Alternative Print Surface

I’ve always had trouble with ripping my Kapton tape. Prints are can be removed easily, without damaging the tape if the print bed cools down, but it takes so long to heat up, I hate to let it cool too much. Also, if I want to cancel a print and restart it right away with tweaked settings, I’m too impatient to cool it down first.

The solution is to forget the Kapton altogether. I went to a frame store and had a two pieces of glass cut to 6″ (a hardware store might be able to to this for you). I used small binder clips to hold it to the aluminum bed and heated it up. Originally I put Kapton on the glass, which was a lot easier to do outside the printer. However someone posted a tip on Thingiverse to use hairspray, and I found using that on the glass without Kapton worked great for ABS.

The great thing about using glass, is that when the print is done I can take the glass off and let it cool on the table without needing to turn off the heat. When I put a piece of glass back on to the bed, it only takes about a minute to warm up again. One thing to be aware of is the Z offset screw. My glass was about 3mm thick, so I needed to turn the screw down that far to keep the glass from hitting the nozzle when homing Z. If your screw doesn’t have that much space available at the top, you might need to get a longer one.

The problem with covering the aluminum with glass is that you can’t get to the leveling screws.  This is easily solved by printing the thumbscrews here –  Just drop a little superglue inside and twist them on, letting the bolts cut the threads.  The glue will hold them well enough to turn the bolts, but if you need to take them off, you can still break the bond.




6 thoughts on “Alternative Print Surface

  1. A glazier friend of mine has given me some 160mm squares cuts of glass that are 6mm thick. Do you think 6mm might be to thick for the heat to transfer through? or should be ok? I understand ill need to replace the z offset screw for a longer one and print out the handles for the levelling screws. thanks

  2. Hi Ian,

    I’ve not received my printer yet, but am reading up as much as possible beforehand. I think you have made me ever making a successful print a reality with your amazing information on this blog.

    Quick question for you about the glass: I ordered the basic unit with non-heated print surface – would the glass help in my situation avoid the tape? I’m assuming I’ll still need a raft for most of my prints?

    If glass may help me, I’m more than happy to get the sheet cut before the unit arrives.

    Thanks much and keep posting 🙂

    • Nothing really sticks to kapton which isn’t heated. It can be hard to print ABS without warping on an unheated bed. I often squished the ABS too hard into the acrylic bed of my Solidoodle 1 and found it almost impossible to scrape off. If you have a removable glass bed, this is a lot easier to deal with. You will want to use a raft for anything bigger than about 60mm.

      You would probably be better off printing with PLA most of the time. It doesn’t have much trouble warping, and unheated glass is pretty much the standard surface for it.

  3. I’m going to give this a try, especially since my bed is slightly warped, and this is the cheapest fix. I got my glass via a cheap 6×8″ picture frame for $5. The same store wanted $32 to custom cut a 6×6″ piece. I do have a couple of questions:

    1. Is there any danger of the glass shattering from heat? A couple times now I’ve had glass objects explode like a firecracker without warning when heated. Is 100C hot enough to be dangerous to cheap, un-tempered glass?

    2. What brand of hairspray do you use, and how much do you apply? A liberal coating, or a light mist?

  4. Hi Ian,

    I just tried the trick with the glass bed + hairspray coating with my Solidoodle and it works fine so far!

    My local glass specialst was a bit sceptical when hearing that my plan was to heat 3 mm glass to 100 degrees celsius. Therefore he recommended to use 6 mm glass instead and to grind/polish the edges to avoid cracks. I did as he recommended which resulted a higher price of course – I’m not sure whether the extra money was worth it, because I have no long-term experience yet.

    By the way: my levelling screw was long enough to handle even the 6 mm extra height.

  5. As one who works with glass fusing a lot I don’t believe there is much risk in heating a piece of glass to 100 degrees Celsius, provided you do so slowly over time. It’s not so much pure heat that causes glass to crack and shatter, but rather unbalanced or rapid heating/cooling. I work with glass at 1475 degrees Fahrenheit and at those temperatures it contains a lot of energy. The primary risk of cracking is when you cool the glass too fast so the outside cools first. Because the glass expands in relation to temperature, this causes stress to build up inside the glass as it solidifies and turns it into a ticking time-bomb.

    For the purposes of 3D printing, you would just want to make sure that you don’t heat up your bed too rapidly so that the heat has time to evenly disperse across the glass pane. Unless the glass itself already had considerable stress in it from too-rapid cooling during manufacturing, you should be okay even with thinner pieces.

    Btw, for those looking to source your own custom sized glass beds, check to see if there are any stained glass shops in your area. The ones near where I live will sell you custom sized glass pieces at a fixed cost per inch and it’s generally cheaper than what a framing shop would charge.

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