I have a steel framed trailer with aluminum skin inside and out. (Don't want to get into What Brand). It is a 2004. The aluminum is put on with two sided tape. There are spots where the aluminum is turning into powder. One of the spots is near a window. Last week end I pulled the window. There is no paint on the steel just rust. The rust was piled up in a corner of a joint and resting on the aluminum. From what I can tell, no paint or anything protecting the steel anywhere. I bought the trailer used and I really like it other wise. It looks like a very big job getting the aluminum off to paint trailer frame. If it took five years to show spots is this something that you just have to live with. any suggestions Is there any way this could make the trailer unsafe. Most of the spots are about the size of quarters. That would be a couple of dollars worth.
Posted 2009-05-22 9:55 AM (#105319 - in reply to #105307) Subject: RE: Steel touching aluminum
Regular
Posts: 54
Short answer is YES!! Your trailer could be unsafe. I would tape off and paint any exposed surface. Is the electrolysis(powdered aluminum) on the floor or only on the sides? Are the doors and drop down windows doing this only? With that information someone can give you the best course of action to fix your problem.
Posted 2009-05-22 11:14 AM (#105324 - in reply to #105319) Subject: RE: Steel touching aluminum
Member
Posts: 31
The floor is wood over steel. The problems are only on the aluminum sheets inside and out. All of the exposed steel is painted,it is the stuff on the inner wall that is not. When I removed the window, you can see the steel that the windows are mounted on and they are un painted and rusting. the only spot that I could get to had a pile of rust that had fallen from the steel an collected in a joint. this was rusty steel touching aluminum. I can only assume that that is what I would find if I pulled the aluminum sheets off and looked. I thought I could loosen the aluminum and go in and over spray the steel. But there is foam between the aluminum so that won't work. Unless some one has an idea I think this is something I will have to live with.
Posted 2009-05-27 2:47 PM (#105549 - in reply to #105307) Subject: RE: Steel touching aluminum
Member
Posts: 31
I'm thinking that would be a little less than ethical selling it with out knowing the extent of the problem. Over the week end I drilled holes into the aluminum and took a tube and blew in a anti rust primer. Then filled the hole with a screw. Don't know how much coverage I got but it was something, Also cleaned up the bottom and re-undercoated. Plenty of rust down below but it was something I could fix. I don't know if I would have bought the trailer if I knew what was going on. Other than that it has served me OK. I just hope the problem is checked.
Posted 2009-05-28 9:33 AM (#105616 - in reply to #105549) Subject: RE: Steel touching aluminum
Expert
Posts: 5870 Location: western PA
Originally written by luckysid1 on 2009-05-27 2:47 PM
Over the week end I drilled holes into the aluminum and took a tube and blew in a anti rust primer. Then filled the hole with a screw. Don't know how much coverage I got but it was something, I just hope the problem is checked.
I'm afraid that your efforts were for naught. The proximity of the aluminum and steel has caused a galvanic reaction between the two dissimilar metals. Whenever two dissimilar metals touch, the softer of the two will suffer the most. Your white powder is active corrosion and a failure of the structural integrity of the aluminum sheeting. The only repair is the replacement of this metal.
The only way to prevent any future damage, is to physically isolate the two metals from any electrical contact.
You have a major reconstruction to consider, one that may exceed the value of your trailer.
Steel touching aluminum
I have a steel framed trailer with aluminum skin inside and out. (Don't want to get into What Brand). It is a 2004. The aluminum is put on with two sided tape. There are spots where the aluminum is turning into powder. One of the spots is near a window. Last week end I pulled the window. There is no paint on the steel just rust. The rust was piled up in a corner of a joint and resting on the aluminum. From what I can tell, no paint or anything protecting the steel anywhere. I bought the trailer used and I really like it other wise. It looks like a very big job getting the aluminum off to paint trailer frame. If it took five years to show spots is this something that you just have to live with. any suggestions Is there any way this could make the trailer unsafe. Most of the spots are about the size of quarters. That would be a couple of dollars worth. 
