Ender 3 bed element removal

[picclock]

Has anyone removed the original bed element from an ender 3?

I want to replace it with a silicone pad heater, but am reluctant to just stick it over the old one.
The original construction looks like it has been printed overwith a high temp ink ? maybe epoxy. The element looks like its just copper with kaptan or ink insulation.

Any other help much appreciated.

Best Regards

picclock

[picclock]

On further investigation it appears that there is a gray insulating layer of filled epoxy or similar(?) between the copper element and the Aluminium. It is quite hard and I have been unable to find a solvent. 

I have 4mm aluminium in 'stock' so I have the option of sticking the heat pad over the old element, removing the insulation/element by mechanical means or making a new bed.

Thanks for your interest

Best regards

picclock
 

[russ57]

Sounds like a new bed would be best. Sticking over the old seems like potential for uneven heating.

-Russ

[picclock]

@Russ57
Rather annoyingly, the bed is 3mm thick, and whilst I have good stocks of 2 and 4mm The remaining pieces of 3mm are too small  .

I may attempt to machine the rear surface of the original with a flycutter - nowt else to do with lockdown.

Best Regards

picclock

[russ57]

Would the extra mm be a problem? Give better heat distribution.
But milling the old clean should work OK, although irreversible...

-Russ

[picclock]

Well, I gave it a go but no-go,  The other side of the bed has a layer of magnetic rubbery stuff which the print surface sticks too. This lets it to spring when clamped to the mill table. Also when it cuts through the grey layer the aluminium tends to grab the tool making it deeper at that point.

All rather sad really. I have other bits on the way, including 3mm aluminium and sticky magnetic sheets good for 130C continuous, so it was always going to be a stopgap. Also have a spring steel pei coated build surface on its way.

Could use 4mm, as you suggest but the extra weight ~150 gms (around the same weight as the silicone heater) would slow down the action even more. Just feel that 2mm aluminium is too flimsy.  Original bed weight inc heater but no wires is around 560gms excluding print surface. Weight of bare aluminium sheet is 447 gms, so I reckon original bed heater is ~60 gms, allowing 50gms for magnetic rubber.

Well at least I found out why people dont do it that way 

Best Regards

picclock

[ddmckee54]

picklock:

If the original print bed is hosed and you are going to replace it anyway, try loosening up the heater with an aircraft type paint stripper.  The kind that will strip any paint off any surface.  That might make the original bed heater soft enough to scrape off the print bed.  At this point you haven't got much to lose right?

Don

[picclock]

@ddmckee54
I'm not sure what the white/grey chemical is. I have tried all the chemicals I have readily at my disposal including acids and most solvents, (excluding those that react with aluminium) to no effect. What is the active ingredient in aircraft paint stripper ?

Its really just an academic exercise atm, as I have new stock of 3mm aluminium, and can use clips to hold the build surfaces until the magnetic self adhesive surface arrives.

The mods I am doing are to my ender 3 are to enable printing of higher temperature materials, and to bring it up to spec with my old printer. Fast bed heating and auto bed levelling are a must for me. Automatic homing using the stepper motor drivers will also be a first (no microswitches  ).

If anyone is interested I will do a mini build write up in project logs.

Best Regards

picclock

[awemawson]

"What is the active ingredient in aircraft paint stripper ?"

Methylene Chloride probably

[Brass_Machine]

...
If anyone is interested I will do a mini build write up in project logs.
...

Please do. I have an all metal hotend (coastal robotics) but hadn't thought about replacing the bed heater...

What do you plan to use for the auto bed leveling? I have a BLTouch though I am still not sure if I like it.

[picclock]

@Brass_Machine
I am just in the process of fitting a BLTouch (clone). What issues do you have with it?

On my old printer I had a servo with a mechanical positioning switch from a photocopier which outlasted the machine. I never looked back once it was fitted.  I'm also considering fitting the E3Dv6 head but thats a future thing.

Do you have the Ender 3 Pro version?. One of the not so hot features of the original Ender3 is the 20mm Y gantry section. Very small adjustment tolerances can allow the far edges of the print surface to move in the Z direction. I'm not a great fan of the 40mm Pro version but so far it seems to be adequate.

Will do a write up in the hope it may prove useful.

Best Regards

picclock