shadowfax wrote:I think that Eric has found us an awesome solution in the form of an 43 micron filter screen to go over the orifice (I believe you'll have to get the custom-made orifice Eric is also acquiring; it'll be incompatible with the LM gicleur).

The notion of using a filter has been mentioned several times in this thread. But wouldn't a filter tend to get clogged as well?

shadowfax wrote:Ken,

I hope that you have better luck with the 0.8 mm gicleur. I assume you know (or LM-USA told you) that the 0.8 will substantially reduce the "preinfusion" you get from the stock gicleur, and I am curious to see how that works for you. If you are unhappy with it (or suspect you might be), I think that Eric has found us an awesome solution in the form of an 43 micron filter screen to go over the orifice (I believe you'll have to get the custom-made orifice Eric is also acquiring; it'll be incompatible with the LM gicleur). This would allow you to go back to smaller 0.7 or 0.6 mm gicleur (Eric can probably get any size you want) if you feel inclined to. It also looks like the custom gicleur and filter will protrude about as much as the stock one from LM... IIRC that one is 20 mm, and it looks like Eric's solution will be a few mm shorter, more in the range of 15 mm.

The TL30 part has the tube with the gicleur on it side by side with the longer tube that goes to the dispersion block. In Eric's drawing, it appears that with the filter installed the diameter of the filter-protected gicleur would be considerably larger than the gicleur itself. This means that in order to use Eric's solution, you would have to either have some sort of an extension tube to get the gicleur away from the rest of the TL30, or you'd have to bend away the tube into which the gicleur screws. I don't know how either approach would work in practice and I think you would need to be prepared to make some adjustments on the fly if you tried to install it.

ken

Ah, looking at your picture:



I see you have a point. I forgot to snap a photo of mine the times I had it out, but I am not remembering it being so close to the group feed tube. Nevertheless, I do think the pickup tube should be easy to bend downward just a bit, and this is what I will do when I get Eric's part. I will be sure and document this for those interested.

After 2 days, the flow through my recently reinstalled (but virgin) stock 0.6mm gicleur went down to 380ml/minute. Having seen this movie before, I already know how it ends This suggests to me that no matter what is the cause of the repeated blockages, that simply cleaning off the TL30 and removing its corrosion will not, in and of itself, solve this problem of gicleur clogging in this machine.

My young friend and French teacher was over this afternoon for 2 hours of French conversation. He has become quite interested in coffee after spending much of the last 3 years over at my house. He'd expressed interest in watching me change the gicleur on the GS/3 before, and since the flow had already diminished enough that I knew I was going to replace the gicleur, I went ahead and did it during our conversation.

When I removed the TL30, there was no new corrosion present, which is not surprising since it was only back in the machine for 2 days. I unscrewed the gicleur from the TL30 and both of us examined it with the aid of a 10x lighted loupe (magnifier). Both of us concluded that the channel was partially blocked by some sort of debris. This is a tricky evaluation and the fact that we both reached the same conclusion leads me to believe that our conclusion(s) were correct. As before, when I did introduce a thin wire through the gicleur hole, it was impossible to be sure whether or not anything was pushed through. The hole is simply too small and the amount of potential debris too minimal to see for sure.

The new, custom 0.8mm gicleur from LM looks to be much larger (the hole inside, not the thing itself) than the original. I installed it in the TL30 and got the machine back together. The flow is enormous, between 800 and 900 ml. per minute out of the group head. Just on examination alone, I think that this larger gicleur is not going to have the propensity to clog up as did the stock original ruby gicleur.

A couple of hours later, after we had gone out for dinner and come back, I pulled us each a shot. I expected to get a gusher but in fact the extractions were fine and with the same timing as before, with the first drops of espresso exiting the bottomless PF at around 6 or 7 seconds after initiation of the shots.

I must emphasize that I am making shots that are dosed lighter than many here use, around 14g in a double basket. Given the markedly increased flow, I think it is very possible that someone else, used to updosing who changed over to this sort of gicleur, would experience significant channeling unless their basket preparation is perfect.

ken

shadowfax wrote:Ah, looking at your picture:

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I see you have a point. I forgot to snap a photo of mine the times I had it out, but I am not remembering it being so close to the group feed tube. Nevertheless, I do think the pickup tube should be easy to bend downward just a bit, and this is what I will do when I get Eric's part. I will be sure and document this for those interested.

Nicholas,

The gicleur is not very far above the bottom of the neck of the group head where it is located. What I'm saying is that there is not a lot of room in there to play around with. I'm also not sure that the pipe will bend very easily and there is a risk of breaking it. I'm sure there is a solution to this problem and it may involve using an extension piece of copper that has at least one bend in it.

If the larger gicleur that I am using turns out to work, I think it will be a much simpler solution to the problem than any other, assuming that one is still able to dose as one wishes, which I am not quite sure of at this point.

ken

Ken, I recall you weren't able to remove the gicleur last time you had the group apart. How hard was it to unscrew the gicleur? What tool did you use? It seems like using pliers would risk damaging the stainless casing.

erics wrote:I do agree with Ken - not sad that I agree with him but that the filter/gicleur combo may not fit. But the parts are ordered (~$36 for 4 sets - no problem whatsoever on this end) and we'll see. Yes, I too did not realize that the tubes were THAT close and there may exist an easy fix and may not.

The other parts, essentially duplicating what Paul Pratt did to the dispersion screw, are in and look fine.

If I'm understanding your posts in this and the other thread correctly, Eric, you're proposing a dual solution: 1) tap the dispersion screw so an easily-removed gicleur can be installed, and 2) replace the ruby gicleur with a screw-in fitting that contains a 43 micron screen. Is that correct?

Seems to me the easily-removable gicleur alone would be sufficient to solve the problem and that the screen wouldn't be necessary. Also, the screen would be difficult to access if it got blocked.

Of course, the question of how much a gicleur at the dispersion block would restrict pressure relief after a shot remains to be answered.

So... can I get one of those dispersion screw sets you're making?

Peppersass wrote:Ken, I recall you weren't able to remove the gicleur last time you had the group apart. How hard was it to unscrew the gicleur? What tool did you use? It seems like using pliers would risk damaging the stainless casing.

Hi Dick,

This is actually the THIRD time, for me. Familiarity may breed contempt, but after 3 times working on this part of the machine, it has become rather simple and straightforward.

The first time, which is when I was unable to remove the gicleur, was the one time when I did not get the TL30 part and gicleur out of the machine, only part of it as I photographed earlier in this thread. The tricky part in getting the TL30 out of the boiler is in getting the bolt out that attaches the main pipe to the dispersion block. The bolt is harder to get out than it is to get back in. Basically, you need to push it out part of the way from the front so that it doesn't need to exit the boiler along with the acutely curved portion of the TL30 which attaches to the dispersion block.

The last two times (including this one) when I did get the TL30 part entirely out of the boiler, both times it was easy to remove the gicleur. The gicleur unscrews just like most things unscrew, in a counterclockwise direction. I used a pair of pliers. There may be some tiny marks on the exterior of the gicleurs I have removed in this fashion but they are not obvious and there is no damage to the part itself. I would reassemble with a little bit of teflon tape on the threads, as this is how LM originally installs the gicleur on the TL30 and I assume they have a reason for doing so.

ken