Urethane RTV Rubber
RU-448 (45A Shore)
RU-448 A/B Two-Component, 100% solids Urethane Elastomer RTV (45A) that is easily processed. This system provides semi-flexible, abrasion resistant rubber compound with good elongation for easier demolding. Use for creating molds and rubber parts, especially large molds where dimensional stability is required to avert distortion. Molds are used to cast cement, wax, and plaster parts.
Features:
- Easy to Process 1 to 1 Mix
- Excellent Physical Properties
Typical Physical Properties:
(For Components) Component A Component B
Viscosity (cps): 5000 1000
Mix Ratio, By Weight: 100 100
Color: Yellow/Clear Green
(For Cured Material)
Shore A Hardness: 45
Tensile Strength (psi): 425
Elongation %: 850
Tear Resistance (psi): 103
Specific Gravity: 1.03
Coverage: 27 CU/IN/LB
Reactivity Data:
Gel Time: 30 minutes
De-Mold Time: 12-16 Hrs
Preparation of Master:
Urethane elastomers will adhere to most surfaces. A proper mold release must be used on all surfaces-- MR-150 or ER-2300 is recommended. Wood, plaster, stone, pottery, masonry, or any porous surface must be sealed with lacquer or clear shellac prior to applying release. TR#4 or shellac is suitable for sulfur & water based clays. Allow 24 hours to dry before preparing master with mold release. Plaster masters can release air when pouring larger molds due to some heat generated. Venting the base of your master by ( drilling several ¼” holes) will release the air downward to avoid air release into mold cavity. Urethane RTV cures to a flexible rubber in above cure times. These products are safe to use as directed, check MSDS for safety information.
Mixing and Curing:
Before adding A to B, urethane B should be stirred or shaken for 1 minute to assure that any separated material is remixed. Select a clean, dry container for mixing. Avoid using wood or paper products, which could cause cure problems. Weigh the proper ratio A to B and mix well. Two containers may be used to assure that all materials are well mixed.
Pour mixture over master slowly allowing material to fill void and push air out of cavity. A vacuum chamber can be used to remove excess air bubbles before pouring. After mixture is poured a light mist of ER-2300 can be sprayed on top of the surface to break tension bubbles. Urethane RTV will cure to solid rubber at above cure time. Urethane rubber that is colder than 75°F will cure slower. During colder weather material may be heated in a hot water bath (place container in plastic bags first) and the master model should be warmed. Accelerated cures can be reached by heating the mold and material at 100-150°f for pre-determined time. Cold weather or off-ratio material can result in unacceptable rubber results.
Using Mold:
The use of a release aids demolding and is recommended prior to each casting. Release selection is based on material that is to be cast. R-100-50 Release is recommended for casting concrete. No release necessary for wax or plaster products.
Brush-On Mold: RU-435TH Brush-On RTV Available
A material with low sag may be obtained by mixing a powder- PE Mini Fibers. Various ratios of 5% to 10% can be used to achieve different thickness and flow control. A mold can be made with only four coats applied within an hour, which can be brushed or toweled onto surface. A mold release should be used to separate the mother mold from rubber mold.
Storage:
Material should be stored in warm, dry area with lids secured tightly. Once containers are opened, material should be used in a short time period. Component A can react with moisture and turn solid over period of time. Pre-test any aged material before using.
The information and data contained herein are based on information we believe reliable. Each user of the material should thoroughly test any application and independently conclude satisfactory performance before commercializing. Suggestions of uses should not be taken as inducements to infringe on any particular patent.