Ask iFixit: How Do I Fix Sticky Plastics?

Final month, I pulled my previous Okay-Combine USB audio mixer out of the underside drawer, and it was lined with mud and sticky goo. The rationale? Its soft-touch coating, which lends an opulent really feel to plastic surfaces when new, had deteriorated. So, after all, I set to fixing it. 

Sticking Level

Why do producers use these tender coatings within the first place? One cause is that they actually do really feel nice at first. As an alternative of laborious, easy, cheap-feeling plastic, you get a rubbery contact that feels fairly elegant. And these coatings may also conceal floor flaws from the injection-molding course of. As a comparability, I’ve a pair of Genelec speakers in raw, unfinished aluminum, they usually look nice, however the aluminum floor is flawed, patchy, and exhibits sanding marks. It’s a glance that many individuals dig, however that’s aluminum. Flawed plastic is much less enticing. 

The issue with these supplies is that they break down over time, and find yourself both cheesy and lined in mud, or really sticky, so whenever you contact them they really feel gross, virtually such as you spilled juice or honey on them. To make plastics really feel tender, producers use compounding components like oils, antioxidants, and stabilizers that may come to the surface over time and create a sticky feeling. This course of known as plasticizer migration. It’s an issue well-known each in car dashboards and guitar knobs. 

One of the simplest ways to keep away from that is to not purchase soft-coated merchandise. You possibly can decelerate plasticizer migration by holding your stuff cooler—it happens faster at higher temperatures. However in the event you’re right here, studying this, it’s most likely too late for that. 

Additionally, it’s not all the time apparent which surfaces will break down. That’s as a result of there’s not only one materials that causes this. Whereas soft-touch plastics are a possible candidate, different supplies can get sticky too. Rubber stuff goes sticky by way of a course of referred to as “rubber reversion.” Turning the sticky sap of the rubber tree into automobile tires and recreation controller grips requires heating it with sulfur and different components. This curing course of, referred to as vulcanization, makes the sap’s polymer chains be part of collectively into a powerful, stretchy matrix. When these polymer crosslinks break down with time and warmth, the rubber will get sticky once more.

Nikon’s F100 film SLR, from 1999, has a reasonably customary rubberized end, for instance, nevertheless it’s notorious for going sticky. I gave mine to my dad, after which, years later, he gave it again, and the rubber was cheesy and unsightly, and attracted mud. However I fastened it. 

Easy Operator

So long as your sticky factor has no delicate electronics, your finest wager is to begin the cleansing course of with heat, soapy water. In a whole lot of circumstances, cleaning soap will loosen the migrated plasticizers and restore a non-sticky end. 

If cleaning soap and water don’t do the trick, you may strive baking soda: Add sufficient water to show the baking soda right into a slurry paste. Unfold it on the sticky floor, let it sit for quarter-hour, after which wipe it away.

If it’s nonetheless sticky, you’ll have to discover a solvent. At all times you should definitely take a look at a small, unobtrusive space first: Relying on the plastic and plasticizers concerned, a solvent may really break down the plastic additional and make it extra sticky. Because of this, we advocate staying away from solvents in the event you’ve acquired a sticky car steering wheel.

The go-to solvent for cleansing up sticky plastic is isopropyl alcohol. Pure, or almost-pure, alcohol is nice for electronics use as a result of it’s non-conductive. We’ve got a full guide on isopropyl alcohol for all the main points, however for cleansing functions, right here’s what it’s good to know.

Isopropyl alcohol dissolves oils, kills viruses and micro organism, and evaporates with out leaving a hint. For cleansing delicate electronics elements, you need the pure stuff, 90% alcohol or larger. However for cleansing sticky plastics or rubber, you may get away with decrease concentrations, since you don’t have to fret about something shorting out with residue. If it does depart seen impurities from the water, you’ll be able to simply clear once more. Check out the listing of substances: No matter you’re utilizing must be nothing greater than isopropyl alcohol and water. “Rubbing alcohol” typically contains fragrances or different chemical substances that may not play effectively along with your devices, and they’re going to most likely additionally depart a odor (despite the fact that it might be a odor you want). 

For the Nikon’s rubber, the repair is to softly rub it with isopropyl alcohol. Keep away from drips, and go sluggish. It could take a number of purposes to repair, however ultimately, the rubber will cease feeling sticky and as an alternative really feel like, effectively, like grippy rubber. Professional tip: don’t use bathroom paper when cleansing with alcohol, because it disintegrates instantly and simply provides to the issue. I take advantage of squares ripped from previous cotton t-shirts, they usually work effectively.

For the Okay-Combine mixer, pictured right here in all its sticky-finished disgrace, the scenario was extra dire. Even after an isopropyl rub, the coating stayed cheesy. As you’ll be able to see, I used to be capable of scrape a lot of the coating off after which use isopropyl alcohol as a soak/scrub to complete the job. 

One of the simplest ways for this explicit job could be to disassemble your entire unit to take away simply the case, scrape it (with a plastic scraper like a Halberd spudger or plastic card, ideally, so that you don’t scratch the floor), after which soak the case to take away the rest. 

Different Solvents

Typically, nonetheless, alcohol isn’t the reply. For instance, in the event you take away the paper labels from some meals jars, the residual glue is finest eliminated with lighter fluid, aka light naphtha, the type of gas you’d drip right into a Zippo lighter. However in case you are utilizing lighter fluid to scrub one thing apart from glass, you need to positively take a look at it first, to ensure it doesn’t destroy the underlying plastic itself. 

One enjoyable truth about lighter fluid is that it’s protected for cleansing classic electrical guitars with their delicate nitrocellulose lacquer finishes. However in that case, you need to positively keep away from acetone, which is able to “soften” the end (anecdotally, you may additionally keep away from DEET-based insect repellents whereas taking part in out of doors gigs, for a similar cause). 

Acetone, finest generally known as nail polish remover, has its makes use of. We use it in our adhesive remover, for instance. However it may injury ABS plastics, which is a disgrace as a result of it’s fairly nice at dissolving every kind of undesirable coatings.

Orange oil is a well-liked solvent for scraping away adhesive residue (and it’s one of many issues that makes in style adhesive removers like Goo Gone work). After seeing some reports of its effectiveness at cleansing up sticky plastics, iFixit sustainability director Liz Chamberlain tried it on a water bottle that was tender and have become sticky. A wipe-down with an orange oil-soaked rag, then a rinse, made the end on the bottle visibly smoother and not cheesy. 

The one technique to know which solvent or methodology will work in your explicit sticky plastic merchandise is to check it. Begin with isopropyl alcohol, which is fairly benign to devices, and go from there, testing on a hidden spot earlier than committing. 

As for security, keep away from inhaling fumes, put on gloves, and use in a ventilated house. Eliminate all cleaned-off gunk appropriately, and watch out with these solvent-soaked rags, as a result of they’ll be a hearth hazard.

And if all this looks like a significant problem, that’s as a result of it truly is. When you’ve scraped and de-gunked one gadget, you’ll be loads much less seemingly to purchase a soft-touch product ever once more.

That is the most recent in a sequence of solutions to widespread restore questions: How do I stop stripping screws? Ought to I even hassle making an attempt to repair this stupid, busted printer? I spilled liquid on my laptop—now what? If you happen to’ve acquired different broad restore questions you’d like us to reply, depart a remark beneath.