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Unglazed underglaze pencil signature


Stassclay

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Posted
hi everyone! Thank you for your advice in advance. 

I’ve been signing the bottom of my pieces in blue and/or black amaco underglaze pencils. I noticed that some of them smudged and left some color on my finger when I rubbed it, after glaze firing. Is that harmful? Or is it ok since it went through a glaze firing? Can that piece still be safely handled/touched? I am specifying that my pieces are not food safe to my customers. Is that enough?
 
Btw, I am not signing my work with underglaze pencils going forward, just wondering about the pieces I’ve already sold or given away.
 
thank you for any thoughts!
Posted

According to the SDS sheets from Amaco, if there’s transfer you should just wash your hands. Links here for black and here for blue. They’re pretty benign, and any precautions mentioned seem to pertain to an instance where your pet ate a pencil, or similar. Even then it’s just “give them some water or milk and keep an eye on it.” 

The good news is that  durability thing seems like a nuisance problem at most. The amount of transfer from your signature isn’t enough to worry about. 

Posted

Thank you Callie! I’ve read the safety sheets actually and that’s  what made me wonder. If they are saying wash your hands if pencil comes in contact with skin, does that mean I need to tell my customers to wash their hands after handling my pieces?? Haha 

I wish I knew how much of the pencil powder is actually harmful, vs nothing to worry about. 
 

thank you all for your thoughts. 

Posted

SDS’s for the underglaze pencils are next to useless. Logically they are going to contain clay (kaolin or ball clay), some flux and silica, probably an organic binder and then the colourants. We know the blue will contain cobalt either in stain form or oxide, might have some modifiers in there too. Black could be a stain or made from raw materials possibly including cobalt, manganese, iron, copper and possibly chrome. Thing is this is going to be the poison is in the dosage situation. Eat the entire pencil and there might be an issue, a bit smudging off your signature is not going to be. I would take a piece of wet dry sandpaper and using it wet sand off any that smudge. Going forward the high temp brown china markers are inexpensive, have only iron as the colourant, and don’t smudge when fired, might be an option for you. 
https://www.nordisco.com/products/dixon-phano-china-marker-brown-hi-heat-95-00095-box-of-12 

  • 4 weeks later...
Posted

Thank you all so much! I was hoping to find these Dixon Phano China Marker Brown Hi-Heat pencils in black…but they weirdly seem to only come in brown. 

Posted
13 minutes ago, Stassclay said:

Thank you all so much! I was hoping to find these Dixon Phano China Marker Brown Hi-Heat pencils in black…but they weirdly seem to only come in brown. 

They seem to come in black in the UK
image.png

This seems to be their US site, and the "Buy Today" button seems to link to several US suppliers.
Dixon Industrial Phano China Markers
https://dixonwriting.com/product/dixon-industrial-phano-china-markers/

Posted
24 minutes ago, Stassclay said:

Seems like colors other than brown are not hi heat…from what I can find. 

Looks like you are right .................................................................↓↓↓
image.png.a7d10dc54f29a80eb16fd999c51d84ca.png

The High Heat version is available in Brown only. The marks remain visible up to 1093°C.

... I assume because the brown uses iron oxide as the pigment.

 

Posted
3 hours ago, PeterH said:

The High Heat version is available in Brown only. The marks remain visible up to 1093°C.

I’ve used Dixon High Heat brown pencils for about 20  years to mark test tiles. Visible to cone 7, I haven’t used them higher than that but I would imagine they would go to 10. 

Posted

Do you guys think it’s safe to use the pencil indoors? Is there danger of producing too much pencil dust if I draw pretty detailed designs on bisqued stoneware and fill some in  ? And any special ways to clean up the particles that may fall on to the table? 

Posted
53 minutes ago, Stassclay said:

Do you guys think it’s safe to use the pencil indoors? Is there danger of producing too much pencil dust if I draw pretty detailed designs on bisqued stoneware and fill some in  ? And any special ways to clean up the particles that may fall on to the table? 

This says that they are PMA Certified Non-toxic
Dixon Industrial Phano China Markers https://tinyurl.com/3ve9zxyh

This discusses the certification standard
Pencil Certification  https://tinyurl.com/2p84e4p9
The PMA Certification Program ensures that only pencils manufactured from materials that are free from toxins and do not cause harmful effects if chewed receive the seal of approval.

As always  beware of dust inhalation, but I don't expect it is an issue here.
 

Posted
2 hours ago, PeterH said:

This says that they are PMA Certified Non-toxic
Dixon Industrial Phano China Markers https://tinyurl.com/3ve9zxyh

This discusses the certification standard
Pencil Certification  https://tinyurl.com/2p84e4p9
The PMA Certification Program ensures that only pencils manufactured from materials that are free from toxins and do not cause harmful effects if chewed receive the seal of approval.

As always  beware of dust inhalation, but I don't expect it is an issue here.
 

Sorry! I meant amaco underglaze pencils, not these special phano markers, which seem more eco friendly.

Posted
4 hours ago, Stassclay said:

Do you guys think it’s safe to use the pencil indoors? Is there danger of producing too much pencil dust if I draw pretty detailed designs on bisqued stoneware and fill some in  ? And any special ways to clean up the particles that may fall on to the table? 

I wouldn't have the slightest hesitation using underglaze pencils indoors. They are not chalky/crumbly so I can't imagine how you could create enough dust to be of concern.

Posted

Years ago, I forgot to wax the bottom of a teapot, and had to sponge off the glaze after dipping. In the process I also removed my signature. (Which I made with an Amaco underglaze pencil.)

I found that moist bottom made it much easier to write my name. The porcelain slip surface is already smooth but the added moisture allowed the pencil to glide over the surface. 

Posted


my comment:  I use a water-iron oxide "ink" to make my identification mark.  apply the mark to greenware when the item is ready to go to the bisque kiln.  This makes a mark that does not wipe off during the glazing steps.  Early on I used underglaze pencils and/or liquid underglazes; switched to an iron oxide and water ink which -- cheaper than  underglaze.

LT
 

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