How to Clean Parking Stencils

Cleaning stencils is a pain, but it is one of the keys to successful stenciling and will help give your stencils a long life. Also with the few tricks we describe below it can be done in just a few minutes at the end of the shift. While this is specifically targeted for our professional 60 and 125 mil LLDPE stencils the same basic techniques will work with the mylar stencils.  

• Start with clean stencils
• Apply a silicon spray lubricant before painting
• Soften the paint by soaking
• Use a soft bristle, non-abrasive brush

Prep your stencils:

1. Make sure that the stencils will lay flat. If they have not been stored properly or if they have been rolled for a long period of time, they need time to relax and again lay flat. Lay them flat on warm pavement or in the sun. You can also put some weight like a piece of plywood on them. Heat and weight can accelerate the process.
2. Clean stencils work better than dirty ones, clean them before use if you have time.
3.  Pro Tip: Right before painting add a lubricant to the top(painted) side of the stencil  surface to make it hard for paint to stick to it. We have tried many, but our favorite is silicon spray. It is inexpensive, easy to use and is very effective. Other options which also keep paint from adhering are Pam, WD-40 and even water misted on with a sprayer. During a big job is can be done in between uses. Just spray again on top of the painted stencil, no need to wait for the paint to dry.
   

   Two test stencils made from our line striper preferred 1/8th inch LLDPE material. Silicon lubricant added to the bottom Stencil.

Painting with Stencils:

1. This will sound both STUPID and obvious, but the most important idea is to put the paint through the stencil, and not on the stencil. Paint on the stencil is wasted, might drip off the stencil while moving, and also has to be cleaned. It makes a mess and the paint always gets all over me.
2. CHECK YOUR TIPS: Use of a spray tip that has too wide of a fan for stencil spraying or use of a worn spray tip will waste paint and create a mess. For most stenciling jobs, I prefer a tip with a 2 - 4 inch fan width (For a Graco Line Lazer this is a LL5215 or LL5315.)  Spray manufacturers say that tips last about 300-400 gallons
   
   
   
   Painting the stencil: it was January and 10 degrees outside. Had to go with the roller.
   
   Stencils with about 10 coats of paint, cured over a weekend. We did the opposite of what you should do, we put the paint not through but on the stencils.

Clean up after use:

1. Soften the Paint. For water-based paints soaking with water works. After use, get them in water as soon as possible, but still do it even if they have spent the winter in the garage.  Hot water is more effective and the longer you soak it, the better as well. in our test we waited a few days before soaking and saw the paint soften in just 10 minutes. We use a kids wading pool. It is large enough so our stencils can fit in completely, and we keep it on our asphalt parking area so it gets nice and warm especially on a sunny day.  Even after curing, most latex film will absorb the water and start to separate from the plastic surface. Making it easier to remove. If you are using solvent based paints, ask your paint supplier can tell you the appropriate solvent to use. (note: a pump sprayer is helpful here.)
2. After a good soak, the paint should soften and start detaching from the stencil. Rub with a soft, nylon bristle brush. You want to avoid roughing up the surface of the plastic too much. The rougher the plastic gets, the easier paint will stick to it. (for the same reason you sand wood before painting.) After softening the paint, some use a pressure washer. This can work but too much pressure and the water can cut through the stencil and ruin it. If you try this method, use a Green or white sprayer nozzle and keep the pressure low.
3. Solvent paint is always tougher. On top of the purchase and clean up of the solvent, we find that it softens but does not release as well.  The paint turns into a goo and has to be wiped off with a cloth.  
4. If you get to the point where you need to scrape, then use a plastic scraper, not metal. Plastic will not cut the stencil material as easily.
5. Over time the stencil will get rough and it will get a coating of paint.  Keep cleaning to keep the paint coating from getting too thick. The stencil is still usable as long as the paint openings are clear. Use a plastic scraper to keep the corners square.  
6. Once clean, make sure you store the stencil properly. It is best stored in a way the stencil can lie flat.  Either flat on a shelf or pallet or hang on the wall. 

Check out the our other tutorials and instructions.

Without a water soak you need a scraper to get the paint off. The bottom stencil with the silicon spray comes off much easier.

After a soak, we can use a soft bristle brush takes the paint right off. The stencil with silicon spray is done in seconds.