Which welder?

[Argyll]

I need to weld a piece of metal on to the underside of my trailer (blue piece). I could ask someone to weld it for me but I wish to weld it myself as I have a wrought iron fence that also needs repaired at some point. It's something I've never done but have always been keen to learn.

My cousin suggested investing in a mig welder as he said it's easy to use. I looked at some online today but from what I can gather mig welding is only suitable for metals up to 4mm thick. The blue piece of steel at it's thickest part is 7mm thick.

Any advice appreciated.

[kellys_eye]

Simple stick welder will do it just fine - provided you know what you're doing!

Red necks would use a couple of car batteries and a stick at a pinch.

[wine~o]

buy a new trailer...??

By the time you've spent out an amount on the welding kit and failed to get it right , then I think there was a problem with bushes or summat..

[Argyll]

With all new respect buying a new trailer is a side issue. I did consider it but wanted to invest in a welder anyway so thought I'd try and repair it first of all.

The whole ethos of this site is to repair things ourselves rather than dump and buy another

I'm not sure what you mean about bushes.

[Dave54]

As said get a stick welder, but do a bit of research first, some of the real cheap ones don't get good reviews.

Galvanised is horrible stuff to weld. Read this.
http://www.sperkoengineering.com/html/a ... anized.pdf

Be quite tricky for a beginner to weld the relatively thin stuff on the chassis to the heavier I section as well. You tend to burn into the thin stuff. Practice on scrap until you get the technique.

An auto welding mask is a great if you're going to do more than a small amount.

[Hitch]

Expensive little setup for a very irregular user.

MIG or MAGS (its proper name when used on ferrous metal) is perfectly suitable, providing you have a suitable machine.

I use MIG/MAG for welding most stuff, with suitable machine and user, 50mm+ isnt a problem.

MMA, or Stick, or Arc would be a cheaper setup, if you don't plan on welding under about 2mm thick.


A small but capable MMA inverter would be £200, plus rods, gloves, mask.... A half decent setup for about £300.

Cheaper machines from the likes of ALDI work, but aren't great. £100 would just get you a junk setup.

A MIG setup capable of that sort of thing would be about 170amps+ Looking at £400 for anything other than junk tbh, plus gas, mask, regulator, wire more like a £5/600 setup then (new prices)

MMA machines will be quite a bit smaller too, so no real storage issues for an occasional user.

MMA would be better to use outside tbh. A little harder to use than MIG initially, but fairly easy to pick up providing you allow yourself a bit of practice time prior to expecting decent welds....



Whats your budget?

[kellys_eye]

Consider simply renting a welder for the weekend. You could do some serious learning AND some decent welding over a long weekend and for the smallish outlay just hire it when you need it. They're hardly a use-it-every-day item for most people.

[thescruff]

I'd defy anyone to do that job other than a coded welder. and certainly not a beginner.

[dewaltdisney]

Take it from me, welding is a skilled job. I bought a cheap arc welder from Lidl and my ventures into welding were a bit of a mess. Galvanised metal is a bast to weld and it gives of toxic fumes. I would say hire a MIG welder as arc welding is really hard.


DWD

[Hitch]

Not helped by the equipment there DWD. A little £150 inverter is a world apart.

[dewaltdisney]

Yes, it was only £40 I recall I could never hold the gap, the rods were to big, and probably the voltage to high for the thin sheet I was trying to tack on and old mower. Blew bloody great holes

DWD

[Retired]

Hi,

I've been welding mild steel for over 50 years but have never used MIG or TIG welders. I was taught arc welding (Stick) and oxy acetylene (Gas) welding/cutting as an apprentice in the pit. Arc welding isn't very difficult with some practice on scrap metal first. Since leaving the pit I've owned my own arc welder it currently being a SIP Weldmate which I've owned and used for well over 20 years it doing everything I needed as to welding jobs.

http://www.ebay.co.uk/itm/SIP-05741-Wel ... Sw7FRWauxO

http://www.screwfix.com/p/impax-e6013-w ... prox/17503

Beginners to arc welding usual suffer some degree of "arc eye" this is caused by not having the welding mask in place as the arc is running; I well remember the discomfort but I quickly caught on and was soon running decent beads. Experiment with the angle of the stick; a shallow or low angle won't have a lot of penetration but is the way to go with thin metal; it's amazing how much you'll learn and pick up in an hours practice. Not only eyes need protecting but all exposed skin needs covering; welding or rigger gloves are a must not only to protect from the actual arc but you'll only pick up one hot welded piece of metal once because it bites. Practice with welding current; electrode sizes; electrode angles and feed rate; once the arc is struck then the electrode needs feeding in as it melts and forms the weld; there are no hard and fast rules as long as the weld is man enough. A chipping hammer will remove the slag and I find an angle grinder a huge asset; a small angle grinder doesn't cost much. A cheap box of electrodes from somewhere like Screwfix will give plenty of electrodes to experiment with and the size I generally use is 2.5mm; if I'm welding heavy metal I simply remove slag and go over again building up the weld thickness. If you get serious then you can upgrade to BOC electrodes but I've never bothered. Until a couple of years ago I used the small hand held welding shield supplied with the welder and many times still use this; I bought an automatic welding helmet costing £35 but find I can see the arc better through the cheap hand held shield.

Mild steel angle/channel iron is the stuff to practice on; just run beads on the surface until you get used to striking and maintaining the arc; once you can run a bead then place two pieces of metal together and try to join them; it's highly likely first welds will start on the joint but run off in one direction or other; strong welds will come with a bit of practice; galvanised steel I agree is not the best metal for welding but can be made a bit better by going over the welding area with the angle grinder; wear safety kit throughout welding and grinding because both are hostile. Beginners struggle with striking the arc because the electrode glues itself to the metal being welded; I gently tap the end of the electrode where I wish to start the weld letting it bounce clear of the metal surface; if the electrode sticks badly just switch off the welder. Any electrode without flux coating right to the tip will stick badly and electrodes need to be kept dry.

Please don't be put off Argyll because once you can weld you'll wonder how you ever managed without a welder. I doubt anyone rode a cycle the first time they tried; I fell off enough times when I first tried and it's just the same with anything new attempted; a guy I knew showed me some welding he had done using his mig welder and this too was on a trailer; he was so proud of his welding but it looked like bird droppings and I certainly wouldn't have towed the trailer; I've been welding heavy metal over the last week; one weld was to extend a length of 6"x3"x 1/4" thick channel iron; the picture below shows the heavy metal I'm working with and I think the setting is about 120A. I'd say go for it Argyll and please add a thread showing your progress; show any poor welds or welds that have wandered then others can follow your lead and be encouraged. The quickest way to learn is to jump in and have a go; pity you don't live nearby otherwise I'd soon have you welding.

Please take all safety precautions especially if welding/grinding in a workshop or garage; the fire risk is high if flammable liquids in containers are showered with sparks. Don't let spectators watch as welding progresses and don't allow kids anywhere near.

Kind regards, Col.

DSCN2056.JPG (204.38 KiB) Viewed 12959 times

[Hitch]

Things have come a long way since the SIP Weldmate, the newer inverter technology is so different, you got to be pretty bad to get a stuck rod nowadays with things like 'arc-force'

Spot on with the safety though Col, headshield is necessary, a budget auto helmet is worth getting. Cover hands and arms/legs etc...avoid rigger gloves, the cotton backs catch fire.
And the galv, it needs locally grinding back to bare steel 25mm or so all around the welds....you can easily tell the difference, the galv looks whitish as you grind it, then once you are through the dull steel shous through. Another sign is if theres sparks, you are touching steel, not zinc.

On a bit of a side note, what sort of trailer is that, is it a type approved one, Ifor/BrianJames/Buffalo etc?
There may well be a note in you insurance regarding trailers, to be type approved and not modified....

[Retired]

Hi,

I'm a dinosaur Hitch and for my needs the SIP arc welder is fine; I've looked at inverter type welders and wouldn't mind trying one out; the stick type arc welders are cheap and although old technology they do a good job with a bit of practice and would be a good introduction to arc welding without breaking the bank.

Good point you raise about insurance; if an insurance company can get out of paying they surely will so it could well be worth checking regarding trailer type? The last trailer I towed was over 40 years ago it being a Scammell Crusader hooked up to a bulk tipper.

There are lots of very useful instructional videos covering all kinds of welding on YouTube Argyll which might be beneficial to you; watching how welding is actually done is better than trying to understand through text?

Galvanised steel is excellent for its intended purpose but I've just had a run in with a heavy hollow section which was galvanised; I've been using powerful rust converter and coated all the steel I'm working with; the reaction on the galvanised steel was dramatic as seen in the picture below. Working with old steel can have safety issues due to what the steel is coated with; beware lead paint for instance.

Kind regards, Col.

DSCN2068.JPG (209.54 KiB) Viewed 12934 times

[Hitch]

Worth a look over here for welding specific stuff...
http://www.mig-welding.co.uk/forum/