I'm an office administrator for a mid-sized manufacturing company—manage about $200K in materials ordering across a dozen vendors. When I took over purchasing in 2020, I had a lot of questions about Momentive silicone rubber. Some I learned the hard way. Here are the ones I hear most often from colleagues and suppliers.

1. What's the difference between Momentive silicone rubber and other brands like Dow or Wacker?

Honestly? Not as much as the marketing suggests. Momentive has its roots in GE Silicones—they inherited decades of R&D. The key specs (temperature range, tensile strength, compression set) are comparable across tier-one suppliers. What differs is formulation consistency and technical support. I've found Momentive's product line for industrial gaskets and seals to be super consistent batch to batch. But if you need a specialty compound, I'd compare TDS sheets side by side. My gut says brand loyalty matters less than matching the right Shore A hardness and thermal rating to your application.

2. Is Momentive GE silicone the same as the current Momentive?

Sorta. General Electric owned the silicone division until 2006, then it became Momentive Performance Materials. The formulations are the same—it's not like they changed the chemistry after the spin-off. So if you see "GE Momentive silicone" in old spec sheets, it's still valid. I've used both labels interchangeably and never noticed a difference. But I always double-check the date code to make sure I'm not getting old stock. One thing I'm still fuzzy on: some distributors claim "GE Legacy" means higher quality. I've never found evidence for that.

3. How do I find silicone molds nearby for custom parts?

Searching "silicone molds nearby" usually returns results for craft or baking molds—not industrial. For manufacturing, you want a contract molder that works with liquid silicone rubber (LSR) or high-consistency rubber (HCR). Try searching for "rubber molding services" plus your city. A ton of small shops use Momentive materials because they're widely available. I called three local molders last year; two quoted using Momentive TSE series. The third asked what brand I preferred—that told me they were flexible. Pro tip: ask for sample coupons before committing to a full production run.

4. Can I use Momentive silicone rubber instead of polyurethane foam for gaskets?

It depends on the environment. Polyurethane foam gaskets are cheaper—way cheaper—and compress easily. But they degrade under heat, UV, and certain oils. Momentive silicone rubber gaskets (like the Tufel or Silplus lines) hold up way better in harsh conditions. The numbers said polyurethane was the economical choice for our HVAC unit covers. My gut said the constant heat from the motor would cook the foam. I went with silicone. That meant the gaskets outlasted the equipment. The downside? Silicone costs 3–4x more upfront. But if you factor in replacement labor, silicone won. I've never regretted that call.

5. How do I mount something on foam board using silicone?

Standard construction silicone can eat through foam board—the acetic acid in cure-type silicones dissolves polystyrene. You need a neutral-cure silicone (alkoxy or oxime) that's labeled "foam safe." Momentive has a few: their RTV 100 series in neutral cure works well. Here's what I learned: apply a thin bead, press the item gently, and let it cure 24 hours. Don't use too much—the solvent can still attack foam if it pools. I mounted signage on foam board this way for a trade show; it held perfectly for two weeks. Afterward I peeled it off with no damage. That was satisfying.

6. What hardness (Shore A) should I pick for my part?

This is one of the most common questions I get. Lower Shore A (like 20–30) is soft and flexible—great for gaskets that conform to uneven surfaces. Higher (60–80) is harder and more abrasion-resistant. For a typical O-ring or seal against metal, 70 Shore A is the industry baseline. But here's where I admit uncertainty: I've never fully understood why some specs recommend 50 and others 80 for similar applications. My best guess is it comes down to operating pressure and tolerance for deformation. If in doubt, order sample pucks in two durometers and test. It's worth the $50 to avoid a $5,000 mold rework.

7. Why do prices vary so much between suppliers for the same Momentive silicone rubber?

I hit "confirm" on an order last month and immediately thought: did I just overpay? The same TSE 3582-50 from Distributor A was 18% cheaper than Distributor B, but B included free shipping and a shorter lead time. The numbers said go with A. Something felt off—their sales rep couldn't answer basic questions. Turns out A was a middleman who didn't stock the material; they had to special order it. That added a week. Now I check three things: stock availability, shipping terms, and tech support. Price alone is a trap. The best supplier for me is the one who can answer "what hardness do I need?" without making me feel stupid.