Tube for silica gel, for filament dryer SUNLU S2 and others

by spolfox

# Telescopic Silica Gel Tube for SUNLU S2 Filament Dryer (and others) This practical, easy-to-print silica gel tube is designed to dramatically improve drying performance in the **SUNLU S2** and other filament dryers. Back when the Ender‑3 era was at its peak, I was using one of the very first SUNLU S2 dryers (the early version without a built-in fan). While the heating worked extremely well, the dryer had one major flaw: moisture had nowhere to escape. The humidity inside the dryer kept rising, and even after long drying sessions, it would not drop below 35%. I had to open the lid from time to time just to let the damp air out. That’s when I came up with this clever moisture-control solution. --- ### 💡 The Idea & Development I noticed that I had many silica gel packets saved from various electronics (laptops, 3D printers, TVs). Silica gel absorbs moisture perfectly, but the SUNLU S2 has very limited internal space. Then I realized that **every filament spool has an empty inner core** that is never used! This led me to design a custom tube that fits perfectly inside the spool and holds your silica gel packets right where the heat is. --- ### ⚙️ How It Works & Design Features * **Telescopic Connection:** The tube is made of two separate parts that connect telescopically by friction. This allows you to easily adjust the length (wider or narrower) depending on your current spool width. * **Maximum Airflow:** Both parts feature decorative ventilation slots along the sides so that air can circulate freely through the silica gel. * **Simple Operation:** You simply insert your silica gel packets inside the tube, adjust the length to fit your spool, and place the spool into the dryer. **The Result:** With this system on my stock SUNLU S2, the internal humidity dropped from **35% down to 16%**! --- ### 🔌 Wide Compatibility This model is a universal upgrade and fits: * **SUNLU S2** (both first-generation and newer versions with fans). * **Other Filament Dryers** (e.g., ESun