http://www.soliforum.com/post/12339/#p12339

Using 1/4" cork glued onto 1/4" MDF, 50degC -> 95degC in 9 minutes flat.   Cork is supposed to ignite at 300-320 degC, so it seems safe for this application.

Found this while picking up some things at Walmart in the pots and pans section on one of those clip on racks hanging from a shelf.  I think it was only a couple dollars $2.99 maybe?  It's a silicone pot holder and trivet.  It's sold under the brand name gourmet club, and is distributed by Best Brands.  It says it's up to 450F heat resistant (=232C) so it should never be an issue of burning or melting to the bed.   

My test was to start a timer at exactly 50C and stop at 95C
Control test was just glass and alum bed.  22m 31s
W/ pot holder on glass time was improved to  14m 32s

8 minute improvement seems worth it to me, saves me from starting my prints too early when I get impatient.

I picked up a pack of two at our local Meijer store for $4.99. They are square and fit perfectly on the bed.

how about using an external heating device to preheat the glass ready to just swap out on the already heated bed..?  i have a $15 toaster oven in my workshop that i use to dry out plaster models, if i have it turned on to low with the glass sheets sitting inside, then all i need to do is take one out, spray hairspray, clip on and print..

i have just scored an order for about 200 prints of a simple token design, have already got the glass bed thing down, with multiple sheets of glass and quick clips from a picture frame.. am thinking i will give this a go to try and save myself some wait time..

(though i have to say the wait time gives me a good reason to catch up on a lot of other little jobs in the 'shop)

One thing I've done is run a thermocouple along the wire bundle with the end of it near the extruder.   That way I could keep an eye on the ambient while blowing the space heater into the case, and make sure it doesn't get hot enough to endanger the extruder.   You might start to get into trouble with it at around 70-80c.

I don't really recommend ordinary styrofoam at this point due to its combustibility, but I need something rigid and non-sticky to work with the automatic retraction mechanism I'm currently building. 

Dow makes an orange fireblock version of it foam-in-a-can product, so I'm thinking I might spray some between two soapy sheets of glass to mold my own fire resistant bed cover.  Might work.

I'm usually just reheating the bed so it takes much less time.  A full heat up from 20c is not much more time.

I also have a 8x8 silicone mat from QU-BD on my CNC.  It takes 10 minutes to get up to temp from 20c and that is without the heat gun.  I'm sure the 6x6 would heat up faster so that might be a good alternative since you don't have to hold a 600 degree Farenheight gun and worry about where you put it down.  I've already melted the wires of the gun by putting it down wrong.

Interested to see the unscientific results of this compilation.

Also, how do I run PID Autotune on the heat bed, you can see it wobble in the graph.  Do I just swap connections and run the M303?  I think it is the same Thermistor settings in Firmware.

TheBogueRat

p.s. Don't laugh at my enclosure, it works great!

Glass on Stock Bed - 22.5m warmup from 50C to 95C

• Silicone Mat - 8min improvement

• Welding Blanking

• Foam Block

• Cardboard

• Heat Gun - 18min improvement

• Microwavable heat pad

• Towel

If anyone has the bags from cornhole or whatever you call it locally try microwaving them and setting them on top of the bed.  I don't have the game or I'd try it.  I always thought that would be a great solution but haven't tested it.

My solution before this was to leave the heater on all day for the bed on days when I was using it.

bahstrike wrote:

Wavesurf wrote:

I use a hot air gun to get up to 90c in under 3 minutes.

That's fast.. about the same time it takes the extruder to come up to temp!
Are you using a glass bed?  If so, and you have no cracking, that's impressive and I might consider it.
How far away do you hold it?

I tend to use my hot air SMT rework station for everything including heatshrink, so I could repurpose the hot air gun for this XD

It's unlikely to be as powerful. A heatgun is typically 1000 W at least, and your hotair station is almost certainly not above 200 watts. 

That said, you would want some sort of diffuser, and it could help. You can make a cone of alu foil in front of the hot air gun maybe, and a fan on the exit. I'm not sure

The SMT rework station is 500w  but I wasn't going to use that baby for heating the bed 

The heat gun is 1100w but I only ever bought it for heatshrink-  which the SMT rework does fine with.
So the heatgun just sits in the closet, waiting for a purpose