Weld / seal it and then pressurize it. It will still continue to rust at this point though.

ALL MARINE TRAILERS SHOULD BE ALUMINUM... PROBLEM SOLVED!!!

will painted custom trailers on eliminators or DCBs such as extreme trailers rust ? even if maintained and washed properlly?

I wouldn't get any steel trailer near salt, if you're boating in salt get an aluminum trailer, it'll prevent future headaches and be a plus when you go sell it. I won't buy a boat that has a steel trailer, many of coasters won't.

Yes, and much faster if used in saltwater! I never recommend steel marine trailers at all. Some guys like the way they tow. Great, if you dont mind the extra weight, shorter life expectancy, having to repaint them every so often, and poorer resale value on your used boat/trailer package (since 2/3 of the buyers boat in salt)...

HAAAA!!!! 2/3 of the buyers boat in salt? I bet there are more lake lickers here on this site (and in performance boating in general) than real offshore boaters.

Does anyone have any first-hand experience at sealing or pressurizing a box trailer? An Eagle trailer came with a boat I recently purchased, and I'm trying to decide whether to deal with it or sell it. I've owned an aluminum and a steel Myco, so I know the drill.

How do you get dawn into engine? does it come out the exhaust foamy?

What you say is true...however I have found a way to slow it down. On the way home from my coastal ramp I found a fresh water lake with a ramp to dip mine in...I'm lucky...only 15 minutes out of my way but it's worth it.

sell it if you can. if you decide to keep it fill the trailer with nitrogen & install a pressure gauge so you can tell if you have a leak. they will rot from the inside out because you can't paint the inside properly.

I used to fold the hose about 6 inches back pour it in then put the quick connector on.The soap goes in first when I did it on the lift it did make some suds in the water not sure if it really does any good though