So we pulled the mats on our used 2000 Hart today so we can give  it a good cleaning. I really wanted to check it better for pits and what not. So we pressure washed it and there is quite a bit of corrosion on the floor. A few pits but nothing that is too deep or all the way through the floor.

I would like to put the spray in bed liner down before putting our mats back in the trailer. But I have some questions since this is our first alum. trailer.

Will the corrosion continue to get worse if we cover it with bed liner and no longer allow urine to touch it??

Is there something we need to put on the corrosion to stop it??

I also didn't find any drain holes in the floor. Shouldn't there be some?? Can we drill some ourselves??

You have to chemically stop the corrosion before you can apply any coating over the bare aluminum. This is done by acid etching.

I use muriatic acid that I purchase from Lowes. Sweep the floor and pressure wash if possible, you do not have to scrub any contaminates. Move the trailer to an outside area. Do not apply this acid inside any closed structure, barn or garage. Open all the trailer windows, close the pass thru door to your LQ.

YOU MUST USE A CHEMICAL RESPIRATOR TO APPLY THIS ACID. They cost about $40 and have a charcole filter. A dust mask is worthless with the resulting fumes. Wear old shoes, long pants, gloves and safety glasses.

Pour some acid on about a third or quarter of the floor area and quickly spread  it around with a short bristle brush. I use a roof coating brush. You will immediately see fumes rise from the floor; leave the trailer quickly. The acid will start showing bubbles after a minute or two. After about 10 - 15 minutes you will see an even foam of bubbles, with the most reaction being where the floor was the most corroded and dirty. Re-enter the trailer and agitate the wetted area with the broom and leave it for another 5 minutes. Rinse the floor with water and inspect the area, spot reapplying as necessary until the floor is an even color, and there is no black or brown spots in the corroded areas.

Do another third and the last the same way, working towards the door as you go. When you're done flood the floor several times with water. Let it dry overnight and the next day you can apply your coating.

I use a bed liner product that can be sprayed, rolled or brushed. Using a roller,three or even four coats can be applied in one day, and the durability is outstanding. I was quoted $750 for a sprayed Rhino coating like in my truck, I purchased my own materials for less than $100.

I bought a Kubota RTV utility vehicle that has a  hydraulic tilt, truck-like steel bed two years ago. Before we used it, I coated the bed with the same bed liner material I've used im my horse trailers. This vehicle is used to muck out stalls, it has hauled gravel, firewood, sand and much manure. It is stored in the stall area. To date there is no rust or even a chip in the bed liner.

Your horse trailer floor is covered by the stall mats and is not subject to the type of abrasion as in my Kubota. At the end of each season I pull the mats, wash it out and I'm done. During the year I do nothing, and the floor looks like new. While you are rinsing out the floor, you can see where the water puddles, usually along the wall seams or rear floor threshold seam. Drill a 1/4" hole at the lowest point and you're good to go.

This is an easy two day job and will greatly contribute to the longevity of your precious trailer.

Best of luck             Gard

the acid will not eat through the flooring when used in a short duration. It will aggressively attack the corrosion and only clean the other areas.

I bought "Duracote" black bedliner at both an auto parts store and a Walmart that had an auto section. You do not need the whole application kit that the auto parts store sells, only the paint which comes in a gallaon can. One gallon will cover two coats on a three horse trailer. I would recommend at least three coats on the butt half of the floor. Two gallons will give you four coats, a life time of protection

Best of luck

Gard

First of all I made a mistake. The product "Duracote" that I named, is NOT the coating that I used in my trailers and utility vehicle. That is a product that I have considered for other projects, and costs 3 times more than what I used.

The product I did use and will discuss is "DUPLI-COLOR" truck bed coating. (black) Again, I purchased this at an Autozone parts store and a Walmart auto center.

On aluminum, by acid washing the area, you are providing a clean, ready surface to be coated. It is now etched and corrosion free. On steel, the manufacturer recommends that all the areas be sanded, abraded and cleaned before application.

The manufacturer recommends two coats. On a three horse trailer with a rear tack, one gallon will give you a two coat coverage. I bought two gallons and put down three coats, and kept the rest for other projects.

Several seasons ago I treated the stall floor of my Sidekick trailer with this product. We bought the trailer used, and when we pulled the mats, we discovered active corrosion and pitting that had never been treated since new.  Since then, at the end of each season, the only maintenance to the floor has been to pull the mats and hose the floor down. You do not even have to use a pressure washer.

The coating continues to look new, and with the mats on top, has no chaffing issues. As I previously posted, I also coated the steel bed of our utility vehicle. This liner is constantly being subjected to all sorts of abrasion, urine and manure, and again, after two years, shows no wear or chipping.

This weekend I coated the floor of our Exiss which we bought used this summer. It had been consistently cleaned and only showed minor corrosion with no pitting. It now has a new black floor underneath the factory mats.

This stuff would probably work well on steel wheelbarrows, wheel wells, any place where abrasion and durability are a factor. I wish it were available in colors other than black.

Two gallons of "Dupli-color", one gallon of acid, a roller cover, and one cheap paint brush, last week set me back about $100. Actual work time is two or three hours, the rest is waiting for things to dry. You're getting a lot of product for a minimal price.

Best of luck   Gard

Please let me know how it turns out out for you

Gard

If the floor is new as delivered from the dealer, meaning it has never been used or subjected to urine, I would think that you can apply the coating without an acid wash. You would still have to wash and scrub the floor to get off the oils used in the manufacturing process.

But, if it is a few months old, and even while looking new, you still will have to stop the corrosive effects of acids and clean the metal. A water rinse is not enough. This is best done by etching.

Etching is not that difficult or expensive. It is similar in price and labor to washing. ($10-$15) The most difficult part is dealing with the fumes. Muriatic acid is not very strong, it is what brick layers use to clean mortar joints. But is does react quickly to aluminum.

Some of you seem to have the impression that it will eat its way though the metal. It may if left in a bath for a long length of time. I don't know since I'm not a chemist. But when you're using it as a wash for a half an hour at a time, it results in a strong cleaning action, not a metal dissolving reaction.

If you have any further questions, let me know

Best of luck     Gard

What about just using something like aluminum wash and brightener? It has a certain etching effect.

I'm not trying to imply that you don't know what you're talking about,just trying to get out of using something that strong.I don't like to deal with chemicals as strong as muriatic acid.

If the floor is new, the aluminum brightener should work well, much better than soap because it does lightly etch the metal. Good idea.

Most of the time I don't know what I'm doing or have all the answers. But I try to fake it as much as I can, to get through life as easily as possible. Asking a lot of questions has solved many of my problems, and I'm very thankful to the people who have provided them.

Having different ideas doesn't mean there is an argument, it just means that there are different ways to solve the same problem. Some are better than others and your's are better than mine.

BOL  Gard

I just happened to think that if the brightener has any wax or silicones in its mixture, it will NOT work. I've never used a brightener, so I don't know its make up. Check its ingredients before using.

A properly prepared surface is one with bare metal and no contaminates on its surface.

Gard

Thanks for all the help Gard. Now I have one more question, not just for you but anyone with experience. I went out the next morning once the floor had dried from pressure washing it. I got a better look and we have 2 small pits that go all the way through. They are about the size of an ink pen tip. The one I acutally made bigger by picking at it with my fingernail. It had some dirt in it and I was trying to see if went all the way through. So by being able to pick at it and make it bigger scares me.

Do I need to repair these spots since they are so small?? If so how??

Also I'm assuming the acid etching like you said WILL for sure stop the corrioson in its tracks even on the pits that go all the way through?? I'd sure hate to cover them up and not be able to see if they get worse ya know. So I'm just doubleing checking

Several years ago we did an inspection on the rear belly of a commercial aircraft. We saw some whitish streaks with black dots in them. Touching them with a screwdriver left several holes as big as your fist. We ended up re-skinning a major sized panel.

Many people think that because aluminum doesn't rust, they own a maintenance free structure. Urine, road salts, any acidic material is destructive to an aluminum trailer. Owners take pride in keeping the shell sparkeling; when is the last time you have heard of an owner washing the BOTTOM of his trailer? If you live in a snowbelt area you wash the bottom of your car.

Corrosion on aluminum is similar to rust on steel. When you see a little blister on the paint, you probably have rust holes underneath.

Your trailer has active corrosion. You have to determine the extent of the damage by poking,  prodding, doing whatever you can to open up the holes until you reach good metal. A rat tail file works well. Then you acid etch to stop the rest of the corrosion. Now you can start the repairs.

If the holes are small and tapered, you can use a two part epoxy like "JB Weld" (liquid metal) If the holes are larger, (dime sized) you will have to have them repaired by welding in patches or panels as required. This can only be done by an accomplished welder that knows about, and has worked with aluminum. Check your phone book under welders and fabricators or as a last resort an RV repair facility. I say last resort because most RV places charge outrageous hourly labour rates.

Once the repairs are finished and the floor is etched, coat with the liner material and you will propably never have that problem again.

Best of luck   Gard

This works great under trailers...

North Star Stainless Steel Under Car Cleaner — 16in.

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200330915_200330915

You can also use a $15 lawn sprayer

Gard

DON'T SPRAY the acid. The atomization will aggravate the fume problem. Pour it from the container onto the floor and spread it with a broom. You will almost immediately encounter the fumes. They will be strong at first and it's best to leave the area. After a couple of minutes, go back in, spread it out more evenly and leave it alone for 15-20 mins or until you have a relatively even coating of foam. If you have a problem area, add more acid without flushing the area with water.

Do about a third of the trailer at a time. When everything looks good to you, FLOOD the floor with water. Let it dry overnight. The next day is easy using a roller on a broom handle, and a brush to get into the corners. The liner drys in a little over an hour depending on the temp, I would wait a little longer to recoat.

You will be very pleased with the results

BOL  Gard

Lawn sprayers don't have the spray intensity...

45-60 psi (household water pressure) is enough to flush off acid contaminates on an undercarriage

Gard

Probably so,but,it is not as strong as the straight stuff,because I have some by Streakmaster and it does not smell strong,and I don't have to leave the inside of the trailer when I wash with it.