Applying oxalic acid ?

[Boo2]

Hi,

I've previously applied oxalic acid by using a foam pad type mop but that's not great as it's quite tiring to apply and also the pad rots with the acid so you can only use it once.

I was thinking of using my pressure washer which has a plastic bottle thing for applying eg detergents. Has anyone tried this and can say how well it works ? Would adding a bit of boat/caravan cleaner into the mix help it wet the surface do you think ? How do you apply oxalic acid to your boat ?

Thanks,

Boo2

 

[alahol2]

I mix in some washing up liquid to help with wetting the surface. I apply it with a paintbrush. Usually I'm doing it in winter/early spring when the temperature is low so I keep painting, round and round, until the job is done. I then give it a good going over with a hose to clean off the residue.

 

[William_H]

I think applying oxalic with a pressure washer might be wasteful. Oxalic takes time like a few minutes to act so needs to be applied to stay there for a bit. I use a pump spray bottle as used for gardens etc. Just stay clear of the spray or wear a mask. Indeed I use this in water to clean up the above water line stains. I have never had a need to add detergent though. good lcuk olewill

 

[Colvic Watson]

Hi,

I've previously applied oxalic acid by using a foam pad type mop but that's not great as it's quite tiring to apply and also the pad rots with the acid so you can only use it once.

I was thinking of using my pressure washer which has a plastic bottle thing for applying eg detergents. Has anyone tried this and can say how well it works ? Would adding a bit of boat/caravan cleaner into the mix help it wet the surface do you think ? How do you apply oxalic acid to your boat ?

Thanks,

Boo2

Scary! What about people and boats downwind?

 

[Spi D]

Paint roller, and brush for smaller details, does it for me. Used in modest (spring cleaning) temperatures it's almost like applying the effect stroke by stroke.

I use oxalic powder dissolved in plain water. Rinse immediately after the desired result has been reached.

And be careful on coloured gelcoat - !

 

[rbmatthews]

Use a saturated solution of oxalic acid (140 g crystals per litre warm water, IIRC) with a dash of wallpaper paste to make it stick to the vertical surfaces, apply with a wide paintbrush, leave for 15 mins, then wash off with lots of water. Wash brush afterwards. Seems to work for me, and no rotten brushes so far.

 

[Bobc]

What happens if you put it on dark blue stripes that a lot of boats have these days?

Does it fade them?

 

[VicS]

Hi

I was thinking of using my pressure washer which has a plastic bottle thing for applying eg detergents. Has anyone tried this and can say how well it works ? Would adding a bit of boat/caravan cleaner into the mix help it wet the surface do you think ? How do you apply oxalic acid to your boat ?

Thanks,

Boo2

It sounds like an incredibly stupid way of applying a toxic and hazardous substance like oxalic acid to me.

Just apply by hand with a brush to the areas to be treated.

 

[Spi D]

What happens if you put it on dark blue stripes that a lot of boats have these days?

Does it fade them?

The acid will remove yellow(ish) dirt and bleach any surface. You do not notice this on white gelcoat, though

On coloured stripes I'd rinse immediately and use other products to clean.

 

[duncan99210]

We use oxalis acid with a paint brush for cleaning small rust stains and the like. When we've had larger areas of stain to clean I use an old squeazy bottle (fairy liquid) to squirt it where required. Leave for 10 - 20 minutes and rinse well. For the hull, I just use a bit of rag to apply the stuff. Hasn't had any effect on the coloured stripes that I can see.

 

[Bobc]

The acid will remove yellow(ish) dirt and bleach any surface. You do not notice this on white gelcoat, though

On coloured stripes I'd rinse immediately and use other products to clean.

Thanks for that. That probably explains why my blue stripes are now a much paler blue than when they started life (not me, but I bet someone who shall remain un-named used it on the boat a few too many times).

 

[LeonF]

Def not a pressure washer. I just use gloves, a soft brush and thick washing up liquid or wall paper paste solution on vertical surfaces. Add the acid to the bucket, not water to the acid.

 

[sailaboutvic]

If you can't get wallpaper past , use flour .

 

[VicS]

Def not a pressure washer. I just use gloves, a soft brush and thick washing up liquid or wall paper paste solution on vertical surfaces. Add the acid to the bucket, not water to the acid.

If you insist but use fairly hot water otherwise it takes a while to dissolve. Allow to cool before using.

 

[Spyro]

Oxalic acid in a power washer has to be one of the craziest ideas ever

 

[aquaplane]

Add the acid to the bucket, not water to the acid.

Not necessary, it takes some effort to get oxalic acid to dissolve in water as already said. You are thinking of the exothermic dilution of concentrated sulphuric acid where adding acid to water is to be advised.

Don't use the galley slaves best galvanised bucket to make up your oxalic solution, it's take the shine off and gain you minus several brownie points.

When doing the woodwork on our boat I put some (maybe a couple of tablespoons) oxalic crystals in the plactic bucket.
Add an inch or two of hot water and stir to dissolve.
I brush on the conc solution with an old (or new) paint brush and leave it to do it's stuff.
Wash hands immediately after applying, or use marigolds.
Go drink tea for a bit.
When the crystals have dried on and are twinkling in the sun go and see if it needs a bit more on, re treat if required.
Rinse off the oxalic and the green/black carp.
Admire the bleached almost white woodwork as it dries off.
Curse profusely as you notice that runoff has left streaks in the brown beard round the waterline and you are going to have to do all that too, more work.

 

[Seajet]

My story about oxalic acid; apologies to those who've seen this before but I think worth repeating.

I was degreasing my boat's topsides prior to painting, so used an off-the shelf oxalic acid cleaner from a chandlery.

As the instructions said ' to deactivate, add water ' I foolishly thought it must be feeble stuff; I let the residue run down my bare arms.

Within minutes I knew I was in trouble, so ran to the loos and put my arms under running water.

This did not work, by now the burning was so intense I thought it might go down to the bone !

Luckily Pat, an ex hospital Matron knew what to do; I had to fill a basin with cold water and keep my arms submerged for a good 40 minutes.

Pat remarked afterwards that the burns were quite shocking even to her, a minute or two more and it would have been an ambulance job.

I wasn't even using eye protection, I'm sure if it had got into my eyes I'd be blind now.

This was about 1990 and I'm assured by people who should know that this must have been an unusually strong oxalic acid solution compared to todays' stuff; however, don't chance being a chump like me, it wasn't much fun !

Wear protective clothing especially eye goggles, and bear in mind neighbouring boats and passing people.

 

[Spi D]

Thanks for that. That probably explains why my blue stripes are now a much paler blue than when they started life (not me, but I bet someone who shall remain un-named used it on the boat a few too many times).

More than often coloured stripes are vinyl stickers / tape. They respond differently to the acid and can, worst case, be replaced.

 

[Hoolie]

If you can't get wallpaper past , use flour .

Don't use either. In hot weather it must be horrendous to get off. A concentrated solution with detergent applied with a brush will do just fine. As it dries it gets more concentrated and when it's sparkling with crystals, rinse it off.

BTW I found my pressure washer was chipping the gelcoat, particularly on the textured non-slip areas. Needless to say I don't use it on board any more ... ...

 

[rbmatthews]

Don't use either. In hot weather it must be horrendous to get off. A concentrated solution with detergent applied with a brush will do just fine.

Only if you let it dry. Washing it off after 15 minutes is fine. But each to his own.