Heated Bed Surfaces/Coatings

#1
If your BuildTak surface is damaged and needs to be replaced, you need to head over to BuildTak for a replacement. https://www.buildtak.com/ They sell 16" x 16" sheets, a perfect size for the gMax. Or you could try one the following coatings/surfaces many have experimented with and reported success. Before installing any surface, make sure the glass is clean. These are experimental options that you will come across while searching the internet for heated bed surfaces. Most, but not all, of the following methods have been tested on the gMax with varying degrees of success. It is highly recommended that you stay away from any coating that is flammable. The heated bed puts off a lot of heat and draws a significant amount of electrical current.


PEI

PEI is a costly option but well worth it. A PEI surface will work with every common material. Use an adhesive to stick the PEI sheet to the glass. This will not work when cold. See Dunginhawk's response below for details.

PVA (Elmers glue)

You can mix water with Elmers glue and coat the mixture to your borosillicate glass. Mix 8 parts water with 1 part Elmers glue. Apply it cold, let it dry. Before your first print heat the bed to 60C and let the coating cure for about 30 minutes.

Glue stick

Yes glue stick. The same stuff our kids use for arts and crafts. Evenly apply the glue stick to the borosilicate and give it some time to dry. Heat the bed to 60C and let the coating cure for about 30 minutes.

Uncoated Glass

Uncoated glass will work for smaller PLA parts. The trick to success with bare glass is to keep it clean. But if all you are printing is PLA than a heated bed is not necessary. The only thing a heated bed is doing is wasting electricity and decreasing the effectiveness of the extruder's cooling fan. You should use the acrylic bed if the only material you use is PLA. In short an uncoated bed is not an option that makes sense.

There is an advantage to a clean glass bed. That is the reflection of the hotend is so clear and easy to see that you can use it to help manually level a bed.

Commercial Coatings

There are many commercial coatings specifically designed for 3D printing. Give them a try. I have yet to hear of a mixture that does not work well. Some are sprayed on like hairspray while others are applied with an applicator brush.

3M Blue Tape

Many people have reported great success with blue painters tape. This is probably the most common bed surface. It is cheap and easily accessible. You probably already have some laying around. Be careful not to leave any gaps or overlaps. These will show up in the model. Painters tape will not work well with ABS. It is my opinion that an unheated acrylic bed is more practical than heated glass with 3M tape.

Kapton Tape

Kapton tape is specifically designed for high temperature applications. Similar to painters tape, be careful not to leave any gaps or overlaps. These will show up in the model. Kapton tape should work well with ABS but is twice the price of blue painters tape.

Feel free to leave any comments or questions. Please share with us your experiences with different coatings and bed surfaces. Refer to Richard Horne's blog on bed surfaces. It is a wealth of information. http://richrap.blogspot.com/2015/01/stick-with-it-3d-printing-print-bed.html
 
#2
Kyle, please dont mind if I jump in here on PEI (the rest I dont really use anymore, so my thoughts would be dated) However this is my wheelhouse.


"PEI

PEI is a costly option but well worth it. A PEI surface will work with every common material. All you have to do is clamp a thin sheet of PEI to the borosilicate glass. "


1. Costly, perhaps up front -50$ or so to get the PEI and the 3M adhesive tape sheet (more on that later).

2. It will NOT work with Ninjaflex at all, unless you put another layer of something between it and the PEI. Ninjaflex will bond SO well to PEI it will literally not come off... Ive broken glass before the part gave way.

3. Clamping a thin sheet of PEI to borosilicate glass wont really work. Its too thin, and will buckle given its huge surface area, once heated. You can try it, but its a losing game. Instead, go to lowes or wherever you can get glass cut, and get a piece to fit your bed (its like 16.5" x 16.25" i think to account for the clips (bigger if you have the heated build plate).
THen buy 3m adhesive sheets ( http://www.amazon.com/TapeCase-squares- ... ge_o06_s00) and attach the PEI to the glass with these.
a. Be VERY careful when peeling the sides of the 3m tape, if you arent SUPER careful it will peel wierd and you will get lumps under the PEI touching the glass, making for an un-even bed .
b. you will need to buy 2 of these http://www.amazon.com/Polyetherimide-Of ... ge_o06_s01 . Then cut them down (sharp scissors will work) I have 2 pieces on my bed, but if its done right the nozzle never knows.
c. Once you have the PEI adhered to the glass you can clamp it to the gmax. One clip left side front, one clip right side front, and 2 in the back . Those are the safest places to put the clamps so you dont bump the Z axis lead screws.

4. Once everything is ready to print there is generally 1 more step I do. Use 1500 grit sand paper and rough it up. Corner to corner. No need to get crazy, just looking to take the shine off it (the link i suggest for PEI has sheets that have 1 side glossy, and one side matte. I prefer the matte side) You need to sand it a bit once every 20 prints or so (probably less) to make sure you have great adhesion. Wipe it down with IPA and have at it.

5. Be VERY VERY aware that PEI does NOT work without a heated bed. Not even with PLA very well. Heat is the key factor in making sure PEI works. So well in fact that you can heat it, print on it, let it cool and most times the parts pop off on their own. Sometimes you need a tool.

6. With smart use, and no gouging etc the PEI will last you forever. I had PEI on my Flashforge for over a year with no issues. Given that bit of info, it ends up being about the cheapest thing out there.


Thanks for writing this up Kyle, great content for sure.
 
#3
Just throwing it out there but I did not rough up the surface on my PEI bed to get it to work great. I clean after every print with a cloth and isopropyl alcohol and it has worked for 75 + prints so far. Good point about the rough handling though as if you cut or gouge the PEI than IT WILL show on your part.

Dennis
 
#4
Dennis, you are right... to an extent..
1. If its the glossy side, PLA will stick to it without sanding just fine, but almost nothing else (like ABS and parts that warp). So on the glossy side I always scuff it.
2. on the matte side you dont have to sand it down for MOST parts, i still would for ABS... I just do it as a course of habit :)
 
#5
dunginhawk said:
2. It will NOT work with Ninjaflex at all, unless you put another layer of something between it and the PEI. Ninjaflex will bond SO well to PEI it will literally not come off... Ive broken glass before the part gave way.

Please forgive my ignorance of PEI. I have not tested it yet. Though Amazon prime is on their way...

Would Ninja flex work if the PEI was cold? or the first layer under extruded?
 
#6
Cold doesnt matter, but maybe a .4mm layer or something would help , that i didnt try... But I still think it would stick like crazy... I think people have gotten it to work with a buffer layer of some sort, like glue stick
 
#7
gCreate_Kyle said:
dunginhawk said:
2. It will NOT work with Ninjaflex at all, unless you put another layer of something between it and the PEI. Ninjaflex will bond SO well to PEI it will literally not come off... Ive broken glass before the part gave way.

Please forgive my ignorance of PEI. I have not tested it yet. Though Amazon prime is on their way...

Would Ninja flex work if the PEI was cold? or the first layer under extruded?
I agree with dunginhawk. Cold does not matter with NinjaFlex. Even LulzBot recommends/requires you to use glue stick on their PEI beds because the NinjaFlex will stick like mad.
 
#8
another tip... dont try to take off a part (petg) while the bed is hot. Its bonded SO strong that I chipped the pei with my tool.
I knew it would happen, but i was stupid and lazy.
once cool it popped off without any tool.