Welding Ignorance - Help Please

A

alan

Well-Known Member
Joined
7 Jun 2001
Messages
1,112
Location
Nettuno, Italy
Visit site
I am looking to buy a welding set for use in the garage mainly on boat bits and pieces, but am completely ignorant of what I need. Can any of you experts out there point me in the right direction. Requirements:

(1.) I would like a small set for fabricating the odd bracket e.t.c.
(2.) Should be able to weld both steel and aluminium
(3.) Small enough to be reasonably portable

Can anyone advise me of what I should be looking for? e.g. are there special requirments for ally? What max current would I need for steel e.t.c.

I will buy a book on the subject, but wanted to do some pricing first to see if it is economical getting one just for fun and the odd job.

Thanks in advance for advice.

Alan.
 
I've got an arc welder and a MIG welder and I'd suggest you need a MIG.
It's easier to use and can cope with both sheet and thicker metals. You can also weld non-ferrous with the right gas bottles and wire.
If you can draw with a pencil you can MIG weld, it just doesn't always look pretty.
Having said that, if you learned using gas welding on rusty cars, any new metal welding seems easy.
Penetration is the goal, then worry about pretty welds.

Don't know about Italy, but all tools factors do cheap MIG sets for £150 ish. Never buy the lowest spec set. You'll be disappointed.
 
I think you are wasting your time. You need a TIG set and Helium for aluminium, if you are welding aluminium of any thickness you will need an AC high current set which will be three phase only. Stainless steel is an easier proposition but you will still need a Tig set but this could be a smaller single phase set.
You aren't in general terms however looking at easy light or cheap for anything except conventional steel.
 
OK, not an expert but I did do a 10 week welding course at night classes and have done a bit of welding at home.

The simplest welding process for a beginner is MIG, there are two types of MIG welder in DIY stores, gasless ones which only work with special wire which has flux in it. I would not recommend a gasless one, since it probably restricts you to welding mild steel at a guess. So you probably want one that supports both gas and gasless operation it will cost a bit more. The other main spec on the DIY welders is just how much current they can supply, a bigger number means you can weld thicker metal, but anyway thickness will be limited to something like 6mm on the kind of DIY welding gear that is available.

There are also arc welders in the DIY store, I reckon that this will take you longer to learn in the beginning and is more suitable for doing "heavy" work with thicker materials.

The rolls royce welding process, and one that is very suitable for aluminum is TIG, where you use an electic torch with a welding rod. But to learn TIG it is a good idea to learn to weld with oxyacetelene first and it would be true to say its a more skilled process than MIG (which our welding teacher described as a "semi-skilled" proces).

Welding aluminium is a difficult one, you can buy ally MIG wire and suitable gas but I personally didn't have much luck. Its very easy to blow holes in aluminium and it doesn't give you the same kind of "feedback" that steel gives (where you can see the pool of molten metal easily).

So it depends how serious you want to get about this. A MIG welder from B&Q, screwfix etc and a good book on techniques can do most of what you want (at least 1&3) in both mild steel and 316 (stainless being slightly more technical but I have managed successfully). If you're really serious about aluminium then maybe the best way forward is to see if you can do a course at a local college and try a lot of different equipments and see what works, as well as getting a few pointers with aluminium.

Chris
 
Aluminum - ~AC
Steel (in particular Stainless Steel) - -DC
Current range up to ~140Amp
FCAW and GMAW not recommented for stainless boaty bits or Aluminium.

My preference would be go for switchable AC/DC GTAW unit with HF start, pre and postflow, with an amp range 10 to ~ 140A and preferably invertor / thyristor control, in addition a small plasma cutting torch would be an advantage.

Have a look at the ESAB range

In answer to your question "is it worth it" IMHO NO.
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
Agree with Cliff, not worth it unless 1.you are welding frequently, and 2. you know how to. Its easy enough to get it right, but even easier to get it wrong if you dont know what you are doing, and the best (only?) way is to be taught properly.

The cheap welding machines from e.g. A***s are a waste of money for all but the smallest jobs.

And get a decent pair of goggles of the right type for the work your are doing. I used the wrong pair when i was doing a bit of electric arc brazing once, and ended up at the local A&E 6 hours later in real pain - furtunately no permanent damage. Not an experience I would either recommend, or repeat!
 
It really depends what you want to weld as the requirements are quite different for different materials and thicknesses. Also you need much more than a 13 amp plug power supply for all but the smallest welding sets.

In general you get far better penetration with conventional stick welding and it is possible to weld steel and stainless steel but requires quite a lot of practice and you can't weld aluminium. If you only have a 13 amp plug just buy the biggest transformer set that will run on it which will probably weld up to 4mm. It is usually obvious to the operator when a weld is satisfactory. A bad weld is a real pain to grind out and you would be advised not to weld repair anything unless you are confident about your skills or do not mind scrapping the component.

Mig welding is ok for thin sheet but I think the mechanisms on cheap sets make them unreliable and difficult to use. Peneratration is very limited on low power amateur sets. Gases in small bottles are expensive but you cannot skimp on the gas shield so having a friendly co2 supplier (Pub?) is useful Argon etc is very dear. I dont have experience of the gasless sets. I have actually managed to weld aluminium successfully but it takes a lot of practice to get a good result. I would be doubtful about using amateur MIG for anything that is load bearing. A bad weld is easier to recover than with stick welding as there is no slag. But you still have to grind away mistakes.

TIG is very expensive to set up and run and has limited applications so I doubt you are likely to proceed along this route.

I would suggest going on a diy welding course would be a huge benefit. Otherwise a good basic library book and get the largest transformer set that will run off your power supply to practice stick welding mild steel. You will always find the odd job that will recover your outlay eventually.

Like painting preparation is everything and takes 90% of the time. If you havent set everything up correctly you cannot do a good job. That includes being comfortable and supporting the cables properly (probably over your shoulders) so that they don't drag on your welding hand.
 
Taught myself Tig on stainless. It is worth it. You need to do a lot of reading and stay safe. Fumes, thoriated electrode grinding!, radiation burns, eye damage.

You will need a lot of other tools to make the joints as accurate as possible. Welding fresh air is not easy!

Turned out well, and was overall a tiny fraction of the cost of having the parts made. It was fun also.

Met a magician 6 months later that only had an old transformer and SS sticks that were a bit damp. His welds were better than mine. Good tools really help but skill goes a lot further.
 
Thanks very much for all your replies, guys.

I think that you have answered my questions and that it is really not worth it for the type of jobs that I was intending without at least attending some sort of training course first. Here in Italy night schools are not plentiful and I have yet to see any offering the sort of courses that are offered in the UK (e.g. bricklaying, metal work e.t.c.).

Thanks a lot for the rapid and details answers; I'll stick to drafting up the drawings and getting stuff made by locally for the time being.

Alan.

P.S. Welding looks so easy on Discovery Channel ..... people knocking up motorbikes, cars e.t.c. in five minutes !!!!!
 
"TIG is very expensive to set up and run and has limited applications so I doubt you are likely to proceed along this route."

Come again? /forums/images/graemlins/grin.gif I do not know where you get your information from but I suggest you do a little more research before you present misinformation.

GTAW is the ONLY way to go.

As for small sets being limited, I better let Shell know as a few years ago I was on a LNG plant where the majority of the site welding was done with portable, 240V single phase invertor sets (16amp plugs). This approach was then taken on to other plants as productivity was not affected and the ease of moving the machines (the machines were so small and light you could pick it up and carry it with a strap over your shoulder and they still had the capacity to burn 4 and 5mm rods and produce welds upto 4" thick.
--------------------
hammer.thumb.gif
"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>
 
For aluminium I use a propane gas torch and a process called Lumiweld. Look here for details. It is a bit like soft soldering but does in fact produce a true weld. It works on sheet material and castings and is much used by vintage motorcycle repairers for dealing with things like cracked gearbox cases. The trial kit is fairly cheap. To use it you clean the alloy to be welded with a stainless steel wire brush, clamp together and heat, then apply the Lumiweld rod and scratch the surface of the parent metal with a stainless rod to scrape through the oxide layer, to allow the weld to form.
 
Sounds like just what I want.

Fitted a Ford XLD 1800 engine (from ebay) in the boat I am building.

Starts great , runs great but after fitting there was a small oil mark in the bilge. There is a crack in the alloy sump about 10mm long. I have had the engine too long to complain at the seller. Probably got damaged when being transported to me.

I have been quoted £70 for a sump from a scrap dealer.

I think that if I remove the sump, clean up the crack and use this stuff it should do the job.

Iain
 
You will need a lot of heat for the sump if it is cast, also there will be oil in the crack. Beg, borrow or steal a big propane torch for background heating. Even if the sump is sheet metal unless it is very thin it will conduct heat away from the work area very fast, so you need to have a big torch and heat it evenly. If the sump is cast metal, grind out the crack first with a thin cutting disk. Lumiweld will fill a gap if you take care. Thin sheet metal is the hardest stuff to join, as it is easy to melt a hole in it with the torch. Lumiweld works at a temperature not far below the melting point of most alloys.
 
Yes thanks,

any advice is appreciated.

I have experience on welding cast iron on road repair equipment (Scarifier teeth which required preheating of the whole assembly), plating rusty cruiser hulls after hirers ran them aground. I have welded stainless all on various powers and various types of stick welders.

If and when I go ahead with it, I anticipate having to drill at each end of the split to stop it spreading and will be using a dremel (equivelent) to clean the split out. Will still require some luck.

It's a ford alloy sump probably cast so as you say I will have to be very careful not to burn holes through it and will also have to preheat the whole assembly.

I still have the back up position of just replacing the sump if everything goes pear shaped.

Cheers

Iain
 
Do not be too frightened of melting it, more jobs fail through too little heat than too much. The instructions with my Lumiweld kit are now lost but were pretty comprehensive. A good way of telling if the temperature is right is to cut a few small pieces of the welding rod, heat the job and drop one on. If it melts and forms a globule like a rather dull looking drop of mercury, (without the blow-lamp flame playing on it) then the job is up to temperature. You simply keep heating until the job passes the above test.
 
i agree, done my fair share on anything from a wheeled lincoln set to a carriable two stroke engine driven beast, also have used cheap transformer 13 amp supply thing, all useable and stick welding on mild, cast iron and stainless is relatively easy to learn. the cheaper the set is the less reliable and powerful it is.
stu
 
Yes, ark welding is relatively easy. It's much more difficult to use mig or tig especially when the wind is blowing.

I have an old (over 25 years) original SIP 140 amp welder

Been used for everything. Replaced leads etc but never any problems and it has been very abused now worth virtually nothing.
Don't make them like that now - everything is value engineered to the extreme.

Toying with buying an invertor but cannot really justify it.

Also, in the past, have used petrol/diesel generator welders, invertor welders and good quality mig's.

But, now that I am retired the old SIP is now used for most things. I have however now got one of those self darkening helmets (magic).

Had to borrow a tig to use on the pushpit/pulpit of the boat I am building however.

It's a matter of horses for courses.

Iain
 
[ QUOTE ]
There is a crack in the alloy sump about 10mm long. I have had the engine too long to complain at the seller. Probably got damaged when being transported to me.

I have been quoted £70 for a sump from a scrap dealer.

Iain

[/ QUOTE ]

Iain,
Drain the sump oil. Grind out the crack slightly, this is optional, you may have a fin or something in the way. Spray the area with brake cleaner, watch your eyes. Fill the crack or area with Devcon plastic steel epoxy filler. /forums/images/graemlins/cool.gif
 
I rue the day I sold my old arc welder. It was an Oxford oil cooled one and for some reason welding with it was like running treacle into the joints. I find my air-cooled buzzy box much more awkward to use.

418-25weld.jpg
 
You must log in or register to reply here.

Share this page

Top