Pre-paint cleaning?

I have an older (1992) two place horse trailer I'm "re-purposing" to store our IHC
Collector Club signs and such. Beats keeping them in my shop!!! The trailer is
in amazingly good shape. The wood floor is great, very little deteriration, mats in good shape
and only surface rust on the outside. No rusted thru spots. Apparently it was not used
very much for horses or stock. I would like to repaint it (someday!!).
It is a faded gray with some surface rust. I plan on removing the aluminum trim pieces, as they are only
pop-riveted on. I would like to do a two-tone, probably red and white.
I visited with the Shermin-Williams auto paint shop the other day. He suggested
go over it lightly with a sander or wire brush, especially the surface rust spots, then washing it with
a solution of TSP, carefully following the instructions. Then use a good etching primer
that does not require sanding, then paint it.
I am wondering if anyone here has used the TSP for cleaning and how successful you were.
I don't relish the idea of stripping it to bare metal and starting from scratch.

P.S. I'm also planning on removing all the windows and such, too.
They are just pop-rivited in, so easy to remove and replace.
Only one window is in a rubber gasket. The other windows are sealed
with silicone, so I'll have to do a good job of cleaning it off, too.

I have not used tsp for pre-paint clean-up. That being said, your goal before preparation is to get the surface completely clean of any loose soil, oil, grease and silicone, etc. A good, strong detergent and hot power wash should do. Prepare by sanding everything and cleaning again with prepsol or equivalent. The etching primer is a good choice but I always scuff it with Scotchbrite no matter what the instructions say.

TSP is a great cleaner for grease and general grundge, but not for just plain rust. What you want is to get the big stuff with a cup style twisted wire wheel, Then apply rust converter to "kill" the rust so that it is not popping through again in two years. Rust converter is expensive but it goes a long way. You could also get milk stone remover from a dairy supply or limescale remover from a restaurant supply either of them has the same active ingredient as the rust converter but costs a lot less. The advantage to actual rust converter is that you have the instructions to follow. Once you have the rust well treated you prime with epoxy primer.

Your paint is 29 years old and has done it job and now worn out. What surface rust spots you are seeing is the tip of the iceberg, the metal is rusting under the paint. If you want the paint to last you need to sand as much of the old paint off as possible and start over. Otherwise as the old paint completely fails it will take off the new paint with it. The TSP is a good cleaner however I've had as much good luck with purple power.

Even if you don't strip the paint down to bare metal I would recommend at least sanding it with 220 grit paper before priming. The scratches created by the sandpaper will create a mechanical bond for the paint. It helps the paint to have something to grip. Depending on what topcoat you are using the etching primer should be fine. Epoxy primer if it's compatible with your finish would be better. Be careful using automotive finishes, many you need to suite up and use an air supplied respirator to spray them. Especially look for the word isocyanate in the list of ingredients. It's really bad stuff. I sprayed two gallons of it onetime outdoors with a cartridge respirator on holding my breath when down wind from the paint and I coughed for six months.

Hi Wheat 47 what chapter of the IH collectors club are you involved with. I am presedent of Chapter 45 witch is the Great Britain one. MJ.

We are Chapter 40, basicly the state of Montana.
At least I know of no other chapters in the state at this time.
One of the reasons I'm re-purposing the trailer is to be able to
take our signs and supplies to another show site.
We had our anual show in Ryegate, Mt for 5 or so years, then last year we moved it
to our place, near Billings, Mt. which is about 75 miles closer.
The tenative plan is to have the show here for 2 or 3 more years, then move it up
to what we call the Hi-line, about 200 plus miles to the north, not too
far from the Canadian border.
When we moved it here, we gained several new members who brought more tractors and
machinery to show off. The idea to go to the Hi-line so the people there can show off thier
toys with out having to haul them a hunderd or more miles.
With our signs and supplies in the trailer, we can say, "Where's the show??
Take the trailer and go!" Besides, it gets the stuff out of my shop!!
I have enough (too much) "stuff" in there anyway!!!

Thanks, everyone for your great replys.
In chatting with a few local friends, you guys all have good
ideas. I probably won't get to this project until this fall,
if not next summer. I plan on gathering up all the tools and equipment
as time goes by, so I'll be ready when the time comes.
Thanks, again everyone.

When you think youve done enough prep let it sit a couple days come back to it again and redo it all do that about twice and youll about be ready to paint