Removing Red Diesel stain from plastic CAV bowl

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RIBW

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Dear All,
Has anyone successfully removed the staining by red diesel on the inside of the plastic bowl which forms the lower half of a ‘CAV’ style sedimenter/water separator? Currently, it is extremely difficult to check visually for water or dirt/bugs.

I have quickly tried Brasso, Bleach and Baking Soda on a spare bowl (which is less darkened than the installed unit) with no success. Also, after scraping lightly with a Stanley knife blade, it would seem that the dye has permeated the plastic i.e. it can’t be scraped off.

I have asked if it is possible to buy a new bowl but SSL only hold the complete unit.

As I suck out from the bottom of the fuel tank every six months until only clear fuel is delivered, I have never had an issue with contaminants, so doing a visual check falls into the ‘wouldn’t it be useful’ category rather than ‘top of the work list’.

Cheers
Bob


Water Separator_Rd_3480.jpg
 
If the dye has permeated the plastic (something I'm sure it was designed to do) then it is time for a new bowl I'm afraid.

If you do get one, make sure all of your tank and supply pipes are cleaned or replaced; otherwise any dregs of red will stain the new one.

There are professional fuel tank cleaning companies that steam clean them. They do a good job and afterwards your adoption of white diesel and marine 16 will ensure fuel supply reliability and compliance with unfriendly foreign fuel inspections when abroad in the summer.
 
Thanks LL,
My problem is solely with the visibility into the installed bowl - I'm not worried about the rest of the system. So, if a change is made, I'll replace the old unit entirely with a new combined filter and separator (but that isn't going to happen soon).
I was (wildly) hoping that, perhaps, the spare bowl could be immersed in something for a while which would clarify the plastic.
Cheers
Bob
 
You say you have used Brasso but perhaps something a little more abrasive would be better. I have had acceptable and passable success in the past with Solvo Autosol chrome cleaner paste on an oil tank sight glass bowl. Granted it doesn't restore it to "like new" but it certainly allowed the contents to be seen a lot easier.
 
Graham and SoG,
Perhaps my photo is a little misleading. It took great excavation and flexibility to take that photo. You can see from the shadows that daylight is off to the left. The hatch is about 1 metre away. Getting a light near the bowl is extremely awkward.

However after much googling, I have found some MoD surplus stock and bought a new bowl (£16 incl. p&p). Part number 7111-693.

It would be good to know if there is some means of 'clarifying' the bowls if only out of curiosity.

Giblets,
I'll pick up some Autosol and give it a go.

Cheers
Bob
 
I think you're unlikely to polish it out. The bowl and fuel are both hydrocarbons. The dye has permeated into the plastic. But there isn't a dye that can't be bleached. It might be as simple as UV light. I hear that if you leave red diesel in the sun it eventually clears.
 
I would try polishing the inside of the bowl, starting off with wet and dry at perhaps 400 grit wet.
That will tell you if the dye has gone a long way into the plastic.
400grit, 1200 grit, solvol autosol is a reasonable polishing sequence.
Or you can go to a finer grit like 2000 or more, followed by Farecla or whatever.
The bowl would probably be OK left matt inside, but stuff might stick to it.
Is a glass bowl available instead?
 
Bob, I had the same problem. Eventually bought a new bowl, 6 months later same problem. White GRP behind mine helps a bit.

Yours is much worse than either of mine. Fit a new bowl.
 
RIBW said:
Graham and SoG,
Perhaps my photo is a little misleading. It took great excavation and flexibility to take that photo. You can see from the shadows that daylight is off to the left. The hatch is about 1 metre away. Getting a light near the bowl is extremely awkward.

However after much googling, I have found some MoD surplus stock and bought a new bowl (£16 incl. p&p). Part number 7111-693.

It would be good to know if there is some means of 'clarifying' the bowls if only out of curiosity.

Giblets,
I'll pick up some Autosol and give it a go.

Cheers
Bob
Click to expand...
When I suggested putting a torch behind it I also had in mind to suggest permanently fitting an LED light behind the bowl but omitted it in the interests of simplicity:)
 
Thanks to everyone for your thoughts!

Having located a new bowl for the boat, I will now sacrifice my 'pink' spare in the name of curiosity. If I have any success, I'll report back.

SoG (and Graham),
I had that thought too. A vertical LED strip behind the bowl might be easy - I think I have some accessible 12V on the other side of the bulkhead. Based on Pete7's experience that could be useful!

Giblets, lw and Andy,
I'll try combinations of the actions suggested plus another suggestion (soaking in hydrogen peroxide, hair bleach - £1.70 from Tesco/Sainsburys etc). The UV contribution may be tricky in February?

lw,
I couldn't find a glass version. (It took a long google to find the plastic version)

Cheers
Bob
 
Reporting back:-
Total failure. None of the remedies so far have worked.
The only remedy left to try is the long exposure to UV.
The bowl is now fixed in a suntrap outside and time will tell!
Thanks for all your suggestions.
Cheers
Bob
 
RIBW said:
I couldn't find a glass version. (It took a long google to find the plastic version)
Click to expand...

Maybe a long way out of your way, but Newry Auto Supplies is a good source. Lots of fans of vintage tractors locally and they don't pay marine prices.
 
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