I've been doing this with copper pipe metallic paint from Wilko but I only use a brush and just do random directions .. Couple of layers no sponge and it's awesome when the light hits it you can see every brush stroke I love walking past it to see it all different lights... Candle light at night is awesome with it too... Try not using the sponge your taking away all the work with the brush that's so effective
Nice work! From Australia 👍🏼👍🏼 have u tried using a spray bottle to finely spray some water on it and see if I gets a blotchy water mark effect? Just curious if this’d work.