Packing types

Could someone help me in understanding packing types and their best uses. My 8x12 press had a few layers of card stock underneath a tympan sheet.

I have read where people use different materials like pressboard or foam or several sheets of copy paper under the tympan. I guess it depends on the job but what I’m asking is what jobs equal what packing?

Can you kind people give me some scenarios (cards, stationary, low impress and deep impress) for best packing of different jobs that will keep my press from damage as well as give good results?

Right now I am hoping to print some coin envelopes with a Christmas metal block I bought.

Thank you and all the best!!

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I would say you should play around and see what works for you. I like to start with a couple or 3 sheets of copy paper and a pressboard, if you want a soft packing put the copy paper on the pressboard, if you need a hard packing put the pressboard on top of the copy paper. For envelopes which have seams and different thicknesses you will have to do some makeready. i cheat and remove my packing and use a thin rubber blanket instead of packing for envelopes. Remember the more type or area you try to print the more pressure you will need to make it happen, sometimes you will have to add a few sheets of copy paper. The larger the form and the deeper the impression the more strain you put on your press, keep the forms simple and small to start out, a thicker softer paper will give you a better deep impression. good luck Dick G.

I tried tonight with putting a magazine under the tympan and wheeled the press slowly by hand and it wouldn’t make the full circuit, so I backed it off and ripped the magazine down to half it’s thickness and the press seemed to go through the circuit fine.
Curious, how thick is pressboard?

Another ? Is on a platen press 8x12 what is the thickest packing you can use and the press move thru its cycle freely? I figured once the wheel stopped and slight urging to turn was not working that I better stop lest I break something.

A pressboard is only around .015” thick, and you could use any hard-finish material about that thickness for the same effect.

It is difficult to tell you what thickness a proper packing should be for your press as it has been adjusted by someone for a particular thickness of packing, and may be less or more than normal. “Normal” would be around .035” or so, but, as I said, the last owner may have had his/her own ideas about packing, and would have adjusted the press to suit.

I prefer a fairly hard packing as it tends to work well for small type and detail. Even if trying for deep imparession, the impression does not come from the packing, but from the ability of soft paper to “absorb” an impression within its own depth, so soft packing would hinder a sharp deep impression. I don’t think any press operator would use foam as a packing material, but some do use a rubber sheet in the packing as Dick suggested to even the impression for uneven paper layers. I prefer to do a cut-away makeready for envelopes as long as they are consistent in folds and glued seams.

I also use old film as a packing material under the topsheet as it has an extremely hard surface with very uniform caliper.

John H.

That gives me something to consider… Didn’t know you could adjust for different packings. This press is like a cp and it seems the bottom impression bolts would be difficult to adjust

How do you tell what thickness adjustment has been made?

Adjusting the platen is not trivial - leave it alone if you can.

The way to tell if your platen is flat is to lock up four large cap letter “M”s - one in each corner of your chase - and carefully make an impression on a test sheet of paper - if all letters have equal impression, then your platen is adjusted flat. If it’s not very flat, then you may have to adjust the platen.

On old printer who checked it for me said it was level, but, I will remember the test…thanks !

when you do the test to see if your platen is level you must have a normal packing like jhenry says, by putting a magazine in there you could break the press, or jam it so you can’t move it either way. like Bill says leave the impression bolts alone, if you have to adjust them you close the press to get to the top ones and open it to get to the bottom ones, the bottom ones are harder to get at. if an “old” printer says its level then i’d leave the bolts alone. you don’t have to adjust them after they are set correctly.

The platen is only level for the packing conditions in which it is set. Add a magazine’s worth of packing (a very radical adjustment to the press) and the lower portion of the platen will punch and the upper portion won’t even touch.

P imp
We call this toe ing and healing ,a heavy impression at the platen hinge is too much packing and too much at the top of the platen is under packed .

Thanks to all! I will post a pic of my first project on it here. I really appreciate all of you, and please any additional posters please do so, I need all the help I can get!