Cleaning for solder

B

Bob Hollinshead

In the past I've had difficulty cleaning tight nooks and crannies when prepping areas for body solder, a spot blaster has worked fine to clean the areas where a wire wheel or sanding won't reach, no problems to date but now I question if this is a best practice considering the issues people have with some acid etch primers over blasted steel???? your thoughts? anybody else doing solder work without problems over blasted steel? I wonder if a pre-clean with muriatic acid and a good rinse might be a better way to go? I think trapping acid or improper tinning are the two common causes for solder failures if they happen.
 
Bob, I was just reading an answer by Kent White (The Tin Man) to a question on lead work and one of the things he mentioned was that the lead should not be sanded with Aluminum Oxide because of intergranular corrosion. Personally, I think embedded sand will also cause problems so I preclean with phosphoric acid and a SS wire brush. I also use a SS brush to work the flux in.

I once had an engine block dipped in sulfuric acid, and the machinist complained about the block flash rusting very quickly between operations. And I also dipped a set of exhaust manifolds at home in sulfuric acid, because it doesn't eat up the cast iron like phosphoric does, then coated with some natural cast paint. But they started rusting much too quickly, and I think it is because the sulfuric acid just opens the metals pores too much.
 
Bob, I have not soldered in last 10 years but use to do a ton of it and cleaning it up with a spot sand blaster was how I did it.
Not sure right or wrong but have 30 years worth and never had a problem.

I was taught this in the 70's at a chebby dealer by a bodyman that did this all day long back then.
Acids scare me.
 
Barry, good to hear. I haven't had any problems doing it that way, but had never heard of anyone else doing it this way. Fred, good tip on the stainless wire brush but I wonder what difference SS would make? maybe to just keep the acid from deteriorating the brush? I know Muriatic/hydrochloric acid is harsh and I usually avoid it because of the embrittlement it causes but it sure can clean good in short time. A friend of mine cleaned a 1970 LS6 block with Muriatic years ago and most of the bores cracked during boring-I think embrittlement was to blame. I'll continue to stay away from the Muriatic acid. And the brown acid! LOL
 
Back
Top