Hi,
I did not use any sealer, three shades of blue ready mixed dye, off Ebay from Village Green stains. I tried my best, but it just turned out a total mess, whatever I did. I religously followed the advice on Youtube. I have ordered some Hycote white primer, and while waiting, will sand the ply yet again. I will use Hycote primer, colour and finish gloss. If I fail again, its for the bin. This all started because the veneer was paper thin by the f holes, when I lighly sanded with 400 grit, the spalted finish was quite bland as well, the kit is from Coban guitars UK, but obviously made in China, it cost £214. When I emailed for advice, was told to try more dye, and told good luck.
At nearly 75 years old and on a state pension only, this has turned out to be a costly mistake. The kit was more than a weeks pension. I just wanted to build a dream, and learn to play the blues, well believe me I have got plenty of blues now.