Thermography Help?

Print with any ink. The only requirement is that the ink needs to still be sticky (wet) enough for the powder to stick, so you typically may have to print in batches (of the quantity you can thermograve in a reasonable time). Obviously drying time (of the ink) will vary depending on ink, stock, etc., but you can’t thermograve it once the ink is too dry!

A freshly printed sheet goes through a powder “bath” (or however you wish to apply powder) and the excess powder is vacuumed, vibrated, shaken, or tapped off (depending on your setup). All the printed image should have a coating of powder, but there should be none on the non-image area of the sheet.

The sheet then goes into the heating unit for just as long as it takes for the powder to turn clear (assuming clear powder). If you watch, the image suddenly goes from a whitish “covered with sugar” look to a glossy black (or whatever the ink color). This may only take a dozen or so seconds in the heat unit, depending on the unit, adjustments, paper, and coverage. If you take the sheet out too soon (or the heat is uneven), the powder will still have some areas looking somewhat “grainy” (this can often be “repaired” by a few more seconds in the heat). If you wait too long, the powder turns liquid and starts soaking into the paper, as well as spreading beyond the printed image, and that sheet is ruined.

The newly fused powder will be hot and sticky for a few seconds as it comes out of the heat unit, but as soon as it cools down completely it’s “dry” and ready to handle.

Most papers can be thermograved, but some thick, soft stocks seem to absorb so much of the heat that they don’t work too well, and occasionally certain coated stocks will blister under the heat. Each paper thermograves a bit differently (longer or shorter time, etc.).

For best results, use fine-grind powder for fine, delicate, or small type; coarse-grind powder for larger, heavier type and solids. Clear powder comes in matte and gloss finishes and several grinds; various colored powders including opaque white and metallics are available.

Let me know if you have other questions!

Dave (the Ink in Tubes guy, trying to figure out how to best package thermograving powder).

dave, i still have some powder from kelsey, they put it in a tube. also if you use gold or silver powder you can use black ink, don’t look so bad. be careful when rasiing some papers, they can curl very fast, if they touch the heater you can have a good fire. good luck dick g.

printing on coated(cast or krome kote) stock and onion skin stock can leave moisture pimples on the stock lengethen the time of delivery to the powder head and use minimum powder. also add alcohol to the water fountain this will cause the excess moisture to disipate eleminating the pimple effect. Thre are laser safe powder and u.v. lamps to allow the use of thermo powder in laser printers as well. DO NOT USE A STANDARD THERMOGRAPHED LETTERHEAD SHEET IN A LASER PRINTER YOU WILL RUINE THE LASER PRINTER HEAD. Todd former pressroom supervisor for a thermo company.

Also if u plan to do foil stamping with printing ink and the foil overlays the ink (flat print) you must use wax free ink. The non wax free ink will melt under the heat of the foil process. todd

printmastert, water fountains on letterpress’ ? “moisture
pimples lengethen the time of delivery” Does the moisture
stretch the steel delivery chains or gripper arms? I’m
thinking some people might be confused by your advice.
best james

I was in the thermograved business card business years ago. Dave post is great. Just make sure the type impression of the image is NOT deep into the stock. The impression should be good to have all the type and image touch the stock, and the thermography powder will stick to the wet ink. The printed items doesn’t need to be in the heat very long.

The if the ink isn’t wet the thermography powder will not work. You need to get the thermography powder on the ink within seconds of the impression.