I haven't used it since doing Porter's finishing course but from what I know of those folks, if they say 'use this or that' I would .... I am sure there would be many methods for sealing milk paints and I guess the web will reveal them .. (BTW I bought milk paint from the US for cheaper than I could here) but when it comes to their paints, I reckon they know their stuff inside out.... actually, I think they make their paints themselves.
I have been researching making kitchen cabinets with Milk paint finishes and was advised against it due to the soaps and fats causing greasy blemishes. From memory, it was suggested that I use polyurethane of some sort to seal it. Haven't had time to trial it yet.
FInally... and I am NOT saying anyone here does this, but I have seen far too many jobs when ppl try to age things, with totally unconvincing results ... For example, many people rub back the middle of each door panel on a dresser... I just can't imagine a circumstance where this is likely to happen, or where a surface is dented with the same dent and the same spacing ... I use this simple rule - can I imagine a story about the piece of furniture, that makes sense of the rubbing, scrapes, 'repairs' and dings? We eat at a 250+ year old scrubbed pine table - at some stage in its history, a candle had burned right down to the wood and left a blackened, divot ... over time the divot has been rubbed by hands and polish cloths etc. and has left it the shiniest part of the top ... whenever folks visit and we eat at the table, their fingers invariably trace the lines of that burn .... it is one of those so called imperfections that make our table perfect
It is a real challenge to re-create a period look and feel convincingly .... when it's well done, it really is spectacular
....catchy phrase here