Getting an implement galvanised....

[Billydooker]

I'm currently making a link box for the 3 point linkage for shifting calves around etc. It's mostly out of steel box section, I've welded an A frame too it that I got recently, only thing is the A frame(female part) came undercoated.
If I send the whole thing away to get galvanised will I have to remove the paint from this first? Or will it come off when they acid dip it?
The rest of the link box is made from new steel and I've got the holes drilled etc where the box ends are capped.

 

[chaffcutter]

Yes you need to clean everything down to the bare metal, and drill vent holes in any box section or tube that is not open.

 

[Kevm]

I had a tow bar galvanised and just left them to gritblast it, they didn't get into the corners very well, so I would suggest that you at least take the grinder to the corners/welds and try and get all the nitty gritty bits clean and shiny.
You could leave the galv. company to gritblast all the big open bits.
Have a good think about how they will dip it and make sure you have vents and drains in the right places.

 

[RagnarHairybreeks]

Wherabouts are you @Billydooker?

 

[Cab-over Pete]

I find the best way to shift paint is burn it off with the gas, blue flame but you don’t have to get the steel red hot.

Takes seconds and the residue is easy with a wire brush.

 

[TripleSix]

Doesn't matter how rusty it is, but make sure all the paint is removed.

 

[tinman]

it id be no harm to remove some of the paint off it, altho the crowd i send my stuff to ill clean it with acid if i tell them to.
give it a good pasting of thinners and a lot of it ill rub off after a while or it ill make it easier at least.
hot wash it either.

only thing id be worried about is the large flat plate areas will come out like a sail, you can massage it back with a sledge and timber if your picky but id say it will flex some.

i have a loader bucket/fork here and it could do ith a paint, its not old but the paint isnt good.
i was for galvanizing it til i got to wondering what it id come out like.
good thing is i can watch to see what yours comes out like.

 

[Billydooker]

Wherabouts are you @Billydooker?

Sunny southwest Scotland [emoji1] [emoji295]️

 

[RagnarHairybreeks]

OK, sorry, I thought I might be able to help but I've got no customers in that area (thermal spray galvanising).

 

[jellybean]

OK, sorry, I thought I might be able to help but I've got no customers in that area (thermal spray galvanising).

That sounds interesting, I have a machine I would like to galvanise but it has some bits that would need not to be done; holes for pins etc. Can you tell us more please.

 

[RagnarHairybreeks]

@jellybean Sure.

I work for the company that makes these;

https://www.oerlikon.com/ecomaXL/files/metco/oerlikon_DSE-0003.3_16E_EN.pdf&download=1

Basically you gritblast the steel and then ‘paint’ it with the spray gun. Instead of paint though it is microscopic droplets of molten metal. These ‘splat’ on impact and grip the grit blasted surface (and then each other) to build up a coating of zinc (or aluminium, or stainless steel, or pretty much any metal you choose),

There is very little heat transfer so no warping problems, you can mask off areas you don’t want coated, you can paint over the top if you want it to look pretty and there is no size restriction (railway bridges are often coated on site).

This is the most basic of our tools, we have others that can coat with ceramics, tungsten carbides - imagination is almost the only limiting factor.

 

[Exfarmer]

There’s painting and then there is hot dip galvanising, never make the mistake of mixing the two!

 

[RagnarHairybreeks]

There’s painting and then there is hot dip galvanising, never make the mistake of mixing the two!

I was being simplistic Exfarmer. Thermal spray is not painting, it produces a pure metal coating just as hot dip does. One of my customers uses it to build up aluminium to a radial thickness of roughly 3cm. Yes, centimetres. This is then machined to make vanes on an impeller pump that moves hydraulic fluid around passenger jets. We are not talking about paint here.

And you absolutely can mix the two (as in put paint on top of thermal spray coatings, or for that matter, hot dip) It doesn’t improve the corrosion resistance but it does look pretty.

By the way, no real affiliation as I am leaving the company in a few weeks for another opportunity.

Damn good kit and coatings though.

 

[RagnarHairybreeks]

Incidentally, by the way (and remember the note above about no commercial affiliation as I’m working my notice) a full set up, assuming you have a fairly decent compressor, would cost you under 6K. Galvanise what you want, when you want, for the cost of zinc wire, oxy and acetylene. Feel free to pm me if you would like impartial advice.

 

[jellybean]

Thanks for the info on the Oerlikon, it isn't going to suit my situation though. I will have to stick with hot dip galv and find a way of bunging the holes that don't want doing, or just drill out again afterwards.

 

[Exfarmer]

I was being simplistic Exfarmer. Thermal spray is not painting, it produces a pure metal coating just as hot dip does. One of my customers uses it to build up aluminium to a radial thickness of roughly 3cm. Yes, centimetres. This is then machined to make vanes on an impeller pump that moves hydraulic fluid around passenger jets. We are not talking about paint here.

And you absolutely can mix the two (as in put paint on top of thermal spray coatings, or for that matter, hot dip) It doesn’t improve the corrosion resistance but it does look pretty.

By the way, no real affiliation as I am leaving the company in a few weeks for another opportunity.

Damn good kit and coatings though.

My mistake, some people think that zinc primer is the equivalent of hot dip, it certainly is not.
I know nothing of your system but have heard of it, and yes you can certainly paint over zinc however applied provided you use the correct paint.

 

[the-mad-welder]

Thanks for the info on the Oerlikon, it isn't going to suit my situation though. I will have to stick with hot dip galv and find a way of bunging the holes that don't want doing, or just drill out again afterwards.

I was once told to fill any holes you don't want galved with fire cement. Never actually done it myself though so can't say if it works or is even recommended. I tend to drill out the holes afterwards. With a tapped hole. I send it drilled just below pilot drill size and then drill and tap it once its back.

 

[The Stig]

Silicon will fill the hole and stop the galv getting in

 

[opininionated]

Incidentally, by the way (and remember the note above about no commercial affiliation as I’m working my notice) a full set up, assuming you have a fairly decent compressor, would cost you under 6K. Galvanise what you want, when you want, for the cost of zinc wire, oxy and acetylene. Feel free to pm me if you would like impartial advice.

How does your system compare in cost to hot dipping, in terms of consumables and zinc, and how quickly does it spray cover the parent metal, is it a similar speed to spraying paint for example?

 

[RagnarHairybreeks]

How does your system compare in cost to hot dipping, in terms of consumables and zinc, and how quickly does it spray cover the parent metal, is it a similar speed to spraying paint for example?

With regards to real world application costs it does depend on the geometry of what you want to coat (fiddly stuff wastes more material as you are shooting past it), but running costs are not expensive. The wire is around £4.60 per kilo delivered at the moment. I just dug into an old spreadsheet I produced a few years ago and to spray to 150 microns thickness should cost you around £25 per square metre on a flat surface (including amortisation of the equipment over five years based on spraying only a few jobs - goes down as you spray more of course).

In terms of speed 100 square metres should take around 12 hours to spray (at 100% duty) and require 179Kg of wire to do it. Coating weight (zinc) is roughly 1Kg per square metre.

Hope that helps, if you need more information please don't hesitate to PM me and I can email you some files.