The Shop > Metal Stuff

New lining for the iron furnace

<< < (12/14) > >>

ironman:
Have a look at chirpys tinkerings channel on youtube , he copied my furnace from the video showing how it was built. Because he could not get the zircon paint he used satanite instead. He has a video making a furnace using ceramic fiber and coating it with satanite. I have never used satanite but it seems to be a good substitute for the zircon paint I use.

vtsteam:
I've received some Satanite, and will be trying it out.

vtsteam:
An update on my furnace:

I received the Satanite, and it's a good and inexpensive fireclay based coating. It is high in strength and you can put it on thicker than ITC100 (which requires thinning with 50% water). However, it isn't a highly reflective coating, like the ITC100. Best practice would be to put on the Satanite first to a reasonable thickness to protect the blanket, fire it to harden, and then paint on a light coat of ITC100 over that for the benefits of a reflective coating.

On my furnace, the lid insulation has been a continuing problem, despite mechanical fastening. The cause was in trying to piece the blanket on in layers horizontally.  Ironman in the propane furnace construction video below shows doing the lid in many vertical profile pieces, which are adhered to the lid with sodium silicate.

In my experience, horizontal blanket layers cannot be cemented together successfully with sodium silicate. In using sodium silicate, the blanket-to-steel bond is good, but the blanket-to-blanket bond is poor. the adhesive is absorbed by the blanket and yields a dry joint.

When I first built mine, I pieced the blanket in horizontal layers because I only had remnants of 2" thick blanket to work with, (not 1" thick, as Ironman used in the propane furnace lid). The remnants were irregular in shape, and weren't large enough to cut out the numerous vertical sections required for vertical piecing. I did split the pieces into 1" thicknesses, in order to create two layers, which would allow staggered joints.

However after half a dozen melts, my lid insulation was continuing to loosen and drag across the top of the furnace when opened. Pieces would flake off -- and the lid required continued patching with expensive compound. An attempt at reinforcing with metal fasteners horizontally through the rim of the lid also did not completely solve the problem. Where there were vertical joints in the lower layer of blanket, cracks widened and blanket shrank away from the joint because hotface compound couldn't reach very deep into the cracks to protect it. Large sections of blanket would loosen and sag.

Finally, yesterday, I removed all of the insulation from the lid. I now have sufficient 1" thick blanket to do the vertical layer type blanket insulaation. I've ordered some more sodium silicate, and hope the lid built this way will last better

Ironman's propane furnace build:

vtsteam:
Today after some delay I attacked the lid. Well I guess attack isn't the word -- I trashed it and started again.

New (scrap) metal welded together. new insulation blanket installed. The philosophy this time WAS to do only vertical piecing. Horizontal layers don't work, because there is no reliable way to laminate layers together. Vertical piecing means that every individula section of blanket is in contact with the top of the lid and is cemented there with a generous amount of sodium silicate.

I started out trying to do the vertical half-width slice-of-pie method, as shown in the above video, but pretty quickly that showed it wouldn't work. My furnace lid is about 17" in diameter, while the oil can in the video is about 12" Maybe you can cram the inner ends together in a 12" circle, while the outer ends expand enough to fill the spaces, but not on a wider lid.

So I ended up doing a sort of roll-up method, with strips and pieces attached concentrically, except at the center. The final 3" around the exhaust hole was done in the pie wedge method -- and it made sense there -- especially because I wanted to have a leg of each piece extend up through the hole -- similar to the way Iron Man did it in the video above.

Here is the new lid packed with insulation:

tom osselton:
I had the same problem when my son cut off the lid too shallow forcing us to lay it down horizontal my fix was to use some nichrome wire going through the fiberwool and the lid I’ve never had a problem with it so far mind you I’ve only done alu & brass so far.

Navigation

[0] Message Index

[#] Next page

[*] Previous page