R Jennings

[steve1coelho]

I'm using Newman's and clamping the square end. Also I am using a oversized screen so I cannot put a shim at the end for off contact.

[chubsetc]

If putting the shim in the screen clamp to raise your off-contact you then do not need the shim above the print the be on the frame, just place it enough above the image as to not affect your squeegee pull but hit the top of the platen.  Cardboard taped to the screen works great as it is very light.  The main goal is to raise the screen equally at the screen holder and at the top of the print.  As other posters have stated if you have pitch your press is not setup properly and needs adjusting.

[Sbrem]

My thinking -

An auto raises the platform and the squeegee drags across maintaining equal distance between the screen and the platform maintains even off-contact as the swipe occurs.

I believe with any manual 'back clamp' press, there will be flexing in the arm when you pull (or push) a squeegee across the screen due to the only thing holding the screen up is the arm and pressure exerted down will be more than the arm can withstand without flexing.

So if you taped any object (paint stick, cut yard stick, etc.) laterally under the front edge of the screen so it contacts the platen when pulled down, the mesh will maintain the off-contact and roll like an upside down tsunami when printing.  Without a shim, flexing will lay a larger than desired part of the mesh down on the substrate and could compromise the print by picking up an undesirable amount of ink back to the underside of the screen.

IMO

Um, what he said too...

Steve

ps. the main reason I like side clamps. Haven't shimmed anything since the seventies...

[Frog]

My thinking -

An auto raises the platform and the squeegee drags across maintaining equal distance between the screen and the platform maintains even off-contact as the swipe occurs.

I believe with any manual 'back clamp' press, there will be flexing in the arm when you pull (or push) a squeegee across the screen due to the only thing holding the screen up is the arm and pressure exerted down will be more than the arm can withstand without flexing.

So if you taped any object (paint stick, cut yard stick, etc.) laterally under the front edge of the screen so it contacts the platen when pulled down, the mesh will maintain the off-contact and roll like an upside down tsunami when printing.  Without a shim, flexing will lay a larger than desired part of the mesh down on the substrate and could compromise the print by picking up an undesirable amount of ink back to the underside of the screen.

IMO

Um, what he said too...

Steve

ps. the main reason I like side clamps. Haven't shimmed anything since the seventies...

And back in the '70's, those side clamps helped flatten those warped screens as well.

[sweetts]

Once the clamp is set up paralell, a shim underneath the screen should not add pitch.
A shim of the same thickness added to the front of the screen merely adds support<br/>

This