11-01-2020, 11:33 AM
(This post was last modified: 11-01-2020, 11:40 AM by Nick Lettington.
Edit Reason: Troll fingers...
)
I thought this common knowledge, so sorry for delay responding.
A number of years ago I atttended a course on maintenance painting of steel structures. You will all know, when steel rusts, small deeper pock marks appear. Often when a car is half restored and left in primer, these small marks appear all over the surface. Over time, the rust pits develop and hydroscopic ferrous salts form that litterally pull water through most paints. It is very difficult to fully remove them when refinishing rusty panels, so without a full strip down it is likely that any microblistering will reappear.
Now it's probably 20 years since I did the course. I believe I may still have the notes in a box at work but if I remember correctly, it is possible to minimise the problem by scrubbing the surface with water after removing the visible rust as these salts are soluble in water... A second clean up would doubtless be necessary, but it would reduce the risk of blisters.
I have never applied this to car bodywork as I like cars I can drive all year and take kids and rubbish and Christmas trees in... But the science applies equally to any painted steel.
A number of years ago I atttended a course on maintenance painting of steel structures. You will all know, when steel rusts, small deeper pock marks appear. Often when a car is half restored and left in primer, these small marks appear all over the surface. Over time, the rust pits develop and hydroscopic ferrous salts form that litterally pull water through most paints. It is very difficult to fully remove them when refinishing rusty panels, so without a full strip down it is likely that any microblistering will reappear.
Now it's probably 20 years since I did the course. I believe I may still have the notes in a box at work but if I remember correctly, it is possible to minimise the problem by scrubbing the surface with water after removing the visible rust as these salts are soluble in water... A second clean up would doubtless be necessary, but it would reduce the risk of blisters.
I have never applied this to car bodywork as I like cars I can drive all year and take kids and rubbish and Christmas trees in... But the science applies equally to any painted steel.