Making a straight edge out of an old cast iron level as a first scraping project ?

[johansen]

To heat treat long items like that at home, put them inside a steel pipe filled with sand. Take an oven heating element and straighten it out, pass it through the pipe, or coil it around it.

Then wrap the pipe in fiberglass. You may not be able to hit 1150 but 1000 for sure before the fiber melts.

I heated a 7 foot long beam that weighed 350 pounds to 1000 F with a 3500 watt element and 2 rolls of fiberglass

 

[M.B. Naegle]

......

Other question: "japanning" - how can this be done at home? Anyone done this?

I started a thread on this awhile back Here. I need to update it but I currently have 3 straight edges that I'm Japaning.

My process takes awhile. About a month for a coating to air dry (dosn't need to be dry to do another coat, I'm just in no rush and there's less mess if you let them totally air dry). Once I'm happy with the overall coating thickness, a few hours in an oven (or out by the camp fire in the case of one SE too long for the oven) does the final hardening, which is what really makes it durable.

A couple of these straight edges are brand new and the other is an old poorly made one that I'm fixing. While each has had some scraping done, I'm doing the Japaning before the bulk of the scraping as the heat does discolor the bare surfaces.

While I'm still building layers, overall I've been pleased with how smooth and durable the Japaning is. Materials are not that expensive, it just takes longer than typical painting.

 

[max.levesque]

To heat treat long items like that at home, put them inside a steel pipe filled with sand. Take an oven heating element and straighten it out, pass it through the pipe, or coil it around it.

Then wrap the pipe in fiberglass. You may not be able to hit 1150 but 1000 for sure before the fiber melts.

I heated a 7 foot long beam that weighed 350 pounds to 1000 F with a 3500 watt element and 2 rolls of fiberglass

Did you control the heating element with a sensor and controller ?
It seems like a pottery kiln controller could be used for that.

 

[dgfoster]

To heat treat long items like that at home, put them inside a steel pipe filled with sand. Take an oven heating element and straighten it out, pass it through the pipe, or coil it around it.

Then wrap the pipe in fiberglass. You may not be able to hit 1150 but 1000 for sure before the fiber melts.

I heated a 7 foot long beam that weighed 350 pounds to 1000 F with a 3500 watt element and 2 rolls of fiberglass

Very creative way to use "junk"to accomplish a task. I like it. Of course, fiberglass tape is available in any hardware or home improvement store and probably is just eough to get 'er done. But, ceramic blanket is also available online and at ceramic supply stores as well as commercial foundry suppliers at reasonable cost. 30 bucks on Amazon, as an example. And the blanket is rated at least (there are various grades) to 2400F and is easy to use. (Before someone starts spouting comparisons of ceramic blanket to asbestos, I will point out that OSHA, the NIH, and various health agencies have never found, despite countless studies, a correlation even with industrial use of ceraic wool and lung cancer, COPD, or asthma.

NIH Ceramic Wool Statement

Occasional use certainly has much less associated risk than walking down the sidewalk.)

My purpose-made heat treat oven is simply a metal shell lined with ceramic wool with resistance wire heat elements controlled by a cheap progammable control---in other words a pottery kiln, but one I designed and built for my castings.

Denis

 

[johansen]

Did you control the heating element with a sensor and controller ?
It seems like a pottery kiln controller could be used for that.

I have done that before.

Self tuning pid kiln controllers are pretty cheap.

Fiberglass insulation melts around 1100F.

Newer self cleaning ovens are insulated with rockwool.

 

[Miannini]

I have never attempted Japanning. I have only used shaker cans to apply glossy or semi-glossy black enamel to various vintage Stanley planes, draw knives, and router planes after replacing or fabricating any missing parts and scraping their soles. (A scraped sole really makes a good Western metal plane work even better.)

But, I have wondered about doing it at some time in the future. Were I to give it a whirl, I think I would use this guy as a prime resource as he seemed to really look into the history and several different methods of trying to make a suitable tool finish. And he seems to have honestly and critically looked at his results.

Japanning Methods Video Link

Denis

Thanks for the link on japanning!