Tej’s Lab · Kit No. 001

Layer lines
go in.
A mirror
comes out.

A cordless polisher, three shaped tips, cutting compound and finishing polish. One box, one evening, one mirror.

Shipping included across Canada and the US. Ground only, because two of the four are liquids. Two to five days in Canada.

In the box

01Cordless polisher, variable speed, charger in the box

02Three tips: flat face, ball, and a cone for corners

03Cutting compound. This is the one that kills layer lines

04Finishing polish. Takes the haze off and brings the reflection

The first part guarantee. Run the kit through compound and polish on one printed part. If that part does not come back reflective, tell us inside 90 days and we refund it, used or not. One kit per customer, and you keep the kit.

Designed and tested by Tej Grewal, engineer · @tejslab

No reviews yet. This is a new product. Every one we get goes up, including the bad ones.

A 3D printed part, half straight off the printer with visible layer lines, half polished to a mirror

Off the printer After

Drag to compare · rendered, not photographed. Real part photos replace this before launch.

01 · THE TOOL

Speed, not force

A cordless rotary running slow enough that the plastic never gets a chance to soften. This is the whole trick, and it is why a bench grinder and a drill both fail at it.

A ball tip resting on a printed part — Rendered. Keep the head moving.

02 · THE TIPS

Reach

Flat for panels, ball for curves, cone for the inside corners everything else skips. A printed part is not a car door and a car pad will not touch half of it.

Three polishing tips: flat, ball and cone — Flat · ball · cone

03 · THE COMPOUND

Cut

The heavy pass. Layer lines go here, and the part looks worse before it looks better. That is the step people quit on, one minute early, every time.

The same part after the cutting compound: layer lines gone, surface still hazy — After compound. Lines gone, haze left.

04 · THE POLISH

Mirror

Clean tip, fine polish, light touch. The haze lifts and you catch your own hand moving across the part. This is the one that ends up on camera.

From the workshop

The whole thing, ninety seconds

Video slot · the reel, cut to the polish

Two sentences from Tej go here, in his words: why he started polishing prints, and why this is the box.

Tej Grewal · @tejslab

Worth knowing

Three things that
decide the finish

Heat is the enemy

PLA starts going soft not far above a warm day. Park the tip in one spot and you do not polish the part, you smear it. Keep the head moving, always, and let the part rest if it stops feeling cool.

Low speed wins

Every instinct says wind it up. Speed makes heat, and heat is the thing that ruins the surface. Start at the bottom of the range and only climb if nothing is happening.

Finish the cut first

The compound has to fully remove the layer lines before the polish goes anywhere near the part. Polish over unfinished compound work gives you a shiny surface with the lines still in it.

Materials

Works on

PLA and PLA+, the easiest of the lot
PETG, slower and less forgiving on heat
ABS and ASA, which take a shine readily
Resin prints, once fully cured
Flat faces, gentle curves, chamfers, outer walls

Does not work on

TPU and other flexibles. Too soft, the tip just pushes it around
Thin walls and tall unsupported features. The tip will flex or snap them
Internal channels and deep pockets no tip reaches
Gaps, layer separation and under-extrusion. Those are print problems, not finish problems, and no amount of polishing fixes them
Anything that has to stay dimensionally exact. This removes material

Specifications

The details

Polisher: Cordless rotary, variable speed, charger in the box. Speed range and battery figures to follow from bench testing.
Tips: Three. Flat face, ball, cone. Sizes to follow.
Compound: Heavy cut automotive rubbing compound. Bottle size to follow.
Polish: Fine finishing polish. Bottle size to follow.
Materials: PLA, PLA+, PETG, ABS, ASA, cured resin
Not for: TPU, thin walls, internal channels, dimensionally critical parts
Refills: $29. Both bottles and three fresh tips. Every six months, or on demand.
Shipping: Included. Canada and the US, ground
Guarantee: 90 days on the first part, used or not

Downloads Quick guide, PDF Compound safety data sheet Polish safety data sheet

Before you ask

Fair questions

Will it melt my print?

It can, if you hold the tip still or run it fast. That is the single mistake everyone makes on their first part. Low speed, constant movement, and stop if the surface feels warm. Practice on a failed print before you touch something you care about, and by the third part it stops being something you think about.

What does it work on?

PLA and PLA+ come up easiest. ABS and ASA take a shine readily. PETG works but is less forgiving on heat. Cured resin polishes beautifully. There is a full list further up the page, including the things it will not do.

How long does a part take?

A palm-sized flat face runs a few minutes through compound and polish. Curves and fine detail take longer. Big flat panels are the easiest thing in the world. Deep internal corners are the hardest, and honestly some of them are not worth it.

Will it round my edges off?

It can, if you lean on it or dwell on a corner. Light pressure, keep moving, and stay off the edge itself until the faces are done. It is the most common mistake after heat, and it is entirely technique, not the tool.

What runs out, and what does a refill cost?

Three things wear. The compound, the polish, and the tips, and the tips go first, because foam loads up with plastic and stops cutting long before it looks worn out. Expect dozens of palm-sized parts from a full kit. A refill is $29 and it is the same three things: both bottles and a fresh set of three tips. Set it to arrive every six months and you stop thinking about it, or skip the schedule and order one whenever the polish stops biting. Change the timing or cancel whenever you want, from the link in any order email.

Shipping and returns

Shipping is included across Canada and the United States, with no minimum. Ground only, because the compound and polish are liquids and liquids do not fly. Two to five business days inside Canada. Returns run on the first part guarantee: use the kit on one part, and if that part does not come back reflective, tell us inside ninety days and we refund it whether the box is opened or not. One kit per customer. If it arrives damaged, tell us and we will sort it out.

Take one printed part
and finish it properly.

Add to cart — $129 CAD

Shipping included in Canada and the US. Ninety days on the first part guarantee.

Layer linesgo in.A mirrorcomes out.