Homemade Pyrometer


A pyrometer consists of three parts.
1. Thermocouple (K type), a heat resistant probe that is placed into the molten metal.
2.Rigid metal electrical conduit, one section straight and one bent at 90 degrees.
3. Digital multimeter.


The pyrometer used is from web-tronics.com, model CSI 9903

 

Electrical conduit protects the wire from meter to thermocouple tip.


K type thermocouple from Mifco.com
.

Close-up of thermocouple wire.

When you use a pyrometer heat to the temp you think it is, then insert into liquid metal. Always pre-heat!

Aluminum thick castings 1225 to1325 F.

Aluminum thin castings 1325 to 1425 F.

Brass thick castings 1825 to 1925 F.

Brass thin castings 1925 to 2050 F.

Some brass alloys are tricky, there are hundreds of alloys that are copper based.

When melting aluminum without a pyrometer: After the last piece has turned to liquid wait 3 to 4 minutes, then pour. Take notes on times and results.