|Remix each of the two components (parts A and B) every time before using.|
1. Mixing of the two components
Add 100 parts of BLUESIL RTV 3433 A to 10 parts of BLUESIL RTV 3433 B.
The two components may be intimately mixed either by hand or using a low-speed electric or pneumatic mixer to minimize the introduction of air into the mixture.
After mixing BLUESIL RTV 3433 A&B, it is strongly recommended to eliminate entrapped air. If the processing is done with the help of a machine and a static mixer, the two parts are degassed separately before mixing.
The BLUESIL RTV 3433 A&B is degassed under a vacuum of 30 to 50 mbar. Under vacuum, the product expands 3 to 4 times its initial volume and forms bubbles on its surface. These bubbles will disappear gradually and the mixture will sink back down to its initial volume within few minutes. Then the vacuum can be released.
Remark: release the vacuum several times imes the degassing. For easier degassing only fill a recipient to 1/3 of its height.
Molds obtained without degassing the mixed A and B parts can contain voids (entrapped air bubbles) that lead to damages of the mold itself upon repeated usage with common reproduction materials. Following the degassing instructions above is therefore a method to increase mold duration.
3. Cross linking
The best curing conditions are at 23°C. The use of the product at higher temperatures will reduce the pot life and increase the setting rate. As opposed to this, lower temperatures will increase the pot life and decrease the setting time.
At 23°C, the cured silicone can be demoulded after the time indicated as "demolding time" (see § 2.Polymerization, pag.1). In order to achieve the best possible performance levels from the molds, it is preferable to wait for 24 hours before using them.
Room temperature curing assures the lowest possible shrinkage, if accelerated cure is desired, mild heat should be preferred. To minimize shrinkage cure the elastomer at maximum temperature of 60°C for 3-4 hours, higher temperatures will cause higher shrinkage.
Be aware that contact with certain materials can inhibit the curing of this RTV:
- Sulphur and its derivatives (e.g. sulphur containing clays; natural rubbers vulcanized with sulphur),
- Ammonia and amines (e.g. amine cured epoxies, epoxy curing agents),
- Polycondensation RTV catalysed with metal salts,
- PVC stabilizing agents,
- Silver salts.
If doubts exist it's recommendable to run a quick test with a small quantity of material in order to assess compatibility. Take duly note that cross contamination due to not well cleaned tools or devices is frequently the main cause of inhibition. The best way is to use only dedicated gear when processing polyaddition RTVs.
4. Dimensional stability of the crosslinked product
Once crosslinked, BLUESIL RTV 3433 is a silicone elastomer which, as all materials and especially elastomers, undergoes thermally driven volume changes. That means that any increase / decrease of temperature of the cured mold causes respectively a volume increase / decrease of the mold itself.
The thermal expansion coefficient of the product is roughly aV = 5.10-4°C-1 (volumetric) or aL = 1,7.10-4°C-1 (linear). By considering these values, following examples can show the influence of temperature on the dimensions of a rectangular mold.
Temperature of crosslinking
Mold dimensions at crosslinking temperature
Temperature of mold use
Mold dimensions at use temperature
10 x 2 x 1 m
V = 20 m3
|10,13 x 2,03 x 1,01 m|
V = 20,77 m3
|9,91 x 1,98 x 0,99 m|
V = 19,50 m3
|9,78 x 1,96 x 0,98 m|
V = 18,73 m3
|BLUESIL RTV 3433 B may be stored at a temperature below 40°C / 104°F for up to 12 months from its date of manufacturing.||Please consult the Safety Data Sheet of this product.|
BLUESIL RTV 3433 B
BLUESIL RTV 3433 A&B is a two component, silicone elastomer which cures at room temperature by a polyaddition reaction (10:1 ratio).
2 Part RTV
- Excellent details reproduction,
- Long durability thanks to a smooth demolding,
- Excellent mechanical resistance,
- Low linear shrinkage,
- No release of toxic substances during or after curing.
Production of flexible moulds with excellent details reproduction and outstanding mechanical resistance.
Its particular formulation imparts the molds made thereof a longer duration.
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