Prusa i3 heated bed/Kapton question

So, I've ordered almost all the parts for my Prusa i3 Rework (came in a tad over $400!), but I'm hung up on one little thing: Kapton tape.

I've done a bit of searching and haven't been able to find a definitive answer. Do I need to cover the bed with Kapton tape if I'm using glass? Also, it looks like there's other places in the assembly that require Kapton, so what size(s) should I get?

The general idea behind covering with Kapton is to increase bed adhesion. These days, most people use hairspray to get ABS to stick, dilute PVA for PLA, glue stick, ABS slurry, blue painter's tape or prayer. With all these options, using Kapton is a good idea to make it easier to clean the bed - just strip off the Kapton when your bed gets a bit rough.

The other place to use Kapton is generally to secure a thermistor to the heater block. You can buy rolls of thinner tape, but it's easy to cut down the thick stuff. I've never been fond of using tape to secure the thermistor, so I've taken to tapping a hole in the heater block and using screw-in thermistors (you should be able to find them on ebay). E3D's new V6 hot end uses a screw and washer to secure the thermistor, which is even better.

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I used Kapton tape to secure a piece of cork to my heated bed. I also used some Kapton tape to secure my heated bed thermistor to the bed.

I've had excellent luck so far with purple Elmer's Washable School Glue Stick to get ABS to stick to the glass over my heated bed. It scrapes off VERY easily with a razor blade when done and cleans up easy.

-Matt

Ah, OK. So coating the bed with Kapton is one of several possible options, but it's used in other parts of the build. I'll go ahead and order some and then play around with bed treatments once I finish the build. I'll be starting out with PLA and Blue Painter's Tape anyways.

I am a little confused about the "easy cleaning" reasoning. What could be easier to clean than a sheet of glass???

Edited 1 time(s). Last edit at 06/03/2014 09:34PM by SimianSteam.

I am using 3m adhesion tape to cope with bed adhesion. It works very well against bed adhesion.

My easy cleanup comment was referring to my perception that some glass treatments take more work to cleanup than others. I haven't used hairspray yet, but my assumption is that it will be a little "sticky" for cleanup. Covering the glass in Kapton would require removing all of it and replacing it for the next build. With the glue stick, cleanup takes about 1 minute with a razor blade and some rubbing alcohol.

I am printing PLA directly on the glass with NO adhesion issues so far. So, I only use clean glass for PLA, and so far a glue stick for ABS.

-Matt

The best thing I have found for adhesion is hairspray for PLA and glue stick for ABS. Clean up is easy, just sit the glass in the sink and turn the hot water tap on high. I just leave it under there for a few min and it usually is clean after that. I immediately take it out and dry it with a clean towel. Make sure towel is clean, you don't want any oil (including from your finger tips) on the glass. When applying hair spray I do it at slightly less than ninety degree angle to the glass and about a foot away. Do three thin coats allowing dry time between (a desk fan will speed this). For glue stick I just put one coat on pressing down until the width of the stick evenly coats the glass, overlap each new line just a little bit. I can't stress that part about no oil enough. If you can't get a smudge off the glass, use isopropyl alcohol (NOT RUBBING). These work so well for me I can't get the parts off. I have to wait for it to cool and then stick it in the freezer. This usually loosens them within a couple of minutes.

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SimianSteam
Ah, OK. So coating the bed with Kapton is one of several possible options, but it's used in other parts of the build. I'll go ahead and order some and then play around with bed treatments once I finish the build. I'll be starting out with PLA and Blue Painter's Tape anyways.

I am a little confused about the "easy cleaning" reasoning. What could be easier to clean than a sheet of glass???

You are right, I should have been more specific. In these parts, rubbing alcohol IS isopropyl alcohol... I know elsewhere it may be ethanol.

Hi when I first started printing I saw some guy on you tube use pva I did that and works a treat when ya prints stop sticking just put under hot tap dry place back on bed recoat reheat let cool ya good to go for some time. and its cheap

I'm also struggeling a bit on if to use Kapton tape
My sofar like 40 test prints I have done on plain glass bed
Adjusting z height until I get adhesion good
Problem still is 1st layers get kinda sunk down ....
I'm thinkin maybe I get too close when printing first layers ... just go get proper adhesion
So is Kapton tape going to improve adhesion compared to plain glass ?
I use ABS at 100 C hot bed and 250 C hot head

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Prusa i3 Reworked, Delivered March 28 2014, RAMPS 1.4
Göteborg, Sweden

Oki, just another little learning for me on this ....
Got pretty good result printing a test object
When choosing another test object, it was positioned like x=40 mm y= 50 mm
That one did not adherse at all
The other one at x=90 mm y=100 mm did
So when I changed my second one to same position as first one I did get good print out
So seems like it's important to even calibrate for what position you place the object ....
My guessing it's due to I don't get same bed temp feedback depending on where I choose to print ...
Ha det gött
Bosse

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Prusa i3 Reworked, Delivered March 28 2014, RAMPS 1.4
Göteborg, Sweden

Just wanted to say that I'm keeping an eye on this, but I don't have anything to comment on until I have my printer built and know what I'm talking about. I appreciate all the observations and advice, though!

I have tried Kapton and had some good results. Howrver the hotend was too low and removed the tape when it hit the edge. My problem is the width of the tape I have, which is 4 cm. I need to lay down 5 pieces to cover the entire bed, which increases the risk of being removed by the hotend. I have ordered a 20 cm wide tape roll, so we'll see if it is a better solution.

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drmaestro
I have tried Kapton and had some good results. Howrver the hotend was too low and removed the tape when it hit the edge. My problem is the width of the tape I have, which is 4 cm. I need to lay down 5 pieces to cover the entire bed, which increases the risk of being removed by the hotend. I have ordered a 20 cm wide tape roll, so we'll see if it is a better solution.

Ok, so adhension is better/improved with Kapton for you ?
Ha det gött
Bosse

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Prusa i3 Reworked, Delivered March 28 2014, RAMPS 1.4
Göteborg, Sweden

I've used nothing but hair spray for both PLA and ABS, I haven't had any issues with either. Adhesion is so good I've had incidences where the glass actually came off in slivers with the printed piece.

Think I'll check out both spray and Kapton .... see how that goes for my printer. Hair spray like any brand... ?? not the expert there
Ha det gött
Bosse

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Prusa i3 Reworked, Delivered March 28 2014, RAMPS 1.4
Göteborg, Sweden

I built my printer about 10 months ago - At that time I had a friend stop by the dollar store and pick up 2 cans of whatever was cheapest. I only popped the cap off of the second can about a week ago if that gives you any idea. I've heard people on Youtube talking about this brand and that brand - I really don't think it matters. Pretty much any can full of sticky will do.