Painting steel beams

[sometimewoodworker]

4 hours ago, canopy said:

Any comments on the quality of this weld? The good, the bad, the ugly. Just anything.

 

Ugly it certainly is. Bad or good is a bit more difficult to tell.

 

It's not really clean enough to be sure, a wire wheel on a drill or angle grinder should clean it enough to get a better look.

 

There seems to be some porosity, though it may not be a problem. The slag hasn't been completely cleaned off and could be hiding something.

 

Edited May 31, 2019 by sometimewoodworker

[CGW]

Not pretty is it, obviously the rod burner is not a "welder" as such. He has a "reasonable" run going where circled, though you would be hard pushed to say it was "good", porosity visible, not undercut - fit for purpose? should be ???? 

 

[mogandave]

I agree, assuming this was vertical, which it looks like.

Be sure to send a photo of his overhead....

As I remember, this is blocking between the rafters, yes? If so, it will be fine.

[canopy]

Here is the same weld after cleanup. This flat matrix of beams makes a flat roof to support a floor on top--no rafters or trusses. Many of these welds are not simply to hold the beams together, but load bearing. For instance a beam that is spliced end to end to extend its length. Beam loading can be upwards of two tons considering dead load and live load on maximum spans.

 

[mogandave]

Here is the same weld after cleanup. This flat matrix of beams makes a flat roof to support a floor on top--no rafters or trusses. Many of these welds are not simply to hold the beams together, but load bearing. For instance a beam that is spliced end to end to extend its length. Beam loading can be upwards of two tons considering dead load and live load on maximum spans.
 

A load-bearing beam that is spliced end to end should be plated.

[canopy]

2 minutes ago, mogandave said:

A load-bearing beam that is spliced end to end should be plated.

That sounds like valuable advice. The frustrating thing is I talked to a thai civil engineer and the welder who has worked all over the world and they both said a simple butt weld is fine for a splice. So now I took a cursory look around the web at splices and see a lot of variations: union plates, cover plates, bolted plates, etc. So I appreciate you experts again if you can recommend something that can be retrofitted onto the already welded and erected beams? And if it is cover plate(s) how should the plate be sized vertical / horizontal? And which sides should get plated?

 

[mogandave]

That sounds like valuable advice. The frustrating thing is I talked to a thai civil engineer and the welder who has worked all over the world and they both said a simple butt weld is fine for a splice. So now I took a cursory look around the web at splices and see a lot of variations: union plates, cover plates, bolted plates, etc. So I appreciate you experts again if you can recommend something that can be retrofitted onto the already welded and erected beams? And if it is cover plate(s) how should the plate be sized vertical / horizontal? And which sides should get plated?

 

 

A simple butt weld is okay if it has a quality weld all the way around.

 

If they weld it on the ground, flop it over to weld and then hoist it up it should be okay.

 

I thought the structure was 6m long, why the splices?

[canopy]

There are eaves extending past the walls so total length of beams can be 8M but maximum unsupported span is 5M which is the span between the walls.

 

The splices were actually welded all the way around and were spliced when laying on the ground (or more accurately laying on a dead straight beam on saw horses) and then hoisted up after.

 

[shaemus]

55 minutes ago, canopy said:

There are eaves extending past the walls so total length of beams can be 8M but maximum unsupported span is 5M which is the span between the walls.

 

The splices were actually welded all the way around and were spliced when laying on the ground (or more accurately laying on a dead straight beam on saw horses) and then hoisted up after.

 

Have you started work on this allready? 

 

If you haven't ill send you some images of the work I have had done. It'll potentially put to bed alot of the contradictory advice you have been given. 

 

As for capping the end of your rafters beam purlins or trusses. It's not a bad idea personally I'd do it as I have done, I had to drill a 3mm hole after all the work was done at the lowest point as there was water dripping from one. So I drilled a hole and maybe a litre came out. 

 

If you go for galv steel. Ignore the chaos comment about C02 burning zinc away. He is wrong, carbon does not burn it mearly provides a shield around the arc so Oxygen does not mix with the various metal as they a metled. Posrosity will occur which is very common on welds I have seen here in Thailand, they call it ant eyes. 

 

Your structure sounds quite small and I might say you are possibly over thinking things. But 1 thing is certain using arc / stick / rods will produce loads of heat and unless your man is prepared to be tacking all steels and the moving around the structure to minimise heat transfer warping will occur. 

 

As for the comments abouts who cares anyway about quality. It takes no more time to do a good job. Just skill or an aptitude to want to know how to do it properly. 

 

MIG welding is the answer to your dramas. Use a flux core wire (no gas) 

 

You might want to visit welding tips & tricks on you tube. Very informative 

 

Let me know if you want images of full welds

 

Shaemus

[mogandave]

Have you started work on this allready? 
 
If you haven't ill send you some images of the work I have had done. It'll potentially put to bed alot of the contradictory advice you have been given. 
 
As for capping the end of your rafters beam purlins or trusses. It's not a bad idea personally I'd do it as I have done, I had to drill a 3mm hole after all the work was done at the lowest point as there was water dripping from one. So I drilled a hole and maybe a litre came out. 
 
If you go for galv steel. Ignore the chaos comment about C02 burning zinc away. He is wrong, carbon does not burn it mearly provides a shield around the arc so Oxygen does not mix with the various metal as they a metled. Posrosity will occur which is very common on welds I have seen here in Thailand, they call it ant eyes. 
 
Your structure sounds quite small and I might say you are possibly over thinking things. But 1 thing is certain using arc / stick / rods will produce loads of heat and unless your man is prepared to be tacking all steels and the moving around the structure to minimise heat transfer warping will occur. 
 
As for the comments abouts who cares anyway about quality. It takes no more time to do a good job. Just skill or an aptitude to want to know how to do it properly. 
 
MIG welding is the answer to your dramas. Use a flux core wire (no gas) 
 
You might want to visit welding tips & tricks on you tube. Very informative 
 
Let me know if you want images of full welds
 
Shaemus

You are welcome to your opinion, but I have been welding galvanized steel for 25 years, the last 18 managing a sheet metal fabricating facility here in Thailand, and you can see our products all over Thailand, Singapore, Hong Kong, Dubai, Taiwan, Korea and India.

We (and most everyone in the industry) MIG weld galvanized using CO2 & hard wire.

I’m not saying you can’t MIG galvanized using flux-core, you can, and (assuming you have a decent unit) flux-core can be better working outside in the wind.

All that said, the OP has all the material and has already contracted a builder that has (as I understand it) started work. The builder is not likely to buy all new equipment, nor are they likely to hire more competent welders. I think the OP wants to make the best of the situation without adding significant cost, effort or frustration to the project.

[CGW]

4 hours ago, shaemus said:

As for the comments abouts who cares anyway about quality. It takes no more time to do a good job. Just skill or an aptitude to want to know how to do it properly. 

Agree 100% - though some will disagree on here! preferring to justify poor Thai "workmanship"!

[canopy]

9 hours ago, shaemus said:

Your structure sounds quite small and I might say you are possibly over thinking things. But 1 thing is certain using arc / stick / rods will produce loads of heat and unless your man is prepared to be tacking all steels and the moving around the structure to minimise heat transfer warping will occur. 

I want a safe, long lasting structure from design to welding to painting. I would not call this over thinking. The welder mentioned he believes the thickness of these beams (3/16 of an inch) mitigated the usual warping issues.

 

[shaemus]

9 hours ago, mogandave said:

 

You are welcome to your opinion, but I have been welding galvanized steel for 25 years, the last 18 managing a sheet metal fabricating facility here in Thailand, and you can see our products all over Thailand, Singapore, Hong Kong, Dubai, Taiwan, Korea and India.

We (and most everyone in the industry) MIG weld galvanized using CO2 & hard wire.

I’m not saying you can’t MIG galvanized using flux-core, you can, and (assuming you have a decent unit) flux-core can be better working outside in the wind.

All that said, the OP has all the material and has already contracted a builder that has (as I understand it) started work. The builder is not likely to buy all new equipment, nor are they likely to hire more competent welders. I think the OP wants to make the best of the situation without adding significant cost, effort or frustration to the project.
 

 

I don't disagree at all. I was putting right the statement of C02 burning zinc. If I have written my statement correctly, then I have stated that I would use glav steel all day long and MIG weld, either with gas or gas less wire. There is quite a large amount of evidence that has less MIG is stronger that C02 or argon mix. The use of portable machines without gas bottles is weighed off against cleaning the slag off

 

As you said it acts as as shield. Stopping porosity. In the welds. 

 

As you say the advantage of using flux core is the lack of need for gas and being able to use in windy conditions  (on a roof) 

 

The OP has had generally good advice. Maybe apart from the material choice. 

 

Most of the galv steel I can buy is coated in Vietnam and has a very thin coating. 

 

A friend of mine had his steel dipped for his roof, and at that time the dippers weren't able to give an indication of the coating thickness. They charge by pre and post weighing the steel to work out a price. Bonkers but T. I. T. 

 

Shaemus

Edited June 1, 2019 by shaemus

[CGW]

15 hours ago, mogandave said:

All that said, the OP has all the material and has already contracted a builder that has (as I understand it) started work. The builder is not likely to buy all new equipment, nor are they likely to hire more competent welders. I think the OP wants to make the best of the situation without adding significant cost, effort or frustration to the project.

Nail on the head! OP has put all the groundwork and planning into the job & I for one admire how he has gone about it, but all the planning and the best materials in the world are mute if you don't have the right people to do the job, TIT - hard to find the right people, the "welder" obviously lacks the skills the OP requires to do a first rate job, I mentioned earlier that it was feasible to put a full weld all around - it is, but you have to have a "welder" that knows how to go about it, which as "sheamus" states, you need to "tack" change sides, minimise heat and know how the steel will react, as I recall the welder stated he couldn't do this, seeing his welds I have no problem believing that, the OP stated that it wasn't possible to change out the "welder" so you are stuck with his skill level, which in all honesty at the end of the day, is going to be "fit for purpose" 

[mogandave]

I don't disagree at all. I was putting right the statement of C02 burning zinc. If I have written my statement correctly, then I have stated that I would use glav steel all day long and MIG weld, either with gas or gas less wire. There is quite a large amount of evidence that has less MIG is stronger that C02 or argon mix. The use of portable machines without gas bottles is weighed off against cleaning the slag off
 
As you said it acts as as shield. Stopping porosity. In the welds. 
 
As you say the advantage of using flux core is the lack of need for gas and being able to use in windy conditions  (on a roof) 
 
The OP has had generally good advice. Maybe apart from the material choice. 
 
Most of the galv steel I can buy is coated in Vietnam and has a very thin coating. 
 
A friend of mine had his steel dipped for his roof, and at that time the dippers weren't able to give an indication of the coating thickness. They charge by pre and post weighing the steel to work out a price. Bonkers but T. I. T. 
 
Shaemus

Pre and post weight is actually the most fair way to pay, and in my opinion the best. That’s usually how they charge in the US.

With the weight differential you can calculate the thickness.

Also, I’d they flat-rate, it’s in their best interest to minimize coating thickness. By using the difference, it benefits them to maximize. Most all their cost is the zinc.

[shaemus]

2 hours ago, CGW said:

Nail on the head! OP has put all the groundwork and planning into the job & I for one admire how he has gone about it, but all the planning and the best materials in the world are mute if you don't have the right people to do the job, TIT - hard to find the right people, the "welder" obviously lacks the skills the OP requires to do a first rate job, I mentioned earlier that it was feasible to put a full weld all around - it is, but you have to have a "welder" that knows how to go about it, which as "sheamus" states, you need to "tack" change sides, minimise heat and know how the steel will react, as I recall the welder stated he couldn't do this, seeing his welds I have no problem believing that, the OP stated that it wasn't possible to change out the "welder" so you are stuck with his skill level, which in all honesty at the end of the day, is going to be "fit for purpose" 

I hope it all goes well for the OP. 

There is a saying going around. "it's the Thai way or the high way. 

 

I have read so many threads here about shoddy workmanship etc etc. 

 

I struggle to find people to work for me as I am quite remote. Anyone with any skill isn't working around here. I find it very frustrating and I often have to compromise material selection and also finish. 

 

I hope the OP gets a decent job built, there are always work round if things go wrong. 

 

When I was researching my job I spoke to lots of welders on the job site I was on. They all said for thin wall tube with stick you have to move fast to avoid the heat. 

 

I found my contractor via the main welding gas shop. All went well. But he got very upset when I told home the galv painting on the joints was rubbish. I made him scrape it off and re apply using masking tape. Hopping mad he was. So the moral of the tale was I had to upset him to get what I wanted. I also had to lend him some labour to do it. 

 

Best of luck OP with the job. 

 

 

[mogandave]

I hope it all goes well for the OP. 
There is a saying going around. "it's the Thai way or the high way. 
 
I have read so many threads here about shoddy workmanship etc etc. 
 
I struggle to find people to work for me as I am quite remote. Anyone with any skill isn't working around here. I find it very frustrating and I often have to compromise material selection and also finish. 
 
I hope the OP gets a decent job built, there are always work round if things go wrong. 
 
When I was researching my job I spoke to lots of welders on the job site I was on. They all said for thin wall tube with stick you have to move fast to avoid the heat. 
 
I found my contractor via the main welding gas shop. All went well. But he got very upset when I told home the galv painting on the joints was rubbish. I made him scrape it off and re apply using masking tape. Hopping mad he was. So the moral of the tale was I had to upset him to get what I wanted. I also had to lend him some labour to do it. 
 
Best of luck OP with the job. 
 
 

Nice work, did you ever work for a carnival?