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I have been working on the new heated bed for my H-1 Tank. There are 60 m4x.7 taped holes and 8 holes for mounting to the table. Still have to machine the recess for the heating element. it is rated at 50 watts at 12 VDC.
I am waiting for a new temp controller that will handle both the hot end and the heated bed.

[img]http://i132.photobucket.com/albums/q3/D ... 0_1187.jpg[/img]

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Hey Dave,

Why all the holes? Will the heated pad be enough to heat the entire bed evenly?
And, where do you get aluminum plate that thick? The LHS don't have much selection, just 1/16" . . .

Dave, what are you using for the heating element?

Cheers,
Michael

Mike

All the holes are there because I do not know what all might get mounted to the bed. The alu plate is .5" 5051. I get my alu from and industrial alu supplier that sells there drops at $1.50 per pound. Because it is a 100 mile round trip I tend to buy every thing I see that I think I may use some day. This plate started out as 2'x3'. Cut it to just over 200X200mm on the table saw. Noisy and throws alu chips all over the place.

I need to mill a 5mm deep recess for the heating pad so the plate will be just over 7mm thick for most of it. The heating pad is held in place with double back tape that comes with the pad. There will be 1/4" of kool wool high temp insulation between the bed and table. The Bed will be held to the table with 4 6-32 jacking screws for leveling and 4 6-32 counter sunk socket head screws to hold it down at the corners so not much heat transfer to the table.

Michael

The heating pad is one I got from my Son in law. They special ordered them from a supplier for a project they are doing. They are similar to the heating pads they put under batteries of trucks that operate in very cold temps.

More progress today. Milled out the recess for the heating element.

[img]http://i132.photobucket.com/albums/q3/D ... 0_1193.jpg[/img]

Here you can see the jacking screw that are in the for corners.

[img]http://i132.photobucket.com/albums/q3/D ... 0_1190.jpg[/img]

Here is the kool wool insulation.

[img]http://i132.photobucket.com/albums/q3/D ... 0_1191.jpg[/img]

Here I am dialing in the table to be level with the nozzle in both X and Y axis.

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Looking good Dave!

BTW nice hat!

How is that heated bed working for you Dave?

What is cool wool Dave. That looks interesting.

Cheers,
Michael

JT It is not. The dual temp controller I ordered from Turkey Is lost in NY, NY. Supplier is going to check Monday and see if he can find out what happened.

Micheal Cool wool is a high temp insulation that is used in kiln and other high temp applications. rated at 2600F

I just ordered a roll of this stuff from McMaster-Carr #9379K91

http://www.mcmaster.com/#catalog/118/3522/=h0rcuo

It is foil backed and 1/2" thick rated up to 2100F. If I put two pieces together (3"x6") and place them directly under my heated bed the H-1 table should not feel a thing.

I like the stuff you are using Dave, but can't get my hands on a smaller quantity of it.

Sorry to hear that Dave! hopefully they get it all sorted out.

McMaster Carr 9328k41 is a 2' x 4' 1" thick mineral wool that withstands temperatures up to 1200F.
Price is less than $7 plus shipping. This would be excellent for insulating hotbeds. Just thought I
would let everyone know of an inexpensive source of high temp insulation.

Regards, Carl

Can regular glass work as the top of the heated bed or do I have to use the expensive high heat glass?

Regards, Carl

Eaglezsoar wrote:Can regular glass work as the top of the heated bed or do I have to use the expensive high heat glass?

Regards, Carl

I think regular glass will work ok, I haven't tried it. One concern is the heating and cooling cycle, I don't know if the glass will withstand it.

The general consensus seems to be regular glass is fine and often flatter than high temperature glasses.
Having said that if the heating is uneven, or you rapidly cool it, it will shatter.

Well I think I can continue with getting my heated bed up and running. I had ordered one of those dual temp controllers that Nuri had a link to. It was being shipped from Turkey and got lost in NY,NY so I broke down and bought another Vellman controller. Just put it together this evening and will do some testing Sunday.

Still have to rebuild my hot end before we are printing again so I've been in CNC Router mode.

[img]http://i132.photobucket.com/albums/q3/D ... 0_1262.jpg[/img]

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That looks sweet Dave!

That is cool.
Are you going to print, route, lathe or even add a wheel?

I did get a dual temp controller from a different source. I was frustrated by it because it was only for higher voltages. 90 to 260 AC or DC.
While I do have to run a separate wire and switch, this one should work with the correct relay. Had about a dozen SSR's here, but of course, not the right one.

Bought one that will control from 3 to 32 VDC and operate 3 to 200 VDC @ 25 amps. This one was $40.00 though. Cost more than my whole collection of SSR's.

I have another little aquarium thermostat coming from Hong Kong sometime. I think it will have issues with the probe. It is short and kinda fat looking.
My other thermocouple I bought is about 6 " long and about 1/8" around. It fits fine between the circuit board and glass on mine.

I am just controlling mine manually until the SSR arrives, but I gotta say it is nice to have an accurate temp readout on these.

Looking forward to what you come up with.