How to protect steel beams left outside from corrosion

[gejohesch]

I bought a number of steel beams (6m long, 1.5mm thickness, various specs : 4" by 4", 4" by 2", 3" by 1.5") to make a new roof for my wife's house in Isan. They are now parked in our courtyard. However, I just decided not to go ahead and have the work done now, for personal reasons, but January next year. I'm concerned the steel will corrode, what with so many months left outside with the rain etc... I thought maybe I can buy strong and watertight tarpaulin-like material and wrap around the steel. Would that work?

[Crossy]

The regular "red-lead" primers applied with a small roller actually do a pretty good job.

 

Keep them off the ground and under cover (but make sure air can circulate) and you're good for a fair time.

 

How long do you expect to be delayed?

 

[VocalNeal]

If it moves salute it. If it doesn't move paint it.

[Lacessit]

Putting them under or in a tarpaulin may be the worst thing you can do, in terms of corrosion. It depends on how much moisture is trapped.

 

Can you store them undercover, e.g. a carport?

 

As Crossy said, keep them off the ground. Isolate each piece by using cement blocks so they are not nested.

 

As long as they can drain properly, you should only get superficial rusting. If they have mill scale, next to none.

[Will B Good]

Used to use Shell Ensis.....if it still exists.

[Lacessit]

10 minutes ago, Will B Good said:

Used to use Shell Ensis.....if it still exists.

Not a bad idea, although rust-preventatives can be a PITA with fumes when welding sections together.

[Will B Good]

5 minutes ago, Lacessit said:

Not a bad idea

After being married for46 years, in total, I feel like getting divorced and marrying you.....555

[Lacessit]

I don't know if vapor corrosion inhibitors ( VCI ) are available in Thailand. They would be a good option if the OP wanted to bundle everything in a tarp to save space.

[Lacessit]

2 minutes ago, Will B Good said:

After being married for46 years, in total, I feel like getting divorced and marrying you.....555

Please, no. I am getting too many proposals from 60 yo Thai massage ladies who say they want to "take care".

[Rimmer]

1 hour ago, Crossy said:

The regular "red-lead" primers applied with a small roller actually do a pretty good job.

 

Keep them off the ground and under cover (but make sure air can circulate) and you're good for a fair time.

 

How long do you expect to be delayed?

 

 

Red oxide is a primer only,  on its own it wont do it, it needs something over it.

 

Cant seem to buy Rustoleum any more, wasn't super good anyway

 

I have used MD2in1 over rust and it seems to work well and stop it dead.

 

I have not used Rust Shield but should be OK over clean steel.

 

MD2in1 is about B500 a can it comes in different colors, I have used the Brown Matt, easy to apply and works well also used their Grey which seems to be a different formula it is thick and a bitch to apply also seems to be gloss, not a pleasant experience at all.... 

 

 

 

 

[Crossy]

2 minutes ago, Rimmer said:

Red oxide is a primer only,  on its own it wont do it, it needs something over it.

 

Whilst this is most definitely the case, we have a fair bit of steel stock that got a very cursory lick of red-lead (I know it's not lead now but old habits die hard) that's been sitting in in the car-port out of the rain that's only showing rust where the primer was damaged. Some of it is approaching 2 years old.

 

Hence my asking how long he intends delaying. For a few months the primer alone will likely be "ok".

[Jake72]

I've used the red and grey primers, seems to work just fine. However these days I buy galvanized square tubes and beams whenever possible, so much easier, then you only need to paint the welds. It's a bit harder to get pretty welds on galvanized steel, but you can just grind the welds with a flap disc and paint them with some primer.

[brianthainess]

41 minutes ago, Jake72 said:

I've used the red and grey primers, seems to work just fine. However these days I buy galvanized square tubes and beams whenever possible, so much easier, then you only need to paint the welds. It's a bit harder to get pretty welds on galvanized steel, but you can just grind the welds with a flap disc and paint them with some primer.

The cold galv. here also rusts, Silver oil based gloss will stop that (no etching needed), and on plain steel. 

[scorecard]

On 3/6/2024 at 12:52 PM, Lacessit said:

Please, no. I am getting too many proposals from 60 yo Thai massage ladies who say they want to "take care".

Just ensure you push them back, especially if you encounter Thai ladies who try to insist that farang men have to have a Thai wife. Friend just beat off such situation.

 

Neighbor invited him in for a beer, Thai lady he's never never seen before sitting in the living room. She speaks English and instantly starts with 'how much money do you have?'  but proceeds quickly to 'it's Thai law you have to have a Thai wife'.

 

Neighbors Thai wife then intervenes and tells the new lady there is no such law and it's rude to keep asking how much money anybody has.

 

A few minutes later the neighbors Thai wife tells the new lady to leave.

 

Why because the new lady had whispered that she was going to ask to see the farangs passport them steal it. Because that would mean he has no passport so he cannot leave Thailand so the police would have to give him an approval document to stay in Thailand. 

[jojothai]

By the description of sizes it sounds like you have steel tube, closed sections. 

Since all steel needs corrosion protection and coating, you would have been better buying galvanized sections.

However, to protect the steel apply a primer as recommended by others. It would be more protective if you put a top coat on, but not essential if you keep them stored well as suggested.

If they are the closed tube( thai description for square or rectangular) you cannot readily coat the inside, then also protect the ends from getting moisture inside. But you should probably not close the ends ( there may be some moisture inside already). I suggest you store them under cover where moist air cannot be blown inside.

Dont just enclose in wrapping, you need ventilation.

[steven100]

if your never going to paint them and they won't be visable inside the roof then you could slap a thin coat of diesel on them, you could use rags to apply it even. Then just ensure they're stacked on 4"x2" or similar so they're off the ground. Place a sheet of cheap plastic over the top but up higher 1ft so air and breeze can pass through.

They won't rust with a diesel coat.

[pacovl46]

I would just get them powder coated. First with zink and then any color you want. This will protect them more or less forever. Especially once they're on the roof and covered by the roof because I have a suspicion, if you don't treat them at all that they will eventually rust due to the humidity in Thailand. Alternatively  just paint them yourself with a zink paint and then regular paint suitable for metal. 

[Bday Prang]

4 hours ago, brianthainess said:

The cold galv. here also rusts, Silver oil based gloss will stop that (no etching needed), and on plain steel. 

                     Stainless steel here also rusts and to varying degrees!   Personally for the non galvanised stuff, I always washed off the mill scale  and any existing oily residue with petrol then gave it a coat or two of red or grey primer, I have some steel fence posts and rails that have been in place over 20 years and still no rust.   Admittedly I paint over the primer with normal oil based gloss every so often so that probably helps a bit too  but I have noticed that the sun eventually destroys that paint yet the original primer appears relatively unaffected. 

                    Regarding the galvanised stuff, I bought a few pieces about 5 years ago to use as edge formwork for a concrete driveway.  100mmx50mmx 1.5mm   I didn't particularly want galvanised but it was all they had in the shop at the time.  I never painted it at all and since I had no further use for it I just stashed it along side the father in laws rice shed, effectively uncovered and unprotected.  To this day the only rust present is in the few places I scratched it when removing it from the concrete, still perfectly usable Although I probably should grind off the the light rust and prime it where its scratched 

                      Any body reasonably competent at welding should have no problem welding it Mr Somchai here didn't struggle at all. and even I can achieve passable welds without too much trouble, certain welding rods make it easier but really for thin steel a MIG is much more appropriate than a stick welder

                       I certainly would not bother with powder coating as suggested by somebody else on here, if its not exposed to the sun normal primer and oil based paint is more than adequate

[Jake72]

4 hours ago, brianthainess said:

The cold galv. here also rusts, Silver oil based gloss will stop that (no etching needed), and on plain steel. 

What do you mean here? I've lived in Thailand more than 20 years and the ones I have lying around have not rusted, sure some might be treated with Zink, but others are galvanized, the fence mesh is definitely galvanized and not rusted. The iron coated with the red and grey primer are also fine, however anything bare iron starts rusting within weeks/months.

[The Theory]

Are they galvanized or black ? If not galvanized you definitely need to paint them by 2in1 that is already suggested. If galvanized, paint both ends and cover them air circulated. 

[gejohesch]

On 3/7/2024 at 7:10 AM, jojothai said:

By the description of sizes it sounds like you have steel tube, closed sections. 

Since all steel needs corrosion protection and coating, you would have been better buying galvanized sections.

However, to protect the steel apply a primer as recommended by others. It would be more protective if you put a top coat on, but not essential if you keep them stored well as suggested.

If they are the closed tube( thai description for square or rectangular) you cannot readily coat the inside, then also protect the ends from getting moisture inside. But you should probably not close the ends ( there may be some moisture inside already). I suggest you store them under cover where moist air cannot be blown inside.

Dont just enclose in wrapping, you need ventilation.

I'm replying to you, but this also is for all the others who have kindly commented on my initial post.

 

First, I will keep the steel tubes, indeed closed sections, for some 10-12 months before using them for the new roof. Not longer. That would be doing the work in January next year. The reason I'm now delaying the work is that I'm leaving Thailand in a few days, and I absolutely do not want to have any work done on the house in my absence, even by a team of guys we have used a few times before and who do good work - certainly compared with a few others who disappointed me.

 

I'm back for a good length of time between August and October. The job could be done them but I thought I would rather wait until January because of the risk of heavy rains.

 

Right now, the tubes are neatly lined up, on cement blocks to keep them off the ground. I could space them up a bit more from each other to facilitate air ventilation. The idea of a tarpaulin cover but, again, with some ventilation space around, is easy to implement.

 

I do not have enough space in the car port for the tubes. But, btw, I have had left over tubes from a previous roofing job (our second house just next door). It's exactly the same sort of steel as our new stock - they are white (or silver?), definitely not black - maybe that's the galvanised type (not sure...). The point is that the car port is not totally closed, it lets a lot of rain come in, and those old steel left overs (2 or 3 years) have not shown any sign of corrosion whatsoever. So I thought that leaving our new stock with no special treatment for 1 year would not be such an issue.

[jojothai]

21 hours ago, gejohesch said:

 It's exactly the same sort of steel as our new stock - they are white (or silver?), definitely not black - maybe that's the galvanised type (not sure...). The point is that the car port is not totally closed, it lets a lot of rain come in, and those old steel left overs (2 or 3 years) have not shown any sign of corrosion whatsoever.

If they are silver, that normally indicates they are galvanised and therefore little or no corrosion.

I am not aware of any standard steel sections in a white finish. Unless specifically painted.

Ensure that rain does not get inside the steel section.

You could make a frame to put over the steel (perhaps cheap from bamboo?) and then cover with the tarpaulins but leave some gaps for aircirculation.

[gejohesch]

1 hour ago, jojothai said:

If they are silver, that normally indicates they are galvanised and therefore little or no corrosion.

I am not aware of any standard steel sections in a white finish. Unless specifically painted.

Ensure that rain does not get inside the steel section.

You could make a frame to put over the steel (perhaps cheap from bamboo?) and then cover with the tarpaulins but leave some gaps for aircirculation.

OK, thanks a lot, sounds like the bottom line advice! Indeed, they are not painted so the colour has to be declared "silver". Little or no corrosion, as you say, fits well with my observation concerning the old leftovers. So, tarpaulin on a frame of some sort + air circulation!