View Full Version : Welding 5-8mm steel box-section tubes

09-05-2015, 03:26 PM
I have no welding experience yet, but intend to learn.
Ultimately, when I've done some small projects for experience, I want to put together a gantry-type cnc router... Probably with 5mm thick box section tubes.
I have no welder, and there seems to be a load of choice/advice on whether to use mig/tig/arc.
I have no welder rig yet, need to get one. What do you folks recommend ?

09-05-2015, 04:59 PM
I have all types of welding gear gas oxy/acy arc welder mig and tig

but for a starter set get a mig 160-180 amp and a rent free large bottle
you should be able to get that for 100-200 and 100 for the bottle or rent one from boc if you think you may only want it for the one project.. or you dont mind paying 40 a year for ever
This will do all you want with mild steel and be nice and easy for you to learn with
Dont think about gas free sets or using the small disposable bottles.
and if you can get a set with a euro torch though that may be difficult at 200 budget

My 2p worth


09-05-2015, 07:01 PM
or buy a 50 quid stick/arc welder and a box of 2.5mm rods. and your welding, plenty of stick welding vids on youtube to get you started

Boyan Silyavski
11-05-2015, 09:32 AM
I welded half of my first frame using DC stick welder, i agree, pretty easy to learn watching you tube videos. Plus you can grind and cover the sh*t when painting so at the end you will finish with pretty frame.

Bought a proper MIG then- 250A (http://www.ebay.co.uk/itm/Schweisgerat-250A-IGBT-MIG-MAG-MMA-230V-GRATIS-BINZEL-ESAB-/221765062564?pt=LH_DefaultDomain_77&hash=item33a23a4fa4)and changed the Chinese gun with bran new Wurth 250A gun, which is re-branded Binzel gun. Obtained from a boot sale for say 50 euro but similar could be obtained for 150euro new on ebay.

Wow, thats a monster combination for a serious manufacturing. Welds 10mm stuff like butter and it has never stopped due to duty cycle limitation, i believe it was something like 100% on 200A

Its good for aluminum also, due to the high amperage plus you will have the second gun for aluminum, when you upgrade one day the one that comes with the unit, which is short by the way, you really will need something like 4m gun hose. The unit on the link is exactly like mine though rebranded.

11-05-2015, 10:43 PM
Hobbyweld do a rent-free tri-gas bottle for 60 plus about 30 for the gas.

09-11-2017, 11:03 AM
I went to the Tig route so that I could weld Steel but also be able to weld Aluminium, Although I still haven't done that as yet. Tig welds look nice and are strong But mig can make beautiful looking welds too , but Tig is harder to learn because you have a foot control (Normally) the torch in one hand and the welding rod in your other hand so each is doing something.

Mig is more forgiving when welding where as with Tig everything has to be as clean as possible to get a good weld, Firstly cleaning the weld material with Acetate before welding.

I am still learning and most of the time things look okay and stay stuck together, well I have blown through material that is thin so thicker material is easier to learn welding on.

Don't forget to budget for a welding helmet and Good Welding gloves and always wear clothes that cover you up. welding can cause Sunburn type burns on your skin.

Most definitely look on the forums because I didn't realise that welding zinc coated items e.g. Nuts and bolts is dangerous to your health so grind Zinc off because you do it and wear a mask if not sure.

Tig is a Higher cost than Mig because you have to use a different gas which the Price is higher using Argon and the Startup costs are higher. I brought a cheaper Chinese tig from ebay and Its fantastic and I still love how much you can make with these things. but still cost a few Hundred pounds but I want it to last for years to come.

Our local college at Coalville does a Welding course sometimes and that is worth looking at your local college first to see if there is a course and they will teach you but also let you get your hands on the kit before you buy.

I brought a rent free bottle from Barnett welding supplies a small family run business and you pay for the bottle for the first time but then it is the Delivery and the cost of the gas.


The gas goes pretty quickly to a bigger bottle is better it lasts in the bottle so can still be stored.



09-11-2017, 11:56 AM
I brought a rent free bottle from Barnett welding supplies a small family run business and you pay for the bottle for the first time but then it is the Delivery and the cost of the gas.


I did similar, but used Hobbyweld as they have a supplier very near to me. My last bottle of argon mix lasted over 3 years, which is better than the disposables ( for ) which can also empty themselves spontaneously.

10-11-2017, 12:00 AM
With my Smashweld 180 MIGs, using appropriate gas and wire, I weld Steel, Stainless Steel, Cast Iron, Brass, Bronze, Copper and Aluminium, sometimes I also MIG Braze Steel.
I don't know why people think MIG is more limited than it is.

17-07-2018, 12:48 PM
I am new to welding - been at it about a year now.
Started off with stick inverter, then bought a TIG torch and bottle of Argon to go with it.
I found I wasted too much gas having to control it manually with a knob on top of the torch, and lift TIG was a pain.
Then I upgraded to a DC TIG.
I love it. It is a very clean process. Minimal if any cleaning afterwards. No sparks so I can do it in the garage. The metal has to be very clean. No welding rusty panels for MOT.
I haven't got a foot control. I have been told it is not necessary if only welding steel.

TIG allows a great range of control I have welded everything from 7mm plate and 3mm box section, to the tips of Stanley knife blades together.

I still have a lot to learn. I am fairly successful at sticking the metal together and getting pretty (and I hope strong) welds. My biggest problem is metal distortion. Maintaining the accuracy would be my biggest concern if I was to tackle a frame for a CNC.

17-07-2018, 05:53 PM
To start I would go with a stick welder (arc welding)

For the price point - say 150 to 200 you can weld all types and thicknesses of steel. a mig to weld over 5mm you are looking at some serious investment + the bottled gas

You can often buy a TIG torch for many of the good Arc welders and do TIG at a later date - but you will need gas ( Argon or Argon Helium mix - this can be used on both steel and aluminium)

Many cheap MIG machines claim they can weld 5mm+ thick but they are really poor welds as the metal does not pool enough to create good adhesion.

You don't need gas to use stick welding

The welding electropdes (sticks) are the cheapest consumable. Normally depending on the thickness of the steel usually determines the thickness of the rod - however people can have preferences - i.e. I like using 2.5 or 3.2mm for most welds unless less than 1.5mm thickness

Stick welding can weld through rust paint ect (however - all steel should be cleaned prior to welding otherwise you will get foriegn objects and porosity that weaken the weld) - but it is the most forgiving

Go watch the videos @ weld.com and follow some of the instructions

There are things like DC+ or DC- (which way the torch and the return is plugged in)
How many amps to use for different thicknesses
Types of weld angles and joints
Type of electrodes (sticks) i.e in UK ppl mainly use 6013 however in the states they use 7018 - they differ as to how much penetration and what position you can weld.

hope this gives you something to look at :o)