I have a small building project where I need to get a generator for welding work on roof steels.

I thought I could just walk in buy a 5Kw generator that would do the job. Apparently, a 5 Kw generator will not do the job which is unfortunate because I had intended to use the generator to power the building after completion.

Can anyone advise me what options I have.

Try a welder with inverter they use less power regards Russell

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Borrow, hire or buy a petrol / diesel welder. You won't be able to power the house with it afterwards so options 1 and 2 are going to be your best option.

Learn to gas weld, oxy-propane is popular here and the kit / gas is readily available.

How far away is your nearest electricity supply?

Borrow, hire or buy a petrol / diesel welder. You won't be able to power the house with it afterwards so options 1 and 2 are going to be your best option.

Learn to gas weld, oxy-propane is popular here and the kit / gas is readily available.

How far away is your nearest electricity supply?

The nearest electricity supply is over 1km away. This is a small 'holiday bungalow' we are building as a prelude to building the main house and getting PEA supply. I know I will need a transformer and I am no rush to get supply. We will need a generator for the bungalow and a 5Kw unit would suffice. It will not suffice for for the welding and cutting that needs to take place over the course of about a week. We were planning to hire a 300 amp welder but it is a conundrum trying to match the power source.

I am surprised that you will need 300 amps.

Rule of thumb is one amp per thousandth of an inch. Or 40 amp per millimeter

This works out to 250 amp to weld 1/4 " - .250" or 240 amp - 6mm

Of course, these are just ballpark - vertical up I like to use a little more amps, but for horizontal it works out good enuf.

If you can get by with less amps, you would need a smaller genset and welder both. And if not welding continuous, you can get by with a lower duty cycle machine.

What thickness of metal are you using ?

I am surprised that you will need 300 amps.

Rule of thumb is one amp per thousandth of an inch. Or 40 amp per millimeter

This works out to 250 amp to weld 1/4 " - .250" or 240 amp - 6mm

Of course, these are just ballpark - vertical up I like to use a little more amps, but for horizontal it works out good enuf.

If you can get by with less amps, you would need a smaller genset and welder both. And if not welding continuous, you can get by with a lower duty cycle machine.

What thickness of metal are you using ?

I hope you consider it related, just looking for a good answer.

Very soon will be welding A frames for a garage roof and will be using roof tiles, not the one and a half metre by sixty cm corrugated boards. The roof peak length will be six metres and the rafter frames 35 x35 at 2 to 3 mm thickness. Would one every metre be overkill or would one and a half metres be sufficient. Garage will be four metres wide.

I would go with the one metre spacing. In a building that size, the additional cost would be minimal.

3mm material is close to 1/8"- .125" so around 120 amp would be about what you would need.

Be sure to clean off any paint around welds before weldlng, and remove flux - prime - and paint welds afterward.

I would go with the one metre spacing. In a building that size, the additional cost would be minimal.

3mm material is close to 1/8"- .125" so around 120 amp would be about what you would need.

Be sure to clean off any paint around welds before weldlng, and remove flux - prime - and paint welds afterward.

When I get around to it I will probably have bought myself a MIG welder, lot less hassle and a lot less cleaning after welding. I did post before on trying to find one at a decent price but here in LOS the best I could find (cheapest) was around 40,000 baht. I will probably have to bite the bullet and go that way unless anything else comes out of the wood work.

Cheers

I would go with the one metre spacing. In a building that size, the additional cost would be minimal.

3mm material is close to 1/8"- .125" so around 120 amp would be about what you would need.

Be sure to clean off any paint around welds before weldlng, and remove flux - prime - and paint welds afterward.

When I get around to it I will probably have bought myself a MIG welder, lot less hassle and a lot less cleaning after welding. I did post before on trying to find one at a decent price but here in LOS the best I could find (cheapest) was around 40,000 baht. I will probably have to bite the bullet and go that way unless anything else comes out of the wood work.

Cheers

But of course the added complication of needing gas in addtion to the filler wire..either argon or CO2 or in combination ie MIG/MAG set up..to be honest...if its structual work...ie roof trusses etc...just go with SMAW...better just rent a diesel powered weldling machine if plug in power is a problem

5 kw is more than big enough, I ran my house on that for a couple of years that included using a welder, you dont need a massive beast of a welder to do your roof A frames, as stated above 120 amp is big enough and you can run that on a 5kw,

5 kw is more than big enough, I ran my house on that for a couple of years that included using a welder, you dont need a massive beast of a welder to do your roof A frames, as stated above 120 amp is big enough and you can run that on a 5kw,

120 amp may or may not be enough....also depends on the size of the electrode he is using... ...

For a one time offer only....Soutpeel's guide to eletrode selection vs plate thickness vs current...this is applicable to SMAW only (Stick for those who dont know what SMAW is)

And if someone can't work with the imperial sizes let me know and will redo this in metric.....

Electrode diameter Amp range Plate thickness

1/16" 20-40 up to 3/16"

3/32" 40-125 up to 1/4"

1/8" 75/185 over 1/8"

5/32" 105-250 over 1/4"

3/16" 140-305 over 3/8"

1/4" 210-430 over 3/8"

5/16" 275 -450 over 0.5"

120 amp may or may not be enough....also depends on the size of the electrode he is using... ...

Quite right, many variables come into play.

As previously posted, I gave ballpark figures to help the OP in choosing an appropriate machine.

120 amp may or may not be enough....also depends on the size of the electrode he is using... ...

Quite right, many variables come into play.

As previously posted, I gave ballpark figures to help the OP in choosing an appropriate machine.

Yeap just did the same but my table came out all c*cked up for some reason..