Cleaning potion formula

[PabloPicasso]

So I have procured oxalid acid in powder form, it comes in a stout cardboard tube.

So what's the magic formula for using it? I've been told various tricks such as mixing it up with wallpaper Paste to get it to stick to the sides of the boat.

Is it a different ratio for cleaning GRP to teak?

Mix up into a bucket of hot or cold water?

Any other ingredients needed? I heard adding lemon juice was helpful?

 

[jwilson]

Mix with warm water till it stops dissolving, at which point you have a saturated solution. After you've used a bit and the solution has cooled down you will probably have undissolved crystals at the bottom: add more warm or hot water to dissolve them.

For GRP the two usual additives are either a dollop (very precise measure - 1 British Standard Dollop) of washing up liquid to make it flow out over the hull surface rather than 'bead', or a bit of wallpaper paste to make it stick onto the hull. I once seriously overdid the wallpaper paste and had trouble getting it off, hence I tend to use washing up liquid these days.

Works far better in warm conditions than cold, almost ineffective on a cold winters day, works magically in summer.

For bleaching wood the same solution is used but no need for additives. Takes longer than getting yellow/brown or rust stains out of GRP.

 

[longjohnsilver]

Mix with warm water till it stops dissolving, at which point you have a saturated solution. After you've used a bit and the solution has cooled down you will probably have undissolved crystals at the bottom: add more warm or hot water to dissolve them.

For GRP the two usual additives are either a dollop (very precise measure - 1 British Standard Dollop) of washing up liquid to make it flow out over the hull surface rather than 'bead', or a bit of wallpaper paste to make it stick onto the hull. I once seriously overdid the wallpaper paste and had trouble getting it off, hence I tend to use washing up liquid these days.

Works far better in warm conditions than cold, almost ineffective on a cold winters day, works magically in summer.

For bleaching wood the same solution is used but no need for additives. Takes longer than getting yellow/brown or rust stains out of GRP.

Pleased to read that I'm not alone in having overdone the wall paper paste trick. Removing it all from a 48' hull is no doddle!!

Oxalic acid is one of the most useful cleaning agents I keep on board. I'd be lost without it.

 

[PabloPicasso]

So what constitutes cold or warm in these wet windy isles, as far as the magic potion is concerned? Don't use under 10C?

 

[Yngmar]

So what constitutes cold or warm in these wet windy isles, as far as the magic potion is concerned? Don't use under 10C?

When it's not quite hot enough anymore to brew a proper cup of tea with, but still hot enough to hurt when you test this by dunking your finger in.

 

[Mistroma]

When it's not quite hot enough anymore to brew a proper cup of tea with, but still hot enough to hurt when you test this by dunking your finger in.

Remember that oxalic acid is a relatively strong acid (stronger than acetic) and it is toxic. Ingestion or prolonged skin contact can be dangerous so best to treat with some care.

As far as I can remember around 10C is the point where the rate of reaction slows almost to a standstill. It's pretty slow to work until temp. gets up a bit. Anything above 25C should provide a fairly quick reaction (i.e. Within a few minutes).

If it was winter in UK and I really needed to clean a small area then I'd sponge on hot water first in order to heat the hull and then apply a hot solution. However, I mostly waited for a nice sunny day in spring (mainly due to more pleasant working conditions ).

 

[Poignard]

I agree about not using too much wallpaper paste. This year, for the first time, I made up my own oxalic acid paste instead of using Y10. I made it of thinner consistency than the Y10 and found it easier, and faster, to apply and remove.

The technique I use is:

1. Starting at one end of the boat, spread a thin coat of the paste onto one side of the topsides using a wide brush.
2. Go back to the starting point.
3. Wash it off using fresh water and a Hozelock car wash brush ( http://www.building-supplies-online...g&m=Abstract&gclid=COP1uLefiM8CFeUV0wod29sPFg ) with washing up liquid in the bowl.
4. Rinse off with fresh water.

My boat is 49 years old but the hull still comes up very white and clean.

 

[alan_d]

It's pretty slow to work until temp. gets up a bit. Anything above 25C should provide a fairly quick reaction (i.e. Within a few minutes).

Bloody hell! That's just a few days a year here, if we're lucky.

 

[Mistroma]

Bloody hell! That's just a few days a year here, if we're lucky.

True but OK on a sunny day even in spring as hull can get quite warm. Use hot solution as well. Problems come when hull is stone cold as it quickly cools the oxalic solution. Pretty certain that most people who say oxalic didn't work on yellow/rust stains used it at too low a temperature.

I always managed to get it to work fairly rapidly in Scotland either spring or autumn from 1986 - 2012 if I picked the correct day.