How to strip water based semi gloss paint off of existing oil based paint on door frames?

[JamesMarshdale]

Hey there,

The situation is this: my partner and I have begun painting our apartment walls which includes the door frames. The door frames are made of metal with what I am sure is some kind of oil based cream coloured paint. I attempted to paint over them with Taubmans Water-based Enamel Semi-Gloss paint, however not only did I not think to sand the door frames before I put on the first coat I was under the impression that as the door frames had already been painted I would not need to use any sort of primer. You can see that the result is less than impressive. The technique I used was quite poor (I was lead to believe that the first coat could be rough as it was just to cover and the second coat would neaten it out.)

This is an example of how the paint has set in one section. I can't really get any other better photos unfortunately.

We have 6 door frames that look like this that we need to strip back and start again. I've used Acetone to strip the paint which gets mixed results (some places strip better than others) and I have also borrowed an electric sander as manual sanding appeared to take too long with slow results. The electric sander works, however it appears to be removing the original coat of paint and is showing the metal underneath.

I suppose my question is this: Is it worth the time to strip the paint right down to metal and start again? Or is it best to keep going with the acetone (or any other effective means of removing the paint) to strip the paint back to the original cream colour and work from there?

Any assistance will be greatly appreciated.

[EricL]

Hello @JamesMarshdale 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about painting your steel door frame.

Your objective is to remove the water-based paint you've put on the surface of the oil-based one. It's not necessary to sand all the way back to steel, but the surface must be sanded down to a very dull finish with the majority of the new paint removed. Because the majority of the oil-based paint is still attached to your steel door frame, I suggest using an oil-based primer. An example would be the Zinsser 1L CoverStain Primer Sealer Stain Blocker. Once the primer cures you can then use a water-based topcoat.

I suggest having a look at this discussion - How to paint metal door frames by @homediynoob. Please note that although we recommend using the Dulux 1L PRECISION White Maximum Strength Adhesion Primer this is on the condition that all the paint will be stripped from the steel frame.

If you need further assistance, please let us know.

Eric

[JamesMarshdale]

Hey Eric,

Thank you for the response. In regards to sanding down the paint, which grit sand paper would you recommend to get the job done? Also would I be able to use an electric sander to get the job done or should I be doing this by hand?

Thank you!

[MitchellMc]

How well adhered is the paint you applied @JamesMarshdale? If it can't be scratched off easily, then you might just have to sand it enough to remove the brush strokes, and that would only require 180-grit sandpaper.

You can use an electric sander, but as you've experienced, it's hard not to go through the bottom layer of paint, too. Personally, I'd be using the electric sander; it's not a big issue if you can go back to the steel.

Just to clarify, was the issue that you could see brush strokes? I wouldn't exactly say the finish you've shown is bad; it would be quite acceptable by many people's standards. You might like to use a short nap roller when re-applying your new paint. You've likely experienced this issue due to touching areas that have already begun to cure. It's best to lay the paint on, then go back over the area to smooth it out, and then not touch it again. The paint will self-level, and by touching it, you can interrupt this process.

Please let me know if you have any questions.

Mitchell

[JamesMarshdale]

Hey there Mitchell, the issue wasn't so much that you could see brush strokes (although it was a lot more obvious in my case, it's hard to show in the photos) it was also that the texture of the paint was rough to the touch and had a patchy textured surface, whereas the original coat of paint was quite smooth and flat. I figured the best thing to do now was to remove the new coat and start again since any coat I put over this one would be just as rough and uneven.

If I use a short nap roller, would I still need a brush to cut into the corners of the door frames?

Thank you!

[EricL]

Hello @JamesMarshdale 

There are areas where the short nap roller will not be able to reach. It will therefore still be necessary to use a cutting brush to paint those areas.

Please keep us updated with your progress, we look forward to seeing your door frames freshly painted.

Eric