Glass printing mat - why to buy it and how to use it

Steel, magnetic or glass? If you are thinking about which printing pad will be ideal for your 3D printer, you are in the right place. But first we will probably disappoint you a little - there is no absolutely universal printing mat that would be suitable in all circumstances and for all types of filament.

In the article, we will focus on the glass printing pad. Chances are, if you just bought a 3D printer, a glass printing mat will not be included in the printer's basic accessories. But we should still think about whether it would be worth it to expand our equipment.

Why choose a glass mat?

Let's summarize the reasons why buying a glass printing mat will be the right idea:

  • Glass material is cheap

In this case, the saying applies: a lot of music for a little money. Printing pads are not expensive at all and have a long life. So if you decide to expand your printer accessories with just a glass base, you don't have to worry about any big initial investment. For example, it is possible to buy a glass mat with an uncut edge from 3,23 eur, with a cut edge it is from about 6,49 eur and above (depending on the dimensions of the mat, of course). Compared to steel washers, where the prices are in the order of hundreds of crowns, the price for a glass washer is not bad at all.

  • The glass material is solid and straight

3D printing is very much about precision. In order to avoid all kinds of deformed prints, poorly adhering layers and other defects, it is necessary that there is the same distance separating the nozzle and the printing pad during the entire printing period. And for that, it is necessary to have a perfectly flat printing pad. Glass will provide you with this requirement, as it is a material that is very strong and straight, even with long-term use and changing temperatures.

  • Easy preparation before printing

3D printing itself is important, but preparing the printer before printing should never be underestimated. Among other things, we are talking about properly cleaning the printing pad. Believe me, glass is one of the materials that will take you a few seconds to clean. It is often not necessary to clean the glass substrate between different prints. But if you get down to it, it is easy to clean from dust, grease and excess filament that can accumulate on the mat during printing.

  • Extra smooth surface of the first layer

If for any reason you want to have a perfectly smooth bottom layer for your printout, or if you are just one of the perfectionists who wouldn't mind a grainy bottom layer, go for the glass printing pad. Its extremely smooth and even surface is also printed on the bottom layer of the print, which will be beautifully smooth without any traces of texture.

  • Easy removal of prints

Although this is not expected many times, because, for example, unlike a magnetic mat, the glass cannot be bent, the prints are easily removed from the mat after the printing is finished. This eliminates the unpopular scratching, where you sometimes have to use force and risk damaging the finished print or even some part of the 3D printer. After cooling, it sometimes happens that the print "bounces" off the mat by itself and you have no work to remove the print from the mat.

  • Long life

We have come back to the fact that the purchase of a glass mat will not be an expensive investment. In addition to the fact that the purchase price is not high, it is also because you will not have to go to buy it again so soon. Glass mats are among the mats with a long service life and will last. For example, with a polypropylene mat/foil, you have to take into account that you cannot simply avoid an earlier replacement.

Glass is not like glass

There are different types of glass and each has a different resistance to temperature changes and chemicals. For that reason, each type is also used in a different industry. We are most interested in Boritosilicate glass, which is highly resistant to thermal shocks and chemical compounds and does not form bubbles that could cause problems during use (if the glass is heated, the air in these bubbles could expand and the glass would crack ). This type of glass is used to make glassware or laboratory accessories and (you guessed it) to make printing pads for 3D printers.

How much the glass is resistant to temperature changes is very important for a glass printing pad. During the printing process, the pad frequently heats up and then cools down. It is important that the mat retains its shape and structure even during this repeated process.

What to think about when purchasing a glass printing pad

  • Material

We explained above that you cannot use any glass. The printing pad must be made of Borosilicate glass (glass containing boron oxide) to withstand temperature changes during printing.

  • Size

The print mat must "fit" exactly on the print bed of your 3D printer. You will need clamps to secure.

  • Thickness

The standard thickness of the glass substrate is 3 to 4 mm. With this thickness, the mat is sufficiently durable and can spread heat evenly. Thinner pads around 1 mm are more prone to cracking and will not have to deal with thermal shock. The thickness of the pad should increase hand in hand with the size of the pad. For larger pads, the thickness is around 6 mm.

How to get the prints to stick to the mat

In the case of a glass substrate, two main aspects ensure proper adhesion - heat and adhesive helpers such as spray or glue.

  • Heat

The correct temperature of the printing pad during printing is the alpha and omega of everything. The heated pad ensures that the first layer of filament adheres properly to the pad. For this reason, it is not recommended to use a glass base on printers that do not have a heated bed. If you print without a heated mat, it could happen that the filament cools down too quickly, does not have time to stick to the mat, twists, and a failed print is born. But it can still be a problem if you heat the pad to too high a temperature. Even in this case, the filament adheres incorrectly to the substrate.

  • Adhesive helpers

If, despite the correct temperature setting, the adhesion of the pad is not ideal, you can try a special varnish or glue. You only need to spray the varnish in a thin layer on the pad that you removed before, so that you don't needlessly cover the rest of the printer with varnish. Let the varnish dry for a few minutes. You can use, for example, specially developed varnish for 3D printers - 3Dlac. Spread the glue on the mat in a thin layer and evenly.

  • Calibrating the printing pad

Correctly setting the distance between the nozzle and the printing pad will not work perfectly if the printing pad is not perfectly aligned.

Quick tips for what to do if the print still doesn't stick to the mat as you would like

1) Check that the washer is absolutely flat and will not need to be replaced.

2) Calibrate the nozzle height.

3) Clean the printing pad.

4) Use adhesive products.

5) Adjust the pad temperature depending on what type of filament you are using.

6) Add a brim or raft to the print. If you are wondering what it actually is, take a look at our article Glossary of terms from the world of 3D printing.

7) While printing the first layer, turn off the fan so that the filament does not cool down too quickly.

8) Use fine sandpaper to create a fine textured surface on the mat (careful - after that the first layer will no longer have a smooth surface).

9) Tape the edges of the printout to the mat.

Cleaning the glass substrate

Cleaning in the case of a glass base is easy and without much effort. And this is one of the reasons that ranks glass among the popular materials for printing pads. Since the glass substrate has good adhesive properties, it is not necessary to use adhesive backing tapes, the removal of which is sometimes difficult.

The procedure is simple - just wait until the mat has completely cooled down after printing, then unclip the clips and remove the mat from the printer. Even if you have used adhesive products such as varnish or glue, the mat should be easy to clean under running water with a kitchen sponge and soap.

You just need to think about not using a coarse wire that could scratch the glass. When the mat is clean, place it on a paper towel, wipe the top with another paper towel and dry thoroughly.

Fastening the pad

Unlike the magnetic mat, which you only need to place next to the bed and the magnetic force will do its work, you will have to attach the glass mat to the bed. Buckles/clips will help you with this. Four will do (two on the front and two on the back).

Sometimes the simplest solution is the right solution. You can use paper clips for attachment. They are inexpensive, readily available, and come in several different sizes.

It is important to choose smaller clips that will not interfere with printing and will not come into contact with the nozzle. If you're going to print a large print where the nozzle might go all the way to the edge of the print mat, move the clips to a different location just to be safe.

In addition to the plastic clip, you can also purchase a metal clip, which has the advantage that it will not interfere with printing. It's a little more expensive than a plastic paper clip, but it's still a minimal investment.

Another option that is offered in the case of 3D printing is to print the clips for the attachment. But watch out for the filament used. The clips must withstand high temperatures. So if you often print from PLA or PET-G filament, you can print clips from ABS, which is more durable.

However, if you are printing filaments that need a higher temperature for printing, we recommend getting office clips. Here you will find instructions for printing the clip.