'What ever I do using etching cream it seems to run under the mesh. You
were suggesting 5 minutes I can have good results only if I leave the cream
on the glass no more than 30 seconds otherwise it runs under the mesh ruining the design so you understand that this is impossible for large areas
like mirrors. Any ideas.' - Mr X. Yiangou - Cyprus
Re: Etching and bleeding
At no time should the etching cream be able to run on its own, unless there is too much cream present on the screen AFTER the actual print. This will leak through and onto the glass below.
There are two main causes that I can think of: 1/ Too much pressure is being applied when printing so the etching cream is being forced through.
When too much pressure is applied the screen can move and hence bleed/ smudge the design.
Try to print with the squeegee at more of an upright angle - about 65-70 degrees - plus print with a lighter pressure.
To print lightly twice is better than heavy once!
After printing there should be very little or no etching cream visibly left on the top of the screen - only what is in the holes of the screen and a very, very light film on the screen (no ribs or lumps).
If there is cream left - simply scrape off the cream from the squeegee (and return to the bottle), with a clean squeegee perform a blank print over the screen and this will collect the excess cream.
This is commonly used when the item can not absorb the ink - such as glass - so the screen is elevated about 5mm above the item.
When you print the screen travels down onto the glass and the ink passes through, but then the screen lifts back off and only the ink is left on the item below.
Whilst it is not essential to use a screen printing jig for off contact printing, it is preferred as you have greater control over getting the height correct on EVERY print.
The aim of off contact printing is to elevate the screen as high as possible - before the edges of the design can not print/ touch the item below when printed with a squeegee (at normal pressure).
Without a jig - place about 6 plastic frames under the screen (or similar thickness wood/ plastic pieces) to elevate the design.
Rub your finger over the design and feel if the screen comes into contact with the item below.
With a jig - place some plastic pieces under the frame in the hinge until the correct elevation is required.
As the frame must be raised, you can not print right to the edges of the screen (it will not travel downwards) so there is a general rule that your design can only be 1/3 the size of your screen.
In your instance I would immediately try the second option and print 'off contact'.
Glass etching can use either the RISO ScreenMaster 70Mesh (supplied in the RISO Screen
Printing Kit) or PRINT GOCCO B6 Print Masters for ultra fine designs.
You can either get the RISO Screen Printing Kit (code: S-868) and add supplies or get the PG-5 Australian Model (code:S-867) and add supplies.
It's cheaper to get the RISO Screen Printing Kit as this comes with a squeegee and also the ScreenMaster 70Mesh.
All you need to add it the Glass Etching cream and a pack of B6 Print Masters (code: S-489) to start printing immediately.
This is the best and most importantly cheapest way to go.