I'm planning on having the Jeep undercoated so it will last as long as possible. It is fairly clean underneath. I have a good shop to go to that uses Corrosion Free stuff.
They said they should be able to get inside the frame pretty well as there are lots of access holes, but I wondered if I should pressure wash it out first or just leave it?
How long you think it would take to dry out before I got it coated?
Should I bother drilling any drains etc?
Just my opinion here but I would probably not pressure wash inside...what you could do is take the nozzle of an air hose and blow out what's inside it...I did that with mine and boy did alot of sand and all kinds of crap come flying out of it! At least with the air hose you are not adding more water to the inside of the frame which you may or may not get all out, and sitting water would be one of the last things you want inside the frame I'd think...
I drilled drain holes in mine. I can't recommend or not recommend that. You don't want to weaken the frame, in any case, especially if it is already thinned by rust.
Time will tell if it works for me, but I reasoned that my frame had big openings in the sides from the factory taking in water and other splash, and holding it inside.
After blowing out the frame and treating the insides, I covered most of the splash prone openings with metal tape and a couple coats of rubberized undercoating--leaving some inner ones open for ventilation.
I drilled 6, 5/16" drain holes along the low parts of the bottom of the rails and painted the drilled metal. Treating the insides, I used rust catalyzing primer (rust converter) from spray cans. The spray from the cans was directed into a stream of air from an air compressor using a blow gun nozzle to help atomize the spray and carry it through the frame until a "fog" was coming out the other frame openings further down, and worked my way down and back along the frame rails. After this was dry and cured for a day or two, I did the same procedure using 3M Rustfighter 1 in spray cans. I used about 1-1/2 cans of the Rustfighter I, all together. After that dried for a day or two, I went around to make sure none of the drain holes were clogged up with any of these products.
After all this I cleaned and painted the outside of the frame and did the rubberized undercoating on the outside only.
...Just what I did to mine.
In God we trust.
All others bring data.
Had mine undercoated. They told me not to wash it before in case there was any moisture that they couldn't get to and dry. I believe they went through with an air hose and blew it all out. Got it done at Ziebart.
Originally Posted by SinfulDragon
Go big or go home is all I can think of from this statement
I drilled my frame as well, I only put one hole in each side, but hey, if ones good... two must be better, right?!
I meant six in each side...so 12 altogether. I was concerned about weakening the frame too much with big holes on the tension side. If I recall correctly from Statics and Strength of Materials, hole size concentrates stress as a function of the square (or cube?) of the diameter. Anyway, something like doubling the size of the hole weakens a member by much more than double.
In God we trust.
All others bring data.
I did indeed end up taking a pressure washer to the rails. I poked it in thru every holes I could get at and ran water till it was clear and worked my way to the back (didn't take long at all actually!)
The rails look quite smooth and clean inside, I was really surprised.
Taking it in Thursday to get undercoated. The place I go to does an amazing job (I've had them do another car in the past a few times.)
I did chicken out on drilling additional holes though, but with how clean they were I don't think I need to right now anyways.
Don't forget now that the underneath is nice,nice.Periodic rinsing should be included say every other oil change? I'll be on my 3rd.season on the beach weekly after every time off beach, park vehicle on a slope start front outer and inner complete rinse to rear.Then drive to dry.I have zero rusting including all bolts and threads.Use self-etching primer for touch-up.I think road salt is just as bad as driving in the surf.Rinse faithfully.