Enamel chipping off on corners

[corsin.b]

Hello everyone,

I have been having trouble with enamel chipping off on the corner of my pieces:

It's on 2mm and 3mm steel with a groundcoat and then 2-3 layers of white enamel and then a decal transfer.
steel tiles are sandblasted before application and it has happened both when I did or did not counterenamel. Some of them have also not chipped off until days or even weeks after the last firing.

anyone have any idea what could be causing the issues?

132041320513206

[art925]

I am no expert but I will give it a go...

Have you tried making these with a slightly rounded corner instead of the sharp 90 degrees? I think I remember reading years ago that enamel does not like sharp corners, they create a stress point.

[corsin.b]

Hi Les,

Thank you for the tip.
I will have to give that a try - sounds like a reasonable conclusion!

[CJ57]

Have you tried any of the specific to enamelling forums? I’m not sure there are many experts in enamelling on here at the moment

[china]

What type of steel are you using, needs to be low carbon, unless you have very sophisticated equipment.
Do you do you own sandblasting, need to protect from rust as soon as it has been blasted, unless you are going to use straight away
Just before using you need to clean with something like Acetone. on steel remove the aris and clean the edge as well, tiny tiny specs of rust can be present on the edge and contaminate the surface.
Success in enameling any metal is cleanliness.

[corsin.b]

Have you tried any of the specific to enamelling forums? I’m not sure there are many experts in enamelling on here at the moment

I have not, I will have to do some googleing to find them :)

[corsin.b]

What type of steel are you using, needs to be low carbon, unless you have very sophisticated equipment.
Do you do you own sandblasting, need to protect from rust as soon as it has been blasted, unless you are going to use straight away
Just before using you need to clean with something like Acetone. on steel remove the aris and clean the edge as well, tiny tiny specs of rust can be present on the edge and contaminate the surface.
Success in enameling any metal is cleanliness.

I've tried different steels - actually have had the most sucess with stainless 304. I have been told stainless is tricky, but I feel like I have had the least issues with it. I do my own sandblasting and usually do use it straight away. I am pretty certain that I have gotten the metal cleanliness and surface preparation to a decent level, as I have had issues with that in the past and this feels different and really just confined to the corners. :confused:

Never heard of using acetone - might give that a go. What does removing the aris mean?

Thank you!

[china]

Aris is where two planes meet forming a sharp edge, in other words knock the sharp corner off.

[corsin.b]

Aris is where two planes meet forming a sharp edge, in other words knock the sharp corner off.

Thank you!

[alastairduncan]

Its not clear from the photos what can be seen under the chips. Is it bare metal or is it white enamel?

[corsin.b]

Its not clear from the photos what can be seen under the chips. Is it bare metal or is it white enamel?

It chips off all the way to the bare metal, albeit with some white enamel showing as well.

[alastairduncan]

How do you pick up the item? Do you touch it at all with your fingers and if so is it by the corners?

Just trying to rule out possible problems.

I've had some chips on the edge even when it has been rounded using wet packing and picking up with fingers. When I've used champleve technique its not been a problem as there is a metal edge right around the item so fingers don't touch where it's enameled.

[corsin.b]

I do pick it up with fingers, wearing gloves. I'll have to pay more attention to it but I think I tend to pick it up by the sides rather than the corners.