This is a 34 page PDF outlining my experience with the problem of pinholing in glazes. I have summarized the many experiments I did with dozens of potters who have had this problem over the years. I divided the solution into pinholes caused by the claybody and then pinholes caused by glazes. I did this to help make the discussion a bit more approachable because when you look for solutions on line you either find oversimplified or overly complex solutions.
I found this solution based on firing oil spots for 20 years which create pinholes by their very nature. And then, because I liked very dark cone 6 bodies and also did some experimenting with majolica bodies, I had to find a solution to pinholing because both of these bodies like to pinhole. I give my two step solution which should, but may not, solve your problem. Then, I list alternative solutions which you could also try. Then I list a bibliography so you can read more because this is a problem that almost all potter’s face at one time or another and so it has been written about a lot and it behoves you read up the subject.
I truly hope this article helps you!