Greetings all!  I just purchased my first horse trailer; it's a 1983 Arndt 2H BP.  As you can guess, it needs some work (it's been sitting for ~2 years), but I'm hoping it will make for a good starter trailer.  It's currently at the metal fabricator's to make a couple structural repairs; I'll get it back at the end of the month.  Since I took it directly from the seller to the metal shop, I haven't had it home yet to really tear into the other mechanicals to see what all needs to be done...

What I DO know is, the lights all work (yay!), and it needs a new breakaway brake system (the cable for the existing one is broken, and the battery is shot). The tires look to be in good shape, but they are of a questionable age, so I'm probably just going to go ahead and replace them as well.  I don't know what kind of shape the brakes are in; I didn't hook them up when I moved the trailer from the seller's to the fabricator's, because I didn't want to risk them locking up and not having the tools available to deal with it on the road.  Fortunately, I have a very mechanically-inclined neighbor who's going to help with the brakes, repacking the hubs, etc., once I bring it home from the fabricator's.

My next question is, what's a good product to deal with the rust??  The roof is the worst area; it's going to need to be sanded and repainted.  I'd also like to sand and repaint the interior (at least the upper walls and roof of the interior) which is peeling/flaking pretty badly.  The exterior walls are in pretty good shape; I'll probably leave that alone for this year.

In browsing old threads, I saw mention of a product whose name escapes me now-- something like sylpho??--that looks like a dark green liquid, supposedly converts the rust to a black layer which can then be painted over.

If $$$ was no object, I'd take it to be professionally sandblasted and repainted, but this is going to be a DIY job... I really don't want to sink $$$$ into a 30-year old trailer.

The easiest way to remove rust is to use a 4 1/2" angle grinder fitted with wire cup wheels. Inexpensive grinders can be purchased from many sources that will complete your trailer. The same grinder can then be fitted with cutting, grinding and sanding discs, all of which are handy for restorations. For less than $20, this single tool will provide most of your labours. If you anticipate further projects, more expensive industrial units can be sourced that are three to five times that cost. For large flat rusted areas, a 5" random orbit electric sander works especially well. A good one will cost ~$50 -$70 and can last a life time. Purchase your sanding materials on line such as EBay, for a fraction of the cost of hardware or big box stores. Klingspor's has excellent commercial materials at nominal pricing. I've dealt with them for some time and have been very satisfied.

Once the loose rust is removed and the metal is ground smooth, OSPHO (phosphoric acid) can be brushed or sprayed over the whole body of the trailer, inside and out. This will result in a blackish surface that can be painted over with a primer and then sprayed with your final colour applications. It also acts as a good base for body fillers and will not inhibit any welding. The Ospho is not a paint and will have to be over coated or else rust will again be present. The Ospho doesn't prevent O2 from reaching the steel's surface, which is the reason for rust.

By doing most of the work as a DIY project, you can save a majority of the costs. It is also very gratifying to have the final project a testament to your efforts and skills.