Puck sticks to screen after screen change

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Issya
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Joined: 4 years ago

#1: Post by Issya »

I've owned a Rocket Mozzafiato for about a month and everything has been going well. I purchased an IMS screen and Cafewerks gasket to replace the stock items. At first I couldn't get the gasket to fit so just used the old gasket with new screen. My pucks started sticking to the screen. Next, I switched to the old screen with old gasket and the pucks are still sticking. Finally got the new gasket with new screen on and they still stick.

I had the sticking issue a few times in the beginning due to overfilling the basket. I now have scales and an 18g VST basket with bottomless PF. Nothing else has changed besides the screen and gasket. Although as mentioned, it started happening on the old parts too.

I dose 18 in and 35-36 out in 25-30 seconds. Sure, I could use less in the basket but how could this be happening all of the sudden?

The screen and gasket are all the way in and appear level.

def
Posts: 452
Joined: 6 years ago

#2: Post by def »

my guess is that you are dosing too much for your screen. Take your normal doze and lock in, and then remove the pf before pulling shot to see if the screen has touched your coffee bed. If not, do then do the nickel test.

Issya (original poster)
Posts: 7
Joined: 4 years ago

#3: Post by Issya (original poster) replying to def »

Thanks for the reply. That seems to be the general consensus but I wonder why it would happen all of the sudden? Sure, it could make sense with the new screen but it shouldn't be happening with the old screen which it didn't have an issue with before.

def
Posts: 452
Joined: 6 years ago

#4: Post by def replying to Issya »

Using the exact same coffee throughout all of this? 18g light roast has less volume than same dose of dark roast.

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C-Antonio
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#5: Post by C-Antonio »

Possible that the screens previously were fitting differently than how you put them back on? Since you own it from a month this could be the first time you removed the screen from that machine in which case I would be inclined to think that they came in one way from factory but somehow you dont put them back in the same way (if that makes sense)...when you fix it on the machine is the position of the portafilter handle as before or it changed?
“Eh sì sì sì…sembra facile (fare un buon caffè)!”

Issya (original poster)
Posts: 7
Joined: 4 years ago

#6: Post by Issya (original poster) »

That was also a thought but it seems there is only so much they can go up.

The stock gasket with either screen is easier to put on. It is obvious which side of the gasket goes against the GH. I tried both sides, the proper side allows the PF handle to get to the 7 o'clock position as it always has. The incorrect side of the gasket allows the PF handle to get to 6 o'clock.

The CafeWerks gasket was extremely difficult to get on. I reverified that both the screen and gasket are the correct size for my machine. It finally went on but the PF fit is very tight. It doesn't go much beyond the slots after putting it on. In that case, wouldn't it mean that the basket is further away from the screen than before? Note that I did clean around the GH before reinstalling the screen which was not very dirty.

I made 3 shots this morning at 18 grams each in the 18g VST basket. Each at 18 in and 35-36 out at around 30 seconds. Inserted each one into the GH then removed before turning on. None of them had any markings from the screen. The first didn't stick while the rest did.

I also ran grindz through the grinder and back flushed the machine while changing the screens but that shouldn't cause sticking.

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C-Antonio
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#7: Post by C-Antonio »

test with the coin also as Def suggested earlier... the puck expands when you brew and you want some headroom
“Eh sì sì sì…sembra facile (fare un buon caffè)!”

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truemagellen
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#8: Post by truemagellen »

Or your scale is failing. This happened to me before. I was dosing way under like 15 when i was trying to hit 18.

If you prove it is not that then your magic number is 16.6 grams.

Silentsim
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#9: Post by Silentsim »

def wrote:my guess is that you are dosing too much for your screen. Take your normal doze and lock in, and then remove the pf before pulling shot to see if the screen has touched your coffee bed. If not, do then do the nickel test.
This is what I would check as I had this issue

Issya (original poster)
Posts: 7
Joined: 4 years ago

#10: Post by Issya (original poster) »

Thanks for the replies everyone.

Put the PF and it does not touch the screen. Also tried the nickel test and the nickel does not touch the screen.

Someone else suggested dosing higher because there may be too much water when suction happens causing the puck to come loose. It's unfortunate that this would all the sudden become an issue even when using the old screen. I also read that although an 18g VST can take higher doses, it is best to stay at 18g.

I will also try charging the scale but the actual tamped dose appears to be at the same depth in the basket as it always has.

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