This adapter facilitates the transition from small-bore heater outlets and branch lines to large-diameter main trunk ducting. Covering the jump from 63mm (2.5") to 100mm (4"), this is one of the most significant diameter shifts in the DT3D Duct Adapter Series, characterized by a prominent, wide-angle cone. While 100mm is the global standard for residential HVAC trunk lines, 63mm is the standard for most diesel parking heater outlets and common marine/van branch runs. This part provides a professional, airtight solution for connecting these two disparate sizes.
Because a 37mm diameter differential creates significant mechanical leverage, the geometry requires more than just a standard print. To prevent the walls from flexing or cracking under clamp tension, this model utilizes a 4mm uniform wall thickness and integrated dual hose clamp grooves at both ends to ensure a secure, non-slip mechanical seat.
✅ Key Technical Features
4mm Uniform Wall Thickness: Maintained throughout the entire wide-angle cone to ensure structural integrity under clamp load.
Dual Hose Clamp Grooves: Provides a positive mechanical seat at both the 63mm and 100mm interfaces, preventing slippage during high-pressure transitions.
Smooth Internal Bore: The 37mm diameter transition is tapered gradually to minimize airflow turbulence and pressure drops.
Metric & Imperial Compatibility: Designed for both 63mm/100mm and 2.5"/4" sizing conventions.
Bidirectional Design: Functions as a 63→100 increaser or a 100→63 reducer.
Support-Free Geometry: Optimized for printing without support structures.
🔧 Application Examples
Diesel Heating: Connecting 63mm/2.5" heater outlets to 100mm/4" HVAC trunk ducts.
Van & Marine Builds: Managing branch-to-trunk transitions in campervans and boat cabins.
Residential HVAC: Connecting 2.5" branch lines to 4" main ducting.
Ventilation & Extraction: 4" inline fan reductions to 63mm flexible ducting, grow tent port adaptations, or 4" workshop dust extraction to 63mm hoses.
📦 What's Included
1× STL File: 63mm → 100mm (2.5" to 4") adapter. Pre-oriented for optimal layer adhesion through the transition cone; print-ready with no supports required.
🖨️ Print Settings — Critical Instructions
The aggressive cone angle and large diameter differential make this one of the most sensitive parts in the series. Do not use standard, low-wall settings.
Material Choice:
PETG: Best for general-purpose use.
ASA: Required for marine, outdoor, or high-heat/exhaust-adjacent installs.
PLA+: For indoor, ambient-temperature use only; not suitable for use near diesel heater ducting.
Slicing Parameters:
Wall Loops: 6–8 walls. The walls must carry the structural load and resist clamp pressure.
Top/Bottom Layers: 5–6 layers.
Layer Height: 0.2mm.
Infill: 0–15%. Avoid high infill; in a rapidly tapering bore, high infill creates frequent direction-reversing passes that can weaken inter-layer bonding without providing structural benefit.
Orientation: Print large-end-down. This orientation maximizes layer adhesion through the wide-angle transition, which is essential for the part to withstand the mechanical leverage of the diameter mismatch.