I am working on some nail polish watercolor coffee mugs. I have completed the color application and want to make them dishwasher safe using dishwasher safe mod podge. I don’t have any experience with mod podge at all and was wondering if anyone has tips or tricks that you wish someone told you before you started?
I would wrap a line of masking tape around the edge of the cup on the outside at the top, because this modgepodge gloss appears not to be food safe. I would also wrap at the bottom for aesthetic reasons.
Although it is water soluble, do not dilute it.
Put the mug to be painted upside down on stick it on a plastic cup. Use the biggest, softest synthetic brush you can find and quickly brush downward in an even stroke from tape to tape. With the next stroke, overlap by 1/16” or 2mm and work your way around. Depending on the viscosity you may need more or less paint.
Personally I would dip the entire outside of the mug in polyester resin. That water-based stuff probably won’t hold up to abrasion and if it isn’t food safe I wouldn’t want to accidentally drink a chip. Something like this would work. Use an S-hook to hold the handle, dip it in the mixed resin, hang above the dipping container for five minutes and then place on a coaster to cure. Use in a well ventilated area and don’t get it on your skin or in your eyes.
I would never trust a non-ceramic surface in the dishwasher. Enameled mugs may last a long time if you hand wash them, but if you care about them, go ahead and put your best finish on and then hand wash them. The problem is the detergent. It's highly alkaline.
Potters work very hard to develop glazes that can withstand that hot, alkaline environment over the decades. I have a treasured collection of glaze recipes that have stood the test of time. I have others that, though beautiful, I use only on decorative pieces. Even though they may be food safe (most of them), they can't hold up to the dishwasher. Mod podge is not going to hold up to the dishwasher.