More Soda-blast problems

[Barry7363]

Last week I posted a "cry for help" related to the discovery after soda blasting our C-34, that the gelcoat had been removed by a PO. Thanks to your responses, I was re-assured that it wasn't a problem. My new problem now is "what to use to remove the stains on our deck and coach roof, that are a result of 'overspray' of the bicarbonate of soda that resulted from the process". I was advised by the contractor prior to the application that removal of these "inevitable" stains is typically done by a simple washdown of the decks with soap and water. Due to problems with his equipment, the cleaning took place over a two day period, and I began cleaning on the morning of the third day. Bottom line... the soap & water didn't have any effect, and neither did MacGuire's hull & deck cleaner, Spray 9, Alcohol Rubs (recommended by the soda supplier), Starbrite hull cleaner, etc., leaving compounding the deck with the equivalent of a 600 grit compound the only material that 'sort of' works, but not particularly effectively. The stains were initially quite yellow in color, and turned to dark grey within a day. I used 600 grit wet sanding to clean the rail area, but this isn't feasible on the non-skid deck. The areas affected are approximately 25% of the horizontal surfaces above the rail line. The hull is mostly ok as they hosed it off as they went. Has anyone seen this and found a solution? Your feedback is much appreciated,

Cheers,

Barry (currently not so cheerful)

 

[duality]

try barkeepers friend! i nevered had your problem, but in chicago most sailboats are stored on the calumet river area for winter where coal and iron ore is stored and brought in daily on barges and rail. the dust leaves a film that needs to be scrubbed off and barkeepers friend is the ticket for us. good luck

live slow / sail fast

mike

 

[Ross]

try some white vinegar on the stains, can't hurt, might help.

 

[CalebD]

Try vinegar first as Ross suggested as it is mild acid. If that does not work you can try phosphoric acid (naval jelly in most hardware stores) which is a somewhat stronger acid. If that does not work get some On&Off marine hull cleaner, preferably the gel form. Just be very careful with the On & Off around any metal deck fittings. Due the high acidity of this stuff it will eat any metal it finds.
You can use On & Off safely on gel-coat and I have on the freeboard on my boat. If your decks are painted then I would be very careful about using this stuff and check with the paint manufacturer or only try it on a tiny spot first.
If it is truly 'soda' the vinegar should do something. Think of what happens if you mix sodium bicarbonate with vinegar...
Good luck.

 

[Barry7363]

Thank you to all... I will try the vinegar this afternoon. It is usually about finding the "right" chemical component rather than a range of general purpose cleaners.
Cheers,

Barry

 

[Barry7363]

Back again...I tried the vinegar this afternoon but without success. I haven't seen the "On and Off" hull cleaner in our area. I will check with the prime marine supplier "The Binnacle" tomorrow.
Thanks again,

Barry

 

[48dodge]

I would try duality's suggestion if you can't find On and Off. I've never used On and Off, but I do know that BF can remove a large majority of stains from gelcoat. Just make a paste with water to keep from scratching the gelcoat.

 

[Hermit Scott]

On and Off

I am restoring a 79 Catalina 30. This weekend I used MaryKate On and Off gel. The gel is about as thick as dish washing detergent. I just brushed it on with a chip brush waited 10 minutes and sprayed it off. I put it on some stainless to see what would happen, all it did was clean it a little. BUT all the rust stains running down the transom from old hardware and the yellow tint just rinsed away. They say be careful because it can eat bottom paint, but it's thick enough so as not to be running all over the place. It took an entire bottle to do the topsides on my 30 footer.

 

[knowitall]

Your "topsides" or your "deck"???

(nm)

 

[Barry7363]

Gentlemen, The "On & Off" worked! (by CRC I believe, as Mary Kate is not available here). So after wasting three days trying everything under the sun, I am back on track. Thanks for the support. This is a fabulous forum for all sailors as we undertake our projects... the willingness of participants to contribute their experience is invaluable, Thanks again,

Barry