in September, too.

So, for the time being, all we can do is hope it gets better!