Genoa car pins on rescue project boat seized...how to unstick?

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yourmomm

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Been using vinegar spray which doesn't seem to be working. Any other ideas? Or am I going to have to get the grinder out and buy new cars??
 
Yep flame not possible as it's GRP. No power on board, and it takes about 25mins to boil 2.5l on my meths stove, so I'll be there for a while....Tried hammering too...was wondering if there was a chemical fix...
 
If you mean the pin that allows the top part (where there is the roller) to swing in and out (Pt & Stb) it is probably best to gently tap on alternate sides using a plastic-faced hammer. This often is sufficient to break any corrosion that binds the parts together.
Trying to drift the pin out directly runs the risk of expanding it in place and making matters worse.

If you mean the pin that holds the car in place on the track you can use a gripper and an extension to improve leverage and (try to) rotate it.
 
Pouring a kettle full of boiling water over it often does the trick.

Mind your toes.

You can back it up with gentle taps with a large hammer just to shake the corrosion loose.

Edit: I see boiling water has already been mentioned and rejected. It's worked for me a fair few times. So worth going out of your way to find some way you can boil water quickly.
 
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Some of the sheaves on my deck organisers have seized. They are plastic wheels (Acetal?) in aluminium alloy frames. I intend dunking them in hydrochloric acid, as I am guessing the cause to be accumulations of carbonates. Care is needed using hydrochloric acid with aluminium alloys, it will attack the pure metal fairly readily but marine grades seem to be pretty resistant, at least for half an hour in my experience.

Photo shows a masthead antenna connection in an aluminium bracket. Immovable due to salts but within ten minutes was completely free. The salts are fizzing but the bracket was untouched.
 
vyv_cox said:
Some of the sheaves on my deck organisers have seized. They are plastic wheels (Acetal?) in aluminium alloy frames. I intend dunking them in hydrochloric acid, as I am guessing the cause to be accumulations of carbonates. Care is needed using hydrochloric acid with aluminium alloys, it will attack the pure metal fairly readily but marine grades seem to be pretty resistant, at least for half an hour in my experience.

Photo shows a masthead antenna connection in an aluminium bracket. Immovable due to salts but within ten minutes was completely free. The salts are fizzing but the bracket was untouched.
Click to expand...

For jobs like that, a dropper bottle sounds like a useful thing to have around. When I were a lad studying geology, we carried them all the time, to allow field testing for carbonate rocks! I daresay you can scrounge one from your local pharmacy.
 
Vyv makes a good point; what we tend to idly assume are chlorides are often carbonates.

Incidentally, boats kept in estuaries in "hard water areas" seem to get a build up of carbonate on the hull.

So another option is kettle descaler. The common ones seem to use citric acid, the more powerful ones use formic acid.
 
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I've had several successes in dismantling jobs by applying a constant force in the "dismantling direction" supplemented with impact using one or sometimes two hammers to apply a vibration. The latter hopefully springs things apart momentarily whereupon the static force shifts them apart a bit in the desired direction. Repeat as necessary.
 
A question for those who clearly had more interest in Chemistry than I did...

I've seen Ammonia recommended for situations like this - to break down the corroded Aluminium, apparently without harm to the good material. I've tried it once and it seemed to help. Your thoughts?
 
anoccasionalyachtsman said:
A question for those who clearly had more interest in Chemistry than I did...

I've seen Ammonia recommended for situations like this - to break down the corroded Aluminium, apparently without harm to the good material. I've tried it once and it seemed to help. Your thoughts?
Click to expand...

Ammonia (ammonium hydroxide) is an alkali. Alkalis react with aluminium, potentially quite strongly, so it would need to be used quite carefully. Many years ago when I rode a motorbike there would occasionally be articles in the motorbike magazines entitled 'Boil your head'. These described boiling aluminium cylinder heads in sodium carbonate (washing soda) solution. This is also alkaline but much weaker, and apparently brings up weathered and corroded aluminium like new.
 
vyv_cox said:
Ammonia (ammonium hydroxide) is an alkali. Alkalis react with aluminium, potentially quite strongly, so it would need to be used quite carefully. Many years ago when I rode a motorbike there would occasionally be articles in the motorbike magazines entitled 'Boil your head'. These described boiling aluminium cylinder heads in sodium carbonate (washing soda) solution. This is also alkaline but much weaker, and apparently brings up weathered and corroded aluminium like new.
Click to expand...

Dissolving Aluminium in caustic soda is quite fun! But don't try it on anything you value, or wish to preserve.

Ammonia solution will certainly attack the metal as well as the corrosion products, but it probably attacks the metal more slowly than the corrosion products.
 
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