Muriatic acid on hull

Willhound

Season is now officially done. Boat pulled and blocked yesterday. As you can see there is a pretty bad scum line. I spent the afternoon with some hot water and a bottle of Starbrite hull cleaner and it took most of the tea stain off and some of the growth line, but not all of it. I'm hesitant to use Muriatic acid, but everyone at the marina tells me it's the only thing that will take that off.

Was going to put some in a spray bottle, apply, let sit a half a minute, give it a scrub and rinse it off. There's no running water where the boat is blocked, I have to bring it in pails and use a garden sprayer.

Am I headed for disaster? Should I just live with the little bit of stain that's left?

Sorry, never thought to take an "after" pic, it does look much better, but still a grey stain from front to back. The tea stain under the swim platform came off beautifully with the Starbrite though.

GMSLITHO

I use the slimy grimy powder with hot water works great 

Willhound

Thanks @GMSLITHO but I'll have to see whats available locally. Has to be done Saturday so need something I can get my hands on fast.

Dream_Inn

I used a 50/50 mix of muriatic acid and water for many years with my last boat.  Pour water in first, then acid.  Wear a mask and gloves.  You may want to use a brush just to get the spray rubbed on evenly.  Leave set for a minute or so, then spray off.

I could also use FSR (Fiberglass Stain Remover).  It works well too, but takes a bit more time to apply.  The Mary Kate On/Off also works, and I believe has muriatic acid.  To me, if you are going to use it, just buy the muriatic acid.

Black_Diamond

The Works toilet bowl cleaner!  Just wipe on with a rag and rinse after. $0.99/qt. 

212rowboat

^that stuff uses acid too- as in citric acid.  

muriatic acid will absolutely work, but it is not kind to trailers or tarmac.  put Vaseline on any through hull metals, too, to protect them before applying acid. wrap your outdrive in a plastic lawn and leaf bag... anything metal or organic won't like it too much, but both citric acid and muriatic do fantastic jobs.  

i'd want to have water present, though, to rinse thoroughly... 

Ian

I did mine last night in it's storage on blocks. Latex or similar gloves and then a second pair as well as mask. Poured into a bundled rag, wiped along the stain, some comes off, leave a moment and then wipe down more and comes off easily. Needed a rub in a few places but otherwise all nice and clean without excess use and affecting anything else.

Willhound

Muriatic still sounds pretty heavy duty. Can't find a supplier for "The Works" in Canada and Mary Kate only available by order through Amazon.
I can get this stuff: https://www.homehardware.ca/en/900ml-toilet-bowl-cleaner/p/4521244
Similar to the Works?

Ian

To clarify: I used muriatic for the prop cleaning - as I learnt from the fine chaps here last year - but "On and Off" for the hull. It is labeled as a boat bottom and hull cleaner.

Cableguy Greg

I have used Lysol Toilet bowl cleaner mixed with peroxide with success. It's a 50/50 mixture used in a pump up sprayer. I have heard it can stain the hull if left on too long, but it never happened to me. Slimy Grimy works great. The original owner was from Pittsburgh and developed it to clean his boat bottom.

Dream_Inn

MaryKate has oxalic, hydrochloric, and phosphoric acids all in it as well.  So, if you are concerned about muriatic acid, then you should be concerned about using MaryKate as well.  FSR does work as well, but has oxalic acid in it.  I'll just add, that 90% of the boats in my marina are on lifts.  The majority of them have been using a mix of water and muriatic acid for many years.  I agree that it is tough on metals, so as 212row said, cover certain things up.

Liberty44140

I’ve used zep industrial toilet cleaner with great success and also the Mary Kate on/off is meant to help remove those stains. I’ve heard that the works that BD mentioned above also works very well but I’ve never tried 

MarkB

Muratic is the standard way to go when cleaning green on the hull. That's what the pro's use.

Willhound

Thanks @MarkB. That's what the marina guys ate telling me. I'm just nwrckus because of the no decent water for rinsing situation. 5 gallon buckets and a garden sprayer. Boat is blocked away from the marina in a field.

Michael T

Agree but - just don't leave it on long. Scrub and thoroughly wash off. I used Muriatic acid for over 20 years for cement finishing. It will leach the resins out of fiberglass fast and cause it to get brittle if left on too long!

Willhound

Well, I now have a favourite hull cleaner. 
These pics in order are the hull fresh out of the water, after a pressure wash, after using Starbrite hull cleaner and then the stuff that actually worked. Only minor burns on my right cheek.

randy56

Rubber gloves are a must when your using that harsh stuff,  I also wore a face mask.  You cannot lick your fingers or pick your nose, at that time. Reminder: to wax those area's before going back in. as you cleaned it all off. Looks nice. 

Willhound

Yrep @randy56 gloves were worn. Should have had a mask, just held my breath a bit here and there and stayed upwind as much as possible. 10-4 on the wax, that's why I was wanting to get everything off this year. I wasn't happy with how it turned out last year. Wax will have to wait until spring though. Heading over to put the winter tarp system on....in the #*^&%* snow!

Glassguy54

Did Willhound say the "S" word?

Willhound

Yep. I swore. Worked in it most of the day. Currently 38F which is the high for the day. Mistress is all put to bed for the winter though. 

Dream_Inn

Willhound, almost looks like a sailboat with the cover on.   Looks good!  I've got mine all covered up for the winter as well.

randy56

Steep roof, guess you need it up there. he did say the S word! Going to be awhile before you can have another relationship with your mistress. Winterized one of mine today. Going in the barn for the winter tomorrow. 

Ian

As of a couple of weeks ago. Although hull is cleaned now. 

Ian

It has a couple of cell mates to chat to but it is in a clean, dry and secure place where I don’t care if there’s 3’ of snow outside. No worries about the weather and shrink wrap. 

Willhound

Dream_Inn said:

Willhound, almost looks like a sailboat with the cover on.   Looks good!  I've got mine all covered up for the winter as well.

That's a system that I bought about 6 years ago for my other boat and have since adapted it to this one. I was able to buy an extension kit for the frame and a bigger tarp, 27x45. I like to keep the tarp up above the radar arch, so yes, it's way up there. Snow just slides right off. I have about $600 invested, which is what shrink wrap would cost me for a single season so this makes more sense to me.

I could get indoor storage here...for about $2000 for the winter between transport and rent...

MarkB

@Willhound, we use 25% hydrochloric acid to dissolve metals like rare earths (cerium, lanthanum) from ores. Not sure I would want to use that on my boat.

Willhound

Well...done now. Rinsed the crap out of it.

McGarnicle

My marina uses muriatic acid for non painted bottoms if you check off bottom wash. Seeing some of the before and afters is pretty shocking how well it works, boats look pretty much brand new. 

Dirtythirty

Never use anything but this stuff...It works GREAT !  my scum line just drips off.  (the $40 price reflects the gallon size ...that will last you 2 seasons

Star Brite Rust Stain Remover - Easily Clean Corrosion Stains Off Fiberglass, Vinyl, Metal & Painted Surfaces

Sold by: Amazon.com Services, Inc

$40.01

natalee520

I know this is an old thread, but I just want to say thank you — this forum is a wealth of information as I learn to boat! The ugly yellow line around the bottom of the boat has been bothering me for a year and this thread helped me figure out what to do. I used the Star Brite (the acid made me nervous!) and it was so easy. Spray on, wait, melts away, rise off. No elbow grease required! Other people at the Marina were shocked as I did it at how easy it was. So thanks everyone (even years later!) for all the insight!

LaRea

Modern living through chemistry!