Min Plastics | Plastic Fabrication & Sheet Supplier

Category: Guides

Plain answers to common plastics questions from the Min Plastics shop in Iwilei.

  • 3D Printing Materials for Hawaii

    Which plastic should your large 3D printed part be made of?

    Hawaii is hard on plastic: sun, salt air, rain and heat. Tell us where your part will live, and we’ll match the material. Here’s how our three compare.

    Short answer: PETG is the economical all-rounder, indoors or outdoors. HDPE or polypropylene suit parts that are submerged or used in a marine setting. Not sure? Tell us where the part will live and we’ll pick.

    Our materials at a glance

    MaterialColor and finishGood forPaint and polish
    Fiber reinforced PETGWhite, matteEconomical all-rounder, indoors and outdoors. UV stabilized for sun.Paints and polishes well.
    Clear PETGClear, glossySee-through parts. Best indoors or sheltered. For outdoor use it can be coated with a clear UV protective paint.Polishes. Can also be coated with clear UV protective paint.
    Fiber reinforced HDPELight grey-greenParts that are submerged or used in a marine setting, and tough in knocks and wear. UV stabilized.Not made to hold paint. Flame treatment helps paint stick.
    Fiber reinforced polypropyleneWhite, matteMarine and outdoor parts. UV stabilized.Paints and polishes.

    Sun, salt air and heat in Hawaii

    Salt air and rain are fine for all of them. Constant water points to HDPE or polypropylene. Heat above a material’s service temperature can affect any plastic part, and a dark part in direct sun gets hot, so tell us where it will be used and what color you want. We plan around those conditions.

    Reinforced or clear?

    The reinforced grades are fiber reinforced, so they are stronger than unfilled plastic. We also offer a clear PETG when you need to see through the part.

    Recycled? Fire rated?

    They’re made from recycled feedstock and can be recycled again at end of life. Our stock materials don’t carry a fire rating, but a fire-rated material can be added for your project.

    What does the surface look like?

    Layered lines, from about 1/16 in to 3/8 in. We can leave them as part of the look or mill the outside for a smooth finished surface.

    Not sure which one you need?

    Send us your measurements on our Contact Us page. You can attach files. Prefer to talk it through? Call our office and speak with a friendly, helpful representative, or visit our showroom.

    See what we’re adding: Large-format 3D printing, made in Honolulu. Or compare your options: Large-format 3D printing vs other methods.

  • Large-Format 3D Printing vs Other Methods

    Large-format 3D printing or another way to make your part?

    The right way to make a plastic part depends on its shape and how many you need. Here’s how we think about it, and we’ll tell you if printing isn’t the answer.

    Short answer: printing shines on complex shapes in low volumes, and on large parts a desktop printer can’t make. Simple parts from sheet or panels are often better made another way.

    Which method fits your part?

    MethodPick it whenKeep in mind
    Large-format 3D printingOne-offs or low volumes. Complex curves, compound shapes or internal detail. A part too big for a desktop printer. You want to review the design and change it before production.New for us. Layered surface (we can mill it smooth).
    CNC routing and cutting from sheetFlat or simple parts from sheet or panel. Sharp, accurate cut edges.Complex 3D shapes need extra setup or a mold.
    Fabricated sheet and panelMostly flat sides with few curves. Reliable and quick to make.Compound curves are hard to make this way.
    ThermoformingSeveral of the same curved part, where a mold pays off.Needs a mold first, which takes setup time and money.
    Traditional molding (injection or composite)High volume of the same part.Tooling makes one-offs expensive.
    Ordering from the mainlandStandard parts and large volumes.Ocean freight adds time and cost, and you don’t control the schedule.
    Desktop 3D printingSmall parts.Too small for large work.

    Why we offer printing alongside the rest

    We’ve cut, formed and finished plastic in Iwilei since 1950. One shop prints, mills, welds and finishes, so quality stays in our hands. Nothing ships across the ocean, and you can review visual edits before production starts.

    Printing is not for every job. If a CNC-cut or fabricated part is the better answer, we’ll say so.

    Quick questions

    Do you still do CNC and fabrication? Yes. We cut, route, form and finish plastic in our own shop, and printing is one more way to make a part.

    Is printing cheaper than a mold? For one custom piece it often avoids the cost and time of a mold. For many of the same part, a mold or thermoforming can make more sense.

    Can I send a drawing and ask which method fits? Yes. Send it on our Contact Us page and we’ll tell you what we’d use.

    Not sure which one you need?

    Send us your measurements on our Contact Us page. You can attach files. Prefer to talk it through? Call our office and speak with a friendly, helpful representative, or visit our showroom.

    See what we’re adding: Large-format 3D printing, made in Honolulu.

  • How to Clean Acrylic (and Keep It Clear)

    How to Clean Acrylic (and Keep It Clear)

    If your tables or guards went cloudy and dull, it’s often the cleaner, not the plastic.

    Restaurants, hotels and offices: sanitizer-safe surfaces

    • Many strong cleaners haze acrylic over time, especially ones with ammonia or a lot of alcohol. Look for fine cracks or a cloudy film.
    • For daily cleaning: mild soap and water with a soft cloth, or a plastic cleaner like Novus #1. We carry Novus, including in our online shop.
    • If your staff has to use a commercial sanitizer, ask us about scratch- and abrasion-resistant coated sheet. It’s a special order, made for surfaces that get wiped all day.
    • Already scratched or dull? Light damage can often be polished back to clear (we do restoration polishing). Deep damage is usually cheaper to replace.

    Still not sure?

    Send us the size and what it’s for. A photo of the spot helps. We’ll tell you what we’d use, roughly what it costs, and when it’ll be ready.

    There’s no dumb question about plastic. We’ve been answering them in Iwilei since 1950.

    Min Plastics & Supply · 921 Kaamahu Place, Honolulu · Call (808) 847-1511 · sales@minplastics.com

  • Replacing a Plastic Skylight Panel

    Replacing a Plastic Skylight Panel

    Most people who call us aren’t sure what to order. That’s normal. If you’re still not sure after reading this, tell us what it’s for, and we’ll tell you what we’d use.

    Skylights

    • Want light without glare? White or frosted sheet spreads the light out and hides the sky. Clear lets in the most light, but also the heat and glare.
    • In a spot where something could fall on it? Polycarbonate is the safer choice.
    • In full sun for years? Ask about UV-protected grades. We can special order extra-long-term UV sheet.
    • Bring us the old panel. That’s what we work best from.
    • No old panel? Make a pattern of the exact shape, and we’ll cut to your pattern.
    • Please don’t bring a frame with broken glass still in it. We can’t dig the old glass out and guess what the size should be.

    Skylight panels are often 3/16″ to 1/4″. Bigger openings need more, and the frame matters as much as the sheet.

    Outside, in sun and salt air

    Acrylic holds up well outdoors in Hawaii. Standard polycarbonate needs a UV-protected grade outdoors. Expanded PVC is great for signs, but it scratches easily and stains, so it suits indoor or covered use best.

    Still not sure?

    Send us the size and what it’s for. A photo of the spot helps. We’ll tell you what we’d use, roughly what it costs, and when it’ll be ready.

    There’s no dumb question about plastic. We’ve been answering them in Iwilei since 1950.

    Min Plastics & Supply · 921 Kaamahu Place, Honolulu · Call (808) 847-1511 · sales@minplastics.com

  • Acrylic Thickness Guide: What Thickness Do You Need?

    Acrylic Thickness Guide: What Thickness Do You Need?

    Short answer: most jobs land between 1/16″ and 1/4″. Use 1/16″ for small frames and small signs, 3/32″ for larger frames, and 1/8″ for small side tables and covers. Use 3/16″ for desk and dining table covers and countertop sneeze guards, and 1/4″ for outdoor tables, larger guards and windows. Go 3/8″ and up for shelves, display cases and anything that carries weight or spans a wide gap.

    Thicker sheet is stiffer and tougher, but heavier and more expensive. The right thickness depends on how big the piece is and how it’s supported.

    Thickness by job

    ThicknessTypical uses
    1/16″ (about 1.5 mm)Small picture frames, small signs, craft and model work, inserts, thin covers. Flexes easily.
    3/32″ (.093″–.098″, about 2.5 mm)Larger picture and poster frames, menu holders, light covers
    1/8″ (about 3 mm)The everyday sheet: small side table covers, small windows, cabinet doors, small sneeze guards
    3/16″ (about 4.5 mm)Desk and dining table covers, countertop sneeze guards, larger signs, windows, small display boxes
    1/4″ (about 6 mm)Outdoor table covers, freestanding and larger sneeze guards, display cases, light shelves, larger windows
    3/8″ (about 9.5 mm)Shelves, larger display cases, risers, partitions
    1/2″ (about 12.7 mm)Heavy shelves, podiums and lecterns, large display cases
    3/4″ to 2″Structural and heavy-duty work: bar and counter tops, large museum cases, tank windows, machine parts
    These are starting points. Size, span and how the sheet is held all matter. Tell us the job and we’ll confirm the thickness.

    Cast or extruded?

    We stock both. Extruded acrylic holds a more even thickness from sheet to sheet and usually costs less, which makes it a good choice for frames, glazing and covers. Cast acrylic machines, polishes and laser engraves more cleanly and handles cements and solvents better, so it’s the usual pick for display cases, fabrication and engraving.

    Good to know

    • Sheet thickness is nominal. A “1/8 inch” sheet is often 3 mm (0.118″), and cast sheet can run thinner or thicker than its label. If an exact fit matters, like a frame groove or a replacement panel, bring the old piece or measure the opening.
    • Thin sheet moves in Hawaii’s humidity. Sheet thinner than 1/4″ can warp in our humidity. In a frame or lying on a table, it stays flat. For a big piece standing on its own, go thicker or plan a way to support it.
    • Need more strength without going thicker? Polycarbonate is much tougher at the same thickness. See Acrylic vs. Polycarbonate.

    Common questions

    What thickness is best for a sneeze guard?

    3/16″ for most countertop guards. 1/4″ for larger or freestanding guards.

    What thickness for a tabletop or desk cover?

    3/16″ for a desk or dining table, 1/8″ for smaller side tables, and 1/4″ for outdoor tables. It lies flat and holds up to daily use.

    What thickness do you stock?

    Clear acrylic from 1/16″ up to 2″ thick, in full and partial sheets, plus colors, mirror and specialty sheet.

    Can you cut it to my size?

    Yes. Call (808) 847-1511 or stop by our shop in Iwilei.

    Shop acrylic: Plexiglass Acrylic sheets · Call (808) 847-1511.

  • Acrylic vs. Polycarbonate: Which One Do You Need?

    Acrylic vs. Polycarbonate: Which One Do You Need?

    Short answer: pick acrylic when you want the clearest, best-looking sheet: display cases, signs, picture frames, sneeze guards and tabletop covers. Pick polycarbonate when the sheet has to survive a hit: machine guards, security glazing, skylights in exposed spots, and anything kids, carts or forklifts might run into.

    Both are clear, light plastics that people often call “plexiglass.” They look alike on the rack, but they behave very differently once they’re in use.

    How they compare

    Acrylic (Plexiglas)Polycarbonate
    ClarityAbout 92% light transmission, the clearestAbout 86–88%, slightly less clear
    Impact strengthStronger than glass, but can crack under a hard hitRoughly 30 times tougher than acrylic, very hard to break
    Scratch resistanceHarder surface, scratches lessSofter surface, scratches more easily (coated grades help)
    Sun and weatherStays clear outdoors for yearsNeeds a UV-protected grade outdoors, or it can yellow
    HeatGood to about 160–180°FGood to about 240°F
    EdgesCan be polished to a glass-like clear edgeEdges stay frosted, can’t be flame polished
    Bending and formingHeat-bends and thermoforms wellCan be cold-bent on site; also thermoforms
    PriceUsually costs lessUsually costs more
    Typical published values for standard sheet. Exact numbers vary by grade and thickness.

    Where each one makes sense

    Acrylic is the go-to for anything people look at: museum and retail display cases, signs, frames, shelving, tabletop protectors and sneeze guards. It polishes to a clean, clear edge and cements into seamless joints, which is why most display work is acrylic.

    Polycarbonate is the go-to for anything that takes abuse: machine and equipment guards, protective barriers, security and vandal-resistant windows, and covers in busy or exposed areas. It flexes instead of shattering.

    A note for Hawaii

    Our sun is strong year-round. For outdoor work, acrylic holds its clarity well. If you need polycarbonate’s toughness outdoors, ask for a UV-protected sheet, or it may yellow and turn brittle over time. Thin sheet of either can also move with heat and humidity, so leave room for expansion when you mount it.

    Common questions

    Is polycarbonate the same as Lexan?

    Lexan, Makrolon and Tuffak are all brand names for polycarbonate sheet, the same way Plexiglas is a brand name for acrylic. We carry Tuffak.

    Which is better for a sneeze guard?

    Usually acrylic. It stays clearer, scratches less with daily cleaning and costs less. Choose polycarbonate if the guard will get bumped hard.

    Can you cut both to size?

    Yes. We stock both in Iwilei and can cut, CNC route, polish or fabricate either one. Call (808) 847-1511.

    Which is better for a boat or outdoor window?

    It depends on what it has to survive. Tell us about the job and we’ll help you choose.

    Need sheet or a cut piece? Shop acrylic · Shop polycarbonate · Call (808) 847-1511.