help sanding trailer

[mysavioreigns]

I have a trailer that needs a lot of TLC -surface rust, 2 layers of paint, mud, etc.

Problem is, I can't figure out how to sand the inside of the frame channels. I have a 4" angle grinder but it's just barely too big. The wire wheels and wire cups work okay but won't remove the original paint worth a flip. The nylon composite sanding pads work VERY well but, like I said, they're too big for the frame channels. I believe they're mostly 3" channels.

So what tool could I use? Electric or air is fine, I just don't know what to use...

Thanks

 

[Brine]

Cup Brush should get it good enough to paint.

Why do you want to take it down to bare metal?

 

[mysavioreigns]

Well, that is a good question

I originally just started sanding away the surface rust and just made my way down to metal. I will be shooting epoxy primer on the trailer, so I figured I'd have to go to bare metal. After some research, though, I see that's not necessarily true. It's preferred, but it's not a rule. So I'll probably just sand down as much as I can easily, and then use a die grinder to get in the nooks & crannies behind welded frames, etc., and then shoot the epoxy primer.

edit: I also just bought a much higher quality (DeWalt) cup brush than the ones I had been using (cheap HF stuff) and that should help do the job better.

 

[lckstckn2smknbrls]

Chemical strippers work well in tight spaces.

 

[Wallijig]

Can use sand blaster also. Could get most any where to get paint and rust off.
Under $60
https://www.northerntool.com/shop/tools/product_33184_33184
https://www.sears.com/craftsman-50-...p-00916706000P?prdNo=1&blockNo=1&blockType=G1

Other type under $30:
https://www.sears.com/pneumatic-gra...SPM6085769901P?prdNo=9&blockNo=9&blockType=G9

 

[nomowork]

I've used Rustoleum rust reformer on metals where sanding or grinding was impractical. Just wire brush or scrape off as much of the surface rust away as possible them brush or spray it on. It converts the rusty surface to a solid shiny finish.