What to use to prevent rust before powder coating?

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Hello,I have a - probably a rather simple question.  Once I have completed welding my piece together what can I put on the steel to help prevent rusting before I get the piece to the powder coat shop?  Any kind of oil? cooking oil?  I hope someone can help.Thank you very much!~TheArk
Reply:Kinda unnecessary. If there is any light rust on the piece, It will be media blasted before coating. I wouldn't put oil on it, That will cause more complications.. like having to prebake it to remove the oil.....  and possibly outgassing or something similar...Miller 211Hypertherm PM 451961 Lincoln Idealarc 250HTP 221  True Wisdom only comes from Pain.
Reply:oh thats excellent.  and this will hold out say, overnight until it is taken to the shop?Thank you very much,~TheArk
Reply:Originally Posted by TheArkoh thats excellent.  and this will hold out say, overnight until it is taken to the shop?Thank you very much,~TheArk
Reply:A 20% solution of phosphoric acid wiped onto clean steel with a dwell time of about two minutes then wiped dry will preclude rusting for a few days. Either media blasting or an acid etch bath with phosphoric prior to coating is pretty standard around here. You may be overthinking the rust issue if only a few days transpire between welding and finishing as the flash rust comes off easily.SlobPurveyor of intimate unparalleled knowledge of nothing about everything.Oh yeah, also an unabashed internet "Troll" too.....
Reply:yeah, it would probably just be overnight between welding and powder coating. thank you all for you wonderful advice.~TheArk
Reply:For custom parts, a reputable coater will blast it before coating or have it blasted by a blast shop that knows what they need.  Any media dust remaining on the part surface is removed with clean, dry air and then hopefully solvent-rinsed to make sure the part is 99.9% clean.  Wiping is generally discouraged as it's a great way to get fuzz or lint stuck to the surface of your part and subsequently make the coating job come out not-so-great.Phosphate treatment is usually something reserved for production operations where they are coating formed, cast, or stamped parts and have the luxury of multi-step cleaning baths and all the process control that goes along with an operation of that scale.  Not saying there aren't some custom coaters that use it, but it's just another variable between the coating and clean metal and if you don't do it right, it can do more harm than good.