Acid Used-How long for damage to appear?

[ts8501]

I am looking at an early 60's model trailer that has had some form of acid wash done to the exterior skin (per current owner). I am wondering how long it might take for water leaks to appear? I have read all the horror stories of leaking trailers due to acid being used to clean off the oxidation (rivet heads mainly). On this unit it was described that a mild acid was used, and then a soapy type of wash, followed by a water rinse.

It was over a year ago that it was performed, and I can see no evidence of internal water leakage. The original caulk (Vulkum?) between the aluminum sheets is still intact. I must have tried to twist a hundred rivets, and all seem to still be tight and in place. There is zero evidence to date of any water leakage internal into the coach.

So how long might it take for water leakage to appear after an acid wash? It would be easiest to avoid this AS, but considering everything I can see with my own eyes, there does not appear to be any negative effects of the acid wash on this particular unit. Opinions and experience welcome on this!

-Tim

[Melody Ranch]

Once again...ALL aluminum aircraft, auto, truck and boat surfaces can, and should, be safely acid etched before painting or polishing. It is the standard. It has always been done that way, is still done that way and should be done that way. Don't do it that way if you please. Do it correctly and you will have no problems.

Aircraft Painting - Solving the Mystery
http://www.menaaircraftpainting.com/Process/process.htm
http://www.oecs.org/eccaa/docs/acs/a...20Aircraft.pdf
GIV Refurbishment Slideshow

etc., etc., etc.

brightener mentioned in aluminum treatment is ACID.

Just be careful and do it right.

[SmokelessJoe]

Originally Posted by ts8501

considering everything I can see with my own eyes, th

-Tim

Tim:

You have to read these pages with caution. There is good advice and bad advice dispensed here. The trick is being able to consider the evidence and make up your own mind.

I’m with Melody Ranch. Professionals use acid washes to prep aluminum before painting all the time.

I spent 3 years rehabilitating a 1976 Argosy. After we stripped the paint off with aircraft stripper, I used acid wash to clean up.

http://www.airforums.com/forums/f227...e-18448-5.html

Before Wiltsie Truck Bodies, a company with more than 50 years experience, painted my trailer more than a year later, they etched it again.

There is no sign of any kind of damage caused by the acid.

If the P.O. used it correctly, following the directions, there will be no damage caused to yours either.

Sergei

[Lumatic]

Originally Posted by Melody Ranch

Once again...ALL aluminum aircraft, auto, truck and boat surfaces can, and should, be safely acid etched before painting or polishing.

I assume the acid wash before painting is for a better bond, right? But why an acid wash before polishing?

[jerrypeterma]

what type of acid are ya'll talking about? muiratic is used for cleaning brick in deluted forms. but I'm not sure if thats what you mean.

[ts8501]

The acid wash takes off the Oxidation. Oxidation comes off black. Acid wash is much less labor than taking it off with Nuvite Grade F7 polish and a Rotary Polisher. Acid wash goes on and is washed off with at minimum water. Polishing is much harder physically, and many more hours of work.

My question is still; after an acid wash, if there was going to be a problem, how quickly would a leak appear? Since it has now been over a year with no water leakage problems, would it now be considered safe?

Tim

[3Ms75Argosy]

I would have to say, that after a year, with no evidence of leaks, you are fine now. I can't believe an acid would remain active after 365 days.
Marc

[ts8501]

Since an Airstream has an outer and inner wall, the only thing I was thinking is that any small leaks in the outer skin rivet heads would possibly be hidden. Also not sure how long the acid would continue to eat at the metal, if it is hidden under the heads. I am much less concerned with where the panels overlap, as I can see that they are 95% intact with what I assume is Vulkum, and what is missing might just be from 40+ years of age. I'd very much like to agree with 3Ms75Argosy, SmokelessJoe and Melody Ranch. There are many threads that say "never, ever, ever under any circumstances acid wash an Airstream", but then you keep reading, and find many people have successfully acid washed. I am hoping that after this much time, there would have to be some evidence of a water leak, and if no leaks by now, this AS is safe.

-Tim

[SmokelessJoe]

Tim,

Melody Ranch and me are telling you the same thing - too many so-called experts out there.

You can easily read yourself into undue concern about many things on these pages.

In the end, trust your own instinct.

Sergei

[Lumatic]

Sooo, Is there a product or a formula for an acid wash, especially for oxidation?

[Alumin8]

The references above give the details for aluminum aircraft and is exactly the same for Airstreams. If you undertake this task, i would do a test spot on the underside of the trailer. Aircraft are often painted after etching. Some aircraft are left bare and polished. It is these sights that I would search for clues.

Good Luck.

[Larry in MO]

Originally Posted by Lumatic

Sooo, Is there a product or a formula for an acid wash, especially for oxidation?

The Blue Beacon Truck Washes use an "acid" wash, or actually two. The citrushine is a mild citric acid base that is used for polished aluminum like on fuel tanks, wheels, etc. The official policy is that the wash will not eat the clear coat off of wheels. This works pretty well for oxidized aluminum. There are a bunch of Blue Beacons and are usually found at large truck stops on the interstate. Dump stations are in the area, as a rule.

They have a different style of acid wash for aluminum trailers such as my car hauler. I do it once a year and it cleans very well. It has not affected the clearcoat on the wheels. I don't know if they will use the good stuff on RVs or not. As I understand it, there is a little of the Cirtushine in the regular soap mixture. The rinse is immediate and thorough.

The stuff is sprayed on by the workers w/ no breathing apparatus or protective clothing. I figure it must not be too caustic or it would eat the workers.

[Melody Ranch]

Brightener is also used as a recommended control....remover of corrosion. Most common in Airstreams is seen on the belly pan as a white stain like powdery substance...usually along the seams. A 5 to 1 dilute solution of muriatic acid, or a brand name aluminum brightener, used with a small brass brush (I have used 3M green pads and rubber gloves with excellent results on airplanes) and then agitate till the area is clean. Thoroughly wash. Now, alodine wash if your going to paint or start your normal polish routine.

Polished Airstream after an acid wash......

[ts8501]

I am going to work on trying to find the exact acid wash that was used. It was in fact completed at some form of truck body shop. I also do not want to lose sight of the original post; So how long might it take for water leakage to appear after an acid wash?

[Larry in MO]

Originally Posted by ts8501

So how long might it take for water leakage to appear after an acid wash?

My guess is that there will be no leakage unless there is already a problem. Acid "eats" until the ph level reaches 7 or neutralizes itself. Large amounts of water speed this up. It won't keep "eating" forever.

If you are unsure, find yourself a couple pieces of scrap aluminum and rivet them together w/ Vulkem as a sealant. Spray the acid wash on the aluminum and see what happens. I don't think anything will happen to the sealant, rivet, or aluminum. After that, soak the piece in the wash for a couple of days. If it doesn't eat the rivet or the Vulkem you will be satisfied, I think.

[ts8501]

This morning I spoke to the person/company that stripped and polished this '64. He used what he called a lighter duty aluminum "brightner". He said he also uses on some applications of truck an 'acid wash", but this is not what he used on this Airstream, and that he felt the acid wash is too heavy duty. The unit was then fuly washed down with rinse water. He then went on to say that he used a two step polishing compound process (I assume like Nuvite, different grades).

I do not know the exact brand, but I believe is was close to this:
Aluminum Brightener, Regular Strength - Removes oxidation from any aluminum surface. Cleans as it works. Dilute up to 50 to 1 with water for light oxidation; use in a more concentrated form for heavier oxidation. ALWAYS WORK FROM BOTTOM TO TOP. Light blue liquid. Hydrofluoric acid based. Caution: Do not apply to glass surfaces. 55 gal.

So what is the opinion of an "aluminum brightner" verus an "acid wash"? Again, I see no evidence of any leakage or water damage, over one year later. I want to pull the trigger on this AS today, but I have hesitated, after reading all the horror stories of "acid wash", and leaking rivets, and junk AS as a result.

Thanks!
-Tim

[3Ms75Argosy]

Tim - just buy the unit! : )
Better?
Seriously, if the acid "damage" would have been evident by now.... if none, just smile!
I'm sure it looks nice... pics after the purchase?
Marc

[Melody Ranch]

Go get that Airstream RIGHT NOW. It's snowing in Fargo this AM. You have to get that baby home and tucked in. Your worries should be completely put aside after getting the "brightener" history from the truck maintenance fella. Now you can concentrate on axels, tires, Corning windows,frame separation, floor rot, leaking panels, aluminum wiring, Univolts, and all the other joys of a Vintage. You WILL love it and the good folks you have in that group.

[ts8501]

I told the PO "Yes", and the check is on its way. I will get some pics posted within the week! Thanks to all for their input!

-Tim

[Melody Ranch]

I'm proud of your decision. Looking foreward to the pics.