Removing Heavy Calcium Scale

[wbeaton]

I recently picked up an outboard motor that had been used on a sailboat. The lower unit is covered in heavy calcium build up. I've put a lot of elbow grease into it, but much of the scale is super hard and not readily coming off. Anyone have any ideas how to remove it?

 

[johnnyd]

Re: Removing Heavy Calcium Scale

I glass beaded mine, and it took the scale and barnacle build up completely off down to the bare aluminum. Then repainted. If you do this tape off and cover any areas you don't want exposed to sand, it gets everywhere, but it is the best method I've used.

 

[Coors]

Re: Removing Heavy Calcium Scale

toilet cleaner; any brand

 

[External Combustion]

Re: Removing Heavy Calcium Scale

CLR brand works well. If it is an antique and you have to be carefull, place it in a trash can and fill the can full of outdated orange juice. In ten to fifteen days all of the deposits and corrosion will be gone. Citric acid will not touch the parent metal. I know this sounds crazy, but I use it on irreplacable antiques. I just got through flushing the radiator on my Caterpillar D-4 with it. The juice cut through over 60 years of calcium biuldup and rust with no problems. It does take time though. I left it in the radiator for ten days.

During the summer the juice will ferment, but that does not hurt it's action. Any citric fruit juice will work. Just go to the local grocers and tell them that you want their outdated product and that you will not drink it or give it away. Most of the time they will give it to you free as they do not have to dispose of it themselves.

 

[wbeaton]

Re: Removing Heavy Calcium Scale

Thanks for the tips, fellas. I'll try the CLR, toilet cleaner and the OJ. I especially like the OJ trick. lol

 

[Wotam]

Re: Removing Heavy Calcium Scale

A bath of cheap vinegar works too... quicker than the OJ.