Dear Lettie,
I’m going to repaint an old galvanized iron roof. Some parts have rust. Can I remove the rust just by sanding? What grit of sandpaper should I use to remove rust from the metal?
Thanks!
From,
Boysen User A
—
Hi Boysen User A,
Treating rust typically requires two steps. The first step involves manually removing the rust by using sandpaper and a steel brush. The second step is to then use a chemical treatment which further removes any remaining rust on the surface.
Though the first step can be enough to remove all the rust, it’s still much better to follow through with the second step as this helps ensure that you get all the rust out. Remember, the rust will only come back or even worsen if you don’t do a good enough job of removing it.
Short answer? You can remove rust just by sanding but I would still recommend a 2-step rust treatment process—that’s sanding and then a chemical treatment afterward. Here’s a more detailed rust treatment guide you can use as reference!
Step 1
With a steel brush and sandpaper, manually remove any rust you see. Use 120 to 140-grit sandpaper.
Step 2
With a rag, clean the area to remove any sanding dust and dirt on the surface.
Step 3
To the remaining rusted areas, apply Boysen Metal Etching Solution using a brush. Wait for 10 to 15 minutes and repeat if you still see rusting.
Step 4
Once all the rust is gone, remove any Metal Etching Solution left on the surface. Do this by wiping thinner on the areas using a clean rag.
Step 5
Apply primer to areas where rust treatment was carried out to avoid flash rusting. Proceed with your chosen topcoat afterward.
If you need a full step-by-step guide to repainting a rusted metal roof, watch this Boysen PinTanong episode.
Hope I’ve been helpful. Good luck!
Your painting partner,
Lettie
Need advice? Paint TechTalk with Lettie is here for you. Comment your painting question below or send an email to ask@myboysen.com.
