although aluminum is impervious to rust, it is still open to corrosion not to mention a steel axle being bolted to it. This weekend I picked up my new Catalyst and once back to the shop I noticed a tilt to my rear left wheel on my trailer which is an inline enclosed steel framed trailer. it is from 2007 and years of parking it behind shop in the grass (which probably was not a good idea) finally took its toll. the rear axle had broke in half, tore the front of the axle mount from frame, twisted the rear, while under there noticed the front r/h axle mount is also separating from the frame and the bottom of that torsion axle is also split wide open and rotted as well. luckily I made it home without a trailer disaster on the interstate. Im going to retire the trailer for storage here and buy an aluminum trailer, I have had them in the past but my question is, does anyone spray the underside of frame with any kind of metal protector? and if so what do you use or have luck with?