Welcome to the SeeMeCNC Community

Hello,
I am working on upgrading my heated bed.

I bought a MIC 6 plate from http://www.sandsmachine.com/alumweb.htm and cut it down to size.
Afterwards, I drilled and countersunk the holes to screw in the plate. Then I put a layer of Kapton tape on one side.

Now, my plan was to take a designated amount of nichrome wire(20 ohms worth) and swerve it back and forth along the Kapton tape. I tried this with 26AWG and 20AWG wire and I found that it is difficult to get it to stay. Since the wire is wound in a coil, it doesn't want to stay down. I could just tape it down, but I am wanting to put some RTV silicone over the wire so that it will conduct better and then put Kapton tape over it. This just turns into a big mess trying to remove the tape holding the wire down, applying RTV silicone, and then taping over it.

What gauge nichrome would you recommend that would keep its shape when it is bent?
Is there an easier way to do this that I am missing?

On a side note, I decided that I would avoid putting nichrome near the holes and then I would use the nylon spacers to keep the aluminum plate a fixed distance away. Do you think that the nylon spacers touching the aluminum will melt or even degrade a bit causing the bed to become unlevel? If so, what would you recommend?

Thanks,
Addison

why add that wire? It will work as a second heated bed?

You ought to just buy a silicone heater pad that's already made and just stick it to the bottom of the aluminum.

If you still want to build your own (which I've considered too) it would probably be easier to build it on a jig first and attach it to the aluminum second. My plan was to use a board and tacks or nails to lay out the heating wire, kind of like a piece of string art, and then pour the silicone on to the jig and remove the fasteners afterwards. You could build your pattern on top of an HDPE cutting board or something similar that would make a nice, releasable surface to mold the silicone against.

Oh I got it wrong
Werner Berry did his own heated bed also.

Check it out:
[youtube]http://www.youtube.com/watch?v=gXUJQuNSLYw[/youtube]
Min 5:46

Tincho85 wrote:Oh I got it wrong
Werner Berry did his own heated bed also.
Min 5:46

That's a very neat way to do the heated bed. So the nichrome wire heats up, and then it relies on convection to heat up the plate. That's neat, but with such a thick aluminum plate I wonder how long it would take me to heat up. I wonder how long it takes him to heat up as well. If it is a reasonable time, then I would choose this over my method because you don't have to deal with silicone, taping, or keeping it electrically isolated as much.

Jimustanguitar wrote:You ought to just buy a silicone heater pad that's already made and just stick it to the bottom of the aluminum.

If you still want to build your own (which I've considered too) it would probably be easier to build it on a jig first and attach it to the aluminum second. My plan was to use a board and tacks or nails to lay out the heating wire, kind of like a piece of string art, and then pour the silicone on to the jig and remove the fasteners afterwards. You could build your pattern on top of an HDPE cutting board or something similar that would make a nice, releasable surface to mold the silicone against.

I was unable to find a silicone heater pad that was around the size of the Onyx and had enough power(500W) to heat up the aluminum plate. I've heard that 3mm aluminum plates warp for some people, so I went the safe route and got the 5/16" or ~8mm I think.

I started on creating a jig with some wood and nails, but I came across the issue of transferring it over to the aluminum plate. With thinner nichrome wire, it would just go haywire when you took it off the nails. I am considering buying some thicker annealed wire so that I could bend it to the shape I want and then apply it.

What silicone were you thinking about using? It sounds like you are wanting to actually use the silicone to help it keep its form.

As for the spacers, I will not place any wire about 10mm from the edge and that should be enough to avoid the spacers. However, I might consider some ceramic spacers as the guy in the video did.