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Technical advise hot dip galvanising
Posted: 22 Feb 2019 12:26
by Rodney
My troll was fitted with a genuine Nissan bullbar by the selling dealership prior to selling it to me.
After a little more than a year at the coast the powder coating is showing extensive signs of rust all over the entire unit. Clearly rusting under the powdercoat. My inclination is to galvanise. However I seem to recall reading somewhere that there is a danger of distortion during galvanising.Can anyone on the forum give me guidance here?
My steelies are also starting to show rust so they would go the same way.
Re: Technical advise hot dip galvanising
Posted: 22 Feb 2019 15:23
by Peter Connan
Hot-dip can cause warping, but I think the chances are relatively small. I have galvanised some fairly large structures (such as a trailer chassis, rock sliders and bash plates) without any problems.
However, paint and powder coating doesn't stick to galvanising very well. So unless you like a raw galvanised look this might not work as well as you hope.
Also, I don't think a tire will seat on a galvanized surface, as it is too rough?
I would recommend decent shot-blasting followed by a professionally-applied epoxy paint system.
Re: Technical advise hot dip galvanising
Posted: 23 Feb 2019 06:59
by Anthony Forgey
You could also consider electro-galvanizing. I'm not sure how many electroplaters would have tanks large enough for a bullbar.
if you do galvanize, make sure to drill a hole on both sides of any tubing that is completely welded closed. it allows the zinc to go right inside and drain out, as well as preventing the tube from bursting in the hot tank.
As peter said, hot dip and paint are not friends. it can be done but if you electrogalvanise it wont be a problem.
Re: Technical advise hot dip galvanising
Posted: 23 Feb 2019 07:20
by juice
You can powder coat hot dipped galvanising ' you need to tell the guys where you get it done not to passavate it ( so when you get it back it a dall colour and not shiny) the powder coating sits on the surface like no tomorrow, All clear view fencing is done like that
Electrogalv plating does not get into the inside of the pipes to stop them from rusting from the inside
Re: Technical advise hot dip galvanising
Posted: 25 Feb 2019 08:22
by Rodney
Thank you for the feedback. I will tackle this after the easter period and let you know the outcomes.
Re: Technical advise hot dip galvanising
Posted: 25 Feb 2019 10:26
by SCUBA Patrol
Galvanizing sort problems but there are cons to it.
1. weight, calculate the weight added to the bar before considering galvanizing (the galvanizer should be able to assist you here)
2. Drilling holes of suitable size into tubes at the correct positions are critical as holes in the incorrect position will add additional weight and cost! (you normal pay for the zinc after galvanizing). Drilling holes might damage the integrity of the bar, (my opinion)
I would rather get all the powder coating off, gritblast and paint with "Hammerite" paint. This is easily repairable, just give another coat of paint. Hammerite have both a smooth paint and a "hammerd" look that hides a lot of imperfections.