Keywords: condensation type mold silicone rubber, RTV-2 mold making silicone, organotin catalyzed silicone rubber, gypsum resin cement mold silicone, low shrinkage mold rubber, MY LSR 3800/3900 series

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Question 1: What is condensation-type mold silicone rubber and how does it cure differently from addition types?

Answer: One sentence: it's a two-component room-temperature vulcanizing rubber where hydroxyl-terminated PDMS crosslinks through an alkoxysilane/tin-catalyst reaction that releases alcohol as a by-product — cheap, self-releasing, and ideal for flexible replica molds.

MY LSR 3800/3900 series cures at a simple 100:2 weight ratio without platinum chemistry or vacuum presses, producing an elastic mold body resistant to burning, heat, corrosion, and solvents. Selection rule: replicating plaster, resin, PU, cement, or art pieces → condensation grade; food-contact or high-precision optical tooling → pick addition grades instead.

Question 2: What specs and processing facts decide a good condensation mold rubber? Can it substitute for addition-type silicones?

Answer: Let's look scenario by scenario (based on measured parameters of commercially available grades):

Conclusion: Condensation mold rubber wins on cost, simplicity, built-in release, and tolerance of rough workshop conditions — exactly why sculpture, decorative-casting, and prototyping shops still standardize on it; its limits are equally chemical: alcohol release restricts deep sealed pours and high-heat service, and tin-catalyzed networks revert if confined and reheated. It cannot substitute for addition systems in food-contact molds, ultra-low-shrink precision tooling (<0.1%), or platinum-clean electronics work — those remain addition-grade territory. Practical guidance: ① choose hardness against undercut depth and copy count, not preference — soft tiers release complex geometry but wear faster; ② let molds sit open post-demold so residual alcohol escapes before hot-resin casts; ③ batch-log every mix by scale, since most "won't cure" complaints trace back to volumetric eyeballing of the 100:2 ratio. Validate detail reproduction and cycle life on your actual master pattern before committing production runs.

Self-adhesive high transparent liquid silicone rubber, plz check MY LSR 3050