Etching

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I've used nitric acid to etch my welds, and it works rather well. But the etched pieces don't have much of a shelf life and rust usually becomes apparent after a few minutes. Is there something I can do to prevent rust from occurring? We have some 400 welds to check in a given day and can't waste time re-etching parts.
Reply:Can you spray them with rust preventive oil or WD-40 after etching?John 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker
Reply:We macro-etch certain welds, too, but never as many at once as you've described.Many of our test pieces are alloy materials, and some are carbon steel.The alloy ones can be etched and examined at any time, as they don't rust. Pretty nice, actually.But the steel ones have to be etched right before examination.Rich
Reply:etch them, rinse, dry, and spray with a clear lacquer. I've used hair spray as well (which is basically a clear varnish). Works great...
Reply:If they never have to see paint in the future, you can use a squirt of Clearco SFG 350 or one of their similar products.  These put a rust protective coating on that quickly dries and lasts about a year.  Basically mineral oil and silicone mix that is FDA approved so no issues with toxicity.  http://www.clearcoproducts.com/silic...e-sfg-350.html.  It's not that expensive and a little goes a looooong way.We often use it on carbon steel fabrications that have to be degreased and stored for a while.  Works great on machine tables and tools too.
Reply:cut&etch,Why do you need to start at least 3 threads about the same damned thing?  It's fairly simple **** to neutralize an acid etch to a degree and preserve it for a short time. Are you looking for immediate, real-time response? Then ask your Mother. Do some basic research about chemistry.  It's scary to know you work with Nitric acid and have no real clue what is going on. The Snozzberries taste more sour when they still have acid on them. Do not lick the finished weldment."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Jet fuel doesn't melt steel beams
Reply:Originally Posted by cut&etchJet fuel doesn't melt steel beams