301, 302 and 352 cements
Numbered cements appear in Johns-Manville plant and product records. A 1968 company letter discusses No. 352 Cement among named insulation materials.
Johns-Manville historical product research
Johns-Manville Insulating Cements and Finishes
Historical cement and finish names can help identify the materials handled around pipes, boilers, tanks, ducts and industrial equipment.
Names preserved in company records
450, 500 and 505 cements
A later company response identifies replacement sequences involving 450/460 and 500/505 cement names during the 1970s.
Insulkote ET, ST and SG
These finish names appear in historical company records. A 1968 company correspondence names Insulkote ST and ET among insulation materials being discussed.
Aertite and weatherproofing materials
Historical plant lists include Aertite coating, weatherproofing felts and various jackets alongside pipe and block insulation.
Other numbered and specialty cements
The company plant lists also name 0352, 319 semi-refractory, 340, 364 and 678 semi-refractory cements.
Remember the process
Mixing and application
Bags, buckets, trowels, finishing coats, patching and cleanup may be remembered more readily than a manufacturer.
Maintenance cycles
A boiler outage, steam leak, pipe replacement or insulation repair may anchor the date.
Paper trail
Job specifications, warehouse slips, invoices, contractor records and equipment drawings may preserve a grade or product number.
Original company records
Read the historical source: plant products and insulation replacement chronology ↗
Read the historical source: 1968 correspondence naming insulation materials ↗
Continue exploring Johns-Manville history
Historical product library → Company history and Manville Trust → Start with what you remember →