Help! Pinging mugs :-(

[Katy W]

Hello, I'm new to the forum but have been reading it a lot and have just bought the DF1 press from BMS and a Ricoh 3110 printer (and BMS mugs). I made my first mug yesterday and it looked great, so I went to make a cup of tea in it and as I poured the boiling water in it pinged quite loudly and a long horizontal hairline crack appeared in the glaze about 4mm up from the base.

I have since made another two mugs and one of these also pinged ominously as I poured hot water in to test it and has a similar crack.

I have been heating the press up with a scrap mug in first and cooling with a fan. Having read all the posts on here about how cooling the mug too quickly (in water) causes problems with cracking, I'm wondering if heating the mug too quickly (from room temperature to 170 in the press) could cause the same problems. Do people generally heat the mugs first and could anyone advise me on the best way to do this? I'm thinking a portable electric hob with a single ring (too hot?) or a food warmer with candles (the mugs won't fit on the radiator).

Any help would be much appreciated!

Thanks, Katy

[pisquee]

Maybe the mugs were slightly damaged in transit (from manufacture - BMS - to you) but not enough to show until put under pressure and/or heated.
Maybe your press is too tight?

[bms]

Hello, I'm new to the forum but have been reading it a lot and have just bought the DF1 press from BMS and a Ricoh 3110 printer (and BMS mugs). I made my first mug yesterday and it looked great, so I went to make a cup of tea in it and as I poured the boiling water in it pinged quite loudly and a long horizontal hairline crack appeared in the glaze about 4mm up from the base.

I have since made another two mugs and one of these also pinged ominously as I poured hot water in to test it and has a similar crack.

I have been heating the press up with a scrap mug in first and cooling with a fan. Having read all the posts on here about how cooling the mug too quickly (in water) causes problems with cracking, I'm wondering if heating the mug too quickly (from room temperature to 170 in the press) could cause the same problems. Do people generally heat the mugs first and could anyone advise me on the best way to do this? I'm thinking a portable electric hob with a single ring (too hot?) or a food warmer with candles (the mugs won't fit on the radiator).

Any help would be much appreciated!

Thanks, Katy

Hi, the recommended instructions provided are an idle temp if 110, operating temp
of 170 and time of 140. Put mug it at idle temp and start cycle, when time reached we normally cool
the mug in a bowl of water. Pressure should be such that the blanket is tight around the mug and the blanket may start to form over the top and bottom of the mug.

[James990]

Hum, interesting. I have never had one ping on me!

[Katy W]

Thanks very much for the replies. Bms, when you say I should put the mug in at idle temperature, does that mean I have to let the press cool back down to idle temp between each mug? I was hoping to put them in one after another without waiting in between.

I have since tested another four straight out of the box, without pressing them, and two pinged and I have two more cracks. Although these aren't obvious to start with, when the mugs have been used and washed up a couple of times, the crack goes brown.

I'm thinking Pisquee is right and maybe they've been dropped, or there's a problem with the glaze not being compatible with the ceramic and they're expanding at different rates - but then everyone else would be having the same problem!

[bms]

Thanks very much for the replies. Bms, when you say I should put the mug in at idle temperature, does that mean I have to let the press cool back down to idle temp between each mug? I was hoping to put them in one after another without waiting in between.

I have since tested another four straight out of the box, without pressing them, and two pinged and I have two more cracks. Although these aren't obvious to start with, when the mugs have been used and washed up a couple of times, the crack goes brown.

I'm thinking Pisquee is right and maybe they've been dropped, or there's a problem with the glaze not being compatible with the ceramic and they're expanding at different rates - but then everyone else would be having the same problem!

It's unusual to get a problem in transit - I presume you had a case of 36 mugs which are all bubble wrapped to protect in delivery. The second and subsequent mug can be put in straight away so you don't have to wait for it to return to the idle temp I'd think the problem must be local (delivery problem or something related to pressing) - next time you order we will replace mugs for you so don't worry about that. The important thing is to resolve the problem.

I would offer 2 pieces of advice for now - (1) to reduce the operating temp to 165 degrees and increase the time to 150 seconds and/ or (2) slacked off the pressure a little so the mug is still held firmly but not so tight keeping the original time/ temp settings.

[Katy W]

Thanks Bms. The latest four I tested hadn't been through the mug press but two still pinged with hot water so I'm thinking I might have a faulty batch. I have another 3 boxes of 36 so I'll test some from each box, with and without pressing.

I have reduced the temperature as you suggested and also loosened the pressure but then I got a faded edge, aargh! It must have been just tight enough before.

Apart from that, the prints look great!

[SmokingGun]

I received batch of mugs from magic touch and had a few ping whilst in heat press, not happy !

[NikGrey]

Have you checked the actual temperature of your heat blanket?
You will need an Infra Red Thermometer for that, everyone in this business should have one as standard equipment.

[pisquee]

Have you checked the actual temperature of your heat blanket?
You will need an Infra Red Thermometer for that, everyone in this business should have one as standard equipment.

You say that, and I do agree that having one can be a good thing, but it does seem to be a more recent development of people buying them in, and most have survived without for a long time.