Can I leave the backing on a stick-on mat and use binder clips instead?

Question

I need to replace my build mat. My printer came with stick-on mats, where this is an annoying process involving scraping off the old adhesive from the metal plate below. I already have a replacement mat that is also the stick-on variety, with an adhesive backing.

I'm thinking about leaving the backing on the mat, and NOT sticking the mat down. Instead, I'll hold it in place with binder clips, to save myself needing scrape the adhesive again when this mat wears out about a year from now.

I'm concerned this may cause problems, because the mat was not designed for this:

• The backing or adhesive may hurt heat transfer from the heated plate to mat surface, causing problems with print adhesion.
• I could have "seepage" of the adhesive trapped between the mat and the backing
• The heated plate might melt the backing from the mat to the plate, giving me an even worse time scraping off the build plate (and much sooner).
• If the stick-on mat is not rigid enough, I could tend to end up with air pockets blocking heat transfer or causing an uneven/rounded surface that won't stay level, again: hurting print adhesion.

But I don't know whether or not any of these concerns have actual merit, or are just worry.

So my question is: will this work, or should I do something else (like get a different mat or just go with my normal adhesive one more time)?

Answer 1

A concern for not sticking the build surface to the base, depending on the materials you print, shrinkage may cause your non adhered build surface to wrinkle when prints are large and shrink. You need the build surface to be attached to a stiff base.

All your worries and troubles could have been avoided when you buy a magnetic sticker and steel coated plates. You'll need to peel the original bed surface once, or not, but, if a coated plate wears out, just replace the spring steel plate.

Answer 2

Having had to remove the PEI sheet from a Prusa MK2 many years ago, I can appreciate what you have experienced. The "standard" process for doing so was to remove the bed from the printer and freeze it. I found that dry ice worked just as well, although with the attendant expense. The PEI sheet peeled off in a matter of seconds, leaving behind some incredibly strong adhesive. Three or four hours later, it was clean enough to apply the replacement sheet.

The problem with the Prusa was that users (public library makerspace) tended to place the model in the center of the build plate, by default. This eventually reduced the effectiveness of the surface, causing models to release mid-print. "Policy" was changed along with the plate surface, resolving that problem.

For your example, it appears that you've cleaned the metal bed. Your biggest concern with using binder clips is that they do not contact any moving parts or while the bed moves, that the clips do not contact anything stationary.

The clips should not contact any heating element on the underside of the bed, which may be challenging. If there's a protective coating on the heating element, you'll have a safety margin, which can be increased with durable tape, heat resistant such as Kapton™. If there's no protective coating, the Kapton™ tape should provide.

Your concern about heat transfer is minor at one level. If it's paper backing, the heat will travel through it without impediment, perhaps a second or two longer. If it's plastic backing, the melting temperature is a consideration. Many heated beds will reach 100 °C but a plastic backing should not melt at that temperature. The adhesive won't affect the heat transfer, after all, it's in place during the original configuration.

You should not have adhesive seepage when in use. If installed in the "normal" manner, you did not experience seepage and there's little difference in this modified method.

The non-flat aspect is the most severe consideration, in my opinion. Even that is somewhat trivial, as you should be able to secure the clamps while the sheet is on the bed and the sheet should be flat, the first time. Subsequently, when you release the printed parts, any distortion to the sheet could change the z-height at those points. You may be able to resolve that by returning the sheet to the bed, unclamped, heat it up, let it cool and re-clamp it.

There's your experiment for you.