As well as being a driving instructor I also do a lot of work on my computer (websites, programming, and so on). So being comfortable is very important.
I’m not one of those people who likes to lean back – I’d much rather sit up straight. And I hate it when the arm rests catch the table when you swing round, or get in the way of your elbows. So for some years now I’ve been using one of those backless ‘kneeling chairs’, and I find them very comfortable and versatile. But they’ve all had quality issues.
I’ve had two wooden ones, which I deliberately bought from different places. But it seems like there is a worldwide conspiracy, because no matter where you buy them from they seem to be imported from the same place. They’re exactly the same – and they cost over £50 !
The initial problem is that all the screws that hold them together – they’re self-assembly – keep coming loose and dropping out (even if you try and glue the threads), and if you’re not careful you’re likely to end up with it suddenly moving. Possibly connected with this repeated loosening, in the later stages the wood starts to split in various places: around the seat pad and on the castor spars. Oh, and it is standard that one of the castors will fall off at some stage – if you’re fairly agile you can avoid being tipped headfirst into the wall or out of the window.
The last one disintegrated completely around one of the castor spars, so I began to look for an alternative supplier. I was building myself up to pay upwards of £120 (some of them are £300-£1,000 ) for a decent handmade wooden one when I discovered a supplier of steel ones. Well, the word ‘steel’ automatically conjures up visions of ‘only an iceberg will take this baby out’, so I went for it – it cost over £80.
When it arrived I noticed that it was exactly the same basic design as the wooden ones I’d had – it had obviously come from the same supplier/source as the wooden ones – but at least it was metal (albeit thin – the wind could have blown it over).
Within a week of starting to use it one of the castors fell off, and on inspection it became clear that the threads that the castors screwed into were like small round nuts welded to the castor spar – but they were welded using just a single arc-weld dab (see diagram to the right): it didn’t go all around to increase strength, and the whole thing had snapped off!
Now, I could – and should – have sent it back. But I needed the chair and couldn’t be arsed (have you ever tried sending something as heavy as a chair back in the post?) so I took the other castors off, jacked it up using the height adjuster, and used it without wheels. To be honest it was actually better like that. And another reason why I didn’t send it back was that I’d taken the precaution when assembling it of supergluing the screws so they wouldn’t easily come undone. I’m sure I’d have got away with it, but I didn’t fancy the argument which would probably have followed had they decided to be arsey about it.
After a few months it started to creak. I checked all the screws and they were still in place and tight. So I didn’t think about it any more. But then I noticed it was wobbling when I sat on it – and after a good examination I realised that the weld which held the main support strut to the seat platter was coming apart, and it had caused the box-section steel to start to tear (both struts: their are two of them side-by-side). Even worse, on closer inspection the original weld didn’t go all the way around the box sections, but only two sides of it! So it was weak to begin with. And add to that the fact that the box section appears to be made of 18 s.w.g. or thinner metal, the whole thing is a disaster waiting to happen.
Anyway, like most things I started to puzzle over how to get around the problem. I’d thought about drilling holes and fitting long bolts to act as supports – then I discovered how hard it is to drill holes in mild steel unless you have the right equipment (and a powered handheld drill isn’t it), and if the thing you’re trying to drill isn’t in its component parts any more (and I mean pre-weld, not pre-assembly from flat-pack).
Over the additional months, as the wobble had been getting worse, I was thinking about the possibility of building a kneeling chair from scratch – one that was strong enough to withstand re-entry after being chucked out of a space shuttle. What put me off was that it would cost an absolute fortune to get the necessary equipment to do it. Or so I thought.
I’d need an arc welder, of course, but I’d also need materials. And something which was really putting me off doing it was cutting these materials to length accurately enough – I can remember whole lessons in metalwork class at school cutting through solid bars of steel with a hacksaw to make a medallion (which no one would ever dare wear, and that only Geoff Capes could wear), or screwdrivers (which would bend if the screw it was screwing was more than finger-tight). I could see hard work looming. But then I had a thought: it’s the 21st Century. Surely you don’t have to cut metal using a hacksaw and elbow grease any more?
Enter: the angle grinder. It only cost me £20 (plus VAT) from my local Makro. The job was looking more viable already.
I’d been wondering where I’d get the raw materials from – I’d had visions of having to crawl around a load of industrial estates buying far more metal than I needed from fabrication shops. But I found a company on the Internet called Metals4u, and they will supply any quantity of material (there’s no minimum). It was far cheaper than I expected, too, and they did all the standard box sections and plates
But there were still two issues: building a new chair (which would take time) and doing something about this one that was disintegrating more and more each time I got up and sat down again. So it looked like a short term repair was needed.
I’d noticed when I last went to Makro that they were also selling Fairline Arc Welding Kits for £50 (plus VAT), so I went and got one. It includes a hand-held welding mask and a slag hammer/brush, but nothing else.
I nipped into my local Machine Mart to get some welding rods and a few other bits and pieces and I noticed they do a nice line in bench drills and bench grinders. These’ll come in handy when I build the new chair. Another trip, this time to B&Q , and I got a few strips of mild steel (2mm thick).
The next step was to work out how I was going to fix this broken chair. I cut out some strips of paper the same width as the flat steel (30mm – equivalent to the 1 1/8″ box section on the original) and made some templates (the yellow and blue sections in the repair diagram). I traced these on to the metal strip ready for cutting.
Christmas Day 2008 – the day I’d set aside for doing this – dawned. Some hours later, I dawned as well. About midday, actually.
I set up the portable workbench and set to cutting out the shapes I’d drawn on the metal strip. An angle grinder isn’t what you’d call a precision tool and I made sure I left a few millimetres of excess material next to my lines. I was quite pleased that I avoided severing an artery or something whilst doing all this – there were razor sharp burrs everywhere on the cut pieces. But the coarse grinding disc I’d bought turned out to be ideal for eating down to the lines I’d drawn, removing burrs, and straightening any rough cuts. It could eat away a couple of millimetres of 2mm steel strip in seconds. I wire-brushed all surfaces and edges of the cut pieces to remove protective varnish coatings.
Next step was to use the finer grinding disc to remove as much of the paint on the chair frame as possible so that the cut pieces were lying against bare metal. I had to compromise here – I’d planned to effectively sandwich each of the two main support struts and weld my additional struts either side (so there’d be four new struts in total). However, I couldn’t get between the main struts so I decided just to go with reinforcement on the outer faces of these.
I also had to compromise on elegance – the existing weld made it impossible to have the strut coloured yellow in the diagram lying flush with the main strut’s surface. But I needed the end of the additional strut to butt up to the seat platter, so I just had to go with it not lying flat.
You will notice throughout this that I have not mentioned any concerns over the part of the job which involved welding the parts together. Well, this is where the title of this post comes into it.
Welding is not easy.
Things I discovered:
- Striking the arc is easy
- Maintaining the arc is harder
- Welding rods get used up really quickly
- Getting the welding rod stuck is easy
- Leather welding gloves don’t keep heat out for very long if you hold a hot welded surface
- Ending up with a very messy weld is easy
- Getting black bogeys (or ‘boogers’ if you’re American) is a given
To cut an already long story short, the repair I have done looks a bloody mess. But the chair is now as solid as a rock. I thought I’d got arc-eye, as well, but it turns out I was wrong!
Incidentally, I’m getting alot of hits from people using the search term ‘welding rod keeps sticking’ or some such. This can happen if you are holding the rod too close to the weld – the current is therefore lower, so I guess the weld is cooler and solidifies more quickly, hence the stuck rod. It is even worse if you’re so close that the rod keeps touching the weld, as this can cause the arc to extinguish – also resulting in a frozen rod. Also make sure you are using the right current setting for the thickness of rod you’re using. I jumped up a thickness when I was building my chair project and couldn’t figure out why the rods were sticking so much (especially when I put a new one in) – I’d forgotten to increase the current accordingly from where it was when I did the repair on the old one, and once I did it was perfect!
Also incidentally, I’m getting a good few hits from the search term ‘welding b&q’. I’m not exactly sure what people are looking for, but I do know that B&Q carry a range of welding equipment with arc welders starting at around the DIY price range going up to large industrial units. It also supplies welding accessories and materials. Take a look at their website here.
And ALSO incidentally, Makro do a full range of Fairline tools – including various size angle grinders (that keeps coming up in the search stats, too).
I will post the result of my complete chair-build project next year. But I will practice welding before I do it, though.