Silicone for the SILASTIC® 3481 Base forms
Silicone for forms with a high durability is ideal for detailed reproduction of figures, objects of art and similar objects. Hardness is 26 Blinders A.
- The high fluidity and long operating time facilitating production of irregular shapes.
- Guarantee of excellent separation of castings from forms and the high tensile strength providing reproduction of originals with fine details and deep undercuts.
- The high elasticity providing ease of office of castings of irregular shapes.
- The choice of bases and the curing agents for receiving rubbers with various properties.
Silicone rubber for production of casting molds Silastic® 3481 represents two-component material, consisting of a basis, which when mixing with the curing agent of the Silastic® 81vulkaniziruyetsya series at the room temperature due to condensation reaction.
The composition of materials is picked up so that to provide the increased service life of forms when casting from polyester pitches, polyurethane, plastics.
Method of application:
Preparation of a surface
The surface of the original has to be pure and free from poorly fixed particles. If necessary, especially at a porous substratum, use the suitable dividing agent, such as vaseline, soap solution.
To carefully mix the basis Silastic® 3481 before use as at long storage the filler can drop out in a deposit.
To give 100 parts of a basis of Silastic® 3481 and 5 parts of the curing agent Silastic® 81 in pure capacity. To mix until the curing agent completely is distributed in a basis. It is possible to use manual or mechanical hashing, but it is not necessary to mix too long and to allow temperature increase higher than 35ºC (95ºF).
Mix rather small portions to provide careful hashing of a basis and the curing agent.
It is strongly recommended to remove the taken air in the vacuum chamber, having allowed mix to extend completely, and then to fall down. After 1-2 more minutes of stay under vacuum it is necessary to check mix and if it does not contain vials of air, it can be used. At vacuum decontamination of mix its volume increases by 3-5 times so it is necessary to choose rather big container.
Attention: long stay under vacuum will cause removal of flying components from mix that can lead to bad hardening in thick layers and to a deviation from typical properties.
Note: if the equipment for vacuum decontamination is inaccessible, capture of air can be minimized having mixed small quantity of a basis and the curing agent, and then having applied mix on the original with a thin layer by means of a brush. To leave at the room temperature until the surface is cleared of bubbles and the layer does not begin to harden. Mix one more portion of a basis and the curing agent and repeat operation, do not receive a ready form yet.
Filling of mix and hardening
As soon as possible fill in mix of a basis and the curing agent on the original, avoiding air capture. Under the influence of the catalyst material will harden to a condition of flexible rubber then the uniform can be taken off (see details in the table of typical properties). If temperature or humidity are indoors very high, operating time with mix will be reduced. Final level of mechanical properties will be reached in 7 days.
Use at high temperatures
Some forms made from silicone of ovy rubbers with condensation hardening can be exposed to degradation at influence of temperatures higher than 150ºC (302ºF) during the long periods or at storage in closed form at high temperatures. It can lead to a softening and loss of elastic properties.
Foundry materials resistance
Chemical firmness completely cured Silastic® 3481 is magnificent. The composition of materials is picked up so that to provide the increased service life of forms when casting from polyester pitches. Nevertheless, It should be noted that, eventually, pitches and other aggressive foundry materials influence silicone forms, changing their physical properties, coupling with the surface of casting and, perhaps, the physical sizes. During long batches of a form it is necessary to check periodically.
Silicone Silastic® 3481 rubbers represent industrial products which it should not be used in the appendices connected with casting of foodstuff, tooth prosthetics and removal of molds from human skin.
If it is planned to do molds from vertical objects or surfaces for receiving qualitative forms it is necessary to modify catalytic mix special Silastic ® Txiho Additive additive.
1. Prepare an original surface: carry out its cleaning.
2. Cover the original with a thin layer of catalytic mix. After passing of hardening of the first layer repeat the procedure of drawing. Repeat the specified procedures before formation of a layer thickness> 2 mm. Leave mix to harden at the room temperature before full hardening.
3. Prepare the new catalytic mix Silastic® 3481, add 3% of Silastic® Txiho Additive and mix before formation of a pastelike consistence. The deaerating of mix is not required.
4. I use the pallet apply tiksotropny mix on a surface. Let's harden mixes within 24 hours (or during smaller amount of time depending on the used curing agent) at the room temperature.
Other curing agents:
The standard curing agent for Silastic® 3481 Base is Silastic® 81 NW Curing Agent. For special cases of Dow Corning offers several additional curing agents:
- Silastic ® 81-F NW Curing Agent for removal of forms after 6 hours.
- Silastic ® 81-VF NW Curing Agent for removal of forms after 2 hours.
- Silastic ® 81-R NW Curing Agent for increase in service life of forms which contact to polyair.
The card of safety is available on demand.
Term and storage conditions:
At storage at a temperature not over 32ºC (89,6ºF) in the original not opened packing of a basis Silastic® 3481 and Silastic® 81-R NW Curing Agent have an expiration date of 9 months from the date of release.
Silastic ® 81-F NW Curing Agent and Silastic® 81-VF NW Curing Agent have an expiration date of 7 months from the date of release.
Silastic ® 81-NW Curing Agent has an expiration date of 12 months.
At storage at a temperature of 20 OS of % of Silastic ® Txiho Additive can harden. For its transfer to liquid state of rather simple heating in hot water.
The Dow Corning company carried out rebranding of silicones for the Silastic® forms. The new name SILASTIC® 3481 - XIAMETER® RTV-3481.Characteristics
|Appearance||White viscous liquid|
|Addition of the catalyst||5% on weight|
|Viscosity of mix of a basis and catalyst, mpa*s||22000|
|Jellification time, hour||1-1,5|
|Hardening time, hour||24|
|Hardness, Blinders A||26|
|Durability on razdir, kN/m||18|
|Lengthening to a gap, %||545|
|Linear shrinkage, %||0,2-0,4|
- Price: 386 UAH/kg
- Minimum volume of the order: 25 kg
- Way of packing: Buckets on 5 kg (5 buckets or multiple quantity), buckets of 20 kg (5 buckets or multiple quantity), barrels of 200 kg (4 barrels or multiple quantity).