Oven brazed Evaps

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06-09-2008, 02:18 PM
piotres

On that photos evap has been cleaned after brazing or not ?
06-09-2008, 02:57 PM
teyber

those are your evaps correct? any details of the internals?

great work...
06-09-2008, 05:43 PM
Xeon th MG Pony

Oxidation turns your oil into liquid sand paper, and will clog your metering devices and cause lots of other issues, heat transfer being the absolute least of the problems
06-10-2008, 05:30 AM
toaster

Quote:

Originally Posted by teyber

those are your evaps correct? any details of the internals?

great work...

the evaps are from cold ice ;)

nice work, philipp :)
06-11-2008, 12:41 AM
PhilippF

Quote:

Originally Posted by piotres

On that photos evap has been cleaned after brazing or not ?

I did go over it with a cleaning mesh for about 20 seconds. If I want to have extremely clean evaps, I have to use a lot more gas in cooling down. So I accept a very thin layer of copper oxide (I think some micrometers) and go over it with the cleaning mesh.

Regards,

Philipp
06-13-2008, 03:26 AM
NotSoCoolJ

Of topic sorry.
06-13-2008, 08:32 AM
godmod

And how exactly is this related to the topic?
08-20-2008, 05:21 AM
FLuxUs

Quote:

Originally Posted by teyber

oxidation is a insulator in a way, so it does hamper performance... I don't think your oxidation from leaving it out in the atmosphere is going to change your temps by 1c though alig, just saying if you braze without purging...

regards

is oxidation from leaving it out in the atmosphere different to the oxidation coming from brazing without purging?

i thought it was the same oxidation. just that the process of oxidation takes place much faster. the amount of oxidation is therefore relative.

Quote:

Originally Posted by teyber

o :P yeah that definately isn't good. you will problably need to soak it in a acid, and oven-bake it. Don't know of any chemicals off the top of my head though

a good way to clean the evaps from oxidation is to boil them in a pot with salt and vinegar. after that they need rinsing in fresh water and quick drying with a kitchen towl. its probably a good idea to dry them in the oven to get rid of the water inside the evap. they will look as new.

philipp
08-20-2008, 07:54 AM
Xeon th MG Pony

Quote:

Originally Posted by PhilippF

I did go over it with a cleaning mesh for about 20 seconds. If I want to have extremely clean evaps, I have to use a lot more gas in cooling down. So I accept a very thin layer of copper oxide (I think some micrometers) and go over it with the cleaning mesh.

Regards,

Philipp

Use a 5% Hydrogen mix in with your sheilding gas as an oxygen scavenger.
08-20-2008, 10:19 AM
teyber

Quote:

Originally Posted by FLuxUs

is oxidation from leaving it out in the atmosphere different to the oxidation coming from brazing without purging?

i thought it was the same oxidation. just that the process of oxidation takes place much faster. the amount of oxidation is therefore relative.

a good way to clean the evaps from oxidation is to boil them in a pot with salt and vinegar. after that they need rinsing in fresh water and quick drying with a kitchen towl. its probably a good idea to dry them in the oven to get rid of the water inside the evap. they will look as new.

philipp

thats very easily asking for big problems- You must do repeated rinses with very pure iso alcohal in a ultrasonic cleaner after you rinse a evap with vinegar. the acid is really bad for the compressor oil. If you don't cap off a evap for a while it "discolors" but doesn't get that, for a lack of proper name, terrible black cr*p that will flake off and possibly clog your metering device
08-20-2008, 04:15 PM
FLuxUs

Quote:

Originally Posted by teyber

thats very easily asking for big problems- You must do repeated rinses with very pure iso alcohal in a ultrasonic cleaner after you rinse a evap with vinegar. the acid is really bad for the compressor oil. If you don't cap off a evap for a while it "discolors" but doesn't get that, for a lack of proper name, terrible black cr*p that will flake off and possibly clog your metering device

well i quess my experience with copper pots, distiller parts, etc. doesnt apply then in that area. how come i never get that flaky black cr** on other copper things that i cleaned that way?:confused: thx for warning me though i would have probably cleaned my first evap that way.:eek: glad i havent had the time...
08-20-2008, 06:13 PM
Xeon th MG Pony

Quote:

Originally Posted by FLuxUs

well i quess my experience with copper pots, distiller parts, etc. doesnt apply then in that area. how come i never get that flaky black cr** on other copper things that i cleaned that way?:confused: thx for warning me though i would have probably cleaned my first evap that way.:eek: glad i havent had the time...

your right your experiance doesn't apply in this area as this is some thing entirely differant. allot of people make the mistake of under estimating the problems cuased by water and such.

The oxide basicly turns your oil into liquide sand paper and the water turns it into acid.
08-21-2008, 03:09 AM
FLuxUs

Quote:

Originally Posted by Xeon th MG Pony

your right your experiance doesn't apply in this area as this is some thing entirely differant. allot of people make the mistake of under estimating the problems cuased by water and such.

The oxide basicly turns your oil into liquide sand paper and the water turns it into acid.

thats why i thought getting the copper oxide off with salt and acid and then properly rinsing off the acid with distilled water and then properly getting rid of the water by drying the evap in the oven would work.
08-21-2008, 03:14 AM
Xeon th MG Pony

Quote:

Originally Posted by FLuxUs

thats why i thought getting the copper oxide off with salt and acid and then properly rinsing off the acid with distilled water and then properly getting rid of the water by drying the evap in the oven would work.

Not really, you have to dehydrate the unit verry theroely, much better to not let oxidization to form in the first place!
08-21-2008, 05:50 AM
wdrzal

If you use a acid, you need a base to neutralize it or a whole lot of flushing. some alkaline soda ash(sodium carbonate) will neutralize the acid. Use ph test strips,unless you have a water analysis test kit.

In systems where the water is acidic I use chemical injection pumps to pump in a metered amount of soda ash dissolved in water to bring the ph into a normal range.

I know of a few homes where there ground water was very acidic and the installers didn't test the water(well water) a hydronic heating system with copper tube was installed. In 10 to 15 years they had a sprinkler system instead of a heating system..
08-21-2008, 06:19 AM
FLuxUs

well, i am sure due to the CO2 from the atmosphere every water is slightly more acidic as it contains bicarbonate and hydronium ions that formed as a result of the CO2, while carbonic acid is only formed in strong acidic solution. however, distilled purified water has a ph of 7, unless exposed to air where it will reabsorb the CO2 and becomes slightly more acidic again. nonetheless, i dont know weather that process takes place that quick. i mean when rinsing the evap. with distilled purified water properly and drying it straight away i dont think it will have actually even dropped from 7.0pH to 6.9pH. i could be wrong though.

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