Gaggia Orione restoration - Page 5

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
User avatar
Paul_Pratt (original poster)

#41: Post by Paul_Pratt (original poster) »

Cleaning up the boiler flanges and other surfaces

Right, to get them ready for the gaskets I like to get them nice and true and since I will be using teflon they need to be immaculate. Teflon is great, but it is also quite unforgiving if your metal surfaces are pitted or have big scratches in them.

So today I was getting the sight glass assembly ready, I used the same procedure I used for the main boiler plate flange and the group neck flange on the boiler - go back a few posts to see the results. Basically I sand them down - this procedure could also be called "poor man's head skimming" to use an auto term.

The first step is to remove all the old gasket material, I like to use sharp wall paper scrapers or stanley blades. Doing this under running water keeps the dust down. Then you need to get some emery cloth or sandpaper. I wouldn't go too coarse but start off with something like 120, then a 240, and finish with a 400.

Lay the paper on a flat surface, it needs to be very flat for this to work. Preferably the paper should be glued or taped to the table so that it does not move. Then you put your part on the table and obviously the surface you want to clean and finish contacts the sand paper. Like this...

The idea is you move the part back and forth on the paper and slowly sand the surface. Imagine the old days of people scrubbing laundry on a washing board. Don't press down too hard, let the paper do the work. This takes time, don't expect a few swipes and it is done. You can also use some cutting fluid (e.g. Rocol) to lubricate the paper, or I guess water would work too.

Once you think the surface looks even, go onto the next finer grade of paper. Anyway here is my sight glass assembly after about 5-10 mins.

It is not too bad, you can see that the casting is actually a bit warped since the edges still have some nickel plating whereas the the inner sections are showing brass.

So that is it, if the part is too large to move on the table then you can always use a flat block of wood, wrap the sandpaper around it and try and sand the metal flat.

Making gaskets

So I had a go at making the teflon gasket for this sight glass. This is 1mm thick teflon sheet, which is not too bad to cut. When you get to 3mm it is hard to cut. Luckily I was able to get the old paper gasket off in 1 piece and can use it as a template. Otherwise I was going to use the glass itself as a template.

I roughed out the basic shape in the form of a rectangle. Then I laid the paper gasket onto the teflon rectangle and taped it together as best I could. But how on earth could I accurately cut the rounded shape on the inside???

Then I had an idea to use a drill to drill holes at each end. I discovered the gap inside the gasket was 15mm therefore a 15mm drill bit would produce the exact same shape as the ends.

After that it was just a case of joining up the holes with a sharp scalpel and cutting the rest of the outer shape as well. It wasn't the most accurate of cutting jobs but it works......

After that I assembled the glass and tested it with water, I flushed it first by running the water through for a few minutes and then capped off one end whilst the other end was still connected to the water supply. At mains pressure of 2 bar there were no leaks. Job done.

The last job for today was starting to sort out the chrome pieces. I need to determine which pieces are reusable and which need to go for rechroming. I have said earlier that the chrome on the group is good, in fact a lot of the chrome is in good shape.

The first job was to clean all the oil and coffee away by soaking in in a backflushing detergent.

After that I was left with this.

The corroded parts were put to one side as they will go for rechroming. But I was also left with a lot of parts that looked good but have a few scratches and dents. So I decided to try and polish them out in exactly the same way you buff out steel. You can be quite brutal with chrome as long as it is thick, and this chrome plating looked very thick. If it is not thick you will buff it right off and be left with brass.

Anyway my hunch paid off and the chrome buffed up very well using my polishing wheels. For example here are two of the steam valve levers, they looked rubbish but buffed up very well.

As did this steam valve.

So now I have a problem. 90% of the parts polished up well enough not to require new chrome. That is great because it means I will have a lot of original parts left on the machine, but it also means I do not have enough items to justify a trip to the chrome platers yet.

Delaying this project whilst I wait for other parts is not an option as I want to finish it. I do have other machines waiting to be restored so it may mean I will have to take parts off yet to be restored machines so I can get a good quantity of pieces together to rechrome.

I shall have a think about it and see what other parts I have from other machines that can be done.

User avatar
Team HB

#42: Post by drgary »


Thanks for that great tutorial on gasket fitting, surface prep and polishing. My Prestina thanks you too!

What I WOULD do for a good cup of coffee!

User avatar
Clint Orchuk

#43: Post by Clint Orchuk »

Paul, which compounds and wheels do you use to polish chrome?

User avatar
Paul_Pratt (original poster)

#44: Post by Paul_Pratt (original poster) replying to Clint Orchuk »

No problem I'll take a few pics tomorrow if I get a chance.


User avatar
Clint Orchuk

#45: Post by Clint Orchuk »

Thanks. I'm getting great results polishing aluminum using black on a sisal wheel (or gray on a stitched wheel if it's not too scratched), then tripoli on a stitched wheel, followed by white on a loose cotton wheel. Haven't tried chrome yet, but I've got a bunch of it I'd like to polish.

User avatar
Paul_Pratt (original poster)

#46: Post by Paul_Pratt (original poster) replying to Clint Orchuk »

That's probably roughly the same as me. On sisals I use a brown cutting, green cutting and then finish with a white on loose cotton. When I have visited the pro polishers they have a first step on very badly scratched panels. They coat sisal mops with glue and then roll them in some grit, I think it was carborundum grit. This is rock hard.

The polishing motor makes all the difference, I have a professional buffing motor that never loses torque no matter how hard you push it. A bench grinder will just stall.

User avatar
Randy G.

#47: Post by Randy G. »

When I was teaching, on summer temp job I had was at Whittaker Controls working in the parts room. If you do not know the company, their fluid control valves (fuel, air, etc.) are on many, many aircraft from private to commercial to military. Air-to-air refueling couplings was one of the things I saw. Some of the valves dealt with chemicals and others with heat, so the internal seals had to be dependable. They used carbon (graphite?) piston rings on the operating pistons in these valves. These had to be hand finished for proper thickness. The techs would use something like 1200 grit on a 3 to 4" think granite slab. Their motion was a figure 8 and they would often stop, turn the piece, and repeat. Then the other side was done the same way until the correct thickness was achieved. This kept the surfaces parallel. Considering that lives depend on the proper operation of some of those valves, as an occasional air passenger, I appreciated it.

Other polishing compounds that are sometimes overlooked are aluminum oxide powder and flour of pumice. The aluminum oxide on a piece of leather can be used to stop a blade or polish other hard surfaces. The flour of pumice can be mixed with water or oil (I use WD-40) to polish metal surfaces by hand.
* 22nd Anniversary 2000-2022 *

User avatar
Paul_Pratt (original poster)

#48: Post by Paul_Pratt (original poster) »

Thanks Randy, I also remember seeing a video of using pumice to polish items.

Sadly I have done hardly anything this week. I did manage to dismantle the lever group completely and get the parts ready for chrome plating.

The last part of the group to come apart was the part that the lever arm threads into and which in turn raise the piston. On the end you will see a round disc with 2 cams (spring metal strips) attached to it. The round disc is fixed to the main part with a keyway slot.

Since the main part is badly pitted it needs to go to chrome plating. But this disc would not come off at all. The lever cams came off easily. I tried for days to get it to come away but no luck. I used my bearing puller but it still did not budge. In this situation it is better to come back to it the next day rather than damage it.

So I thought about it and decided to try again with the bearing puller - I even made a special brass bushing as well so that the inner pin of the puller could push up against this brass piece. This time after locking the bearing puller on I heated the disc using a torch, then quickly I tried to cool the inner parts with water - it did spit steam a bit but it was ok.

After rather a lot of force it finally surrendered and came off.

So with that out of the way I started on getting the brass pieces ready for the chrome plater. This may seem excessive so if you have a weak stomach look away now. :roll: When you give parts for plating the workers don't really know what the bits and pieces are, as such they just use big old buffing wheels to get surfaces flat. More often than not you end up with edges that are round and pits in the surface which I do not like. So I have got into the habit of doing a lot of prep work so that I can square up edges and hopefully get an accurate part at the end.

Here's that lever part that I just took off after a quick visit to the lathe.

Here's the portafilter spouts in process. These need a lot more work since they are really badly dinged up.

These are the lever bearing covers, much like a caseback on a watch these have big gouges where someone slipped with the pliers.

And after refacing on the lathe.

One of the last pieces to take apart was the bezel on the pressure gauge. I then noticed it had a big split, the actual metal on these bezel is really thin. So I had a go at silver soldering to repair the split.

I got there in the end but it was a real PITA. The metal is so thin anytime you heat it, the solder that was there already just melts and the split opens again. After some trial and error it was ok.

And that is where I am now up to. Metal polishing tomorrow!

User avatar
Clint Orchuk

#49: Post by Clint Orchuk »

Outstanding work and perseverance Paul. I lived in HK for 8 years. Wish I had known you were there. Would have loved to drop by to see you and your shop.

User avatar
Paul_Pratt (original poster)

#50: Post by Paul_Pratt (original poster) replying to Clint Orchuk »

Yes it's a fun place, but totally crazy.

Right I had a go today at polishing a few of the stainless panels. So here is my polishing motor, it has been removed from it's little stand. The light switch on the front was an optional extra :D

The motor is 1HP but thanks to the capacitor has a lot of torque and no wind up time. I generally have 3 compounds I use. A brown tripoli compound on the left wheel, a green stainless compound on the right wheel and in the middle a white finishing compound which I mainly use on aluminium. The brown is the coarsest wax I have, you can get a black emery compound which is even coarser.

The motor is really powerful and you really have to concentrate when you are using it. No loose clothes and I never wear gloves either. Goggles and a mask are also a must.

You can find many great websites these days on polishing which will also sell you the supplies you need. Caswellplating is a good one.

So I did the main front panel first, here is the before photo...

And here it is after an hour of work.

It came up very well, there are still some swirl marks to remove but it is almost there. So to recap I started with the brown compound on a sisal mop, then went to the green compound on a spiral mop. There were not that many deep scratched so I was quite lucky. The front drain tray will be a different prospect as it is heavily scratched, I will probably have a go at the other panels over the weekend.

The chrome parts are almost ready to take to the chrome platers. I'll try and drop them off on monday.