Acrylic, PETG, PVC, foamcore or styrene? Choosing an indoor sign material

Most indoor signs are printed on one of five sheets: clear acrylic, clear PETG, foamed PVC, foamcore or styrene. From across a room they can look alike. Up close, and over a few months on the wall, they behave very differently. One looks like glass, one bends without breaking, one shrugs off a wet cloth, one is light but dents, and one is thin enough to slide into a shelf channel.

This guide explains what each material is, how stiff and how heavy it feels, what its cut edge looks like, where it can and cannot go, and how it is usually mounted. It also explains how mirror (second-surface) printing protects a print. At the end you will find a picker for offices, clinics, retail interiors and events.

The five materials at a glance

The thicknesses below are the ones listed in our catalogue. The other columns summarise the sections that follow, where each point is linked to its source.

Clear acrylic: the glass look

Acrylic is the clear sheet most people call plexiglass. A display maker's material guide describes it as the most common alternative to glass: cheaper and lighter than glass, easier to handle, and with more rigidity and scratch resistance than PETG or polycarbonate. The same guide lists it at 92% light transparency, which is why a clear acrylic panel looks so much like glass on a wall.

Acrylic is far tougher than glass, but suppliers quote very different numbers for how much. One sheet maker, via its distributor, says its acrylic is up to three times stronger than double-strength window glass; the display maker above says seventeen times more impact resistant than glass. The tests and the glass being compared are not the same, so treat the multiples loosely. What the sources agree on is the limit: where a sign will take real knocks, the display maker recommends PETG or polycarbonate instead of acrylic.

Edges and finish

Acrylic's edges are part of its appeal. The display maker notes that acrylic edges can be flame polished and scratches can often be buffed out. A polished edge catches the light and makes a thick panel look like a block of glass. Our clear acrylic signs list polished edges as a finishing option, along with stand-off hardware.

On the catalogue page, our acrylic is clear cast acrylic in 3, 6 or 12mm with a vinyl-mounted graphic, sized for logos up to 36, 48 or 72 in wide, or to custom wall dimensions. Artwork is needed as vector AI or EPS files with fonts outlined. If you have only a JPG of your logo, say so on your quote.

Indoors and outdoors

Acrylic as a material does well outside. One sheet maker says its acrylic is designed to endure harsh outdoor conditions and carries a 10-year limited non-yellowing warranty, and the display maker states that acrylic does not yellow over time. Our catalogue, though, lists clear acrylic signs for indoor use: receptions, offices and showrooms. If you want a clear sign outside, ask on your quote rather than assuming the indoor product will do.

Clear PETG: the tougher clear option

PETG is a clear plastic that is easy to print and hard to break. The display maker's guide puts its impact strength at about 70% of polycarbonate's and much stronger than acrylic or glass. Sheet makers go further in their own marketing: one says PETG is 18 times tougher than acrylic, and a print supplier says five times stronger. The figures disagree, but the direction is the same: PETG survives knocks that would crack acrylic.

There is a trade-off. According to the display maker, PETG bows more easily than acrylic of the same thickness, scratches more easily, cannot have its scratches buffed out and cannot be flame polished. It is also a little less clear: the same guide lists 86% light transparency for PETG against 92% for acrylic. A print supplier agrees that PETG scratches more easily than acrylic and adds that it can bend, while acrylic stays rigid.

Where PETG wins is printing. The print supplier notes that acrylic needs a special digital coating before UV inks will hold, while PETG does not require one. The display maker also calls PETG UV-printer friendly with no adhesion promoter needed. A sheet maker lists screen printing, digital printing, spray paint and hot stamping, and calls out indoor signage and point-of-purchase displays among its uses.

What we offer

Our clear PETG signs are 40pt clear PETG, printed in reverse (mirror) with a white ink backer, so the colours read through a clean, glossy face. Sizes are custom and the sheet is cut to size. PETG artwork should be a vector PDF with fonts outlined, and you should mark any areas that should stay clear, with no white ink behind them. The catalogue suggests PETG for window displays, counter signs and premium retail graphics.

Is PETG fine outdoors? Sources disagree. The display maker lists it as suitable for indoor and outdoor use. A UK plastics supplier says most standard PETG grades lack UV stabilisers, so it is best indoors or for short spells outside, and recommends acrylic for long outdoor exposure. Our catalogue lists clear PETG as an indoor product.

How mirror (second-surface) printing works

A clear sheet has two faces. Printing on the side facing the viewer is called first-surface printing. Printing on the far side, so the art is seen through the clear material, is second-surface printing. The print supplier that explains the terms puts the benefit simply: the clear material shields the print, which gives a protected, glossy look.

Because the viewer looks at the print from the other side of the sheet, the artwork has to be laid down back to front. A PRINTING United Alliance article on reverse printing describes the order: process and spot colours go down first, then white ink goes over them. From the viewer's side the stack runs clear sheet, then colours, then white. The white acts as the reflective backing for the colours, and an uneven white lets whatever is behind the sheet show through. The article also notes that text and artwork must be prepared for reverse orientation, which is why we call it a mirror print.

Why the white backer matters

Colour ink on its own is transparent. An inkjet printer maker's guide notes that CMYK inks printed on clear substrates without white ink appear frosted and translucent, and that white ink is what creates areas of solid colour. That is useful as well as a limit. If you want part of the design to stay see-through, like a window in the middle of a logo panel, we simply leave the white out there. That is what our artwork note about marking clear areas is for.

What it protects, and what it does not

Mirror printing protects the print from the front, where hands, cleaning cloths and bags touch the sign. It does not make the back indestructible. On a sign-makers' forum, one shop described a second-surface print scratched on its back within minutes of unboxing; other members back such prints with vinyl or handle them with care. For you, the lesson is simple: the printed face should go towards the wall or into a holder, not out where it can be rubbed.

PVC: the plain, wipeable workhorse

Sign PVC is a foamed or expanded sheet: one maker describes its board as moderately expanded, closed-cell PVC with a low-gloss satin finish and a density of about 0.55 to 0.75 g/cm³. It is light for its stiffness, solid all the way through and white (or coloured) to the core. The display maker's guide points out that a cut edge shows a grainy cell structure, while the board maker says edges can be routed, sanded or painted for a finished look.

PVC is the most practical of the five. The board maker says it withstands moisture, acids, bases and common cleaning agents, cuts and drills with standard woodworking tools, and takes screws if you pre-drill. Our catalogue describes our PVC signs the same way: rigid sheet that shrugs off moisture, cleans easily and takes screws, which is why it is the usual choice for washroom and facility signs, covered exteriors and retail fixtures.

Our PVC comes in 3, 6 or 12mm, printed direct or with a vinyl mount, in 12 × 18 in, 24 × 36 in, 48 × 96 in or custom sizes, with drilled holes available. Artwork is a PDF at 150 DPI at full size in CMYK, with 1/8" bleed.

Indoors, and covered outdoor spots

Sources differ on how far outside PVC can go. The board maker describes its standard sheet as designed primarily for interior use and suitable for short-term outdoor use, with a maximum service temperature of 60 °C (140 °F). The display maker says PVC works for indoor and outdoor signs but does not recommend dark colours outside, because of thermal expansion and sun damage. Our catalogue lists PVC for indoor and covered outdoor use, such as under a canopy or in a vestibule.

Fire ratings: ask for the sheet's data

Fire performance depends on the exact board. One maker states that its PVC sheet is self-extinguishing and Class A under ASTM E84 in thicknesses up to 5mm. That is one product's claim, not a rule for every PVC board, and the display maker's guide advises checking the flammability ratings of the specific material. If a landlord, venue or inspector asks for a fire rating, tell us on your quote so we can look for the data sheet for the board we would use.

Foamcore: light and simple, indoors only

Foamcore is a polystyrene foam core sandwiched between paper liners, usually white clay-coated paper, according to a plastics distributor. It is made from about 1/8 in to 1/2 in thick, takes ink and adhesive well. The same distributor is clear that standard foam board is intended for indoor use, and points to PVC or corrugated plastic for outdoor jobs.

Its weak point is the surface. The paper faces dent if the board is knocked, and the display maker describes tougher foam boards as more durable and dent resistant than standard foam core. The distributor also notes that only certain grades are made to resist warping in humid rooms. Treat foamcore as a material for presentations, easel signs, photo displays and promotions that last weeks or months, not years.

Our foamcore boards come in 3/16" or 1/2", printed direct or with a vinyl mount, in 24 × 36 in, 36 × 48 in or custom sizes. The catalogue suggests vinyl mount for the richest colour. If you like the weight of foamcore but need it to stay flat and resist knocks for longer, look at our ultra board signs, which the catalogue describes as a rigid, moisture-resistant foam board with harder faces than standard foamcore.

Styrene: thin sheets for shelves and counters

Styrene, or polystyrene, is a thin printable plastic sheet. The display maker's guide lists standard thicknesses from 0.020 to 0.060 in and uses that are all about retail: ceiling hangers, danglers, shelf dividers, shelf talkers and posters. It die cuts with a blade, can be heat bent or vacuum formed, and can be laminated. A plastics retailer describes high-impact styrene as having a matte surface that prints well on one or two sides, and lists point-of-purchase displays among its uses.

It has limits worth knowing. The display maker lists outdoor signage under when not to use styrene, warns that cold makes it brittle, and notes that thin styrene can dent and is translucent unless it is a dead white or opaque grade. It is a sheet for inside the store, where it slides into shelf channels, hangs from the ceiling or sits in a counter holder.

Our styrene signs are 20pt styrene, printed direct and cut to custom sizes. The catalogue calls it the go-to for shelf and aisle signs, counter cards and window graphics. Artwork is a PDF at 150 DPI at full size in CMYK.

A note on recycling codes

The display maker notes that styrene can be recycled as a #6 plastic if the symbol is printed on it. Keep in mind what that symbol means. The ASTM standard behind it says resin identification codes are not recycle codes: they identify the plastic, and do not mean a program exists to collect it. Whether a used sign is accepted depends on your local program, so check before you put it in a bin.

Display boards and photo panels

Two more catalogue items sit close to these materials. Our display boards are rigid printed board in 24pt or 40pt, for point-of-purchase displays, easel signs, presentation boards and counter cards. The 40pt board is the thicker, stiffer one for easels; the 24pt board is lighter, for counter cards and inserts. Our photo panels are photos printed on rigid panels for walls and desks, quoted per order. Ask on your quote which board a photo panel uses and how it hangs, so you can compare it with the materials above.

Mounting: standoffs, tape, screws and easels

How a sign goes up matters as much as what it is made of. The display maker's guides give the usual methods for each material, summarised here.

For acrylic and PETG, the guides recommend screws or standoffs for large items, and silicone or VHB tape for smaller ones. For PVC they list screws, standoffs, silicone or construction adhesive, and for styrene double-sided foam tape, laminating adhesive, screws or construction adhesive.

Standoffs

Standoffs are metal fittings that pass through holes drilled in the panel and hold it a short distance off the wall. A print supplier lists drill holes and aluminum standoff hardware as the finishing for its acrylic signs. That gap gives the floating look our catalogue describes for clear acrylic in receptions, offices and showrooms. Our acrylic product page also notes that a full-size paper mounting template showing the drill and tape positions comes with the sign.

Tape

Foam mounting tape is quick and leaves no holes, but it is only as good as the surface it sticks to. An article on tape surface preparation, sponsored by tape maker 3M, says a 50:50 mix of water and isopropyl alcohol is enough to prepare most surfaces, but not ones with oil or grease on them. If the sign might move later, ask about holders or screws instead.

Easels and holders

For signs that stand rather than hang, the catalogue points to foamcore for easel signs and the 40pt display board as the stiffer easel option. For counters, floors and walls, our sign holders keep printed signs upright; tell us the sign size and where it will stand. At a show, remember that venue rules can limit where easels go: the convention centre rules above say easels and signs must stay inside the booth, not in the aisles.

Which material for which space

Offices and receptions

For a logo behind the front desk, clear acrylic on standoffs gives the glass look and polished edges, and catalogue sizes run to logos 72 in wide. For a lighter clear sign with full-colour artwork, such as a glass-look room sign or a framed notice, clear PETG with a mirror print keeps the graphic under a glossy face. For door, room and washroom signs that simply need to be clear, sturdy and screwed up, PVC is the practical choice. Foamcore suits a presentation board for a meeting, not a permanent office sign.

Clinics and health offices

Clinics get wiped down often, so start with PVC: the board maker says it withstands moisture and common cleaning agents, and our catalogue says it cleans easily. A mirror-printed PETG sign also suits busy areas, because its print sits behind the sheet, away from cloths and hands. Keep acrylic for the reception wall, where its look matters most. If your project includes regulated signs, such as accessibility or exit signage, confirm the requirements with the right project professional before production; this guide does not cover them.

Retail interiors

Retail uses all five. Styrene is made for shelf talkers, aisle signs and danglers. Clear PETG suits window displays and counter signs, where a glossy face and a tough sheet help. Foamcore handles a short promotion on an easel or a wall, and ultra board is the step up when the display has to last longer and resist knocks. PVC is for signs that stay put, such as department names, fitting room signs and fixture panels.

Events and trade shows

For a one-day event in a meeting room or hotel, foamcore on an easel or a 40pt display board is light and easy to carry. Convention centres are different: check the exhibitor manual before choosing any board, because, as the callout above shows, at least one Toronto venue prohibits foamcore and requires approval for plastics. PVC is a sturdier option for signs you will reuse, but ask for its fire data if the venue wants it.

What to send for your quote

• Size and quantity. Width and height of each sign, and how many of each.
• Where it goes. Wall, door, window, counter, shelf or easel, and whether it is indoors or in a covered outdoor spot.
• How long it must last. A weekend, a season or years. This alone often settles the material.
• How it will be mounted. Standoffs, screws, tape, a holder or an easel, plus a photo of the wall or fixture if you can.
• Your artwork. Vector files with fonts outlined for acrylic and PETG, and for PETG a note of any areas that should stay clear. For PVC, foamcore and styrene, a PDF at 150 DPI at full size in CMYK, with 1/8" bleed for PVC and foamcore. Our artwork guide has the details.
• Venue or landlord rules. Any fire rating or material rule you have been given.

Production time depends on the product — your quote gives you a firm date before you approve anything. Nothing prints until you approve the proof. If you are unsure between two materials, list both and tell us where the sign will go, and the quote will recommend one. You can also compare pairs side by side: acrylic vs PETG, foamcore vs PVC and styrene vs PVC.