Best way to apply ABS Slurry to Glass build plate

[furicks]

I've been playing around with methods to apply a "perfect" layer of slurry to the glass build plate.

The methods I've tried have worked pretty well but I'm just starting testing and looking to see how other people have done it. 

I made a squeege out of a piece of scrap glass with kapton tape on the corners so there is a ~5 mill gap on the bottom. 

Drizzle a line on one edge of the build plate and scrape it across the HBP while cool. 

This creates a very even layer but is potentially too thick. The film will tend to peel up when you remove a print. 

I've also done the same method when the HBP is hot. This creates an interesting textured effect as the acetone boils off. 

It doesn't impact the print finish.

I've also considered getting a second piece of glass just slightly smaller than the one on my HBP. 

Put the slurry in the middle and then sandwich it inbetween the 2 glass pieces.

Any extra slurry will be smushed to the edges of the build plate leaving only the thinnest layer in the middle. 

How are other people doing this? 

[Damian Gto]

Some time I also you abs/acetone mix.

The trick is to make the mix right. To much ABS and you will get to much plastic on the build plate and it look bad on the print. It will also be removed with the print.

To little plastic and you will not get the print to stick.

I try to mix it so it just very little plastic and I go over the build plate 2-3 times.

The first layer I do not see the plastic. it just get little foggy after it did dry.. 

The second layer it little more foggy, but I do still not see the plastic color.

Then I heat up the build plate to 115 degree and look how it will be.

I make a small test print to see if its okey.

If not I let it cool down and put on one more layer.

[furicks]

What are you using to get the mix spread evenly on the plate? 

When you apply it this way do you need to reapply after each print? 

[Damian Gto]

Only with a brush. I find it very easy to use and its kind of easy to get a even layer with it.

No I do not reapply it often. If it not stick then I just use clean acetone and  brush the build plate with.

That works most of the time.

I only put on a new layer if needed. I do not want to much plastic on it. You only need a very very thin film of plastic.

[Matthew Stonebraker]

I don't mean to deride your printing methodology, but is there a reason you prefer ABS slurry on your glass bed over hairspray? Just wondering.

[furicks]

Personally I don't like the idea of spraying hair spray all over the inside of my finely tuned and lubricated machine. 

[Matthew Stonebraker]

Great point. I think for any fixed bed machine, hairspray should not be seriously considered. But I am wondering, if the glass can be removed and sprayed, are there reasons one might prefer ABS slurry?

[Steven Furick]

I have only tried the hairspray once and it was a bit of a pain since the 2x's HBP doesn't easily remove from the unit to spray. One nice thing about the slurry is that it's the same material you are printing with. 

This doesn't matter to many people but it ensures that any part you print is 100% ABS without any contamination. I do worry about the evaporated acetone getting into something it's not supposed to but the quantity is so low I doubt it would have any impact. 

I also like the idea of consistency. It's much easier to get an even layer of liquid slurry than it is to get hairspray perfectly even. I only worry because if a missed spot is less sticky it might cause failed prints. 

Personally, I had an excellent experience with kapton tape until recently. Maybe I didn't clean the glass well when I put this last piece down but I was getting quite a few air bubbles and prints that would pull up the tape. 

For that reason I decided I would give the slurry a try and it does seems to be working quite well. Also the finish is amazingly smooth since it's basically printed directly on top of the glass. 

On Mon, Jul 1, 2013 at 2:19 PM, Matthew Stonebraker <stoneb...@gmail.com> wrote:

Great point. I think for any fixed bed machine, hairspray should not be seriously considered. But I am wondering, if the glass can be removed and sprayed, are there reasons one might prefer ABS slurry?

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[Matthew Stonebraker]

Thanks for the explanation! I think your points about contamination and consistent coverage are very good points. I definitely have had a print or two on glass+hairspray that I've needed to abort in the first layer due to inadequate bonding at all places. I will say though that the bottoms of the parts are still smooth as glass with hairspray; it doesn't seem to affect the surface finish at all, no matter how many coats I apply.

[MBuser]

Maybe something else that will work in spray paint. Acrylic, enamel, etc.

[Stan Velijev]

I bought some heat resistant spray enamel and I'll probably try it out on the glass or aluminum plate I've bought. Haven't used either because I can't get prints to stick and I hate tape. A bit worried it'll come off on prints as it's black, but I guess I'll see.

Been using acrylic sheets from tap plastics with a printed tab I've super glued on, has been the most reliable solution thus far.

[Stan Velijev]

Alright, well it helped with sticking but the enamel itself broke off and left black bits on the bottom of plastic.

One interesting thing I noticed though is when trying to clean off the stuff with acetone the effect it had was actually diluting and smoothing out the surface where the plastic was, so there might be some hope in getting clear acrylic spray paint and after each print just wiping down lightly with acetone to renew the surface. I still haven't gotten off all the gunk the spray enamel left on, which if the clear acrylic spray is similar might mean 1 spray might last up to a month before you'd need to fully clean and re-apply.

Might make a trip to the hardware store soon to try that out.

[furicks]

Does the ABS stick directly to the acrylic sheet? Is it nice and flat like the boro glass?

[furicks]

Wow the brush works amazingly well. I just grabbed a cheap disposable brush from the hardware store for $1 and it puts down a consistently even layer. Thanks for the tip!

I am still getting too much plastic it looks like. I "watered down" my solution about 400% but I still get a very thin layer of plastic that peels off with the print. Additionally, the back of my print is peeling up slightly causing prints to fail (this exact problem was happening with Kapton tape also.) Ideally I was hoping to get a solution that worked better than Kaptop tape not just created a nicer finish. 

Any idea what I'm doing wrong? 

[Damian Gto]

Good it worked for you :-)

Just keep add acetone to it until you see the right results ;-)

One trick you can do also is that make sure your build plate is clean is to use Thinner, but do it on a well ventilated area. 

I use to do that to start with to remove all stuff, even the kapton tape I use it the first time I just put it on. Most of the time the print will fasten on the surface very good.

You can also make sure you have 115 degree on the first layer and the print will fasten even more.

[furicks]

Can you see in this photo how the edge is peeling up the thin layer of ABS? This is about the same level of curling I got with kapton tape. My bed is printing at 115. Any idea what I'm doing wrong? The Slurry is put on so thin as to be almost clear and it still comes off with the print. 

[Damian Gto]

As I do not use glass I can only think it depending on the fact your glass plate is to "slippery" for anything to grab to.

What you can do is to use a 1200/2000 grit sand paper and make the glass little dull or use a chemical to etching the top layer of the glass plate.

This will make the slurry, kapton tape or hairspray to fasten better to the glass. 

Even if glass is almost perfect flatt it is not perfect to get things stuck to it. 

[furicks]

Yeah I had thought about etching cream. I have some available but it's very permanent!

What are you using instead of glass for your build plate? 

[Damian Gto]

I still use the aluminium plate with kapton tape. I have no problem with that, more that the kapton tape is is to expensive and it getting wasted sometimes after only one printing( if I am unlucky).

But I am sure when I do use glass I will use etching cream or sandpaper to make the surface little more "ruff" so the kapton tape or abs slurry will fasten better.

[furicks]

I see so you are putting the slurry on top of the kapton tape on top of the 2X's Aluminum HBP. 

I agree with you that I would really like to get away from the Kapton tape as it seems to love bubbles and tearing. 

I'll test a print with etched glass this weekend and see if I can post some results. 

[Damian Gto]

Yes I do that to. But also on the raw aluminium plate. Most of the time I do not need any slurry ontop of the kapton tape. I just need to clean it up real good, then it do work good.

Do so and report back how it do work.

In my mind it should work fine. After all if you look how you paint a car you always use etching paint to start with and that is on a surface you sanded. Even on other layer you do that if the paint has been dryed.

[MadReasonable]

If you are using borosilicate glass then the cream will probably not work.  I found a home sandblasting kit at a local art supply store and it worked great. 

I also had to raised my HBP to 130 for it to be ~110 at the surface of the glass.  It's possible that all I had to do was raise my HBP tempurature but the frosted glass doesn't hurt anything and the finish on the bottom surface of my prints are still super smooth.

[furicks]

You were definitely right. The Etching cream didn't even make a mark on the piece of test glass I used. I cleaned it extremely well before trying. I was using Armor Etch brand from the craft store. I'll make another trip and try out the sandblasting kit. Really interesting idea about the surface temp. How did you manage to measure the surface?

[MadReasonable]

One of the components added to borosilicate glass makes it extremely resistant to chemical corrosion which the what the etching cream is trying to do.

To read the temperature at the surface of the HBP I stuck some masking tape to the glass and measured it's temperature with an infrared thermometer.

[MadReasonable]

If you're going to use something like http://www.amazon.com/Armour-Products-Sand-Etch-Kit/dp/B004ZMC610, make sure you are wearing eye protection and a particle mask.  It's not toxic but it gets everywhere.