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Best primer to paint steel

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2 hours ago, transam said:

Touchy........... Ignore list, do what you like chap......😷

Let's just say i have a low tolerance level for certain types of people. On ignore now.

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4 hours ago, giddyup said:

The contractor who is going to build my pergola in steel says he is going to use galvanised. I believe that galvanised needs a special preparation before painting, I read washing with white vinegar first will do the job.

Using vinegar will help, but unless you use the right primer it it is not likely to to stick. RusTech will absolutely stick, as will zinc-chromate, and some of the zinc-rich primers. ZRC is great for treating welds. 

 

I would go with RusTech, but again be advised it has a short pot-life so you have to work quickly.  

 

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18 hours ago, Yellowtail said:

 

And AL is not as strong as steel so you typically have to use more, and steel lasts longer. After a few years, mill-finish AL starts to look pretty crappy, and paint options are pretty limited. Unless you plan to do the welding yourself, it will be very difficulty to find a shop to fab it for you, and extremely difficult to a welder to work on site that can provide decent results.

 

Stainless will generally be cheaper and easier to work with, and there are no shortage of shops around that can build and install it.   

 

Again, if one goes with channel and or angle rather than tubing there there is no "inside" that has to be painted. 

 

All true, but when someone wants to build a strong, durable, rust free structure on their boat, aluminum is the go-to.  It's not as strong as steel, but at 1/3 the weight, it doesn't have to be to support itself.  That said, anodized is the starting point- not mill finished.

 

The problem with stainless is they skimp on the wall thickness for most consumer profiles like square tube.  Great for decorative.  Not so much for load bearing structural projects.  You can get a thicker wall, but bring money.  Lots of it.

 

And for decorative structures, rectangular or square tubing presents much nicer finish than angle or channel.

 

Edited by impulse
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7 hours ago, impulse said:

 

All true, but when someone wants to build a strong, durable, rust free structure on their boat, aluminum is the go-to.  It's not as strong as steel, but at 1/3 the weight, it doesn't have to be to support itself.  That said, anodized is the starting point- not mill finished.

 

The problem with stainless is they skimp on the wall thickness for most consumer profiles like square tube.  Great for decorative.  Not so much for load bearing structural projects.  You can get a thicker wall, but bring money.  Lots of it.

 

And for decorative structures, rectangular or square tubing presents much nicer finish than angle or channel.

 

 

Actually for boats I think it's mostly 316L for towers, rocket-launchers, outriggers, hardware and whatnot. Seeing more powder-coated Al for lower end marine applications. In any event, weight isn't much of a concern when building a permanent structure outdoors. Also, Al is much more subject to fatigue and cracks than is steel, which is a concern for permanent structures.  

 

Stainless is much stronger than mild steel so it can run a bit thinner than mild, and much thinner than Al. Heavy-wall is the same cost per-unit weight as thin tubing so 

 

Anodized is great, touching up the welds can be a hassle unless  you're going bolt-together.

 

Yeah, tubing looks better, but unless your structure is designed to drain, corrosion can be a big problem. 

 

The biggest issue is the number of guys doing custom stainless compared to the number of guys doing custom aluminum. Personally, I would go with hot-roll steel and paint it. 

 

 

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The "contractor" just quoted me 23,000 baht to make this 6m x 3m pergola. This includes all the materials and the painting of the finished product with 3 coats of paint, including a galvanised steel primer. Does this seem fair? Pretty hard to know exactly, it's like how long is a piece of string. He's done a few jobs for me previously and his work is generally pretty good, but he does seem a tad on the expensive side.

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1 hour ago, giddyup said:

The "contractor" just quoted me 23,000 baht to make this 6m x 3m pergola. This includes all the materials and the painting of the finished product with 3 coats of paint, including a galvanised steel primer. Does this seem fair? Pretty hard to know exactly, it's like how long is a piece of string. He's done a few jobs for me previously and his work is generally pretty good, but he does seem a tad on the expensive side.

Does that include concrete?

 

Sounds okay to me, but If he's providing the material, you should get a bill of material the includes the thickness of the material as well as the brand and type of paint. 

 

I generally agree to the price, subject to approval of drawings and material.

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17 minutes ago, Yellowtail said:

Does that include concrete?

 

Sounds okay to me, but If he's providing the material, you should get a bill of material the includes the thickness of the material as well as the brand and type of paint. 

 

I generally agree to the price, subject to approval of drawings and material.

No concrete needed. The front posts will fasten to the existing cement at the front fence, and the rear is attached to the steel rafters of the house. The pics give some idea.

P1050887.JPG

P1050888.JPG

Edited by giddyup

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9 hours ago, Yellowtail said:

 

Actually for boats I think it's mostly 316L for towers, rocket-launchers, outriggers, hardware and whatnot. Seeing more powder-coated Al for lower end marine applications. In any event, weight isn't much of a concern when building a permanent structure outdoors. Also, Al is much more subject to fatigue and cracks than is steel, which is a concern for permanent structures.  

 

Stainless is much stronger than mild steel so it can run a bit thinner than mild, and much thinner than Al. Heavy-wall is the same cost per-unit weight as thin tubing so 

 

I'm not disagreeing with any of your points.  But just a little info from bopping around China for 10+ years and buying/ exporting a lot of stainless to customers in the USA. 

 

For the most part, that pretty, polished decorative stainless you see in the builders' markets is made of 201 stainless.  That's the stuff that's affordable for "around the home".  Sometimes, it's 304 SST (or more likely the Chinese alternative to 304, which is 302- 1Cr18Ni9)  They're all great for indoor projects, but they do rust and they do stain over time.  They don't disintegrate like carbon steel, but you'll be polishing the rust stains off of them every year or so in humid outdoor projects.  And generally speaking, the wall thickness is adequate for decorative fluff, but not for structural beef.

 

If you want 316 or 316L, you're looking in very different material markets, generally those that cater to marine uses and refineries.  Not the markets catering to folks that are adding on to their home.  And when you go to those industrial markets to buy 316L and/or thicker structural stainless, bring money.  Wheelbarrows full.

 

Edited by impulse

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1 hour ago, impulse said:

For the most part, that pretty, polished decorative stainless you see in the builders' markets is made of 201 stainless.  That's the stuff that's affordable for "around the home".  Sometimes, it's 304 SST (or more likely the Chinese alternative to 304, which is 302- 1Cr18Ni9)  They're all great for indoor projects, but they do rust and they do stain over time.  They don't disintegrate like carbon steel, but you'll be polishing the rust stains off of them every year or so in humid outdoor projects.  And generally speaking, the wall thickness is adequate for decorative fluff, but not for structural beef.

I’m sure you know more than I on the subject. Our gate is now 4 years old no rust at all the only problem has been an investigative  snake 51E31082-3926-4A3B-8B20-5B6759C562B4.jpeg.c1f008bda25b8b0fc02c02c878bc7503.jpeg

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11 hours ago, impulse said:

 

I'm not disagreeing with any of your points.  But just a little info from bopping around China for 10+ years and buying/ exporting a lot of stainless to customers in the USA. 

 

For the most part, that pretty, polished decorative stainless you see in the builders' markets is made of 201 stainless.  That's the stuff that's affordable for "around the home".  Sometimes, it's 304 SST (or more likely the Chinese alternative to 304, which is 302- 1Cr18Ni9)  They're all great for indoor projects, but they do rust and they do stain over time.  They don't disintegrate like carbon steel, but you'll be polishing the rust stains off of them every year or so in humid outdoor projects.  And generally speaking, the wall thickness is adequate for decorative fluff, but not for structural beef.

 

If you want 316 or 316L, you're looking in very different material markets, generally those that cater to marine uses and refineries.  Not the markets catering to folks that are adding on to their home.  And when you go to those industrial markets to buy 316L and/or thicker structural stainless, bring money.  Wheelbarrows full.

 

 

I thought we were talking about custom fabricated products for permanent outdoor installations, not cheap, SG Chinese consumer goods.

 

While I can't speak to China, I did spend over thirty years building made-to-order fabricated steel products, the last twenty of which were in Thailand. I can assure you that 304 is readily available in Thailand, and while 316L is not as common, it it is also available and generally does not cost significantly more than does 304. There are a lot of traders in Thailand which makes stainless prices competitive.

 

The "corrosion" you see on stainless is often not corrosion but rather staining from carbon contamination, or from SG fasteners. Any time you drill, punch, roll, draw break or perform any other process on stainless using carbon steel tooling, the carbon residue can oxidize and stain the stainless. This is why you often see "rust" around stainless fasteners, fittings or welds. 

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