Universal Spool Weight ⧸ Core Insert for any AMS

Stop spool wobble, hopping and rattle for good with a universal core insert that adds up to 400 g of perfectly centered weight – fits almost any spool, installs in seconds, and keeps your AMS running smooth and quiet.

TL;DR

• Universal core insert for AMS-compatible spools
• Adds up to 400 g of internal weight using any filler
• Eliminates spool hopping, wobble, and rattle during retractions
• Fits all spools with core diameter ≥ 54 mm and width ≤ 66 mm
• Works with cardboard and plastic spools across all major brands
• Profiles for two versions: one for 0.4 mm, one for 0.6 mm nozzles
• Screw-on lid with dual-start thread and integrated click lock
• Spill-proof, mess-proof, frustration-proof
• No supports required and compatible with most slicers
• Recommended: PETG-HF or ASA for AMS use during drying
• Optional: PLA for unheated storage environments
• Designed for permanent use – one per AMS slot is ideal

One Insert to Stabilize Them All

Loose spools and lightweight rolls are the silent troublemakers in any AMS system. They rattle, they bounce, they slip during printing. This insert fixes the issue right where it starts, inside the core of the spool. By adding up to 400 g of centered weight, it removes instability exactly where it matters most.

Whether you are printing quickly, switching materials often, or running nearly empty spools in a multi material setup, this core insert keeps your AMS smooth, quiet and reliable. It fits nearly every spool on the market and installs in seconds without tools, tape, guessing or screwing.

Fill It Your Way

The core insert weighs 28 g when empty and can hold up to 400 g of added material using whatever you have on hand: steel balls, screws, coins, metal scraps, sand, even concrete. If you want to go all in, use lead shot and thin set cement to exceed 500 g total weight.

One Fit to Rule Them All

This model fits at least 98 % of all filament spools on the market. It works with core diameters from 54 mm and up, and supports spool widths up to 66 mm.

It fits both cardboard and plastic spools with equal reliability. If a spool fits in your AMS, this insert will fit inside the core.

No support is needed for printing. Just slice, print, fill, and use.

For best results, use the correct nozzle size for your version and select the Arachne wall generator in your slicer. It still works with nearly all slicers and settings, just a bit slower or less clean without Arachne.

The rim of the insert base is designed to act like a built in brim, increasing adhesion and reliability even for difficult filaments. That means excellent grip on the bed and warp resistance during the print, even with materials like ASA or PC.

Smart Threading and Spillproof Design

The screw cap uses a dual thread start to make placement easy and screwing on fast and smooth. A built in click lock adds a secure snap feel and prevents accidental opening or leaks.

The container uses an external thread, the lid uses an internal thread. That means the container can be filled without clogging or contaminating the threads, even if you use concrete, lead shot, or liquid fillers.

Everything locks in tightly with no risk of spilling, rattling, or shifting during use. The click lock is strong enough to resist movement even under vibration and keeps the lid firmly in place until you twist it off.

Permanent Setup – One Insert per Slot

This model is designed for long-term use. Once printed and filled, it can stay in your AMS for good. No need to swap or remove between prints. Just insert it into the spool, load your filament, and forget it.

Because it works with over 98 % of all spools and fits both cardboard and plastic variants, you can prepare one insert per AMS slot and be done. No more matching shapes or digging through boxes. Just grab a spool, and you're ready to go.

If your spool already holds a desiccant container, you probably don't need this. But if you prefer not to store silica gel inside the spool, this is the perfect alternative. Universal fit. Always works. Everywhere.

No Filler Talk – Just Facts

Weight empty: 28 g
Weight filled: up to 400 g with steel balls, scrap, screws, sand, or concrete
More than 500 g possible with lead shot and liquid cement
Compatible spool width: up to 66 mm
Compatible core diameter: from 54 mm
Material: any stable filament, recommended PETG-HF or ASA
Two print profiles: 0.4 mm and 0.6 mm nozzle optimized
No supports needed
Works with Arachne and classic wall generators
Fully slicer agnostic

Print it. Fill it. Forget it.
The Universal Spool Weight – your silent upgrade for smoother, quieter, more reliable printing.

Filament Guide - Choose the Right Fit for Your Setup

Pick a filament that matches your typical temperature range and workflow. The AMS two Pro can reach up to 65 °C and sometimes even hotter in certain areas. PLA struggles under these conditions.

To make your choice easier I have sorted filaments into four tiers based on their heat deflection temperature. Higher tier filaments are always suitable for any lower temperature use case. As long as your filament matches your operating temperatures you can leave the desiccant in the spool safely even during filament drying.

My top recommendations:

• PETG HF – The all-rounder for classic AMS and everyday use.
• ASA  – The gold standard for AMS 2 Pro and AMS HT, and a great choice for most demanding situations.
• PAHT-CF – The heavy hitter for extreme environments: blast drying ovens, high-end filament dryers, etc.

Tier C – up to 45 °C (Bambu Lab AMS & Direct Print)

• 52 °C PLA Galaxy
• 53 °C PLA Silk Dual Color (only 0.4 mm nozzle)
• 55 °C PLA-CF (0.4 mm or 0.6 mm hardened nozzle)
• 55 °C PLA Glow (0.4 mm or 0.6 mm hardened nozzle)
• 55 °C PLA Sparkle
• 56 °C PLA Marble
• 57 °C PLA Basic
• 57 °C PLA Wood
• 58 °C PLA Matte
• 60 °C PLA Silk+ (only 0.4 mm nozzle)
• 62 °C PLA Metal

Tier B – up to 65 °C (Bambu Lab AMS 2 Pro)

Here’s where the magic happens, these are fully compatible:

• 69 °C PETG HF - recommended by the designer
• 70 °C TPU 85A / TPU 90A (soft, unsuitable for this model) (only 0.6 mm nozzle)
• 70 °C TPU 95A HF (soft, unsuitable for this model)
• 70 °C TPU for AMS (soft, unsuitable for this model)
• 74 °C PETG-CF (0.4 mm or 0.6 mm hardened nozzle)
• 74 °C PETG Translucent 
• 87 °C ABS

Tier A – up to 85 °C (Bambu Lab AMS HT)

• 99°C ABS-GF (0.6 mm hardened nozzle recommended)
• 100 °C ASA (0.4 mm nozzle recommended) - recommended by the designer
• 110 °C ASA-CF (0.6 mm hardened nozzle recommended)
• 113 °C PC-FR
• 117 °C PC

Tier S – up to 180 °C (Convection Oven, Extreme Drying)

• 186 °C PA6-CF (0.6 mm hardened nozzle recommended)
• 186 °C PA6-GF (0.6 mm hardened nozzle recommended)
• 194 °C PAHT-CF (0.6 mm hardened nozzle recommended) - recommended by the designer
• 205 °C PET-CF (0.6 mm hardened nozzle recommended)
• 227 °C PPA-CF (0.6 mm hardened nozzle recommended)
• 264 °C PPS-CF (0.6 mm hardened nozzle recommended)

Pick your filament, match your use case, and unlock the full potential of your AMS and drybox - every time, with total confidence.

Translation Notice: I am not a native English speaker. I write all descriptions in English to ensure the best automated translation into other languages. To make the text smoother and more readable, I use language tools to refine my wording.

Bill of Materials Notice: Hero Shot models are usually printed in Bambu Lab PLA Basic, primarily Pumpkin Orange, Purple and Matte Charcoal Black. The Bill of Materials contains the recommended filament for the model, which may differ from the filament used for the photos.

Purchases made via the BOM support my work through the Maker World Commission Incentive at no extra cost to you.