On occasion, I will have the need to write something on a piece. A happy birthday, a date, or something. Normally I use the needle tip little bottles that I fill with underglaze. Frequently people use this technique on the low fire ready to glaze bisqueware for thinks like class auctions and benefits. Someone might want a large serving dish with all of the first grade kids names written on it.
I decided to try out these underglaze markers that I have seen in various catalogs etc. So here is my review.
I tried the black one first. After ample shaking and pressing down to get the tip to fill with the glaze - there was little result. I did this again several times and finally the tip filled up. I did a test on a blank white already bisqued 4x4 tile. The pen made nice dots when using it to simply press down, but as a pen to actually write - became almost immediately dry and I could not get a clean line. I could in no way use this as I would a marker. The tip was too fat and fluffed up to write anything clearly. Part of the tip was no longer stinking out very far, due to having to depress it so many times to get the glaze to fill the tip.
My results were basically the same with the red marker - only worse. It too was not liquid enough to get any sort of a clean line. It looked like a kids writing with an old dried up marker.
Basically I would not recommend these markers. Back to the old pin tipped bottles, or a nice lean brush. Sorry Glaz-eze.... not so eze for me.