Hempel Cleaning Powder

[Sabre27Admin]

Iain C
United Kingdom
181 Posts

Posted - 01/08/2011 : 22:15:57
No commercial interest or connection whatsoever, but I bought some of this stuff last week and I cannot recommend it highly enough.



Summer Girl's rather yellow decks are now bright white...all the rust stains around the samsom post are gone, and the ingrained dirt that lives under the jackstays is also history.

It's also brought the rather shabby yellowing gelcoat in the cockpit up really well too. Apparently if you get the buffing wheel on straight afterwards teh results are significantly better still.

Well worth it, a tub will do the deck and superstructure (I reckon you'd need another one to do the hull) but wear gloves as it's pretty nasty stuff. It does not appear to bleach sprayhoods or clothes from what I can see either.
keith
United Kingdom
118 Posts

Posted - 04/08/2011 : 11:22:28
I found a similar product in one of Sabreuse's lockers. It was like heavy duty Ajax, i reckon about 15thou of gelcoat had been worn & scrubbed away over the years, still with what she lost in heavy scale of the keel she will be a fair bit lighter!

ken endean
United Kingdom
52 Posts

Posted - 30/08/2011 : 15:40:38
From the info on the manufacturer's data sheet, this appears to rely on oxalic acid, which is very good news because the previous best product for removing yellow stains was 'Wipe Out', which is no longer in production.

I painted the hull of 'London Apprentice' with 2-can poly many years ago and the finish is still very sound but loss of gloss has led to the hull developing yellow stains above the waterline. As the old girl has to act as a photographic model from time to time, I have to care for her complexion and this necessitates removing the yellow. It seems to be biological in origin and accumulates when the topsides are regularly wetted (rough mooring or lots of sailing miles). It can be bleached out by the sun and also by reducing agents such as citric acid (rub with lemon peel)if the temperature is above about 15 degrees C. Oxalic acid is the best available reducing agent and is included in the gell 'Y10' but that is expensive and 'Wipe Out' no longer available, so the Hempel product sounds promising.

A similar oxidation/reduction reaction causes rust and can also remove it. NOTE that the chemical reduction process does not normally require abrasion, so should not be necessary to scrub hard at the GRP and damage the surface. Normally, a concentrated solution on a warm surface will do the trick. Having said that, I note that the Hempel powder does include abrasive, which might be bad news on my paint. Other possible products are Farecla Rapid Stain Remover and Starbrite Hull Cleaner but I have not yet tried either of them. Any feedback would be gratefully received.

Peter OD
United Kingdom
50 Posts

Posted - 30/08/2011 : 19:26:02
Oxalic acid can be bought easily from eBay shop in powder form and mixed with Polycell wallpaper adhesive to make a gell which hoses off easily when its work is done. Just as good and much cheaper than Y10. The Oxalic acid is about £6 for 1kg including postage.

sabre27
178 Posts

Posted - 01/09/2011 : 21:24:37
Hi all,

As a landscape gardener, I have been using Oxalic acid for more years than I care to remember. It is the only thing that I found would remove rust stains from stone or concrete paving. In those days you could buy it from a chemist, but not any more. I soon found that in solution, it would remove rust from just about anything, without any scrubbing and after a satisfactory test on old sailcloth, all the unsightly rust stains on my sails, and everything else, disappeared. It is very good on badly stained wood. Rinse well.

Paul Howard. S27OA Technical Officer.