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I saw someone do this on youtube and tried it. Works great!

Get a can of caned air, turn the can on its side or almost upside down and spray the base of the finished print. the propellant will come out and freeze the bottom of the print making it contract. Print coms off pretty easy

Use this at your own risk.

Sounds like fun, but just so everyone knows... I've already cracked two build plates:
- the first one was from a full plate print that I let cool before removing
- the second one was from a full plate print that I tried to remove too quickly

I'm not sure what would happen on small prints, and I'm not sure I'd try it on large prints.

The rapid change in temp and contraction could just as easily crack your glass as remove the part.

I now remove all prints as quickly as I can from the hot build plate. I'm tired of buying build plates.

freezer for 10 minutes + paint scraper does the trick for me.

cricut spatula is awesome, thin and flexible!!

The LulzBot guys ship an Oyster knife with their printers.

g.

Only had my printer a few days and had a couple of tricky prints (PLA / Supplied Glue Stick (UHU or PRITT in UK I think).

I tried the pallet knife and found on items with large contact faces it was very difficult and could damage the item a bit for these really stubborn items.

Anyway the glue is waster based so I removed the build plate and let it cool to room temp. Then put the entire thing into a tub
of ~ room temp soapy water (add plenty of soap) and leave it to soak for 10-30 mins and the item should just slide off as the glue dissolves
The soap reduces the surface tension and helps the water permeate through the micro fissures between the item and build plate, takes some time but its safe
and your item doesn't get any damage.

I got it wrong first time as I'd just ran the water from the cold tap and put the build plate in and heard a "crack" as the temperature differential
cause the item to "jump off". The room temp build plate/item and soapy water seems safer but requires some patience... worked so far for me though
probably only works if your using the water soluble glue stick method.

It's clearly not a temperature differential or the effect would be immediate this takes time and the item just slides off at the end.

Biggest risk is wet build plate with slippy soapy fingers could end in tears.

This is one of those things where everyone will have a little bit different trick up their sleeve.

When I used window glass instead of boro, I had multiple plates and just rotated them between prints to let things air-cool and release on their own.
This was also nice because you could hairspray the plates that you weren't using and have them ready and waiting for the next print.

Now that I'm using the same plate all the time, my parts have been coming out solid enough that I give them a sideways tap with the padded handle of a set of pliers and they pop right off.

Razor blade scrapers work well on flat and thin things, and a painters putty/trim knife will work on larger pieces if it's ground down to a fine edge (probably similar to an oyster knife, I'll have to google that one).

I've done the compressed air trick a few times. Not something I would recommend doing with a glass plate though. When you hear that 'SNAP!' when parts let go... there's a lot of energy there. I can see how people are breaking their boro plates. I've got a goofy bed material that can take the beating.

Done some testing with the Soapy water technique and it has 100% record with PLA/Glue Stick.

Everything at room temp: water / build plate / Part. Measured the water temp at 20 Deg C and the room temp was about 23 Deg C

Submerge the build plate in a couple of inches of reasonably high concentration soap solution (Washing up liquid 50cm3 + 5Litres water). I used Fairy Liquid.
Just leave the item/build plate submerged for 5 - 30 mins to dissolve away the glue so no force is ever required it just comes free on its own.
So far for me I've not seen anything take longer than 15 mins but something with a large interface with the build plate could potentially
take much longer.

Disadvantages are it takes time and you have to remove and dry your build plate so more than one build plate would be useful.
So had look but can't find anywhere in the UK, not keen on ordering a glass disk from the US and expecting it to survive the journey so
anyone know of a UK supplier?

Overall I can't see me ever using any other technique now as your part comes off with absolutely no chance of damaging it or the build plate (unless you drop it ).

Don't know if it works with hairspray but I don't see why not as that's water/detergent soluble also.

Ah man. I just wish my problem was over-adhesion. But usually it i parts just letting go or curling mid print.

So i am a bit annoyed :@

I print on a layer of painters tape.
So far I just use a small block of wood and tap around the base of the part.
Eventually it lets go.

teoman wrote:Ah man. I just wish my problem was over-adhesion. But usually it i parts just letting go or curling mid print.

So i am a bit annoyed :@

Tried hairspray? I hear it works really well.

I've not tried ABS yet but I'm expecting some issues when I do. Once I use up the 1lb PLA reel I'll move onto ABS.

So far no issues with PLA and a glue stick other than getting stuff off the build plate initially and some odd behaviour with Slicer.
Occasionally slicer omits a layer, I think it's the ratio of height Vs layer thickness causing this. It especially doesn't like cylinders (pipes)
and has strange pathing which I presume is once again due to a wall thickness Vs layer width ratio.

When in a hurry I have laid a wash cloth or strip of paper towel over the part and stacked a few ice cubes around it - the CRACK tells me when to pick it off.
This is with ABS, I still haven't tried PLA or nylon.

Jimustanguitar wrote:This is one of those things where everyone will have a little bit different trick up their sleeve.

When I used window glass instead of boro, I had multiple plates and just rotated them between prints to let things air-cool and release on their own.
This was also nice because you could hairspray the plates that you weren't using and have them ready and waiting for the next print.

Now that I'm using the same plate all the time, my parts have been coming out solid enough that I give them a sideways tap with the padded handle of a set of pliers and they pop right off.

Razor blade scrapers work well on flat and thin things, and a painters putty/trim knife will work on larger pieces if it's ground down to a fine edge (probably similar to an oyster knife, I'll have to google that one).

I had adopted this tactic for a while for ABS and PLA prints. However, I aquired some PET filament recently, Taulman T-Glase and Colorfabb XT, and had a small portion of the glass build plate stick to the bottom of the print when it was knocked loose.

I have since switched to a layer of the Elmers purple to clear glue stick and that has solved that issue. (Three plates of glass later. Thanks McMaster!)

teoman wrote:Ah man. I just wish my problem was over-adhesion. But usually it i parts just letting go or curling mid print.

So i am a bit annoyed :@

Ok I've been experimenting with ABS this week and TBH had very few issues. Yes it doesn't stick down as well and generally self releases on cooling
presumably due to shrinkage and the bigger and faster temperature change cooling from 90 instead of 60.
It doesn't string (or cobweb) as much as PLA and I get a much crisper finish. Made some nuts and bolts of various sizes in ABS and the all fit and work nicely.

I did have a few issues with inter layer adhesion in a cool room (left the window open) and generally it wasn't too good but resolved the general issue tweaking the temps.
Stock was 90/225/228 - (Bed / First Layer / Subsequent Layers) and I got better results with 90/227/230.

I did get some curling on a large flat thin print but after some testing it was simply not using enough glue.

I found a nice technique that has so far been 100% and prevents any loss of adhesion to the plate and curling at corners.

1. Add a thin smear of glue to the plate.. preheat to 90 then let it cool back down.
2. On top of the preheated glue smear on a thicker layer of glue ensuring good coverage where the corners will be and start the print.

Printed off a few test pieces which were essentially playing card size with sharp 90 Degree corners and they didn't lift at all.
A thin layer of glue to a clean plate and they always lift.

Maybe its all beginners luck though ?