SR640 Natural Rubber Lining

This natural gum rubber lining material provides impact abrasion and Hydrochloric (HCl) Acid resistance.

Lining Specifications

Lining Code: SR640

Type: Natural (Black)

Tie Gum: Without Tie Gum / (Available With Tie Gum upon request.)

Properties: Durometer 45 +/- 5 Shore A – Natural soft, black lining for impact abrasion and Hydrochloric (HCl) Acid resistance.

Primers and Adhesive System:

  • One coat Chemlok® 289 on Metal
  • One coat Chemlok® 290 on Metal
  • One coat Chemlok® 286 on Metal
  • One coat Chemlok® 286 on Lining

Cure Time and Temperature:

Cure for thickness up to ¼”

Pressure, Saturated Steam (Autoclave)1 hr. @ 20psi 260°F (126°C)
Internal Steam Cure4 hrs @ 10psi 240°F (115°C)
Atmosphere Steam Cure24 hrs. @ 190°F-205°F (87°C-96°C)

Note: All reference to cure psi represents gauge pressure.

**Cure times may require tunings to compensate for low temperatures, heavy metal thicknesses, and other anomalies. Contact SRR Technical Department for recommendations on lining thicknesses over ¼”.


Ideal storage temperature is 50°F not to exceed 85°F and shelf life is 180 to 45 day range respectively.

Depending on storage conditions it may be possible to use rubber linings beyond shelf life. Please contact Salem-Republic Rubber Company for technical advisement before usage.

Designed Physical Properties

Tensile Strength PSIASTM D412
2800 min
% Elongation at Break
ASTM D412600 min
DurometerASTM D224045 +/- 5
Specific GravityASTM D2971.34
Adhesion to MetalASTM D42930 pli min

Skive: Open (Without Tie Gum), Closed (With Tie Gum)

Repair lining: Same or SR627C

Application Suggestions

  • SR640 lining shows acceptable rubber to metal adhesion without or with Tie Gum. 
  • For gauges greater than ¼” plying up to desired thickness is recommended using a 45°/135° butt splice with offset seams on all but the top layer. 
  • When plying up, the first layer can be installed without or with Tie Gum. The Tie Gum on subsequent layers is not necessary, therefore the top layer may be lapped with an open skive. 
  • Experienced applicators may have techniques which produce equal or superior results and by no means are SRR’s application suggestions meant to replace these proven techniques. As long as those procedures fall within industry standard lining application guidelines.

Standard Dimensions

RollStandard GaugeToleranceRoll GaugeStandard RollMaximum
A Roll.120+/-.05A Roll90ft96
B Roll.180
+/-.010B Roll60ft66
C Roll.240
+.010 or -.020C Roll45ft51
3/8” Roll.360
+/-.0153/8” Roll30ft33
½“ Roll.480
+/-.015½“ Roll23ft27

*Customer specific gauges and widths, other than standard, are available upon request. Please call Salem-Republic Rubber Company at 1-877-425-5079 with any questions or more information about our Custom Elastomeric Linings.