Oven inconsistencies

[Mlef]

Hi everyone,

first post since I’m getting very desperate and know a lot of threads by heart now. If I sound incoherent and like a mad woman, that may be right, I’m about 5 mug boxes along with barely a box of acceptable results.

I have a gigant mug oven and am currently using sublistar mugs. Always used duraglaze in the past but my supplier is discontinuing them.

I get very inconsistent oven results. A batch of three can have a near perfect, a mediocre and a terrible mug.
In the past I had a lot more luck with the oven but I’m not sure if that was the discontinued paper I was using back then in combination with duraglaze. To me duraglaze is like a forgiving mother that even when you messed up your temp or time (too high, too long) will at least provide you with a sharp looking image.

The design I’m working with now is a solid colour teal-ish green. Not sure if that’s what causing issues to surface more prominent.

if I use my regular setting of 185 degrees, the print turns yellowish, faded and blurred. Turning temp down really gives me better results and using my grill-eye pro it seems the temperature on the oven indicator is about 15 degrees lower than on the probe. Bringing the temp all the way down to roughly 160 on external temp and for a long time can at one point give me lovely results and the next batch have hardly transferred.

Basically, I can have a batch of two seemingly come out as perfect, then do the exact same thing again, same temp, time etc, and get a terrible transfer.

Wraps;
the mug wraps are of the red kind that need a machine to clamp. They all had roughly 100-150 mugs on average. I also tried some new ones but didn’t see any improvement. However, I am curious now how I can find out if the mug wraps are getting old or bad and I’ll test and compare these some more.

Mugs;
I think the coating is less hard than I’m used to, but they give me fine results in the mug press and also when the oven feels like it.

ink and printer;
new sg1000 model with sawgrass UhD inks. Think twice before purchasing it already, they’re currently testing because my supplier and I find the dithering worse than on the previous models for certain colours.

paper;
neenah Jetcol. Have tried s-race as well. S-race gives me terrible results but I’ve never been a fan. Jetcol is a very high release paper.

I usually use my handpress as a test, results there are fine, dark, sharp prints at 180/180.

I’m extremely grateful for anyone that can think with me here. If you have any suggestion of things to try for me with my current setup I’m happy to do so. I also have a bunch of spare duraglaze to test and compare if any very experienced people here can rule variations out that way.

My hardware supplier considers the heat distribution being sub par and will test my design in their 140mugsatatime oven. However, that will be their mugs, their paper and their quality check. So I’ll await and share those results. If I knew it was my oven for sure, I’d replace it in a heartbeat since I’m slowly but surely going insane.

Thanks for reading, and even if you don’t have any suggestions, some words of empathy will do as well the struggle is real.

[Mlef]

Also; I had some weirdly good results leaving the wrap on after taking the mugs out of the oven. The only issue being that the coating gets sort of damaged in the process by leaving very small vertical stripes all over. Perhaps due to the shrinkage of the wraps? I can’t quite explain why leaving it to cool with the wraps for a few minutes gives a better transfer.

[Mlef]

After some more insanity testing today it doesn’t seem the old vs new wraps make a lot of difference. Oven placement does.

random question going through my mind; will the placement matter less when adding more mugs to the basket? Will they radiate more heat to eachother?

There was some hope when I used two new wraps and they came out acceptable, but that hope was lost quickly when I started adding a mug with an old wrap and there were different results across the batch again.

[Mlef]

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I think I trumped insanity by doing the same thing over and over and actually receiving different results.

Machines will be shut down for the day. I can’t imagine I’ve been at this for weeks now and I haven’t completely entirely lost it yet. Or did I?

[socialgiraffe]

Hi Mief

Sounds like a complete nightmare...

You need to remove potential problems bit by bit. So for example, if you have printed a successful mug in a mug press it is unlikely to be ink or paper. This point to wraps, oven or mugs.


Without knowing the oven it is difficult to comment on that, but my recommendation would be to get hold of a box of Duraglaze (ring Listawood and see if they will post direct) and give them a test. You know those mugs work with your set up so you need to see if they still work. If they do then it is the mugs and I personally would recommend having a look for a different supplier.

However if they do not work then it will either be the wraps or the oven.

Bear in mind that solid colours are a pain to print using wraps and the wraps must be relatively new so they can keep a nice firm and tight grip.

Thinking as I type I think it might be the wraps. Perhaps grab a load from a supplier and give it a whirl. If you have an oven you obviously do a lot of mugs so they will not go to waste.

Let me know how you get on.

[Mlef]

Hey socialgiraffe! Thanks for thinking with me here!

I still had a bunch of duraglaze left and tried them too. Same thing, I can have two mugs in the oven where one comes out (near) perfect and the other with little ink transfer.

Funny you mentioned listawood since I contacted them last week about future orders if I decided to go back to duraglaze after this client project. They got back to me yesterday with a *gulp* pallet price of 130 pounds to the Netherlands. However, the Durham mug price is still a lot better than the duraglaze mugs from my German supplier so if I buy 1000+ I’ll still be better off. They seem very helpful too. Are they the ones that made the coating?

I started seriously doubting my previous client projects being perfect. We always had a few spots in the oven we preferred to keep empty because it seemed the mug colours were slightly off there. However the designs were multicolored and the variations were acceptable as being a handmade kind of deal.
This design is best described as a solid teal color with a white/transparent cutout.

I came to the same oven or wraps conclusion by ruling paper and mug out through the press.
Yesterday I kept doing batches of three with the two new wraps and an old one included. Results were overall good in the back of the basket but not in the front. I didn’t find any big differences between the wraps, at least not definite or shocking, it seemed to be more of a placement issue.
today I decided to do the same and then rotate the basket midway. It seemed to improve a little but still there was one with a lot of ink left on the paper and a lighter print. That was the one that ended up in the front or mostly center of the oven after the switch so I feel center to front is giving me issues. The heat fan is in the top of the oven.

Im considering trying my home combi oven that spins. Not sure about it’s temperature accuracy but it’s what I have at hand. Buying the same replacement oven is quite a gamble especially since we’re not 100% sure this wasn’t a problem we always had albeit less apparent.

I’m still awaiting my hardware supplier’s findings on the mug in their monster oven...

Any more ideas or conclusions from this story are more than welcomed. You made me feel a little less insane in my train of thoughts.

[Mlef]

Dear everyone,

I can’t express how grateful I am for this forum. I have spent countless hours gathering info here and found my duraglaze/listawood cult.

I have now found the culprit to be the mugs I had and their coating. I found a dusty old box of more duraglaze mugs and they printed exactly as I expected and wanted them to print. No more blur, no more fade, no more inconsistent results that were unacceptable.

don’t ever be me, don’t ever waste day upon day, week upon week trying to find a solution when only 1 out of 10 mugs come out correctly. Seek help.

Yesterday I spent a few hours at Technotape, my awesome hardware supplier. They started troubleshooting with me. Even though we didn’t find a solution there, we did find that we couldn’t get consistently good results with their equipment either. That basically ruled out my tools and left me with a mug or paper issue (again).

This doesn’t solve the fact that my oven heats unevenly but I honestly believe now that that is not an issue with a more forgiving, quality and thick coating like duraglaze.

Today I ordered my beloved duraglaze again directly at listawood. I also became a paid member here on the forum so I even received a nice discount!

I can’t wait to spend more time here with you all and give back to the community with any help or insight I can offer.

you all rock!