cleaning with oxalic acid

[mtorts]

Hey guys i bought a alluminum fishing boat this year which was always keept in the water during the season for several years. The bottom as you could imagine is heavily stained and has algae growth on it. I have heard of people using oxalic acid to clean the hull with great results but i was wondering if it would harm my boat. It is painted alluminum, also would it harm my trailer. I just painted it this season and don't want to destroy it. Any advice or experience using this acid for cleaning would help. Thanks

 

[90stingray]

Re: cleaning with oxalic acid

Have you tried soap and water and a scrub brush yet? Just curious before going with the harsh chemicals...

 

[soggy_feet]

Re: cleaning with oxalic acid

I believe oxalic acid will eat the paint right off...

 

[Philster]

Re: cleaning with oxalic acid

Acids (oxalic, muriatic) work great on fiberglass/gel finishes. For painted aluminum... well, you can't get as aggressive, because the paint layer sits atop the aluminum. Sometimes it takes power washing, but you have to know what you are doing.

Also: Acids can hurt painted and galvanized trailers. The galv trailer can come into contact with the acid, but it must be cleaned off quickly.

 

[mtorts]

Re: cleaning with oxalic acid

ok thanks guys. Yes i have tried with soap and water with a power washer. It took off the top thick layer but there is still a very distinct line. I have some star brite hull cleaner i will try that. Hopefully it will be safe on the alluminum

 

[robert graham]

Re: cleaning with oxalic acid

Oxalic Acid is more for removing wood stains...probably best to steer clear of the strong acids on aluminum or galvanized metals. While acids will clean aluminum very well, I believe it will etch the surface to make it more difficult to clean in the future. I use Purple Power from Walmart($4.87/gallon) for heavy cleaning, it's a strong alkaline detergent that won't attack the metal. Good Luck!

 

[dingbat]

Re: cleaning with oxalic acid

I use Purple Power from Walmart($4.87/gallon) for heavy cleaning, it's a strong alkaline detergent that won't attack the metal. Good Luck!

Purple Power is not to be used on aluminum. It says so right on the bottle.

Handling: General handling: avoid breathing vapor. Do not get in eyes, on skin or clothing. Do not swallow. Keep
container closed. Use with adequate ventilation. Wash thoroughly after handling. Keep away from aluminum metal.See Section VIII ? Exposure Controls and Personal Protection.

Storage: Do not store in aluminum, copper, or galvanized containers.

 

[robert graham]

Re: cleaning with oxalic acid

Purple Power is not to be used on aluminum. It says so right on the bottle.

Handling: General handling: avoid breathing vapor. Do not get in eyes, on skin or clothing. Do not swallow. Keep
container closed. Use with adequate ventilation. Wash thoroughly after handling. Keep away from aluminum metal.See Section VIII ? Exposure Controls and Personal Protection.

Storage: Do not store in aluminum, copper, or galvanized containers.

Well, I've used it diluted to clean my aluminum canoe for 25+ years with no apparent damage, but I wouldn't argue with the instructions on the label, so do whatever works for you! Good Luck!

 

[1980Coronado]

Re: cleaning with oxalic acid

I have used toilet bowl cleaner like "The Works" (oxalic acid or hydrochloric acid) to clean a painted aluminum boat.....it's not going to eat your paint...it's not a solvent! Rinse everything off after cleaning and you'll be just fine.

 

[robert graham]

Re: cleaning with oxalic acid

I have used toilet bowl cleaner (oxalic acid) to clean a painted aluminum boat.....it's not going to eat your paint! Rinse everything off after cleaning and you'll be just fine.

Yep, it's all about the dilution and how quick you rinse it off!...

 

[mtorts]

Re: cleaning with oxalic acid

I just did one side with the star brite hull cleaner. It worked well for the lighter water lines but the areas that are heavily soiled only had mild results. I think i will try to spot clean those areas with toilet bowel cleaner. I have heard of this being used often. I will post results later. Looks like a all day job LOL

 

[soggy_feet]

Re: cleaning with oxalic acid

I have used toilet bowl cleaner like "The Works" (oxalic acid or hydrochloric acid) to clean a painted aluminum boat.....it's not going to eat your paint...it's not a solvent! Rinse everything off after cleaning and you'll be just fine.

And I've spilled some oxalic on an old steel outboard gas tank that was laquered to all hell and back inside. Ate the paint and rust off around the mouth of the tank.

I don't think brake fluid is considered a solvent either, and I know that will eat thru just about any kind of paint you unintentionally spill it on, including a nice epoxy shop floor. :facepalm:

 

[1980Coronado]

Re: cleaning with oxalic acid

And I've spilled some oxalic on an old steel outboard gas tank that was laquered to all hell and back inside. Ate the paint and rust off around the mouth of the tank.

I don't think brake fluid is considered a solvent either, and I know that will eat thru just about any kind of paint you unintentionally spill it on, including a nice epoxy shop floor. :facepalm:

DOT 3 and 4 brake fluid contains a mixture of glycerin and alcohol also known as glycol and is therefore a solvent.