JohnBishop Posted June 11 Share Posted June 11 Hi All, I hope you are well. I have a number of these galvanised post bases, I think I should preserve it as the rust is going to pop up on some of these welds soonish. What paint (multiple coats should I put on it)? Also should it be spray or slap it with a paintbrush? I can see Hammerite but still not sure which one as there are "direct to rust" ones. Cheers Link to comment Share on other sites More sharing options...
Conor Posted June 11 Share Posted June 11 Rub down and spray with zinc primer first. 1 Link to comment Share on other sites More sharing options...
joe90 Posted June 11 Share Posted June 11 I am a big fan of Hammerite direct to rust paint, several coats will be bomb proof (but not the “modern” water based ones that I found to be thin and watery!!!.) 1 Link to comment Share on other sites More sharing options...
JohnBishop Posted June 11 Author Share Posted June 11 1 hour ago, Conor said: Rub down and spray with zinc primer first. ok so zinc phosphate metal primer (1 coat) then Hammerite (1 coat)? Link to comment Share on other sites More sharing options...
Onoff Posted June 11 Share Posted June 11 Black Jack. Link to comment Share on other sites More sharing options...
JohnBishop Posted June 11 Author Share Posted June 11 32 minutes ago, Onoff said: Black Jack. primer then Black Jack bitumen paint? Link to comment Share on other sites More sharing options...
JohnBishop Posted June 11 Author Share Posted June 11 1 hour ago, joe90 said: I am a big fan of Hammerite direct to rust paint, several coats will be bomb proof (but not the “modern” water based ones that I found to be thin and watery!!!.) Do you mean Hammerite is no longer solvent but water based paint? Link to comment Share on other sites More sharing options...
JohnMo Posted June 11 Share Posted June 11 2 hours ago, JohnBishop said: have a number of these galvanised post bases If they were galvanised (hot dip) after welding they should be good for about 50 years. That why they are galvanised. Link to comment Share on other sites More sharing options...
JohnBishop Posted June 11 Author Share Posted June 11 (edited) 8 minutes ago, JohnMo said: If they were galvanised (hot dip) after welding they should be good for about 50 years. That why they are galvanised. Believe it or not but on galvanised one I see rust forming in one spot. I also have one base that supposed to be stainless steel and it also developed rust. These were exposed to elements for about 3 weeks. Edited June 11 by JohnBishop Link to comment Share on other sites More sharing options...
JohnMo Posted June 11 Share Posted June 11 (edited) 13 minutes ago, JohnBishop said: Believe it or not but on galvanised one of them I see rust forming in one spot. I also have one base that supposed to be stainless steel and it also developed rust. These were exposed to elements for about 3 weeks. Good chance they are not actually galvanised, it could be just zinc electroplating (which us cheap rubbish and too thin). If it was galvanised you actually need an etching primer or an epoxy based Paint, to get the paint to stick on. But I would use Rust-Oleum® Stops Rust® Cold Galvanizing Compound Spray. Its 93% pure zinc coating applies a galvanized film with cathodic protection, which resists rusts, scratches and chips. It can go straight on zinc coating etc. Apply 3 to 4 heavy coats. Nothing else needed. Your stainless steel ones will rust if they used tools that were also used on carbon steel or have carbon steel grinding splatter on them or they used the wrong filler wire on the welds. Spray them in the cold galvanise spray also. Edited June 11 by JohnMo 1 Link to comment Share on other sites More sharing options...
joe90 Posted June 11 Share Posted June 11 1 hour ago, JohnBishop said: Do you mean Hammerite is no longer solvent but water based paint? It’s still available in places like EBay but their new “eco water based” stuff is crap in my opinion. 1 Link to comment Share on other sites More sharing options...
JohnBishop Posted June 11 Author Share Posted June 11 (edited) 2 hours ago, JohnMo said: Good chance they are not actually galvanised, it could be just zinc electroplating (which us cheap rubbish and too thin). If it was galvanised you actually need an etching primer or an epoxy based Paint, to get the paint to stick on. But I would use Rust-Oleum® Stops Rust® Cold Galvanizing Compound Spray. Its 93% pure zinc coating applies a galvanized film with cathodic protection, which resists rusts, scratches and chips. It can go straight on zinc coating etc. Apply 3 to 4 heavy coats. Nothing else needed. Your stainless steel ones will rust if they used tools that were also used on carbon steel or have carbon steel grinding splatter on them or they used the wrong filler wire on the welds. Spray them in the cold galvanise spray also. Here it is all 3 different bases: The first one (grey) was the most expensive and supposed to be stainless steel but you can see the rust coming up where the cuts are. The next two (silvery) supposed to be galvanised but one already has the rust in the corners. The 3rd one is the one I am going to use, the cheapest of all, it hasn't been exposed to elements to show any rust yet. Edited June 11 by JohnBishop Link to comment Share on other sites More sharing options...
JohnMo Posted June 11 Share Posted June 11 From the photos not hot dip galvanised Have read https://www.galvanizers.co.in/blog/difference-between-galvanized-vs-hot-dip-galvanized-metal/ 1 Link to comment Share on other sites More sharing options...
SimonD Posted June 11 Share Posted June 11 45 minutes ago, JohnMo said: From the photos not hot dip galvanised Have read https://www.galvanizers.co.in/blog/difference-between-galvanized-vs-hot-dip-galvanized-metal/ And if you can, get double dipped. Single dipped has a matter finish and double a slightly shinier finish and worth the few extra pennies. I also suspect that the stainless is 304 rather than 316, which is usually recommnded for exterior applications: https://www.thyssenkrupp-materials.co.uk/the-difference-between-stainless-steel-304-and-316.html 1 Link to comment Share on other sites More sharing options...
JohnBishop Posted June 14 Author Share Posted June 14 On 11/06/2024 at 19:32, SimonD said: And if you can, get double dipped. Single dipped has a matter finish and double a slightly shinier finish and worth the few extra pennies. I also suspect that the stainless is 304 rather than 316, which is usually recommnded for exterior applications: https://www.thyssenkrupp-materials.co.uk/the-difference-between-stainless-steel-304-and-316.html That's awesome. We started with post bases but now we are into metallurgy and I want to open an iron foundry 🙂 They all seem to make it cheap, galvanised does not equal galvanised and 304 does not equal 316. Link to comment Share on other sites More sharing options...
Onoff Posted June 14 Share Posted June 14 You sometimes see discoloration & rusting on stainless steel around welds. 1 Link to comment Share on other sites More sharing options...
JohnBishop Posted June 14 Author Share Posted June 14 I just received a can of Rustoleum Galva Zinc and a can of ISOPON Zinc 182 Rust Inhibiting Primer I reckon I should choose between one of them. Link to comment Share on other sites More sharing options...
JohnBishop Posted September 4 Author Share Posted September 4 I am commencing work on the pergola which is pretty much the same design as the patio just 3x3 meters between posts. I am looking into these heavy duty post bases I mentioned before. The prices have changed a bit. The one that uses 7mm steel is now over £40 each and it's 140mm not 150mm Someone already pointed out that this one regardless of the superior thickness has been galvanised cheaply. https://www.amazon.co.uk/gp/product/B08FQV9XYW/ref=ox_sc_act_title_1?smid=A1R0D8B1EKTLOP&psc=1 The other one that is 5mm is in 3 flavours: raw steel, galvanised and stainless steel. £31, £42 and £62 respectively. I ordered one few months ago and stainless steel was for £42. https://www.ebay.co.uk/itm/175719585849?var=475106267269 I have one of each and wonder if I should order 3 more of the 7mm or 3x 5mm ones. I lean towards 5mm option but not sure if I should go for galvanised for £42 or just buy raw steel and just cover it with Zinc galvanising paint I already have? Link to comment Share on other sites More sharing options...
SteamyTea Posted September 4 Share Posted September 4 On 11/06/2024 at 15:40, JohnMo said: If they were galvanised (hot dip) after welding they should be good for about 50 years. That why they are galvanised. Exactly. There is a certain amount of self healing with galvanising as well. Why it is used so much in the marine environment. Link to comment Share on other sites More sharing options...
Onoff Posted September 4 Share Posted September 4 (edited) Any stainless brackets I used to have made, I'd ask for them to be "pickled". An acid was applied to remove discolouration and any scale from the welding pieces. Back in the day the part was dumped on the ground and nitric or hydrofluoric acid poured over it. Soaked up by the dusty yard and neutralised when it rained. Happy days! Edited September 4 by Onoff Link to comment Share on other sites More sharing options...
JohnBishop Posted September 4 Author Share Posted September 4 so how do you think can I go for raw steel and paint it or galvanised bases? Link to comment Share on other sites More sharing options...
SteamyTea Posted September 4 Share Posted September 4 Galvanisation Link to comment Share on other sites More sharing options...
JohnBishop Posted September 4 Author Share Posted September 4 2 minutes ago, SteamyTea said: Galvanisation ok, I buy raw steel ones and paint it with zinc Link to comment Share on other sites More sharing options...
SteamyTea Posted September 4 Share Posted September 4 1 minute ago, JohnBishop said: paint it with zinc No, it needs to be applied as a hot process. It is not expensive. Link to comment Share on other sites More sharing options...
JohnBishop Posted September 4 Author Share Posted September 4 1 hour ago, SteamyTea said: No, it needs to be applied as a hot process. It is not expensive. Maybe it isn't expensive as a process but the item price difference between raw steel and galvanised is 30% which is substantial. Link to comment Share on other sites More sharing options...
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