8-Inch Flex Duct Adapter — Rigid Socket to Flex Collar

Description

8-inch flex duct adapter — rigid fitting to flex collar

An 8-inch flex duct adapter for the full-size end of the catalogue: a 203.2 mm outside-diameter plug on one side that seats in any 8-inch duct-fitting socket in the line (bore 204.0 mm and up), and a male flex-over collar on the other — clamp land 201.2 mm, retention bead crest 203.2 mm, 196.4 mm through-bore — that 8-inch flex duct slips straight over.

Eight inches is the size people move to when 6 inches stops being comfortable: a hard-driven S21, an inline fan pulling a long run, two machines merged into a trunk. Those runs are exactly where improvised transitions do the most damage, because a crushed or taped joint in an 8-inch line costs more than the same mistake in a small one. This part keeps the section honest through the change and gives the flex a proper land to clamp on.

Like its 6-inch sibling, the plug is deliberately sized to stay out of shroud collars — that is an interference fit by design, because every D-Central shroud already carries a flex-over collar of its own. This adapter belongs on the rigid fittings: couplers, elbows, reducers, window ports.

What it fits — 8-inch rigid sockets and 8-inch flex duct

• Any 8-inch duct-fitting socket in the line, bore 204.0 mm or larger: couplers, elbows, reducers and window ports.
• 8-inch flex duct, slipped over the collar end and clamped on the 201.2 mm land.
• Not shroud collars — an interference fit by design, since shrouds carry their own flex collar.

If your run is 6-inch, the 6-Inch Flex Duct Adapter — Rigid Socket to Flex Collar is the part you want instead; mixing sizes at a transition is what the 8″ to 6″ Duct Reducer is for.

How it installs

1. Push the plug end into the socket of the 8-inch fitting you are converting, until it bottoms.
2. Slide the 8-inch flex core over the collar end, past the retention bead.
3. Clamp on the 201.2 mm land behind the bead and tighten.
4. On long horizontal runs, support the flex with a strap within about a metre of the joint so the adapter is not carrying the duct.

Why it matters more at 8 inches

Section area is the whole argument for going to 8-inch duct in the first place, and every sloppy joint gives some of it back. A flex core crushed inside a taped joint necks the run down exactly where the air is already turning or transitioning, and inline fans feel that at the worst moment — under load, in summer, with the duct full of hot exhaust. This adapter holds the bore at 196.4 mm through the transition and stretches the change of section over length rather than dropping it at a lip. The bead sits proud of the clamp land so the clamp cannot walk off the end when a heavy insulated duct pulls on it.

• End any 8-inch rigid fitting in flex duct with a single purpose-shaped part.
• Keep the bore open at 196.4 mm through the transition instead of necking it at a taped joint.
• Give a heavy insulated flex run a real clamp land and a retention bead to pull against.
• Match the collar geometry of every other 8-inch flex interface in the line.
• Stay out of shroud collars by design, so the parts can only go together the right way.
• Hold shape in PETG at ASIC exhaust temperatures, unlike PLA.

Specifications

Open source — the whole 8-inch family is published

D-Central Technologies engineers these fittings around real ASIC exhaust work, draws them here, and then puts the files out for nothing. This adapter is our design, start to finish, released under CC BY-SA 4.0 at the 3D models download center — free to download, modify, remix, print and sell, with the plug and collar dimensions in the open so anyone can build compatible parts. Go directly to the 8-inch flex adapter model.

The download is duct_flex_adapter_8.zip and it contains the STL, the CC BY-SA 4.0 licence and the installation and safety guide. This listing is the finished article, made to order in PETG — black or orange — and shipped from Montreal, Quebec. Making it yourself costs nothing and always will; buying the part, or backing D-Central’s fund page, is what funds the next fitting we draw.

Works with

• 8″ Duct Coupler
• 8-Inch Long-Radius 90° Airflow Duct Elbow
• 8″ Window Exhaust Port
• 8″ to 6″ Duct Reducer
• 8″ to Dual 6″ Y-Splitter

The full chain from miner to outdoors is laid out in the D-Central shroud and ducting system.

Frequently asked questions