I have noticed the last couple of times I've 2 stepped HF on bull bars and fuel tanks they are streaking, admittedly they have been neglected for a number of years. Is there a way of counter acting this? They are white Alum not polished. Although, I never have any issues with the stainless components they turn out great.
I run the HF at 2% thru shur-flow then hit with 4% caustic hot downstreamed soap after two minutes dwell time and I apply HF bottom to top.
Could I be running the HF to strong or two weak? It doesn't apear to be removing all the oxidation probably 80% + I am not letting the acid dry before applying soap.
I did have some reasonably good reults a couple of months ago with 20% phosphoric instead of HF @ 2 %.
I run the HF at 2% thru shur-flow then hit with 4% caustic hot downstreamed soap after two minutes dwell time and I apply HF bottom to top.
Could I be running the HF to strong or two weak? It doesn't apear to be removing all the oxidation probably 80% + I am not letting the acid dry before applying soap.
I did have some reasonably good reults a couple of months ago with 20% phosphoric instead of HF @ 2 %.