tenspeed

I have used sulfuric acid before on calcium and lime build up with similar results. One product (IIRC) is called "CLR" (calcium, lime, rust). Muriatic acid is used for cleaning up brick and concrete. I haven't any experience with it and no clue how it would effect your stain. Both can be bought at the home improvement and hardware stores.

I wouldn't worry much about messing anything up. That stain is big and bad. If you do mess up, they will sand it down and repaint. Wear rubber gloves and a apron. Don't wear anything that you value that is made of cotton. It will come out of the wash full of holes. We used to wear wool when we had to perform maintenance on the submarine batteries.

Jelmar | We Clean More Than You Think - Home

babadudu

In the video, he said it's a stronger industrial grade citric based solution that would neutralize the calcium build up. CLR should work but test it somewhere first and maybe dilute it.

Bob Petruska

it does not contain sulfuric acid as you state. Its ingredients include water, lactic acid, gluconic acid, lauramine oxide, Propylene Glycol, n-Butyl Ether, and solvents that dissolve cobalt gel coats and paint.

Bob Petruska

and it's a gel.

Optimum MDR Mineral Deposit Remover, water spot remover for paint, water spot remover glass

Hockeymonkey

Having done a lot of body paint work, I would try the gel. Looking at the pics it does not look like it went all the way through the base paint layer. If it was very acidic and managed to eat its way through the many layers of wax, clear coat, and paint you would be able to "feel" it - like a ridge if you rubbed your hands through it.
In this case try the gel and then get it rebuffed. Worst case is that you do need to get it repainted but I doubt it.
On a sly note: what a scam if the dealer and auto body know this but said lets put wax on the entire car, make it look shiny and say we tried but it would not come out. Lets make $2900 off the poor guy. I really hope not but a part of me says that body shops have seen everything you can imagine.

audi_q5_Md_Dc

Here are the pics after I cleaned the stain with CLR yesterday. Looks much better. I still see some of the stain but I didn't want to put so much 'acid' in one evening..I will try to apply it again tomorrow..

All of this for $10.35...i am disappointed the dealer *and* the body shop didn't think of this or they realized I was going to make the apartment management pay for it anyway and went for the kill - $2900!!

NorthValley

Wow! Great improvement! $2900 is insane. I would take the car back to them when the stain is completely out and then show them the bill for the stain remover. Then laugh heartily as you exit the premises!!!

-hef-

$2900 is beyond ridiculous. they might as well have said $10k. do they assume people are so dumb that they don't know you can hang a new door for under a grand? those latest pics look great. i can't see any remnant of the stain. good job on the CLR reco.

Hockeymonkey

As I stated in my post below, I suspect the body shop knew how to get rid of the stain. Makes me mad because they were going to rip you off huge for an hours worth of work. They would have split with Audi. Horrible rip off business practices!!
As to your car just be sensible in applying like you are doing. Then clean completely and dry, buff with a very very light compound and then apply wax and you should be set.

babadudu

exactly, they aren't called Stealership for no reason....