Carbon air arc gouging

[WALM]

looking to get into gouging, not sure where to buy equipment, and not sure what I need. I want to be able to remove worn pins. They would be about 150mm diameter and about 500mm length. So lots of amps but not sure how many!

 

[Richard.]

It can be done with both a constant current and constant voltage power source but constant current is better and safer on the power source.
You need a big power source for arc air I'd suggest 500 amps as a real minimum and 700-800 been more realistic. A 6mm Carbon is tiny yet still needs 4-500 amps to be effective.
It's all about angle of attack. Depth is achieved by going more straight on and burying the carbon. In skilled hands it can be an accurate process but it's easy to make a real mess. I've done loads of it and bear lots of scars to show for it. Wear serious Ppe and invest in extraction.

 

[WALM]

Ok that is great info thank you. Videos I have seen make it look like a very messy process.

 

[WorkshopChris]

In skilled hands it can be an accurate process but it's easy to make a real mess. I've done loads of it and bear lots of scars to show for it. Wear serious Ppe and invest in extraction.

I can second that, used the process one to gouge out some weld, its very easy to make a big mess until you get the hang of it.
And as richard said PPE then think of ppe on steroids. When that molten metal blows back it can and will find every little gap or crease to sit in till its burnt its way in.
It can make a oxy acetylene torch look like a low wattage soldering iron in comparison.

 

[WALM]

Looks like £30k worth of genny welder to get anywhere close to 800 amps. Possibly just go for a thermal lance??

 

[WorkshopChris]

How often would you need to use this?
Could you buy the kit then hire in a power source as needed.
Should lots about in that size range.

 

[WALM]

You have a point there, that could work. Not very often but would be nice to have my own to practice

 

[davidjohnperry]

put my ideal of running off the 300 then

 

[WorkshopChris]

Do you have a good workshop powersupply or does it need to be deisel.
Big power sources do come up from time to time and two matched power sources can be couples together.
Its something i looked into once buts its getting harder to find people who know what they are talking about with this heavier stuff.
I think Jim Davey has dealt with this sort of thing and may be able to help.

 

[HughF]

300 will gouge quite ok David, remember it will probably run 500a flat out.

Carbon arc torch can be had for 20 quid from aliexpress, then you need some carbons (eBay) and a compressor...

Vantage 400, commander 500, sae400 or a big 3 phase inverter machine required.

 

[pedrobedro]

I used to work in a foundry on a 1400 amp arcair machine smoothing heads on castings after burning bay cut them off. The rods were 1 inch and the dust they kicked up was unbelievable. Serious extraction and PPE, reflective suit and gloves etc.

 

[Richard.]

300 will gouge quite ok David, remember it will probably run 500a flat out.

Carbon arc torch can be had for 20 quid from aliexpress, then you need some carbons (eBay) and a compressor...

Vantage 400, commander 500, sae400 or a big 3 phase inverter machine required.

500 amps flat out will not withstand much Hugh trust me.
It's such an aggressive process on power sources with big lumpy surges of max current to no current to max current and like I say a tiny 6mm will easy need 500 amps to gouge properly. I'd honestly say you need at least 500 and that's for a rare blast.
I used to use 1250 power sources pulling 1000 amps from a 13mm carbon and we had a few of them go over time. Oh and don't forget to the op. Add a good set of ear defenders on the Ppe list.
Gouging with proper current makes a 9inch grinder sound quiet.

 

[Richard.]

I used to work in a foundry on a 1400 amp arcair machine smoothing heads on castings after burning bay cut them off. The rods were 1 inch and the dust they kicked up was unbelievable. Serious extraction and PPE, reflective suit and gloves etc.

Wow. 1inch carbons. That's proper hard core stuff.

 

[Bsmith]

Used to have a diesel Lincoln 600 amp at full grunt for cutting 3/8" thick plate with air-arc, that was about all it would do.

 

[2tpmafia]

Would recommend thermal lance as well for pins. Just run of oxy cylinder. Burn out centre of pin then can push pin out easily normally.

 

[WALM]

Do you have a good workshop powersupply or does it need to be deisel.
Big power sources do come up from time to time and two matched power sources can be couples together.
Its something i looked into once buts its getting harder to find people who know what they are talking about with this heavier stuff.
I think Jim Davey has dealt with this sort of thing and may be able to help.

I have lovely three phase in my workshop, this is fine. i run a 420 nexus mig in there. i'm also on the road with an arcgen 300/compressor/gas etc.... she is old but does everything i currently need. i'm looking at upgrading my van and power source, just to be able to tackle more. i do want to do some beveling on cracks in booms etc... so although i think a lance would be great for some bits and would be silly not to have considering my BOC bills, i do still need to get into gouging.

 

[WALM]

maybe keep the big gouging jobs to workshop only and go for a three phase inverter. where on earth do you start for 1000a plus machines??

all expensive stuff i'm sure, at least i can make a start on the pins with a thermal lance

 

[Richard.]

You'll only need 1000 amps or more if your getting into decent sized carbons. Sub arc power sources are pretty common for gouging but a lot of them I believe are constant voltage. This is ok but you don't have as much control over the current you draw. With a cc power source you can set the amps a bit like a stick electrode and it will either be right or not. With cv your amps are drawn depending on how far you dig into the job so you can max it out quite easily if you start digging deep. Remember if you do go big sub arc power sources your gonna need 63 amps mains supply coming in more likely.

 

[WALM]

ok great info, lots of thought needed i think. thanks for everyones help. constant current sounds like the way to go... might start on some tiny carbons on the 420 nexus to get me going.

 

[HughF]

Vantage 400 on the truck will cover everything you can throw at it, and cover running carbons up to 8mm which is fine for gouging out welds... Thermic Lance for pins, definitely. Vantage 400 will also give enough 3 phase to run a powermax 85 for chopping up plate.

Not cheap, but a good engine drive. I have a smaller 250a multiprocess Lincoln engine drive and it's a bloody good machine.

Also, if you just want to gouge for crack removal, consider a plasma cutter with a gouging setup.