Cost of welding

[C08]

I have been making some davits mounting brackets in 100mmx12mm aluminium alloy and I now need to get them welded up. I have made them in a general construction quality that is reputedly fairly corrosion resistant and easily weldable. In the normal course of events I would get them done with a boaty welder near to the boat whose rates in the past have been "friendly boat club member rates" but I need to get them done before I go down to the boat again and I am wondering what the commercial rate for this welding should be. Approximately 12 runs of weld each 100mm across.
I have no idea about this and it would be good to have a figure in mind before I go and see the welder I have in mind (in Bredbury, Stockport)?

 

[NormanS]

I have very little experience with alloy, but do weld mild and stainless steels. The cost is more likely related to the time of setting up and tacking. If you have it all properly prept, the actual welding won't take long.

 

[Lakesailor]

I paid £35 per hour for someone to weld a crack in an alloy gearbox bellhousing. He used TIG and charged me an hour. He apologised for charging an hour, but he said he had to use a lot of gas to get the material heated enough to weld without cracking.
Probably not an issue with your job.

 

[Rigger Mortice]

Depending how it all fits together your welder may also need to grind the edges to ensure that the weld has good penetration. Grinding could easily cost more than the welding itself.

Don't tell him it's for a boat. Dream up some other purpose for them.

 

[prv]

Depending how it all fits together your welder may also need to grind the edges to ensure that the weld has good penetration. Grinding could easily cost more than the welding itself.

But presumably the OP could do that part himself?

Pete

 

[Lakesailor]

.....and the welder will say "Oh, someone's ground the meat off the faces"

 

[C08]

Depending how it all fits together your welder may also need to grind the edges to ensure that the weld has good penetration. Grinding could easily cost more than the welding itself.

Don't tell him it's for a boat. Dream up some other purpose for them.

I do not quite understand this grinding-is that to remove oxidation at the aluminium alloy surface? Thanks for responses.

 

[prv]

I do not quite understand this grinding-is that to remove oxidation at the aluminium alloy surface? Thanks for responses.

No, it's to create a beveled joint that can be filled with weld.

The simple example would be butt-welding two thick plates together edge to edge. If the edges are square, the weld will only join the top of the joint (it won't just lie on the surface, as it should penetrate to some extent, but it won't penetrate the full depth of the plate). If the edges are made to slope, so that only the bottom of the V is touching to begin with, then the whole V can be filled with weld and the resulting piece of metal will be solid all the way through.

The same principle applies on joints other than butts, and even on butts that's a simplified explanation as you might bevel and weld from both sides. And I'm only a novice hobbyist welder so I'm sure the details are more complicated.

Pete

 

[C08]

No, it's to create a beveled joint that can be filled with weld.

The simple example would be butt-welding two thick plates together edge to edge. If the edges are square, the weld will only join the top of the joint (it won't just lie on the surface, as it should penetrate to some extent, but it won't penetrate the full depth of the plate). If the edges are made to slope, so that only the bottom of the V is touching to begin with, then the whole V can be filled with weld and the resulting piece of metal will be solid all the way through.

The same principle applies on joints other than butts, and even on butts that's a simplified explanation as you might bevel and weld from both sides. And I'm only a novice hobbyist welder so I'm sure the details are more complicated.

Pete

Right I am starting to understand this. As all the welds are one strip butting up against another at say right angles to form a T, I had assumed that the fillet of weld would be in the right angle and that grinding to form a further V would not be necessary. Are you suggesting that I should v the strip butting the other to further grind the end? Thanking for taking the time to clarify this.

 

[prv]

Are you suggesting that I should v the strip butting the other to further grind the end? Thanking for taking the time to clarify this.

I'm not sure, I'm only a baby welder

It probably depends on the thickness of the plate, and perhaps what forces will act on the joint.

Pete

 

[Hugh Foulis]

I think my approach would be to go and see the welder and ask how he would like the job prepped to make life as easy as possible for him. And then get a ballpark price too.

 

[prv]

I think my approach would be to go and see the welder and ask how he would like the job prepped to make life as easy as possible for him. And then get a ballpark price too.

+1

Pete

 

[Rigger Mortice]

Right I am starting to understand this. As all the welds are one strip butting up against another at say right angles to form a T, I had assumed that the fillet of weld would be in the right angle and that grinding to form a further V would not be necessary. Are you suggesting that I should v the strip butting the other to further grind the end? Thanking for taking the time to clarify this.

If you butt the two pieces together and then put a fillet down both sides, you will not get the weld right into the joint. It will therefore not be as strong as possible and, as the plate is 12mm thick, there will be a big strength difference.....we are maybe talking about a factor of 3 or 4 times the strength.

The metal could be prepped in many different ways and, as suggested, it's therefore best to talk to the welder.

 

[Lakesailor]

Which is why I said.....

.....and the welder will say "Oh, someone's ground the meat off the faces"