Conti Prestina Espresso Machine Restoration 101 (Completed and Indexed) - Page 65

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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rotchitos

#641: Post by rotchitos »

great restauration, drgary
can you give me the weight of this conti, please.
thank you in advance.
http://machines.cafeslevier.free.fr/
I look for persons to translate into English one or + pages of my site... :-)

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drgary
Team HB

#642: Post by drgary »

Hi Vincent:

I don't know the weight of the whole machine, especially now that there is water in the boiler. I can only guess 70 pounds or so. I am able to lift it. If you have one in your sights, buy it!!! Then you may be puzzled what to do with the rest of your collection.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

cafebmw

#643: Post by cafebmw »

regarding boiler insulation:
on my gaggia orione i used 1/2" industrial wool felt. kind of hard to come by and in larger quantities expensive, but superb workabilty and insulation. i bought mine in the eastbay, i think in hayward.
on my 1954 i used automotive kevlar insulation, 'ThermoTec'. i plan to run the machine on gas (propane or natural), therefore i needed a high heat barrier.

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rotchitos

#644: Post by rotchitos »

drgary wrote:Hi Vincent:

I don't know the weight of the whole machine, especially now that there is water in the boiler. I can only guess 70 pounds or so. I am able to lift it. If you have one in your sights, buy it!!! Then you may be puzzled what to do with the rest of your collection.
really really :!: :?:



thank you :wink:
http://machines.cafeslevier.free.fr/
I look for persons to translate into English one or + pages of my site... :-)

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drgary
Team HB

#645: Post by drgary »

:lol: Recognizing that you have an amazing collection ... you'll really love the coffee it makes. And with that box left off the group it's pretty steampunk. When I told Barb Garrott I had a chance at one for not much money her response was:

"BUY IT! And if it's too much for you to deal with, buy it for us!"
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

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drgary
Team HB

#646: Post by drgary »

Drip Grate Progress

I didn't know I could cut stainless steel with precision until I managed to do it. Today I successfully cut the top plate for the drip grate. Here's the template on the steel that's protectively coated. I worked with the template until it was exactly the right size for the hole pattern and coverage I want.

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And the template traced onto the steel coating itself, creating cut lines. I used a Sharpie marker for those.

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I learned that a jigsaw is a perfectly adequate tool. Here it is in place with the steel well clamped. The secrets to success with the jigsaw are letting it do the work (not forcing it too fast), knowing that I can hold it place and turn it slightly to make sure the cut is right on course, and changing to a new blade the moment it starts to buck, which isn't extreme. I wore leather gloves and a full face mask for safety. I'm also holding the steel firmly and avoiding scratches by using flat wood held in place by the actual clamps.

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The cutting went fairly quickly, about five minutes for each actual cut. Most of the time was spent setting up the clamps. Here's the successful first cut.

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To make the perpendicular cut I drilled a hole in the corner, carefully aligned and just large enough to fit the jigsaw blade. I began with a Starrett B automatic center punch, which is strong enough and hard enough to dimple steel. If you're not familiar with these, you place the point, then push the end hard with your hand. It's spring loaded and releases to create the dimple. This is one of those tools that isn't right unless you get the high quality brand. I got this one used on eBay of course!

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I used two sizes of carbide bits to drill the hole, carefully.

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This allowed the other two cuts to create the top plate that will extend the drip grate further back.

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The finishing work before getting this welded in place is to file the edges smooth, being careful to not mar the upper surface. I've left some extra steel inside the cut lines so I can carefully fit this to the drip grate holes.

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I've also been working on plumbing in the Sirai PSTAT. It is a tight fit. I'm still struggling a bit to get one of the sweated compression fittings to completely seal, so will solder that again. I'm also following Doug's suggestion to use ties to brace the PSTAT in addition to the pipe that also holds it in place. This is just the first try for leak testing. I think my final assembly will use cable ties.

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An odd element here is the vacuum breaker. It releases a lot of steam and water through the tube before settling down. At first I thought it was malfunctioning but I'm thinking of asking Doug his opinion on a vacuum breaker he tried a few pages earlier, which doesn't seem to need the escape tube. I've not heard of other machines venting so much water just to release the air gap. If I turn the T fitting I may be able to use the existing manometer bracket. In my plumbing layout the vacuum breaker could fit the top of the manometer knuckle and the T fitting attaches to the bottom with the OPV attached sideways and the PSTAT pipe connecting to the bottom of the T.

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Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

jonny

#647: Post by jonny »

I had to go back and see how the piping is arranged. At first I thought it was because the vacuum breaker was mounted below the water line. Now I see the pipe comes down from the top of the boiler. Because of this downhill section, I would wager a guess that water is pooling around those fittings for the manometer, pstat, etc. and when the boiler starts coming up to temperature, the air pushing through that pipe is making the pooled water spit out of the vacuum breaker. If it could be done (I can't tell if there is room for a T fitting or not), the best fix is to mount the vacuum breaker at the top of the "hill" i.e. before that pipe. If that can't be done, you may also get a more acceptable exhaust just by raising the vacuum breaker valve a few inches. This would at least make a little more room for the pooled water to sputter around inside the tubing and hopefully not make it to the vacuum breaker as easily. You can find out how much water is pooling down there if you open up the pipe to the pstat after the machine has been on for a while and turned off and cooled.

I will add, that given the choice, I would absolutely ALWAYS use a barbed vacuum breaker. Over time those little, seemingly harmless sputters will scale up the outside of the boiler and threaten to rust the frame. So if you are draining it anyway, and the spitting water isn't causing other issues, I wouldn't be too concerned. But if you want to fix it, I know my first suggestion will do the trick, and the second should help, but I'm not sure how much. There's a chance the tubing could be too narrow for the air to go round the pooled water, so it just shoots it up the tube and out the vacuum breaker.

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drgary
Team HB

#648: Post by drgary »

That's great advice, jonny. It really tells me what I'm dealing with and not to worry other than figuring out what might be a little neater cosmetically. It did eventually become effective and I now have a large drip tray where it can drain.

BTW what do you mean by a "barbed" vacuum breaker? And, when I've looked inside other machines where there are wires that closely curl in several circles, is that run-off tubing for a vacuum breaker?
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

jonny

#649: Post by jonny »

I think the curled tubing you are thinking of is for manometers. I don't remember why, but it is to add extra length with very low volume, hence long skinny pipes curled up. Maybe it is just for easy hand installation in any orientation? But i thought there was a scientific reason...

I mean barbed vacuum breaker as in one that has a barbed fitting on the exhaust side to hook up a silicone tube to drain. Yours has some sort of cap fitting, no? Equally good. Just anyway to direct the exhaust to a drain is ideal. Here is what is in my Andreja and it is plumbed to the drip tray: http://www.chriscoffee.com/products/hom ... eakervalve
Also it makes for a little show as it's closing: as the machine hisses, a cloud of steam rises out of the drip tray 8)

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drgary
Team HB

#650: Post by drgary »

This is what jonny was calling a barbed vacuum breaker. Now I get it, the barbed connection at the top that holds a hose:

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This one is $12.75 at Chris Coffee.

Today I dropped by Orchard Supply Hardware and found a knowledgeable guy in the tools department so I asked him what I might be doing wrong in sweating the pipe and compression cap. He suggests that the propane I'm using isn't hot enough and says I should use a Mapp torch and heat it well. When the fitting is hot enough, assuming I've done other things right (clean surface, flux, etc.) the solder will flow right into the joint when touched on the pre-heated parts. I may be able to try that on Thursday and have a Mapp torch on hand from when I was trying to free stuck bolts long ago. :|
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!