Thermostat housing inspection F225TXRD

[fairdeal]

Just did an inspection of the starboard thermostat housing -



I last looked at it one year ago to the day.


Its now been 24 months - and >500 running hours -

since I cleaned out the corrosion and applied zinc chromate paint.

I did not take a photo last year, but I recall it looked fine.


Now there are spots where the zinc chromate has bubbled.




Still looks a heck of a lot better than it did in November 2014:

[pstephens46]

Remove paint and reapply?

[fairdeal]

Remove paint and reapply?

I'm mulling that over.

The starboard thermostat on early F225 is not easy to access.

I did what I could two years ago without removing the TPS or throttle bodies -

if I was to do it again, I'd be compelled to make it a more involved project...

[TownsendsFJR1300]

We used the zinc Chromate paint on the inside of my neighbors Suzuki LU after we had it welded (cracked housing and ground down to clear the prop shaft holder).

We cleaned it spotless and still had some of it come off when assembling (ie, it didn't seem to bond as well as I thought it should)...

The only other thing you may do (if you didn't last time) is try to find a small wire brush to go on a Dremel and get in there... If there's any corrosion, of course it won't stick...

[panasonic]

If you want your zinc chromate to stick properly you need to prep the aluminium first.

AT117 ALUMINUM PREP 8oz KIT

Works good. Use it all the time on Comercial aircraft.

Warning: see Manufacturers statement on using this product on High copper content cast aluminum.

[TownsendsFJR1300]

If you want your zinc chromate to stick properly you need to prep the aluminium first.

AT117 ALUMINUM PREP 8oz KIT

Works good. Use it all the time on Comercial aircraft.

Excellent!! Saved for later look up!!

[pstephens46]

Excellent!! Saved for later look up!!

Description mentions not using on aluminum castings. Wonder why? Might be worth a call to their tech dept.

[TownsendsFJR1300]

Description mentions not using on aluminum castings. Wonder why? Might be worth a call to their tech dept.

Panasonic, any idea why?

[99yam40]

maybe cast is not a pure as sheet

[boscoe99]

Syntax can be confusing. Hard for writers to put themselves into the place of a reader.

The language reads as follows:

"ALUMIPREP 33 should not be used on high copper bearing aluminum alloys or aluminum castings."

Are they trying to convey that it "should not be used on aluminum castings" or that it "should not be used on high copper bearing aluminum castings"?

I am guessing the latter. But it is that, just a guess.

[boscoe99]

The Henkel folks have left for Xmas. I will find out some more about this next week.

Curious minds have a desire to know.

[panasonic]

Panasonic, any idea why?

The Prep kit I mentioned says:


"Turco Alumiprep is a non-flammable phosphoric acid based cleaner, brightener and prepaint conditioner for aluminum. Turco Alumiprep 33 should not be used on high copper bearing aluminum alloys or aluminum castings. Cleaning with Turco Alumiprep 33 produces a chemically clean and corrosion free aluminum surface."

I use this stuff all the time on aircraft grade aluminum as per aircraft manufacturers instructions. 2024 grade aluminum is probably the most widely used aluminum in the aircraft industry and it has 4 to 5% copper as an alloy, gives it good strength, but lower corrosion resistance.
Most of what we use is sheet and extrusion, but a fair amount cast aluminum.

From what I can see outboard motors use a lot of 300 series cast aluminum. For example "mercalloy" 367 is only .5% copper alloy which gives it good corrosion resistance. So I don't know why it would say not to use on high bearing copper aluminum alloys when you can use it on the 2024 alloy.

My best guess on the warning is that the cast aluminum is porous and there is a risk of the Alumiprep being left behind if not used properly. Alumiprep33 is phosphoric acid and must be used sparingly and most importantly be completely rinsed away after the etch. You only want this stuff going onto the reworked areas and not splashed all over the place.


The Alodine 1201 part of the kit has no warning.


"Alodine 1201, a registered trademark of Henkel Surface Technologies, is a chemical treatment process for aluminum used to provide corrosion protection and as a surface preparation for paint and adhesives. Sometimes called Caluminum passivation, it contains hexavalent chromium and is intended to provide corrosion prevention even when left unpainted.

Chromate conversion is an excellent treatment method to prep aluminum prior to paint or adhesives since it greatly enhances the ability of an organic coating to form a bond with the aluminum substrate. Being a surface conversion treatment rather than a coating, it will not alter the dimensions of the part.

It is frequently used on electrical and electronic equipment because it provides increased corrosion resistance while remaining electrically conductive.

The Alodine process produces a microscopic thin film commonly prescribed on aluminum to provide the following surface characteristics: High-adhesion surface preparation for paint Improves corrosion resistance Preserves electrical conductivity of surface No change in dimensions."

I Have NOT used Alumiprep on a outboard engine casting, but have used it on badly corroded outboard props after cleanup. Also have used it on motorcycle cast engine cases, frame parts and carb bodies with good results. I would not hesitate to use it on my own outboards.
You can just use the Alodine 1201 on its own,after corrosion clean up, for better primer (zinc chromate) and paint prep, but it will work better with the Alumiprep33 acid etch.


So if you are not comfortable using this acid etch and is not 100% by the manufacturers instructions DON'T DO IT.

I highly doubt calling the manufacturers tech dept will change what they say on the website just for liability purposes, but you never know.

I will post warning on previous post.

[pstephens46]

The Prep kit I mentioned says:


"Turco Alumiprep is a non-flammable phosphoric acid based cleaner, brightener and prepaint conditioner for aluminum. Turco Alumiprep 33 should not be used on high copper bearing aluminum alloys or aluminum castings. Cleaning with Turco Alumiprep 33 produces a chemically clean and corrosion free aluminum surface."

I use this stuff all the time on aircraft grade aluminum as per aircraft manufacturers instructions. 2024 grade aluminum is probably the most widely used aluminum in the aircraft industry and it has 4 to 5% copper as an alloy, gives it good strength, but lower corrosion resistance.
Most of what we use is sheet and extrusion, but a fair amount cast aluminum.

From what I can see outboard motors use a lot of 300 series cast aluminum. For example "mercalloy" 367 is only .5% copper alloy which gives it good corrosion resistance. So I don't know why it would say not to use on high bearing copper aluminum alloys when you can use it on the 2024 alloy.

My best guess on the warning is that the cast aluminum is porous and there is a risk of the Alumiprep being left behind if not used properly. Alumiprep33 is phosphoric acid and must be used sparingly and most importantly be completely rinsed away after the etch. You only want this stuff going onto the reworked areas and not splashed all over the place.


The Alodine 1201 part of the kit has no warning.


"Alodine 1201, a registered trademark of Henkel Surface Technologies, is a chemical treatment process for aluminum used to provide corrosion protection and as a surface preparation for paint and adhesives. Sometimes called Caluminum passivation, it contains hexavalent chromium and is intended to provide corrosion prevention even when left unpainted.

Chromate conversion is an excellent treatment method to prep aluminum prior to paint or adhesives since it greatly enhances the ability of an organic coating to form a bond with the aluminum substrate. Being a surface conversion treatment rather than a coating, it will not alter the dimensions of the part.

It is frequently used on electrical and electronic equipment because it provides increased corrosion resistance while remaining electrically conductive.

The Alodine process produces a microscopic thin film commonly prescribed on aluminum to provide the following surface characteristics: High-adhesion surface preparation for paint Improves corrosion resistance Preserves electrical conductivity of surface No change in dimensions."

I Have NOT used Alumiprep on a outboard engine casting, but have used it on badly corroded outboard props after cleanup. Also have used it on motorcycle cast engine cases, frame parts and carb bodies with good results. I would not hesitate to use it on my own outboards.
You can just use the Alodine 1201 on its own,after corrosion clean up, for better primer (zinc chromate) and paint prep, but it will work better with the Alumiprep33 acid etch.


So if you are not comfortable using this acid etch and is not 100% by the manufacturers instructions DON'T DO IT.

I highly doubt calling the manufacturers tech dept will change what they say on the website just for liability purposes, but you never know.

I will post warning on previous post.

Many of you probably have T-Tops on your boats. I do not but I understand it is a constant battle to keep them from pitting from salt water. These guys around here use some type of wax several times a year. Wonder if this two part treatment would suffice. I also wonder if the aluminum is treated from the factory but slowly wears off.

[fairdeal]

Many of you probably have T-Tops on your boats. I do not but I understand it is a constant battle to keep them from pitting from salt water. These guys around here use some type of wax several times a year. Wonder if this two part treatment would suffice. I also wonder if the aluminum is treated from the factory but slowly wears off.

T-top frames and other marine piping products are typically made with anodized aluminum tubing. Anodizing is a marvelous treatment, but it can be scratched, or abraded off.

Those end caps on your tilt/trim ram cylinders are anodized. I imagine the VST is too - inside & out.

[99yam40]

Many of you probably have T-Tops on your boats. I do not but I understand it is a constant battle to keep them from pitting from salt water. These guys around here use some type of wax several times a year. Wonder if this two part treatment would suffice. I also wonder if the aluminum is treated from the factory but slowly wears off.

most I have seen are made of anodized aluminum tubing that works well,except were it is welded or nicked the anodized coating goes away.
some powder coat the tubing after welding it all up, but any ding will have the same problem