Post Preventive Maintenance

[dale farley]

I know some will say I have too much time on my hands, but that isn't the case. I was washing the bus yesterday, and decided that I would remove the chrome trim around the headlights so I could clean and wax any metal. What I found was about 10 dirt dobber nests. I should have taken pictures before I started the clean up, but I didn't think about it until I got into the process.

Anyway, I also found corrosion in a couple places on the back side of the trim. The nests probably caused/added to this problem by holding moisture in those areas. I have brushed the corrosion away with a wire wheel and finished it with a brass brush. I am wondering what I should coat this area with before installing the trim? I suppose I could use a good primer and paint, but I am not sure if that is the best way to go. The trim is chrome plated ,and the corrosion was the typical white film that appears under chrome. Don't want to have the items rechromed since the outsides (and most of the inside) are perfect. I just want to stop things before they get any worse.

I might also recommend that others take the time to remove the five screws and clean and inspect this area.

[tdelorme]

"I know some will say I have too much time on my hands"

Dale, you have way too much time on your hands. I would have thought a Plastic Shield would have prevented such a problem. Looks like your wiper arms could use a good polishing while your at it.:)

[Jon Wehrenberg]

Dale,

I think you would have to research a little to find the right stuff to prevent further corrosion on the metal base. I don't know if paint, or a zinc rich coating or even coating it with axle grease would be best, but someone in POG (I think) had similar but extensive corrosion in the same spot and the chrome plating was about all that was left and they were having trouble finding a new headlight surround. I think it is important to stop and prevent the corrosion because if the metal fails there becomes a real problem with getting a replacement.

[JIM KELLER]

Dale, I enjoyed this thread. My turn signal housings retain moisture and now I see how easy they would be to replace. I also suspect I have the same problem you have since both Buses are the same year. I have looked for a chrome replacement headlamp housing and found them to be upwards of $ 850.

[rfoster]

Dale, Jim: Time to Trade.

[dale farley]

Ted,
I had to look at the pictures again to see what was wrong with the wipers. I had actually looked at the wiper arms earlier today; and they need nothing, and I know the blades are relatively new, so I realized you were jerking my chain. If the shield is the answer, Jim K. shouldn't have any corrosion behind his.

Jon,
I had considered applying grease, and if I don't come up with a better solution, I may do so. I think I remember knowing (about 35 years ago) that alodine is a good coating to prevent corrosion on aluminum. I am not sure about this application.

Jim K.,
It is rather simple to get to the lights. Since the chrome on the outside of my light housing is in excellent condition and 95% of the back side is fine, I probably won't be spending big bucks on new ones. The corrosion is rather superficial at this time, and I just want to make sure it doesn't get any worse.

[dale farley]

Roger,
I agree, I'll give you my bus and $10K for yours.

[JIM KELLER]

Roger, That Money Tree in our backyard needs some fertilizer or something. Every time I shake it nothing comes out. Perhaps Karen keeps it pruned !

[hhoppe]

Dale: I asume the chrome trim is steel, chrome plated. I would use sand paper to get the bubbles down to bare metal. Naval Jelly has a spray rust disolver. Follow the directions on the label. Next a Cold Galvanizing Compound " Zinc Rich Primer " in a spray can from a welding products supply store. If you want to use a rustoleum exterior enamel over that for added protection. Thanks for waking us all up to a possible problem for our group.

[JIM CHALOUPKA]

Dale, I think the chrome frame is white metal or aluminum. I was told my bus had polished aluminum.

Today when washing my driving mirrors I discovered a similar situation to what you found on the back of the frame, but I found it on the horizontal surface below the mirror glass. On that flat surface water collects and if there is a pin hole where water can enter, then corrosion begins and slowly like a cancer it spreads and eats the pot metal/aluminum in secret. There is no support in the corrosion area for the chrome plating and one day you only have the chrome with a hollow space under it. The chrome then breaks away and you have a pitted ugly casting.

My solution will be to clean the infected area and apply an epoxy over the area and sand that smooth and paint it with a superior paint, Rust bullet.
In your case you may get away with only using rust bullet. For that matter I may as well. We are lucky the deterioration is not visible on the exposed surfaces.

When applying rust bullet wear gloves as any paint on the skin will be there until it grows off.

I am including a link for this paint. There are many uses for it on the bus.

The important thing about the fix is to remove all corrosion, have an oil and moisture free surface on which to apply the paint.

http://www.rustbullet.com/?source=adwords&gclid=CMCt2PeJ8ZYCFQRkswodiRYSYA

JIM;)

[dale farley]

Jim C.
I think the trim must be aluminum. I know it isn't steel, so I think I will treat it as aluminum. I have never heard of the Rust Bullet treatment. Looks like it may do the job. Thanks for the info.

[garyde]

Dale, we use an oxide inhibitor for aluminium wires. You can find it at any Electricall store or wholesale house.

[dale farley]

Gary,

I think I have some of that. I bought a little plastic bottle with a brush in it the last time I did some significant electrical work. That may be what you are referring to. I think it is blue or green.

[sawdust_128]

Clean it and consider a good spay of auto clear coat. You could also use Krylon clear acrylic.

[Jeff Bayley]

Was going to suggest the Naval Jelly for the rust prior to putting whatever you decided on for 2nd coat but someone already suggested that. Don't know how it works on Alluminum but used it on steal before with good results.

After you figure out the rust preventative portion, what about using bottom paint like they use on racing sailboats to keep the bugs from nesting again ? Just an idea, but it contains a poison that prevents barnacles from growing, so maybe it would work on other pests ??? Maybe it's only good for barnacles. Worth writing to the manufacture and asking to see if it might serve as a long term bug nesting retardant. They make two kinds of bottom paint and one sloffes off and erodes by design and is slipprier causing less drag, but has to be recoated the more you use the boat and I belive this one is more poisenous than the other kind that I just used on my boat. You shouldn't have to apply more than once on this application. Maybe the manufacture could tell if it wards off hornets nests also. ???

[dale farley]

So many good ideas. I've been using Ospho rust killer for many years but never tried it on anything except steel. After all the discussion about other products, I read the instructions on the Ospho for the first time in 35 years, (I did read it 35 years ago) and it can be used on aluminum also.

Sprayed the Ospho on the trim late last night, and it looks good this morning. I'll either coat it with Rust Bullet or one of the clear coatings I have in the garage. May cover the entire inside with a clear acrylic as a preventive measure.

[Jon Wehrenberg]

From a metal finisher that has learned some lessons the hard way I suggest you reconsider your use of a coating unless you are certain you have eliminated all corrosion and that you have pretreated the surface of the base metal chemically. I don't know the material you have, whether it is powdered metal, die cast aluminum or some alloy. What I do know is that if the surface has corrosion or has not been pretreated properly any surface finish you apply may actually only cover up the spread of corrosion beneath the surface of the coating.

Aluminum is a bitch to prepare for any kind of coating. Usually an alodine treatment is used, but depending on the metal, surface condition, and the application there may be other surface preps more suitable.

If you think this is a minor issue ask anyone how their Ramco mirrors are holding up. Bear in mind that is a company that makes them by the thousands and is doing the surface finishing in tightly controlled conditions. I would rather have raw metal and have to routinely apply wax or oil or even axle grease, than to put on a coating that will mask the spread of corrosion beneath the coating.

FWIW I protected the underside of a fleet of trucks I had at one time with a mix of the tar like liquid that is sprayed on concrete foundations for waterproofing and motor oil. The tar combined with the motor oil never "set" and it had enough viscosity to stay where it was applied. I don't remember the ratio, but I do remember that in the snow belt (also known as the rust belt) when other trucks the same vintage of ours had rust holes in the fenders and doors ours had no sign of corrosion.

[BrianE]

FWIW, Ospho is a phosphoric acid solution that converts rust (iron oxide) and/or aluminum corrosion (alum. oxide) to iron phosphate and alum. phosphate which are inert and don't progress like rust and corrosion. Used on aluminum it must be diluted more than on steel however the aluminum specific products may be better?? Aluminum also needs a stabilizer to help prevent further corrosion hence the use of alodine, while on steel the iron phosphate conversion is stable enough to be primed and painted. For best results on aluminum would suggest using PPG Alumiprep or Dupont 225S which are phosphoric acid products. Then use Dupont 226S or PPG DX503 (alodine) before priming and paint. Suggest priming with zinc chromate for good penetration of aluminum. The foregoing is all pretty standard stuff in aircraft corrosion treatment.

Dale: My guess would be your Ospho application would be okay if you use alodine also. The Ospho tech support folks are very helpful.

[truk4u]

Or just do what Jdub does, wire brush and spray with Rustoleum!:rolleyes:

[dale farley]

Well, "my final answer" is, "I ordered some of the Rust Bullet this morning. I have used Ospho, I will apply alodine and let it dry, then I will apply the Rust Bullet. I have cleaned the metal to a bare/shiny surface, so I feel confident that the corrosion is gone. If anything, I think maybe this is a little over-kill, but at least, I feel confident that I have taken reasonable precautions.

It looks like Aircraftspruce.com may be the best source for alodine.

[BrianE]

Dale, Your local automotive/industrial paint store should have it. Try these guys: http://repairpal.com/directory/78482-automotive+painters+supplies+incorporated

[dale farley]

Brian,

I tried several other local paint suppliers with no luck. Even tried my local Grainger. I'll give these people a call tomorrow. I know Aircraft Spruce has it if no one local does. Thanks.

[JIM KELLER]

Brian, Holey shit ! I thought you were a pilot, not a nuclear scientist.

[dale farley]

Brian,

I really hate it when it takes someone all the way across the country to tell me where to buy something in my own backyard. Actually, I do appreciate the help. I called the paint supplier this morning, and they have the alodine for $16.95 a quart. I made about 10 local calls (including 3 automotive paint suppliers) yesterday, to no avail. Thanks for the tip.

[dale farley]

This is what my light frame looks like after removing corrosion, treating with Ospho (rust remover), coating with alodine then finishing with two coats of Rust Bullet.

I hope this takes care of the minor corrosion I had to begin with. If the Rust Bullet does what it says it will, I should not have a recurring problem with this particular area any time in the near future. The Rust Bullet is rather thick and does not dry very even, but it looks like it should do the job.