Short answer: The Comgrow Filament Dryer Box is a powered two-spool dryer, not a passive shelf container. Its listing describes a 40-50 C adjustable range, 6-12 hour timer, temperature and humidity display, and feed-through outlets for 1.75 mm or 2.85 mm filament. Buy it for two-spool PLA and other lower-temperature drying jobs where a 50 C ceiling matches the filament maker's guidance. Skip it when PETG, TPU, nylon, PC, or filled engineering materials call for a hotter qualified cycle.
The value is simple: two ordinary rolls can stay enclosed, warm, and ready to feed without buying a larger high-temperature machine. The limit is equally simple: 50 C is the maximum listed chamber setting. Capacity does not compensate for a temperature ceiling that is below the material supplier's instructions.
Affiliate disclosure: GoodPrints3D may earn a commission from qualifying Amazon purchases. This review uses the current exact product listing and buyer-fit analysis; it does not claim hands-on laboratory testing. Product details and availability can change.
Check the current Comgrow Filament Dryer Box listing on Amazon
Fast buyer verdict
- Buy it for: two 1 kg spools, lower-temperature drying, print-through feeding, and a compact shared box.
- Skip it for: any material whose current maker instructions require more than 50 C or a longer cycle than the listed timer supports.
- Do not confuse it with: the six-container Comgrow passive-storage kit that previously appeared on this page. That is a different ASIN and a different workflow.
Comgrow dryer specs that matter
| Listing detail | What it means for a buyer |
|---|---|
| Two 1 kg rolls | Useful when two common materials or colors need conditioning together. Verify unusual spool flange dimensions before buying. |
| 40-50 C adjustable heat | A lower-temperature lane for compatible materials, not a universal engineering-filament recovery box. |
| 6-12 hour timer | Long enough for many routine cycles, but the correct duration still comes from the filament maker. |
| 1.75 mm and 2.85 mm feed paths | Supports both common desktop filament diameters through the listed outlet and tube arrangement. |
| Temperature and humidity display | Shows chamber conditions; it does not directly measure moisture inside the center of a spool. |
| Open vent while drying, close for storage | The listing separates moisture exhaust during heat from the sealed hold state after the cycle. |
The important correction: this is an active dryer
The old page treated this product as a passive dry box. The exact current listing describes internal heating, adjustable temperature, a timed work mode, and moisture removal. That makes it an active filament dryer with a storage function, not a simple desiccant container.
The distinction changes the buying decision. A passive box can help preserve filament that is already dry, but it does not intentionally heat the spool to drive moisture out. The Comgrow unit can run a heated cycle and then act as a more enclosed feed-and-store box. If you only need storage, the dryer, dry-box, and sealed-storage guide explains why a simpler container may cost less and take less power.
Is 50 C hot enough?
It can be, but only for the right spool and the right supplier instructions. The listing names PLA, ABS, and silk-style filament, yet the product title is not a drying recipe. Filament blends, pigments, additives, spool materials, and supplier recommendations vary. The correct temperature is the current instruction for the exact filament, not the highest setting on the machine.
A 50 C ceiling is attractive for routine PLA moisture control and other lower-temperature cycles. It becomes a hard boundary when a supplier calls for more heat. Many PETG, TPU, nylon, PC, and carbon-fiber blends may require a hotter process than this box can provide. Do not extend the timer and assume that low heat always substitutes for the specified temperature.
If PETG or TPU is the recurring problem, use the PETG and TPU filament-dryer guide to compare current hotter options. The Sovol SH02 review covers a different two-spool lane for buyers who need more temperature headroom.
Two-spool capacity: when it helps
Two-spool capacity matters when both rolls are active in the same workday. A printer owner alternating between two colors, running a main material and support material, or keeping a backup roll ready can avoid serial drying cycles. The box also consolidates two feed paths into one bench footprint.
It matters less when only one spool is ever open. A single-spool dryer may be smaller, easier to place, and cheaper. It also does not make sense to mix two materials in one chamber when their approved drying temperatures or times disagree. Because this unit does not provide independently controlled chambers, both loaded spools share the same cycle.
Check physical fit as well as weight. The listing gives an inner size of about 9.29 by 6.49 by 9.13 inches and describes two 1 kg rolls, but specialty reels can be wider or have larger flanges than a standard spool. Measure the actual rolls you plan to use.
Dry while printing, then store correctly
The outlet arrangement uses a silicone sheath, PTFE tube, and plugs, according to the listing. That supports feeding from the enclosed box and closing unused outlets. The listing also instructs users to open the sealing vent while drying so moisture can escape, then close it when the box is not running to help maintain the stored environment.
This is a useful workflow boundary. Keeping every port sealed during a heated cycle can trap moisture-laden air. Leaving the vent open after drying weakens the storage state. Follow the current manual and listing instructions rather than treating one lid position as correct for every stage.
A displayed humidity number is not proof that the spool core is dry. Chamber air responds faster than filament. Judge the result with a controlled print and the actual failure symptoms. The filament-drying workflow guide shows how to compare before-and-after behavior without changing five slicer settings at the same time.
Who should buy the Comgrow dryer?
- PLA-first makers with two open rolls: the listed heat range can align with many lower-temperature PLA drying workflows.
- Shared benches: two common spools can stay enclosed and feed from one controlled box.
- Print-through users: the feed ports and internal rollers matter when a spool should remain enclosed during a job.
- Buyers who want dry-and-store in one unit: the vented heated cycle and closed hold state can replace separate handling steps.
- Owners who will verify settings: the product makes sense when the exact filament instructions fit within 40-50 C and 6-12 hours.
Who should skip it?
- Engineering-material users: nylon, PC, and many filled blends often need a hotter qualified process.
- Independent-temperature workflows: both spools share one chamber and one temperature setting.
- Passive-storage-only buyers: sealed containers and maintained desiccant may solve the job with less equipment.
- Large-spool users: 2 kg, 3 kg, or unusually wide reels need a box designed around their actual dimensions.
- Anyone expecting the display to prove dryness: chamber humidity is a useful operating signal, not direct moisture measurement inside filament.
A five-step proof before trusting the workflow
- Read the filament maker's current temperature and duration guidance.
- Confirm the required temperature is no higher than the Comgrow box's listed 50 C ceiling.
- Load one representative spool, open the vent as directed, and run the approved cycle.
- Print the same small model with the same printer and profile used before drying.
- Compare popping, surface texture, stringing, extrusion consistency, and layer behavior before deciding that moisture was the cause.
If the result does not improve, do not keep adding heat blindly. Use the still-prints-wet diagnosis to separate a real moisture or dryer-capacity limit from temperature, retraction, flow, a partial nozzle obstruction, contaminated filament, or a mechanical feed issue.
Final verdict
Buy the Comgrow Filament Dryer Box when two-spool capacity and a 40-50 C routine drying lane match your real materials. It is a straightforward dry, feed, and store appliance for lower-temperature workflows, with clearer value than the old page's passive-box framing suggested.
Skip it when the exact spool needs more than 50 C. The shared chamber, 12-hour listed timer ceiling, and lower heat range are buying boundaries, not details to discover after wet nylon or TPU has already wasted a print.
See the current Comgrow Filament Dryer Box listing on Amazon