I have to say printing signs is a completely different animal than printing tee shirts. Many of the tools and techniques are similar but working with sign inks can be a challenge, especially air dry inks which are very common in sign printing.
For sign printing the steps to set up are basically the same. In fact the only thing that will differ is the size screen, mesh count, and ink. For this type of printing you would want to use a flatbed press. Many sign shops just use an oversized table with a hinging system for the screen and sometimes a squeegee bar which allows one person to use an oversized squeegee alone.
Sign printing is actually less expensive to get the equipment needed. But it is also more difficult to print because on the inks involved which are mostly air dry types, which have a tendency to dry in the screen and coagulate so as to cause numerous printing problems. Industrial sign printers will use UV ink which cures in a UV oven much like a textile oven.
Depending on the quantity you could use an air dry or a UV ink. If printing metal blanks, you will need to use an enamel so it will bond to bare metal or metals with enamel coatings. If you are doing a large print run of sign blanks, then UV will be better because it is cured in a UV oven, making stacking and packing or handling of the finished product easier. But of course that would mean you will need a UV oven. Air dry inks will require a large area to set the blanks out to dry and it must be a very clean, dust free environment otherwise dust or debris will settle on the wet printed ink on the signs. UV ink will be much easier to work with.
The sign blank itself doesn’t affect printing except in that you need to use the appropriate ink and set the press to handle the thickness of the sign blank. I have a semi automatic flatbed press which is perfect for such jobs. This is different from the rotary textile press I use to print tee shirts. I also have a UV oven.
If this is your first time ever doing any sign blanks you may want to sub it out and try to do some sign printing on your own on a small scale, and not for a customer, so you may see what it is all about and work out any issues you come across.
Thanks for reading!