Prep for painting a bus

SethThomas22 · 02-13-2016, 05:09 PM

Hey quick question. I am looking to do a little bit of prep work for painting two school buses that our church just bought. First off, I heard that you would need to peel off silicone around the windows and scrape it completely off.. Is this true? Secondly, do you need to get an expensive sander to sand the surface with or can I use a more simplistic method?

roach711 · 02-13-2016, 08:49 PM

Some silicone caulk is paintable but you won't know whether yours is until after the bus is painted. I would scrape the existing stuff off and replace with something you know is paintable.

Hand sanding is the cheapest way to go if you don't have a power sander available. You just need to sand until the gloss is gone to give the new primer/paint something to bite into. Wet sanding with 320 or 400 grit wet/dry paper should do the trick.

onenationundergoat · 02-14-2016, 11:53 AM

When we painted our bus there wasn't any silicone around the windows. If you have a long time to get it done, I'd say test paint the silicone and let it dry a couple weeks then see if it peels off easily. If it doesn't, then just go ahead and paint over it. If you have any leaks, though, just go ahead and redo all the caulk. You can hand sand it with 320 or higher grit, but an electric or air sander makes it a lot easier. It doesn't take much, just a scuff, but it's a lot of area to cover. Make sure to wash it good first. We probably had over 100 hours of prep work for painting, because our clear coat was 50% peeled off and we had to go over the entire bus with razor scrapers to remove it all. It was like a peeling sunburn.