Two job-site questions never go away: silicone or polymer adhesive? and what both bonds and seals? The answer depends on whether you need flexible waterproofing, structural grab, or both.
Quick Summary
- RTV silicone — excellent flexible waterproofing; weaker structural bond
- MS Polymer — bond + seal on many substrates
- High Tack — instant grab for panels and heavy trims
- Siliconized acrylic — interior joints you want to paint over
- Never layer incompatible chemistries on the same joint without full clean-down
Quick comparison
| Criterion | RTV silicone | MS Polymer | Siliconized acrylic |
|---|---|---|---|
| Waterproof sealing | Excellent | Very good | Fair–good (interior) |
| Bond strength | Low–medium | High | Medium |
| Overpainting | Usually no | Often yes (check label) | Yes |
| Typical use | Showers, windows | General bond+seal | Interior trim joints |
When to choose 100% RTV silicone
When the main job is flexible waterproof sealing — showers, basins, aluminum/glass joints. American Eagle Silicone 100% RTV is the classic pro multi-use sealant.
When MS Polymer wins
When you need to bond and seal — panels, thresholds, mixed substrates. SUPER 77 and HYBRIFIX SUPER 7 combine sealant flexibility with adhesive strength. For high initial grab, use SEALFIX High Tack.
And siliconized acrylic?
Interior joints you plan to paint over — gaps between frames and walls. ACRYLTOP 666 is built for a clean paintable finish.
RamoBond picks by use case
American Eagle Silicone 100% RTV – Professional Acetic Silicone for Sealing and Adhesion 280 ml
100% RTV silicone
₪10
View product
SUPER 77 – Professional MS Polymer Adhesive and Sealant High Strength 290 ml
High-power MS Polymer
₪22
View product
SEALFIX - High-tech professional polymer adhesive with high initial grip up to 350 kg, 290 ml
High Tack up to 350 kg
₪20
View product
HYBRIFIX SUPER 7 – White MS Polymer Adhesive and Sealant 80 ml
80 ml for touch-ups
₪18
View product
ACRYLTOP 666 – Professional Siliconed Acrylic, White, 280 ml
White siliconized acrylic
₪5
View productFAQ
Can I paint over silicone?
Usually no. If you must paint, switch to siliconized acrylic or a paintable MS Polymer.
Best option for a heavy panel?
High Tack MS Polymer with temporary support per the label — not regular silicone.
Best for a shower enclosure?
Quality RTV silicone for perimeter sealing.
Conclusion
Rule of thumb: water + flexibility = silicone. Structural bond + seal = MS Polymer. Interior paint-over = siliconized acrylic.