Winter Diversions 2 - Learning To Weld

It’s been very quiet around here on the DS front…..

Because of all the building work we are having done, the garage has been emptied and gutted. 

Then......

Now

Still Now

This all started back in November 2018 and there is no way my DS and various parts could have stayed in there while all this work went on. Instead, the car is off site (back at the farm where it languished for so many years). I vowed at the time that the car would be gone no longer than five months. Well that's not working out at all. I think the main building work will take another couple of months and, even then, I want to paint the garage floor and will need to rack out the garage again before I can bring the car back and work on it. At the moment all the parts are stacked in boxes in my workshop……

…..and the wooden shed at the end of the garden. 

Shed

So what have I been up to? Well, I decided to learn to weld! As a DS owner I have a sneaking feeling it might come in handy. I talked myself into it on the basis of being able to save costs by rebuilding my own doors. I was, however fully aware that was a rather skilled art and that I would not be in a position to tackle that job on day one (ed. If at all….). First, I would need to learn some 'craft'. If panel welding proved too tricky, then Plan B was just to use the welder on a number of smaller jobs around the car and for fabricating things. Plan C was that I could re-sell it on if I discovered that me and welding did not get on…..

I won't presume to tell you how to weld because, as a novice myself, I have very little idea. I did think though, that it might be helpful if I explained how I approached all of this. As ever, it started with research.

Research

I  started by eyeing up the different welders that were on the market - new and second hand. I read posts, queries and problems in welding forums, and picked the brains of a couple of people who have restored their own Ds. I reached the following conclusions (Note: other conclusions are also available!)

• ‘Cebora’ brand welders are well-respected in the hobby/ home, non/ semi-professional market. They have been (still are?) re-branded and badged as ‘Snap-On’ welders with the accompanying hoik in price.
• The wire spool and feed mechanism is a crucial component for successful MIG welding. Cheaper welders can have poor quality and inconsistent feed mechanisms.

Example of a wire feed mechanism

• Go for a more powerful welder (more amps). I’d seen dirt cheap, low amp, welders that are only able to cope with the thinnest of metals and wouldn’t be able to cope with some jobs I might want to undertake.
• Go for a welder that provides for a wide current range and that allows you maximum control over that range. I’d seen cheap welders that had little more than an on/ off switch – so no flexibility to cope with different thicknesses of metal.
• Similarly, go for a welder that allows you maximum control over wire-feed speed.

Welding current (1 -6 dial) and wire speed (1-11) controls

• Check the cycle time/ duty time as stated on the spec. plate on the welder. This tells you how much resting ‘down time’ there will need to be between bouts of welding.
• MIG welding needs gas. Many people see this as an unnecessary inconvenience but the gas is there for a reason - it's not optional. It provides a shield around the weld and ensures that the weld is neat, strong and fit for purpose. The give-away on any prospective welding machine is that the welder will have gas hoses and a pressure regulator valve. You can buy welders that don't use gas (instead they use core-fluxed welding wire) - but that's not really MIG welding. So go for gas! Get a gas welder and you have a choice.
• There are different regulators/ valves for different gas bottles. You will need the right one for the gas you intend to buy/ use - otherwise you will need to buy an appropriate replacement regulator for your welder. That's pretty straightforward, just more expense.

Older style regulator - but suitable for MIG Argon mix and for standard BOC bottle fittings

• Buying gas under contract is not cost effective for someone with my planned usage. Research local gas suppliers. Where will you get yours?
• Different welders use different wire thicknesses. Body panels are only 0.8mm thick (!)  so, for body panel welding, you will typically want to use lower currents and so a welder that can handle the thinner 0.6mm welding wire. However you may also want to do larger welding jobs so need a welder that can also take 0.8mm wire. 
• Some modern welders have a ‘tack weld’ time function that allows you to have a short controlled burst of weld. Handy for ‘stitching’ thin panels together and for reducing the risk of ‘blow through’ from applying heat for too long.
• Buying a welder is only the first step. There will be lots of things you then need to source/ buy before you can weld. Most importantly: personal protective equipment (PPE) but also welding gas and other ancillaries and consumables. Leave some budget for these.

MIG Welding Machines
I bought a MIG welder off Fleabay at Christmas.  I ended up with a Cebora ‘Autostar 180’. It's probably 20 years old but in very good condition.

Ebay purchase

The same welder is also marketed as a Snap-On ‘Pro-MIG 160’. The internals are the same but the badging is very individual and only an idiot could fail to tell them apart.

Two brands, one welder.

With a name like 'Autostar 180' it would be tempting to think that you were getting a welder with a max welding current of 180 amps. That's not the case. The actual max welding current is 145 amps. So don’t be misled by a name.

But 145 amps is not bad. I should be able to weld metal up to 6mm thick. Maybe 8mm at a push. There are many small, cheap welders badged as ‘130s’. The actual welding current of these may only be 90 amps, or less in some cases. Added to this, they can have poor duty cycle times, a very narrow operating range and very limited control of how that range is adjusted. If you're shopping for a welder, all the clues are marked on a plate. This tells you about the operating range and other characteristics. Allow me to translate:

Welder Technical Specification Plate

• • The '1' in the top row tells you it has a 'single-phase'  transformer/ rectifier - meaning it can be used on a domestic circuit and has a standard three-pin plug fitted. '3' would mean 'three phase' and require significant re-wiring of your house.
  • The table below this gives you an indication of the welding potential of the particular machine. Related to 'duty time' (see below), the table shows it's maximum capability in one column and in another the power level at which it can comfortably operate without any downtime (that's the '100%' column)
  • The top row of the table  tells you that the voltage and current draw is between 20 amps/ 15v and 145 amps/ 21 volts according to which setting you select (so the maximum welding current is 145 amps).
  • The I2 figures state given welding currents and include the max. value (145 amps)
  • Correspondingly, the 'X' figure and the %s,  tell you what proportion of 10 mins the welder can run for at the corresponding current setting - so mine can operate for 2 mins 30 secs at 145 amps before it overheats. After it's duty time, it needs a 7 min 30 second rest. It also shows you the maximum current it can weld without a break: it can weld all day long (100%) at 75 amps. For welding thin body panels, I expect to be making lots of short tack welds  - so there will be plenty of down time and the duty cycle should not be an issue.
  • The U2 is the corresponding voltage for the approriate welding currents.
  • The I1 figures tell you the corresponding draw on your domestic supply. 
  • The U1 value shows that this model is for the UK market and so a 240V domestic supply.
  • 'IP21' refers to the strength of the case.
  • The big 'S' at the bottom tells you that the welder can take a little bit of dampness but should not be used in the rain.

As you can see, mine has a range of between 145 amps and 20 amps with six settings dividing max. from min. - so a fair degree of flexibility in the settings. The duty time is also more than acceptable for what I think I will need. (If I'm welding body panels, I won't be expecting to weld long beads or the panels will warp). It has a fixed torch (fixed into the body). More modern welders have a ‘euro’ adaptor and the torch unplugs from the welder. It’s designed to handle 0.6mm or 0.8mm wire. The wire feed mechanism seems sturdy and the wire speed control goes all the way up to "11" !! It looks used but not abused and I’m told it was bought secondhand from a body shop – so has probably been used for exactly the same job I plan to use it for. All in all it seems to tick the right boxes. I’m not kidding myself: better welders are available but I think I’ll be happy with mine. 

Further Necessary Expenditure
PPE (personal protective equipment):

• ‘Auto-darkening’ welding helmet. Very common these days. A bit like polarising sunglasses, these ‘black out’ as soon as the welding arc is struck. When the weld stops, the viewing panel clears. Simples! The difference is that they are either battery or solar powered. Check out the reaction time from light to darkened. Mine will change from light to dark in 1/25000ths of a second. That's a fixed speed - not adjustable. Others can be faster. 

Auto-darkening welding helmet

The helmets have other adjustable features and so tend to have a series of controls inside them. 

Helmet set up controls

Look out how sensitive the mask is to detecting changes in light - i.e whether you can adjust the threshold that triggers the darkening action.  Better helmets have more sensors - which mean, whatever the angle of your head, they are better at sensing changes in light and the need to darken. Mine has four sensors. Also see how long the delay is before the window becomes light again. This can be anything up to a second. Although you want the helmet to go dark quickly, you don't want it going light as quickly as a bit of delay helps protect your eyes as the weld cools. Make sure the helmet can be adjusted to the right level of shade needed for MIG welding – you want something including a range encompassing "shade 10" to "shade 13". (On mine, the 'mode' control is a just a quicker way of adjusting shade). Also, try to get one with as big a viewing window as you can afford. The window in mine is 100mm x 73mm. Doesn't sound a lot, but that's quite generous.

• Long leather gloves to protect not only your hands, but also your wrists – preferably with a degree of heat insulation. If you’ve got big hands – beware. Even gloves marketed as ‘XL’ size can be a tight fit – making them uncomfortable and impractical.
• Goggles or glasses. With molten metal flying around, you may want to also wear safety glasses or goggles in addition to your helmet.
• You might also want to think about a breathing mask. (See further below). 
• Footwear. Wear some. You don’t want molten metal on your M&S slippers.

Other Equipment
I also bought some tools and some ancillaries:

• Spare welding tips for 0.6mm wire
• Spare welding tips for 0.8mm wire
• A reel of 0.6mm welding wire 
• A pair of welding pliers. A little extravagant. The main use is for trimming the ends of welding wire, but they are also shaped to help remove hot welding gun tips and to clean spatter from inside the welding shroud.

Welding pliers

• Joddlers

Joddlers

I bought a pair with two functions: they can be used for creating a slight offset edge to a panels for overlap seams.....

Joddled Edge

......and they can also punch holes for plug welds:

Punched Holes for Plug Welding

•       A second cheap angle grinder - again, a bit extravagant, but it means that I can have one fitted with a thin cutting disc and one fitted with a thicker surface cleaning disc. (Thanks for the tip Peter!)

•       And of course I bought gas.........

The main gas used in MIG welding is Argon. A typical mix especially for MIG welding will be argon (95%) – with a little CO2 mixed in (5%). Some suppliers supply a mix that has 3% CO2 and 2% oxygen.

To reduce cost, some people, on friendly terms with a pub landlord, use pub gas. In other words cellar gas. BUT you have to make sure you use the right one - pure CO2. Some pub gases are a mix of gases to stop the drink (bitter for example) being too fizzy. You don't want to be using that gas....... and bitter shouldn't be fizzy anyway.

BOC (British Oxygen Company) might appear a first choice for a supplier of gas bottle, however their business model doesn’t suit the hobby welder who may only want to weld once in a while – or indeed may have a specific short term project and no requirement thereafter. They require you to set up a contract. Their prices are high and their terms include ongoing costs of bottle rental - whether you are welding or not. 

Instead I went with ‘Adams Gas’ – a hobby supplier. That have outlets all over the place. My nearest one happens to be a farm on the outskirts of town. A deposit needs to be paid on the first bottle (this is refundable if/ when you return the bottle) and of course you pay for contents – but that’s it. No hidden charges. Get a bottle and use it as quickly or slowly as you lilke. No contracts involved. You can buy small 9 litre bottles, but I worked out that a 20 litre bottle offered good value.

I still need to buy one (or two different) pairs of snips and several clamps for holding pieces of steel plate together. I'm sure there will be other things I need - such as hammers and dollies?

First Tentative Steps
I looked into welding courses but there were none near me and they were expensive. With the amount I'd need to pay for a welder, ancillaries, consumables, repair sections and the cost of the course, I could have just got someone to repair my doors for me! So I decided to try to teach myself. Before I even turned on the welder, I watched a good number of videos on Youtube. No matter what video you find, they attract very mixed comments in terms of criticism and the right/ wrong way to do things so, while I picked up some basics, I decided that the best way to learn will be by doing……

Although it’s very unlikely I will be running beads on body panels, I started by practicing running some beads on scraps primarily just to gain confidence in handling the equipment but of course also to see what power and wire feed settings worked on different thicknesses, and to see how the torch position and movement speed affected things. I also tried some deliberate ‘fails’ – just so I could understand how to correct errors (that’s my  story and I’m sticking to it).

Very first efforts…….

Very First Efforts

I got a bit braver.......

One Thing badly welded to Another Thing

Ultimately I will have to aim to become a lot more skilled at this if I am going to be welding thin body panels as this is fraught with welding difficulties:  firstly in terms of the thin metal heating, warping and distorting as you try to join pieces, and secondly from the risk of the weight of the molten weld falling through the panels you are repairing – leaving a bigger hole than you started with…….

To get some practice in, I got hold of a dented car door from a skip (just happened to be a Citroen door!). As I needed to weld to clean, bare metal, this door also gave me the opportunity to experiment with various paint strippers and grinding wheels.

Practicing on a Real Thing

I deliberately ran the welder at too much current to find out what ‘bad’ looked like and how ‘blow through’ appeared. "Blow through" is where the weight of the molten metal falls through the welding surface. The light pressure of the shielding gas may play a part, but I reckon gravity is the main culprit. It looks like this:

"Blow Through"

In hindsight, practicing on this door was not such a good idea! It is lined with sound-deadening material and possibly zinc* and has lots of plastic bits tucked away inside. The heat from the welding soon started to generate some very noxious fumes that were clearly unhealthy.

·      * Do not weld zinc plated metals! Remove the zinc! Exposure to zinc-oxide can cause ‘metal fume fever’ – which has flu-like symptoms (so a.k.a. “Welders flu”). And we all know how bad Man Flu can be eh, men?

I've now bought myself some 0.8mm sheet steel. I'll be using some of it to practice on and will have plenty left over for any patching or fabrication that might be needed on my doors or elsewhere. Though the plan at the moment is to fit replacement door bottom kits and buy complete new door skins - to avoid seams and moisture traps if water runs down the inside of the door.