Shell Bond Injection

Shell Bond

Shell bond liquid is a Phenolic resin for use in the production of shell moulds or cores. The resin is of novolak type. The addition of premixed catalyst (Hexamine) is required to cure it with the application of heat. Shell bond catalyst is a mixture of hexamine and a lubricant.

The system consists of following parts:

• Shell bond GB 30/40 - Liquid Resin
• Shell Bond 620 - Powder Catalyst
  

Typical properties of Resin:
610 GB 30/ 40

• Sp.Gravity @ 30^OC : 1.08 -1.12,1.06 - 1.10
• Viscosity by B5 cup @ 30^O C : 240- 450 Secs, 40-90 Sec
• Solid Content : 69 -71%, 64-66%
  

Typical Sand mix:

• Washed Silica sand (AFS 50-70): 100 PARTS
• Shell Bond 620 Cat. : 16-18% by wt. of resin
• Shell bond GB 30/40: 4-6% by wt. of sand.

Resin & Catalyst percentage depend on the type of sand, clay content, grain-size etc. and also type of castings and temperature of the molten metal to be poured.

Shellbond GB 30/40 liquid is developed for use in the production of coated sand with hot air (warm coating process)

Coating process: Charge the sand into the clean mixer. Add shellbond 620 catalyst & mix for 30-60 secs. Then add shell bond resin and allow wet mix for 1 1/2 to 2 mins. Start the hot air of temperature 220 -25⁰C for 4-6 mins depending on percentage of resin and ambient. Continue the mixing first balling stage will come at which lump formation will be observed. After sometime lumps will start breaking and sand will become free flow-able. At this time, discharge the sand over the vibrator screen

The discharge sand temperature should be 60-65^OC. The screened sand should be passed through effective cyclone, cool the sand to room temperature before use.

Typical properties of coated sand: When silica sand with 80-100 fineness and clay content about 0.2% is coated with 4%
Shellbond GB 30/40 & 18% of
Shellbond 620 (BOR) then following properties are obtained.

• Hot tensile strength : 450 PSI Min,
• Gas evolution of cured cores : 25-28 cc/gm
• (At 1000^OC for 3 minutes)
• Stick Point: 206 -212^OF
  

ADVANTAGES:

• Excellent surface finish of the casting.
• High strength of moulds and cores with good resistance to moisture.
• Low gas evolution during pouring.
• No sand fusion to casting.
• Excellent dimensional accuracy.
  

Mould and core paint: Water base coating can be used.
Shelf Life: 6 months from the date of manufacture for shellbond resin and 1 year for shell bond catalyst.
STANDARD PACKING:

• Shellbond GB 30/40 : 200 Kg.M.S.Barrel
• Shellbond 620 : 40 Kg.Cunny bag

STORAGE & HANDLING: Store under roof, away from heat and moisture. Direct flame contact should be avoided. While handling, all safety measures should be used.