What the Printed Arch Shell Does

The part that makes this pair custom is easy to miss, because your foot never touches it directly. It is the arch shell, under the foam. Everything else in the stack is there so that shell can live in a shoe. This page is only about the shell: what it is made of, what it follows, and what you should leave alone.

It follows one foot, not a size

After you pay, you scan both feet with your phone. Volumental records each foot on its own: length, width, and foot height. We print the left shell from the left scan and the right shell from the right scan. A shoe size cannot do that job. A size is one number for a whole foot, and the two feet are often not the same. AAOS notes that difference, and that feet can swell through the day. The scan is what we build from. You still choose a US shoe size for the outline. The scan does not recommend one. The chart on our size guide compares those labels with foot length.

The outline of the insole is still a standard length, Full Length or 3/4 Length, so it can sit in shoes. The arch is the part that changes with the scan. Both lengths are $69.99. The steps, in order, are on how it works.

Why the shell is nylon, not more foam

A foam arch is soft, and it is also the thing that packs down. PA12 is a nylon printed in thin layers on HP Multi Jet Fusion machines. HP describes it as a strong, light material that can bend rather than snap the way a brittle plastic does. In this insole, that means the shell can hold the arch shape step after step, while the foam above it does the cushioning. The open lattice in the print is also how the shell stays lighter and less like a solid block, and how air can move through the structure instead of stopping at a sealed plate.

The shell is firmer under the arch, where the shape has to stay, and the step lands on foam and on the heel cushion, where you want give. That split is the point of printing a shell and then adding soft layers. It is not a claim that the pair changes your foot.

Left and right are two prints

A mirror copy would be faster and it would be wrong for this product. Your two scans are not averaged into one arch and then flipped. Each shell is its own file. When the pair arrives, put the left insole in the left shoe and leave it there. Swapping them puts the other foot's arch under you. The longer note on that is why the left and right are printed separately.

The 16 designs do not change the shell. They change the fabric on top. Ordering a second color later can use the scan already stored on your email, unless your feet have changed and you want new photos.

What you feel, and what you should not cut

On the first day, the arch is usually the new sensation. Store insoles are often flat through the midfoot. This one is not, because the shell is there. The shoe can feel fuller. That is the stack taking space, not a sign that the shell was printed "too much." Give it ordinary days before you decide the length was the wrong one. The first week page is the wearing note. The shell itself does not soften into a different shape to match a mood. The foam on top compresses a little. The printed arch stays the printed arch.

Trim only the toe of a Full Length pair, a little at a time, if the edge bunches. Use the insole you removed as a pattern. Do not cut into the shell, and do not sand the arch to make it lower. A cut shell is a damaged pair. 3/4 Length rarely needs a toe trim, because it never reaches the toes.

What the underside is supposed to look like

Turn the insole over. The shell is the printed piece, often with a fine layered texture. That texture is the print, not a scratch from shipping. HP's Multi Jet Fusion process builds PA12 in thin layers, about 0.08 mm on the machines used for this kind of part. The number describes the print, not a promise that your foot will match a clinic's ruler. Your foot feels the foam and the fabric, not that texture. Do not paint the shell, and do not glue a store-bought arch on top of it. A second arch on top of a printed one is two shapes fighting, and the shoe will not have room.

The shell can look different from the left to the right. That is the two scans. It should not look cracked, powdery, or unfinished. Loose powder is cleared before the foam and the cover go on. If the underside is still dusty in a way that rubs off in your hand, or the shell moves inside the cover, email support@customsole.shop with the order number before you wear it. A finished pair is one piece.

When the shell is not the problem

If the shoe feels tight, check the stack before you blame the print. A Full Length pair belongs in place of the original insole, not on top of it. A 3/4 pair belongs on top of the original. A narrow dress shoe may simply have no room for a Full Length stack. Cycling shoes often have no room for either. The shell cannot shrink to fit a shoe that was already full.

If the pair arrives cracked, split, or clearly not the shape of a finished insole, email support@customsole.shop with the order number. A pair that arrives damaged or made wrong is replaced. Comfort on day one is a different question, and it is not a defect by itself.

What the shell is not

The shell is a printed shape for a comfort insole. It is not a test, and it does not tell you to skip a clinician. If a foot hurts, see a podiatrist. We do not take HSA or FSA. The scan that creates the file happens after checkout, with the same email as the order, on complete your scan. Until that scan is in, there is no shell to print.