Mig, Mag, Tig,Tag....give the dog a bone...welding

[FrenchStag]

Now that I'm spending the kids inheritence on a nice new middle and outer sill (for the PI, sorry), I suppose I had better give myself a fighting chance of being able to weld it (which I am determined to do).

I suppose that my gasless "mini" flux core MIG is not a sensible tool to tackle a whole sill as well as front wing repair panel? Do I really need to go "full A-Team" with a MIG welder plus gas canister the size of a space shuttle booster rocket? Or will a smaller set up do the job?

Any idea what type of kit I should buy? At preferably below the divorce radar price level...

Also, whilst I have some "sill fitting guides" kindly send by the nice sill manufacturing chap, I'm still not fully clear if I need to "spot" weld the new sill on every few inches, or if it needs to be continiously welded (butt or lap or seam I don't know its all greek to me). I suppose it will become clearer when customs actually let me have my solid gold sills....

And then I saw someone on Youtube doing Mig welding with what seemed like a continuous "spot weld" (weld a spot and then immediatelely move to another one next to it. Is this better than "running a continuous bead"?

Thank you for any tips!

[jbuckl]

Continuous where there are any cuts.

Spots where there were spots.

Mig can do spots through a hole.

[Goldstar]

Sills on the stag were spot welded so I’d be surprised if the big saloons were any different although I haven’t checked mine.

RTech do a good range Kev Davies who was a member here got one and was very pleased with it. Pretty sure it was this one. https://www.r-techwelding.co.uk/r-te...tal-mig-welder I’ve got an Oxford which is very good (makes me look like a decent welder).

Once you’re done with it, you’ll recoup a decent chunk of the outlay if the divorce lawyers come sniffing. I use a big bottle of argon mix with a regulator set to about 6 psi (at least I think it’s psi, could be litres per fortnight) and 0.6mm wire.

When I replicate spot welds I use a 6mm hole in the top panel, turn the amps up and slow the wire a touch from what I would use on a seam type weld. I do have a spot welder but they can be difficult to get into the areas you need with sills but they are good in the door shuts and on the bottom of the sill.

Practice is the key.

[FrenchStag]

Thanks, wow its got all the gear. I’ll think of it as an investment

[marshman]

You could do it with your current set up, welds won't be as "nice" and will need more dressing (cleaning up) after, and more likely to "blow holes".

For years I had a Clark 100E MiG running on a pub bottle of CO2 it was adequate. Upgraded to a 5% argon mix which gave a much nice weld - managed to replace the rear quarters on my other halfs MX5 with that set up - did a very presentable job. The 100E was a transformer type not a more modern inverter type welder - a modern inverter equivalent is only around . A couple of years ago I "upgraded" to an R-Tech MiG180 - they are now about £600 and a decent sized bottle of argon mix from Hobby Weld (you pay a deposit for the bottle and then just pay for refils - I used to have Argoshield from BOC but their bottle rental charge got to be extortionate). You can stick with the small bottles but you will be surprised at how quick you go through then if doing a lot. You get a proportion of the deposit back from Hobby Weld if you return the bottle within 5 years. (atr least that used to be the case). Others have bought good welders from Oxford Welders. The R-Tech MiG I got is superb, much, much nicer than the old Clark machine - nicer torch, better wire feed, fully controllable voltage. As with most things you pays your money ....... I went with R-Tech as a) I already had one of their plasma cutters and b) their reputation for quality and customer service and long warrantee. I have used mine loads on my 3rd 32kg "Plus" bottle of gas - yes I do a lot of welding.

With regard to what you saw on the Youtube video:

If you replace the whole sill, carefully drilling out the old spot welds etc. then you can fit the replacement and "plug" or "spot" weld the replacement as per the original - this is acceptable for an MoT (don't care that the car is MoT exempt due to age, it still has to comply to be roadworthy!). If however you are repairing a section rather than replacing the whole panel which was originally spot welded then it must be continuously welded - I am talking structural components here such as sills, chassis sections etc, not a little patch on a wing or wheel arch. To properly spot weld you obviously need a spot welder BUT the usual practice is to drill a 6mm or so hole where you want the weld (only through one piece) clamp them together and then effectively fill the hole with weld, this then joins the two pieces (not well explained so suggest you watch a few more Youtube videos)

One of these nozzels can help with MIG plug welding:

https://www.frost.co.uk/eastwood-spot-weld-nozzle

With regard to the "continuous spot weld". If you are welding a panel or repair section and then it is best to tack (small spot weld) at intervals around the panel to hold it in place the slowly fill in the gaps, a spot at a time, welding a spot on one side then on the other. The reason is to stop the build up of too much heat in one spot which causes the metal to expand and then distort - exactly what you don't want on a body panel. Eventually you will join all the dots/spots to form a continuous weld. go slow and be patient possibly cooling the panel with compressed ar jet or damp rag. that way the panel stays undistorted. If you just start at one point and keep welding the panel will buckle and distort and end up looking like a mountain range and be almost impossible to get flat without the use of copious amounts of filler or hours spent "shrinking" the expanded metal with a shrinking hammer or careful application of localised heat using an oxy acetylene torch both quite skilled jobs.

[bullstarz]

If you're going to be doing long runs or a lot of on time or more than 1.6mm thickness, then you would need a decent higher amp. Min of 150amp Mig. The larger bottles work out cheaper in the long run. Tig are harder to use but do a full penetration weld and a lot cleaner. Plus with tig you can weld ally and stainless. Anyone can do Mig and is quite forgiving, Only a few variables to set, gas, wire speed and amp. But Mig can make weld lot ok but theres no penetration and a week wield. Tig you have to use a foot to control the amps and rising/lowering the power. Then the electrode is also critical as well as the distance you also have to feed the wire in and keep the pool going. Done correctly its look great and is a full wield.
I thin
I prefer TIG and you feel like a god when it turns out good. Theres a lot going on using both hands and a foot. MIG is easy but TIG is so much better. I think my TIG was around £1500, which is great for everything to do on a car but for the same price you could get a higher spec MIG.

[FrenchStag]

Thank you all very much for the advice. Cant wait to get stuck in.

[ramjam2005]

Hi
Just thought I'd add a few pointers on this topic.

I'm actively involved in a full resto of my Stag and fully agree with all the above and can endorse the Hobbyweld Gas option so long as you can find a nearby agent. For cleaner welds the HobbyWeld 5 is a good option way better than CO2 I initially tried. I started using the 9L cylinders but last month decided to go for the larger capacity PLUS 20L as works out more cost effective and convenient between needing refills if you're doing a lot of welding. I also invested in a twin regulator so you can adjust the flow rate to the welder separately. I built myself a welding trolley as it's easier to wheel it about nearer to your work area around the car and saves moving gas bottles about each time.

IMG_2245.jpg

Depending on your budget you might want to invest in some power tools for cleaning up your welds. I use a nice Milwaukee 12v 10mm sanding belt file which is easier to control than a larger flappy wheel on a grinder. Being cordless you can get into most of the awkward areas with it.

Depending on your workshop location, might be an idea to consider your electrical supply. I fortunately have a detached garage with a 5 way electrics supply board so I used a 32AMP type C MCB to provide a dedicated circuit for the welder and ran a heavier gauge twin and earth cable which I think was 6mm with 16amp commando outlet plugs, one each side of the garage. At my old house every time I sparked up the welder the house lights used to dim/flicker .

Also, consider your PPE, a good budget auto-dimming weld helmet and some leather gauntlets because those weld splatters are hot and bl**dy hurt !

Ray

[trunt]

I would stick with Mig, Tig is fantastic but the learning curve for an a beginner is much higher and Mig covers 95% of what you want to do. I only weld every 8 years or so and despite 30 years of doing it need time to get back into the swing of it every time. I start on places that you cant see then as it gets better only move to the fine stuff once I'm back in the groove. However I never fully got to grips with welding from below.. Its hard. As others say Plug welding is relatively easy, and Stitch welding makes things go well without the danger of distortion.

Another thing to get is some copper pieces. When welding into thin metal it helps to get some copper behind the weld as it can reduce blow through and makes it much more forgiving. They sell tools for that including magnetised copper things but a few pieces of copper plate clamped behind wherever you can in will do the job. I would avoid budget helmets, get a decent one with a decent sized window. If you wear reading glasses wear them under the helmet its amazing how much better things go!

Terry

Lesson #1 on my first weld :- remove carpeting before welding the firewall from the engine bay..

[FrenchStag]

Thank you - PPE is high on my list as I managed to get a sore eye last year with an amazon self darkening helmet. No doubt my own fault. And whilst I did start drooling over a combined Tig & plasma cutter I know my limitations and will just get a bigger MIG - with gas.

Cordless sanding belt sounds great, will think about that if the angle grinder isnt enough. Dont think Im quite ready to rewire the garage. Will just have to tell the wife its the washing machine when the lights go dim.

Did have a question about drilling out spotwelds. Is it not easier to grind off the top layer of metal, as drilling though both old sill and the profile it is attached to will leave a hole in this profile that will have to be filled?

And do you really have to take a hammer & chisel to bits of the sill to get it off? Are there metalworkers chisels out there?

[marshman]

Don't grind out the spotwelds. Takes ages, There will be a few, quite a few, you can't get at with the grinder or power file, there will be lots of sparks with the potential to embed themselves in unprotected paintwork, glass etc. and reveal themselves at some point in the future as rusty specs (been there got the -burnt and holey) teashirt!

What you need is a spot weld drill. Get some 6mm and 8 mm "cobalt" ones, a couple of each. These drill through the top layer and leave the second layer in tact. Nice and sharp so no centre punch needed. Once you get the hang of them they are very quick. Match the drill size to the diameter of the spotweld, usually 6mm. If it doesn't quite clear the weld a small sharp cold chisel driven between the two panels will ping them apart.

https://www.ebay.co.uk/itm/113819203820

I have the "basic" welding helmet from R-Tech, much better than the cheapo one I used to have. Has adjustable sensitivity/delayand a shade / darkness adjustment as well.

https://www.r-techwelding.co.uk/r-tech-speedmaster-xl-auto-welding-helmet

And these "thin" gloves. For TIG really but they are thinner and more supple than the cheaper welding gauntlets which give easy torch control but still protect you and "insulate" your hands from the heat and UV.

If you are doing lots of welding don't underestimate how much UV is given off by the are. Any exposed skin on you arms exposed to the arc WILL get badly "sunburnt". In the summer when too hot for overalls welding gloves do not cover enough of the arms. Something like these:

https://engweld.co.uk/product/prs-fire-box-blue-sleeves-33-2320?srsltid=AfmBOorYhXiC5L5_2p8jGrzwptS5GpWiAA8By8ZU_FT-ZRC0N4rupGot6ls

[marshman]

3/8" or 1/2" cold chisel. This one is a bit long and really needs cutting down to about 4" long and the cutting end tapering a bit more to make ot slimmer. Keep it sharp and it will work nicely after you have used the spot weld drill.

https://www.drillfix.co.uk/Products/000f000d/000f000d0016/13-x-150mm-6-x-1-2-cold-chisel-duracut/C261-90042

[trunt]

I like the spot weld chisel… slip it between the joint of metal and even bash sideways to cut any residual bits of spot weld.. any spot weld drill holes left are perfect for plug welds…

https://www.amazon.com/Lisle-51900-Spot-Weld-Chisel/dp/B000BQXBJK/ref=asc_df_B000BQXBJK?mcid=89de6610cd283afc8f25a47 e8bd52b4d&hvocijid=10903573855406997924-B000BQXBJK-&hvexpln=73&tag=hyprod-20&linkCode=df0&hvadid=730434204848&hvpos=&hvnetw = g&hvrand=10903573855406997924&hvpone=&hvptwo=&hv qm t=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=1025197&h v targid=pla-2281435179778&psc=1

The list is growing!

[marshman]

Every day is a school day!! Thanks Terry. Not seen those. Must admit I have ground a few of my cold chisels into similar thin shapes and they work really well, but had I seen these it would have saved me some time.

[FrenchStag]

This is really helpful - now I feel a lot more confident and thank you all very much for taking the time to provide such detailed and valuable advice. Have ordered a spot weld chisel and the spot weld drill bits.

I’ll start by getting the old one off and take it from there!