I have started a new thread for this as the old one (New tile etching) was getting a bit long in the tooth. I previously developed a titanium dioxide mix using PVA glue as the binder. Recently many of you have been experimenting with Gum Arabic. I just had to try it for myself and compare it to my original PVA mix. Here are my findings.
First I have to say Gum Arabic is nice to work with and now I have got the recipe right I’m achieving some nice etched tiles. Here is an image of one done today.
This is my recipe.
Distilled water 200g or approximately 8 fluid ounces (heated in microwave) must be very hot.
50g gum Arabic (food grade)
50g titanium dioxide
Half teaspoon glycerine approximately 3g
Total weight 303g
I used an electric hand whisk and let it settle to get rid of air bubbles. Painted with brush and left to dry. Do not use hairdryer to speed up drying. Gum Arabic mix flakes off the tile when dryed this way.
Speed 1200 mm a minute, power 80% on Atomstack A5 with upgraded 10 watt diode laser head.
I hope this information is of help to others trying to etch tiles.
I do like the easy way this latest mix works. I will in future use this as apposed to my PVA mix. Main advantage is I’m getting a smoother cover on the tiles and it just rinsed off under running water from the tap. Inexpensive too.
I’m not sure glycerine is essential. I have use a recipe recommend of making water colour paint. It said it helps the pigment to stay suspended so thought it would do the same for the titanium dioxide in my recipe.
One other thing that seems important is cleaning the tiles before coating. This mix may work better with a few drops of washing up liquid.
200gm is about 200 mL water on my scale. Add 50gm gum Arabig to very hot water gave me a chunk of hot rubber. Should this have been 5gm instead?
I tried 1 and 2 coats with the same result: The air downdraft peels the coating up from the tile once some is lasered. in other words, adhesion of the coating is too weak. Am I the only one having this problem?
I will admit this mix dries fairly flat without ridges.
Sorry I didn’t answer your question. No the 50mg is correct. Did you add the gumarabic slowly while stirring the water? Even so it should have disoved in time. As for the flacking, was the tile clean before coating?
This is always going to be a problem as you guys across the pond have different names for things to us English guys. A salt pot here is a small vessel with a single small whole in the top. We put salt in them and sprinkle salt over our meals. Using one to sprinkle gum Arabic powder gives you total control over how much is added to the water and gives you time to stir it in slowly. Our measurements also differ, so do remember to make any necessary adjustments.
My laser head also has air cooling but does not affect the coating. It’s just a gentle breeze. Air assist on my machine is a jet of air aimed at the laser beam to remove charcoal etc. When engraving wood. This is never used when etching tiles.
There is a Youtube out there for the Sculpfun air assist. He has a bowl of water inder the nozzle. Without assist, it is blowing the water all over the place. Air assist blows it out of the bowl. No gentle here.