lead bath spring tempering

[JohnN]

Whats the process for lead bath spring tempering ? Might want to try it sometime since I have lead, thermometer, ....

[kudu]

I find that it works great 720 degrees definitely no higher. I get the spring ready wrap a wire around it to submerge in lead or it will float.
I try to keep the lead as close to 720 as possible and submerge spring for 15 min or so remove and let air cool.
easy /peasy never had one break.

I think poor filing and smoothing of sharp corner radiuses and tapers, are the main cause of spring breakage. I check them over with a magnifying glass before any heat treatment.



 

[jerrywh]

 In order to prevent the lead from sticking to the spring, smoke the spring with a candle first. The spring must be in the lead at the proper temp for about 12 minutes. Slight imperfections in the spring such as scratches do not matter if it is tempered correctly.

[Scota4570]

I use my bullet casting LEE pot.  I shoot for 750* ( hate having springs break!).  I use wire to submerge the spring.  I let it soak for about 15 min.  Then let it cool naturally. 

I use Tempilstik 700* and 750* to confirm the thermometer is accurate. The Lyman thermometer has always been accurate when I checked it,

[TMerkley]

Those of you who have been treating springs, what is the condition of your springs prior to? 

Are they from a factory, from the forge, quenched in water, etc....

Just curious

For other information, I worked in a factory that made hose clamps and valve springs for cars,  They used liquid salt and the conveyor took about 20 minutes to work through the Vat.  360 degrees Centegrade