Discuss the different types of equipment needed for screen printing. Topics include manual screen printing presses, automatic presses, dryers, folding machines, starter kits and high end machines.
The last couple times I've printed I've gotten pinhole dots on my shirts. I guess it has something to do with the emulsion? What causes this? One one screen I made about 7 shirts before they started to appear. And on one I just printed one shirt and there were like 7 pinhole dots on the shirt. Am I cleaning the screens too hard?
Screen coating technique may need to be looked at. Some people use firm pressure when coating creating a scraping action. This method leaves a thin coat of emulsion which I will compare to a bald tire on a car "it may pop at any time". To avoid this multiple coats are recommended to build a stencil or "tread" on the screen. This needs to be on the print side of the screen not the squeegee side. Less pressure will increase the "emulsion deposit" but consistant coverage over the entire screen is harder to achieve without practice to develop a feel. Premature breakdown can also be caused but poor screen prep. Always degease your screen before coating. Air bubbles in the emulsion will also cause premature breakdown as the air bubbles will burst causing pinholes. This can be caused by coating too fast or pouring unused emulsion back into the container. I hope this helps.
make sure the glass is clean, and multiple coats is a good idea if you have a good exposure system, I use ulano rlx emulsion it is very hard to control pinholes but the emulsion is the best ever. You will always have one or two here and there. we prepress blot all our pinholes so they dont pop up during the production runs.
God I hate pinholes. As evryone above stated, there are various reasons for them. Photopolymer emulsion combats pinholes better than dual cure, but dual cure has better resolution capabilities.
I ha to switch from dual cure to photopolymer because of unavoidable pinholes and massive production time wasting fooling with pinholes.
Let us know what you find that works for you.
We have found that most of the time, pin holes and fish eyes are caused if the screen is not properly degreased. The other answers here could also cause them.
Been getting pin holes in the screen 
