Rusty Kiln lid

[Wendy Rawlings]

Hi. Can anyone recommend a paint to use for the outer kiln lid as it's beginning to rust?  The rust has damaged the bung hole quite a lot and it is crumbling the metal and some loose bits of rusty metal fall into the kiln itself whilst firing.  Is there anyway I can repair or rebuild part of this bung hole edge?  I fire stoneware and glazes mainly to about 1260.

Any ideas greatly appreciated as I don't want to have to buy a new kiln.

Wendy

[Pres]

Wendy, welcome to the forum, I hope you find many years of information at your fingertips useful.

 

Personal belief is that it would be best to replace the lid. I have replace my lids in the US over the years, last one with extra thickness. It is hard to repair the type of problem you have there, but if you really have to, I would grind/cut back the area around the lid hole, and  sand/grind the rest of it and look for a high temperature paint for the covering. You do not say where you are from, but I assume Europe or Australia.

 

Once again, 

welcome to the forum.

 

best,

Pres

[Magnolia Mud Research]

I would try to find or make a short - say 10-12 cm - cylinder ceramic pipe to fit over the hole.  The metal corrosion is coming from the hot, moist, combustion gases leaving the kiln.  You could make such a cylinder with a sagger clay body consistent with your maximum firing temperature.  We made such a device using preformed piping insulation for a small kiln five+ back.   The stack reduced the corrosion and also had the unintentional benefit of improving the control of the firing.  

LT 

 

[Mark C.]

You will need a small grinder and cut the lid back from hole some. Either a small 4 inch grinder or a small dremel tool with cut off saw on it. If there still is rust you will then need a de-rusting liquid like ospho- after you wire brush the loose material away-you apply it and let it sit one day and it turns rust into a different form. Then use high heat paint on the new metal.

This is the only repair that will give good results other than a new lid

You will have to find products like this in your area of the planet as these are all in the US.

 

I like the idea posted above as it will move the problem and keep rust from failing in. The tube should be easy to make as well.It could be glued in.MMudR was typing at the same time so I missed it.I would do this as its an easier fix.

[Wendy Rawlings]

Hi thanks for that. 

Yes I'm UK based so would need to find similar products.  Does the rust converter need to withstand the high temperatures?  Also if I cut away part of the metal jacket on the lid will it cause a lot of heat loss? I would probably combine this with the ceramic chimney idea as suggested as then the chemicals are moved away from the lid more.  Thanks for all your ideas.

[Mark C.]

Rust converter is just that a converter after it works the high heat paint is needed on the metal

if all this hole is for is heat dispersal just make the tube extension as in the above post and make a smaller plug for that tube. Cement the tube into hole and rust will not fall.

what do you us the hole for?

[Wendy Rawlings]

Ok. So a rust converter doesn't need to be heat resistant.  Hammerjte paint should be ok on top.

The hole is an 'air vent'  which I've always left open with a hollow bung in.  I think it is important with how the heat distributes inside but I'm not massively technical in how kilns work. 

I also have a hole in the side which I leave open for bisque firing to allow the 'damp' out but this hole needs bunging for glazes as it changes the finished glaze appearance on nearest ceramics.

Thanks for your help again.

[Chilly]

I used Kurust, but the rust on my kiln lid and sides was "non-existent" compared to your kiln.

[neilestrick]

You should only need to keep the side peep hole open. If you find you really don't need the lid hole, remove the ceramic sleeve, clean up the hole, and mortar in a piece of soft brick to plug it. Don't worry about the metal other than digging out the loose bits. If you need to be able to open the hole, then I would do the same thing, but then drill a new hole through the new soft brick plug.