Removing zinc layer

[monkeyboy]

Hi,

First post so be gentle! I’ve just bought a Clarke 135TE to do some welding on my car, in particular weld some box section with spreader plates across to mount a seat, and weld in some plate brackets to mount a roll cage to. I believe the chassis has been galvanised before being painted, so in terms of prep work I was going to remove the paint, but I’ve also been reading about the dangers / problems welding steel to galvanised surfaces. Because of the thinness of the material I’m welding to I don’t think angle grinding the zinc off would be easy without going too far and making holes in the car, so I was thinking of trying either an abrasive wheel or wire brush bit in a drill. So, the question is, will it be visually obvious when I have got through the layer of zinc and I’m back to the steel ??

Thanks for any advice
Alistair

 

[piman]

Hello Alistair,

yes the steel is a slightly different colour. I would go for an angle grinder with flap discs.

Being a car body, the galvanising will be very thin not like hot dip galvanising you see on handrails etc.

Alec

 

[zardoz]

make sure you weld it outside of possible, and if you see and white smoke coming from the galv, stop welding and move away, then rub off a bit more of the offending top coat.