PAINT SPRAYING PROBLEMS
There are paint spraying problems common to almost all types of paint sprayers depending of course on the different types of surfaces, equipment and products being used. Even so, in most cases, the majority of issues that a sprayed surface has is either avoidable or repairable.
TROUBLE SHOOTING ISSUES
FOR SPRAYED ON PAINTS AND COATINGS
Below, you will find a list of paint spraying problems along with some possible solutions. You will find that almost all of the situations you deal with tend to involve either dirty (or defective) equipment or the surface being sprayed is dirty or contaminated.
If you cannot find the problem or solution that you're looking for you can use the; Ask a question page below.
Difficulties with paint or coatings bubbling.
Running/sagging of a paint or coating product.
The surface being sprayed has either been improperly cleaned or your repair mud (or caulking) is letting off a gas when wet (or is made wet from the process of spraying). Clean the surface use fillers or properly and that are recommended for use with the products applied or specific surface materials being coated.
Some surfaces can not be properly cleaned and may need a high quality blocking primer. Trial and error is the only way to find out what works best or one can start with the primer first, prior to painting.
Defects in sprayed coatings when dried
This is a good reason to first start spraying by using a practice sheet of cardboard. Applying a number of light applications. Three or more coats works best.
To large of a spray tip (spraying tips come in different sizes, select a smaller sized tip). The sprayer tip may also be defective.
Thinning with an excess amount of solvent or thinner can be one of the reasons for this problem. Airless paint sprayers, in most cases. do not require thinning of the paint. Other paint spraying machines may require product thinning though (an HVLP for example).
Having your gun to close to the project when operating your paint sprayer can also cause sags or runs. Hold the gun at least eight to twelve inches away from the surface being sprayed.
Excess overlapping of the material being applied (spray fan pattern)? Be sure you have an understanding of how much overlapping is needed to complete your project properly. Practicing is the key.
Reducing the flow of fluid (turning the sprayers flow control knob down) can sometimes help eliminate excess product from being applied. Do keep in mind that lowering a paint sprayer's flow can cause the paint to drip (from the gun) or the surface to streak and flash (have a splotchy look) depending on the type of machine being used.
Dried finish of coating has missed or is thin in areas.
Not knowing what primer to use or how to operate a paint sprayer, along with dirt, poor surface filler choice or moisture etc., can cause blistering or lifting of the paint/coating. Watch for these problems when spraying.
Thin the coating properly depending on the product and the equipment being used. Some paints, like latex, may require a 10% thinning while certain (quick drying) clear coats flow better when thinned at a 30% ratio of thinner to coating.
Be sure your material is not contaminated and the project being completed is dust free and properly prepped.
A little sanding, filling, cleaning and priming can save a whole lot of headache in the long run.
Use top of the line paints and coatings whenever possible.
Check that the fluid line from the beginning of the airless paint sprayer to the tip of the gun is not plugged or the equipment being used is not damaged (especially the guns spray tip).
Practice overlapping and speed of gun passes until there are no runs, sags or missed areas. The amount of distance that one moves the gun for each pass can be less (in some situations) or more (in others) than you may think.
REPAIRING SURFACE PROBLEMS AFTER SPRAYING
Most coating or paint issues, that are caused on a surface by spraying, can be repaired. Of course some of the repairs do take a fair bit of time if your intention is to have the best finish possible.
Repairing sags and runs.
Repairing a bumpy, pealing, bubbly, cracked or gritty surface.
Having a small high quality paint brush (one recommended for the type of coating being sprayed) will work best to remove the sag or run prior to the paint or coating drying. Your brush may leave brush marks so try to use minimal and delicate brushing. Keep in mind that surface groves and divots can be be filled, sanded, dusted, spot primed and re-sprayed while a clear coat can only be sanded and then re-sprayed.
Dried sags or runs on the other hand will need to be cut away (use a utility knife/razor blade to do so) or sanded off. When sanding, an electric type sander tends to do a good job. For the best results though, start with a course grade sand paper and then work up to a finer grit. With that said, I do find a rotary tool is the quickest and easiest sander to handle for this type of repair.
While sanding (scraping or cutting), do your best to remove only the sag or run. Once your done, use filler, where needed, (and only if your spraying paint) then sand the dried filler level to the surface. Follow up with re-filling (if necessary), spot priming, lightly sanding, dusting, then spraying on a final coat (or two) of paint to the entire project or surface area.
Clear coats (lacquers and urethanes etc.) can only be sanded and then re-sprayed. So do try to be very careful when doing clear coat repairs and when you're spraying the coating on.
A pealing paint or clear coat requires scraping first then the use a good quality electric palm sander. Start with a course sand paper and work your way up to finer grits of paper (e.g. 100, 120, 220 etc.). Keep sanding until you're happy with the look and feel of the surface.
A very bumpy, grooved or cracked surface (that will be sprayed with paint) can be filled or skim coated. Clear coats, on the other hand, can only be stripped down to the raw wood (with a chemical stripper), or sanded flush and smooth to the surface with sand papers (and or a combination of both).
After everything is sanded nice and level, apply primer (if needed, and when spraying paint). Finish up by then spraying on your final coats of paint or clear coating.
Problems such as dis-colorations or staining can be addressed by priming a painted surface, while a clear coated project may need stripping, bleaching, sanding and dusting, then an application of a colored wood stain, followed by re-clear coating. All of the products need for the afore mentioned work can be found at your local home improvement center.
If I have not mentioned a remedy to your paint spraying problem/s then please use the (free of charge) ask a question page for more help. Do try and give as much detail as possible though so that we can assist you with the best answer possible.
SUMMARY OF PAINT SPRAYING PROBLEMS
Practicing on a throw away surface, like thick cardboard, then moving up to a disposable piece of wood, is the best cure for most paint spraying problems.
Every coating product, from paint to clear coat, can react differently when sprayed. Equipment being used, the surface coated, fillers and the products applied, need to all be of the utmost quality and cleanliness and recommended for your specific type of project. Not following these said suggestions can result in a number of problems arising.
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