I know the basics. Iron (Fe(II)O rust) dust/aluminum dust with possible additives. Having followed RR activity for many years, IIRC, there was a cardboard box that had the word BOOTAE. Falsely for years I have refered to the rail weld by that name. The question is, among the main ingredients is bootae a compound to increase the efficency of the weld?
Boutet .... manganese charge added to the aluminothermic method gets everything in a super hot molten state and minimizes the voids that are the main probable defect to possibly be encountered
Go look at the french gunsmith and what he pioneered....
Overmod said you would know. By chance is the whole package of weld material: called by this name, manufactured with this name, etc.? Thanks for the info. endmrw0228241531
Note that "BOOTAE" is a nearly-perfect phonetic spelling of the French name. The problem was that no existing search engine still does Soundex... I have never really understood why, because that principle is now a half-century old.
See for example French Railway Techniques (which was one of the bibles for high-speed railroad design in the mid- to late Seventies) v19 n3 (1967). This system used a three-piece mold which "permits the welding of joints, even over the ties without moving them aside". Throughput is a joint per man-hour or less. The molds are designed to make them easy to center around a field joint; the three-piece design essentially elmininates a weld bead 'under the flange' (which I understand to mean what we call the 'foot'); and limited careful pre- and post- heating of the ends and the rail is conducted to 'minimize the effect of rail movement during the welding operation'.
The use of the method is of great antiquity in Europe. Railway Gazette (v76 p.266, Feb 20 1942) describes its use on the English Southern Railway during wartime, mentioning that its temperature control produces less brittleness in the HAZ, and that it can be used effectively to produce CWR sticks (without bead issues for flat-bottomed rail) as well as field joints.
In fact we had at least one thread on the old forums (titled "Thermite Welding of Ribbon Rail") which discusses some practical experience with this -- you can find it in Community Search.
A reasonably contemporary (2016) set of rules for UP rail welding with this system is section 110 (about p.124 in the PDF) here:
https://ftp.dot.state.tx.us/pub/txdot-info/hou/projects/hempstead-road-uprr/track/form-7913.pdf
Thermite was a well established method for welding street railway track in the U.S. prior to 1915.
Autogenous welding was a common practice at ATSF by 1919. Of course there were a lot of things it wasn't at all good for in that era, and 'knowing what we know now' about welding it can make fascinating reading what they did and the things they tried.
Practical autogenous welding of boilers, for example, wouldn't really come about until the late 1930s, with formalization only during wartime.
Did you see the bit about Boutet reducing the reaction peak temperature rise, and using very careful pre- and postheating to minimize problems in the HAZ either side of the deposited weld metal? None of that was likely characteristic of early Thermit practice.
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