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neutralize after tinning question

#3
I use tap water and baking soda mixed. I scrub the mixture with a red scotchbright. Wash and repeat a couple times to make sure. I then wirewheel the leaded area and rewash with waterborn before I spray epoxy.

Never sand the leaded areas due to aluminum oxide contamination in the lead. Only file it during entire procedure.
 
#4
Brad J.;26993 said:
I use tap water and baking soda mixed. I scrub the mixture with a red scotchbright. Wash and repeat a couple times to make sure. I then wirewheel the leaded area and rewash with waterborn before I spray epoxy.

Never sand the leaded areas due to aluminum oxide contamination in the lead. Only file it during entire procedure.

That is interesting. I always thought sanding was not recommended to avoid sending the lead airborne.
 
#5
Well, that to. I was taught to use the stuff with a 8" body grinder. Talk about spending lead airborne. The lead is soft and the da sanding discs can leave enough residue to cause possible pin holes later.
 
#7
I think the risk is probably almost nonexistent but most guys on here strive for the best possible outcome. I've seen problems before but never narrowed it down to this or flux/acid bleed.
 
#8
From what I could find out the problem was possibly getting contaminants imbedded in the solder, such as sand blasting or the failure to thoroughly clean after sanding. I use a stainless steel brush by hand during the cleaning and neutralizing stages.

Brad J.;26993 said:
I use tap water and baking soda mixed.
I guess it depends on where you live, in my area we get acid rain and of course that is where our tap water comes from so it is also acidic. Disstilled water is neutral.
 
#10
I use tap water and baking soda mixed. I scrub the mixture with a red scotchbright. Wash and repeat a couple times to make sure. I then wirewheel the leaded area and rewash with waterborn before I spray epoxy.

Never sand the leaded areas due to aluminum oxide contamination in the lead. Only file it during entire procedure.
This is an old thread, but I just recently pulled this car out of storage and it illustrates this very well.

Kent White (AKA The Tin Man--master metal worker) says sanding lead with Aluminum Oxide sand paper can cause Intergranular Corrosion--think dissimilar metals. When dissimilar metals have a conductive solution also, then it is called Galvanic Corrosion.

Kent says, if you want to sand lead, the thing to do is use Carbide or Ceramic Abrasives, but there shouldn't be any need to power sand or grind lead.

The next two pictures are of a car that I have stored for over thirty years. It is a rust free car that I bought in Southern Ca from a guy not long after he had a cheap paint job put on it. It didn't show any problems around the lead seams at the time, but when I pulled it out of storage 30 years later I could see the problem. If you look closely at this factory leaded seam you can see the cross hatch sand scratch, and all the lead seams on the car are the same.



 
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