Thread: Restoring Metal objects and surfaces

Thanks Bob for a very informative thread. I bought 250ml of Fertan last week and it cost $32. I am going to start a WWII Jeep restoration. I did, a while ago strip all the paint off the front guards and grill. I foolishly just put them aside and of coarse the surfaces have a good but light coat of rust. One thing about the surface rust and its treatment may give the paint a good key. I have at times painted disc sanded steel that was really shiny, but it wasn't long before the paint "fell off".

Originally Posted by chambezio

Thanks Bob for a very informative thread. I bought 250ml of Fertan last week and it cost $32.

Ouch!

I am going to start a WWII Jeep restoration. I did, a while ago strip all the paint off the front guards and grill. I foolishly just put them aside and of coarse the surfaces have a good but light coat of rust. One thing about the surface rust and its treatment may give the paint a good key. I have at times painted disc sanded steel that was really shiny, but it wasn't long before the paint "fell off".

That's also been my experience. The blue oxide coating on standard commercial steel also seems to need some sort of etching.

Here is a full sunlight pic of the two treated surfaces on the sanded metal some 18 hours after application.
It's been a dry night and the PA treated surface has fully dried out and is flaking.
The small shiny patches on the edges of both plates suggest further treatment would be appropriate.

Its some 3 weeks later and I thought I'd post a photo of how this experiment is going.

Just a reminder of how these bars started out


These bars have been left outside under an open veranda where they would have been exposed to some spray from several heavy showers we've had during the exposure period.

Top bar is as supplied from steel merchant, blackened steel plate, TA coating on left and PA on right
Lower bar was sanded back to bare metal, again TA on left and PA on right




It's hard to see on the top plate but there are patches of rust in between the black blotches of the PA application.
Although there is a bit of rust on the TA side on the lower plate the TA appears to be outperforming the PA.

The other thing I notice is that application of both PA and TA onto the black oxide steel bar works better than for bare metal
I suspect that even a light rusting converted to either a tannate or phosphate is more protective than coating the bare metal - so the conclusion here is to let your work rust a tad before conversion

A major advantage of the TA is that it dries to a thin coat so multiple/repeated applications are not going to make anywhere near as much of a mess as repeated PA application. I have started to do that in the shed. As soon as I seen a rust spot somewhere I wipe a tannic acid soaked rag onto that spot. It would also possible to do this for tooling like shanks and bits as the TA coating is so thin in most it will not affect tolerances. One thing to be a aware of is that the TA coating is not physically robust and will rub off so repeated applications are still needed.
I don't have that much of a rust problem on tooling probably because I use lube and just blow clean the tooling before putting it away.