Getting worm like crustations off of bronze alloy Props

[QBhoy]

Advice sought....
My father has a large princess motor cruiser and this year and last the crustations are worse than ever on both the rather large props, stainless shafts and bronze alloy rudders.
What are people using to remove, without damage and with as less manual labour as possible ?
Thanks

 

[QBhoy]

Should read "with the least manual labour as possible"

 

[rafiki_]

Much of this will come off with the jet wash when lifted out. There is a prop cleaner that you spray on, but I was less than impressed. What doesn't jet wash off needs scraping or a wire brush on a drill. Good for polishing the props.

 

[QBhoy]

Thanks rafiki
Tried jetwashing twice now. Little or no effect.
A decent scrubbing with light emry cloth got a fair bit off last year but hard work and quite erosive.
I'm not sure if it was in here or the American forum, but a similar thread came up with stainless props. Someone had suggested some sort of bathroom or toilet cleaner but can't quite remember.

 

[sailorman]

Brick ( hydrochloric ) acid diluted will sort them from local builders merchant, plumbing or swimming pool supplies

 

[AllanG]

I use Starbrite Boat Bottom Cleaner to good effect.

 

[duncan99210]

I use a small (1 inch) paint scraper with the corners rounded to stop scoring the metal for a first fix, then one of those stainless steel pan cleaners (looks like a loose Brillo pad but made of stainless steel) to remove the remaining crud before a final polish with Solvol Autosol. That on a Brunton Autoprop off a sailey boat.

 

[JerryC]

I also used to use brick acid but it can take ages to work if the crustation buildup is very bad. I now use a plastic "non-woven preparation wheel" in an angle grinder. £8 from Screwfix and much faster. Being plastic it won't score your SS shafts but you need to be careful on the bronze props.

 

[QBhoy]

Brilliant stuff guys. Really good suggestions. Never thought of rounding the edges on a scraper either.
Another testament to the worth of such a forum.
Really reluctant to anti foul. I'm of the schooling (as an engineer) that such things as propellers are highly engineered and finished items with tolerance etc all in mind, to anti foul would surely be a sin on such a boat. I can understand it on a slower plodder of a boat, but not on this. Especially when every inch of efficiency is at a premium, given fuel costs and two big thirsty engines.

 

[TQA]

I use a variety of wire brushes mounted in a drill. Most work is done with a 6 inch radial brush.Takes me about 20 minutes to clean a badly fouled 17 inch three blader. Mine is a a sailboat so is well into the plodder group. I always antifoul without much long term effect.

 

[longjohnsilver]

I use a variety of wire brushes mounted in a drill. Most work is done with a 6 inch radial brush.Takes me about 20 minutes to clean a badly fouled 17 inch three blader. Mine is a a sailboat so is well into the plodder group. I always antifoul without much long term effect.

Important to,wear a face mask, that dust can be pretty nasty.

 

[Bandit]

Be careful with wire brushes and abrasives.

Brick cleaner, Disclean or similar which is dilute hydrochloric acid, Overalls, boots, gloves and eye protection.

Brush it on with a paint brush, those long handled brushes with the head at an angle work well, brush it on let it do its work, wash it off and reapply as required. Do a good final hose off with water.

If required finish off with some medium wet and dry.

Don't antifoul props shafts and rudders.

A mid season lift and a powerful pressure wash also helps in the long run.

 

[Firefly625]

I do clean props with brass wire wheel, brass is a tad gentler than steel wire wheels. A great many cheaper type wire wheels are brass coated, I use these which are still pretty cheap and solid brass.. https://www.amazon.co.uk/Silverline...d=1481879371&sr=8-7&keywords=brass+wire+wheel

did this on Wednesday with brass wire wheel, just need to finish off with some wet and dry to polish it up, will do next year before re launch.

 

[rafiki_]

Lovely job. Will follow your advice (again) and buy the brushes.

 

[TwoHooter]

The Americans use Barnacle Buster and seem to think its the best thing since barnacles were invented. It is a biodegradable form of phosphoric acid 85% v/v. But it isn't available in the UK. Like a lot of the other good stuff. I have read that you can buy neat H3PO4 in the UK but I don't know where and haven't looked myself yet.

For abrasive removal I have used these:
50mm SCM Discs 'CA' (Brown) x10 qcsc50ca 1 £4.76
Purchased here: http://www.hollisonsupply.co.uk/surface-conditioning-quick-change-discs.html

On our last boat we used Velox on the prop and it worked very well. We applied it to our Nordhavn in April this year and I'll see how it has done when we lift out next year.

This may be of interest:
http://www.passagemaker.com/channels/anti-fouling-tlc-for-your-running-gear/

 

[Firefly625]

I too have used the Roloc sanding / polishing discs for years specifically on allumimium parts and used on drill press for making engine turned dashboards, & also on props, I do rate them highly.

 

[Marine Reflections]

Advice sought....
My father has a large princess motor cruiser and this year and last the crustations are worse than ever on both the rather large props, stainless shafts and bronze alloy rudders.
What are people using to remove, without damage and with as less manual labour as possible ?
Thanks

Request that those areas are given a good blast on lifting, as time spent out of the water seems to further the bond. You'll still have to clean but you'll possibly rid the surfaces of the biggest, hardest bonders.

If dried then you could simply remove with steel / brass wheels, spinning, burnishing etc.
But,... highlighting 'without damage' and depending on how far out of the manufacturers original balance of the prop they were, you might want to consider 'teasing' the bonders from the surface rather than abrasion?

Teasing, as in slowly chemically releasing rather than abrasion willl maintain condition of the surface and would require only polishing to provide the most hostile surface for crustation to further bond in the future.

If the props are already keyed with previous abrasion and are no longer 'shiny' then it's up to you to decide to further improve / restore or continue as they are.
Making them shiny and re-balancing isn't that hard, but a skill never the less.


Starting with the weakest try some limescale removers to break it down over time, some bottom cleaners will dissovle those in minutes but you'd wish for a full face gas and odour mask the moment you apply, so will your neighbours.
The weaker the solution the longer it will take, but a spray every few hours from a garden sprayer is not less manual labour, but it is easier and safer. Seals like the sofly approach also.

 

[QBhoy]

Thanks again for the further posts.
Looks like we shall try some diluted hyd ch acid, diluted of course.

 

[gordmac]

Brick cleaner but be careful it can be nasty stuff, not sure how a cutlass bearing would tolerate it though.

 

[Bandit]

Brick cleaner but be careful it can be nasty stuff, not sure how a cutlass bearing would tolerate it though.

Hose it off with water when it's done it's work.