Rinsing off Oxalic Acid

If I were to use masking tape and polythene attached to the rubbing strake, would that protect the vertical part of the hull (topsides)? As mentioned earlier in the thread, I'm having the original light blue gel coat de-oxidised/polished/buffed by a friend that does car bodywork.
 
Highndry said:
If I were to use masking tape and polythene attached to the rubbing strake, would that protect the vertical part of the hull (topsides)? As mentioned earlier in the thread, I'm having the original light blue gel coat de-oxidised/polished/buffed by a friend that does car bodywork.
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Yes, that will be more than enough to protect the hull (topsides), although if you say it is having the oxidation removed on the blue then probably an overkill as the topside surfaces will be undergoing correction anyhow.
A thorough rinse and further wash should suffice. Had the gelcoat on the topsides not required further attention, then yes, your protection would be more than enough.

Can I just ask, what do you think is causing the yellowing? and what do you have planned to stop it returning?
 
I have several times cleaned my topsides where it gets a nasty stain just above the water line. I have done this with a pump spray bottle as used in the garden. I do it with the boat in the water and me in the water wearing diving mask and snorkel. I just swim along spraying by the time I have circumnavigated the boat it has worked with dramatic cleaning effect. I can then do the places missed.
Never had any concerns re burning on skin. Now Caustic soda as used for paint stripper that is really nasty stuff. good luck olewill
 
Seajet said:
I think Woodlouse must use a very weak mixture, but in any form it's best not to mess around with the stuff, bad news for breathing it in or being burnt by it - also if using it warn any passers by and don't let it spray on nearby boats, let alone people or their pets.
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As I said, I use as strong a solution as I can mix. Obviously some people have more sensitive skin than others, but I don't consider myself particularly leathery. The only time I really notice when I get it on me is if it comes into contact with any open cuts. Still not breathing, drinking or getting it in your eye is probably a good idea.
 
Can someone tell me where to buy Oxalic Acid? I've looked for it in the past with no success, but clearly its pretty readily available!
 
Must have missed the bit about putting on oxalic acid. Have read all the info, I would like the best option for ridding my boat of black ??????? , plus algea in some parts.
1) Will a mixture of oxalic acid and water/ fairy liquid, remove both of my problems.
2) What is the best mix and how do you apply, paint/scrubbing brush, sponge ???????
3) How long do I leave it on to work before I pressure wash it off.
4) Do, I need to cover toe rails and and other woodwork from possible harmm such as spray from washing off onto perspex widows
5) I have a secondary problem of the varnish on the toerails coming off so that it is blotchy, some looking good and some as though it is all off eg a grey colour, would this mix help to get all the varnish off and so speed up another job.

Richard
 
Richard D said:
Must have missed the bit about putting on oxalic acid. Have read all the info, I would like the best option for ridding my boat of black ??????? , plus algea in some parts.
1) Will a mixture of oxalic acid and water/ fairy liquid, remove both of my problems.
2) What is the best mix and how do you apply, paint/scrubbing brush, sponge ???????
3) How long do I leave it on to work before I pressure wash it off.
4) Do, I need to cover toe rails and and other woodwork from possible harmm such as spray from washing off onto perspex widows
5) I have a secondary problem of the varnish on the toerails coming off so that it is blotchy, some looking good and some as though it is all off eg a grey colour, would this mix help to get all the varnish off and so speed up another job.

Richard
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I'm a bit late on this thread.

First I hand wash the hull to get the muck off, leaving only stains/marks

Then all I do is get a washing up bowl, half full of water. Nothing else. Add Oxalic acid crystals a spoonful at a time and stir till fully dissolved. I guess I use about 100g as I only used about 20% of a 500g tub off ebay.

Using my deck broom I paint it onto the deck and cockpit areas. After that I go round the sides of the boat, painting it onto the hull sides. Generally, one bowl is enough, but occasionally I might have to mix up a bit more.

After an hour or so I wander round and maybe add a dab more onto any stubborn areas (not very common) then I just get a hose and rinse it off. I'd avoid a pressure washer as there may be an acidic splashback. Just a slow running hose and a broom is plenty. It lightens my teak areas a shade or two, but I have no varnish so it's pretty even. I quite like the effect. I've never noticed any issue with perspex windows, but I generally avoid brushing it directly onto deck hatches as it'll be of no benefit.

Simple. It always works superbly for me.
 
Seriously, be careful with oxalic acid especially eye protection; I am lucky not to be blind after my stupidly thinking ' de-activate with water ' meant the stuff is feeble !

If having trouble with it burning skin ( for eyes it would be instant 999 ) immerse the affected part in cold water for at least 40 minutes, a running tap didn't help my burning arms, it felt like it was going down to the bone.

Boats are usually above one's head height when working on the topsides - so the stuff runs down ones' arms and can splash eyes, I was saved at least a hospital trip by the advice of club member and ex Matron Pat Crowhurst.
 
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Ok - amazing stuff and no hard work involved :)

How do I remove the light spots where it dripped onto the rib I used??? Do I need to put it all over the rib to bring it back to the same colour..?

Dripped down arms and no adverse reactions.

Yet.
 
Highndry said:
I'm doing the GRP 'white' topsides of my Medina so most of it is a horizontal surface. The vertical surfaces - hull - are being polished out by a chap from the local bodyshop so I can probably get away without the paste.
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Apologies for being so pedantic, but the horizontal surfaces you mention are called the deck and coachroof, the vertical surfaces of the hull are called the topsides and the bit that goes under the water is called the bottom.
 
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