Huge problem after finishing (excessive heat)

mazengh

Well-known member
We had a huge issue today that we only noticed after about 8 hours from the time we packed the magazines (10 signatures 8 up wood free uncoated paper 80gsm) in boxes ready for shipping. The boxes were very hot on the outside and when we opened the box, the issues inside were EXTREMELY hot. We never seen the issue before. Since the magazine was to be shipped by air, we unpacked all the boxes and placed all the issues in a well air conditioned special room, to cool the prints down. Have anyone experienced something like this before? Please find below how the prints were produced.

Printed on a 5 color heidelberg speedmaster 102 CD. Flint F918 BIO ink + Flint 8866 protection varnish on wood free uncoated paper 80gsm. The cover printed on coated glossy paper 250gsm and laminated glossy. no drier was used, and minimal varnish was used(15kgs for 66000 impression paper size 60 x 90 cm). The job was then folded on stahl machines and perfect bound on a muller martini tigra perfect binder. Also note that the fountain solution used was Saphira 510 pure with 5% IPA.
 
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My it's getting Hot!

My it's getting Hot!

Hi Mazengh,

Heat is generated during the Oxidation/Polymerization setting of Litho Inks.



Regards, Alois
 
Print that is over-heated can self-combust.

You have witnessed a near-miss of this, it can be very dangerous.

I presume you are running heat-set?

Maybe your heat controller/sensor is out of calibration.
 
We are running coldset, and without a drier... just overprinting a sealer varnish over ink. It felt VERY dangerous, and it was to be shipped by air, so we are very concerned about this issue for future jobs...

Print that is over-heated can self-combust.

You have witnessed a near-miss of this, it can be very dangerous.

I presume you are running heat-set?

Maybe your heat controller/sensor is out of calibration.
 
Brings new meaning to "HOT OFF THE PRESS" ....

I believe it is just straight sheetfed not heat-set disappointed.
As to the reason for this happening, Interested to find out why & how such a problem could arise.

Perhaps the varnish has a high level of linseed oil or another drier catalyst in it.
The 918 supreme bio ink from memory doesn't contain many driers in it.
 
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Brings new meaning to "HOT OFF THE PRESS" ....

I believe it is just straight sheetfed not heat-set disappointed.
As to the reason for this happening, Interested to find out why & how such a problem could arise.

Perhaps the varnish has a high level of linseed oil or another drier catalyst in it.
The 918 supreme bio ink from memory doesn't contain many driers in it.

Ok, thanks, my experience has been with heat-set sheet-fed which was my assumption.

In that case it is more likely to be an oil or chemical reaction issue, it is still a serious matter though, maybe time to get the ink people in for a chat?
 
Ok, thanks, my experience has been with heat-set sheet-fed which was my assumption.

In that case it is more likely to be an oil or chemical reaction issue, it is still a serious matter though, maybe time to get the ink people in for a chat?

I feel it's a chemical issue. As support is not available, I am considering switching to other suppliers for ink and varnishes.
 
The fact that it was folded and bound and still got hot would point to a chemical reaction, possibly the ink reacting with the varnish.
 
we've used the combination before on thicker paper (120gsm vs this job 80 gsm) both uncoated. and we also used it on a coated 115 gsm paper, and we didn't have this issue...
 
Maybe the thinner paper having less body to soak the ink up, has allowed the total volume of ink on both sides to combine and re4ach a critical point.

As you say, if you have used the products before, but not on this stock, it could well be this reason.

Does the press not have IR drying or was it just not used on this job?
 
The press has an IR dryer but it was not used on this job...

PS: on a side note the Total are coverage was high...
 
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The press has an IR dryer but it was not used on this job...

PS: on a side note the Total are coverage was high...

Then it can only be chemical reaction, especially as coverage was high.

Probably would not happen if the first run was 100% dry, but in the real world.....
 
Probably just an effect of the lightweight paper and the varnish polymerizing, its a chemical reaction and can generate heat.

Looks like a good varnish though :)
 
i always try to use the best, but in this case even the best is not compatible... glad no damages or injuries occurred.
 
Didnt the guys in finishing notice any heat and you would have thought that going through a couple of other processes someone would have said something.
 

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