Orangish layer on boat will not come off

[Ajm1204]

Hello. I have an ebbtide boat. Fiberglass gel coat. I have the tan/orangish layer on the bottom of the boat. I tried everything I know of on it. Instant haul cleaned and on/off. I can scratch it off with my fingernail. Takes effort though. A boat shop said to use a razor blade carefully. Also tried different brushes Any thoughts? Thanks in advance

 

[alldodge]

Scotch Brite pads maybe

 

[flashback]

Some folks like toilet bowl cleaner along with the scotch pads..

 

[Ajm1204]

I thought the scotch brights pads would make the finish look hazy?

 

[Scott Danforth]

Use oxalic acid

 

[dingbat]

No need to use anything other than oxalic acid and a garden sprayer. Disappears like magic

Rinse trailer down with water before spraying

 

[Ajm1204]

Ok. Thank you for the help

 

[Ajm1204]

I was looking. The Instant hull cleaner and on/off products I used have that oxalic acid in it. And they did not work. Is there a specific product you were thinking of? I assume it is more concentrated

 

[Scott Danforth]

I was looking. The Instant hull cleaner and on/off products I used have that oxalic acid in it. And they did not work. Is there a specific product you were thinking of? I assume it is more concentrated

straight oxalic acid. mix per instructions.

https://www.amazon.com/OXALIC-Crystals-Cleaning-Removal-Remover/dp/B0147IFKBY/

hose on, do not let dry. hose on again... do not let dry..... hose on again. get stiff brush and long rubber gloves and start scrubbing. re-wetting as needed.

if you need something stronger, get muratic acid from the pool store. however you will need to cover your trailer with plastic.

 

[Ajm1204]

Ok. Thank you

 

[jimmbo]

I was going to say use Hydrochloric Acid, but Scott beat me to it. Make sure to wear proper PPE.

 

[dingbat]

This is what want I use. 1/4 bottle to a gallon of water in a garden sprayer.

Attwood Marine

Attwood Marine offers a broad range of boating and marine accessories. Visit us to find info for Instant Hull Cleaner and to find out where to buy.

old.attwoodmarine.com

 

[Scott Danforth]

Oxalic acid

 

[jimmbo]

You mentioned Muratic, which is Hydrochloric

In Grade 11 or 12 Chemistry, I remember taking Hydrochloric Acid, and Sodium Hydroxide, mixing the Two together, then after testing the PH, taking a sip. Salt Water

 

[jimmbo]

...

 

[Ajm1204]

Oxalic acid didn’t work

 

[jimmbo]

Try Hydrochloric Acid, just make sure to wear PPE and have adequate Ventilation

 

[chevymaher]

Sand and buff like I did.

 

[briangcc]

Rubbing compound may take that off. Going to have to keep switching pads so you don't grind in the gunk to your hull. Wax afterwards.

 

[tpenfield]

There is a product called "Iron Out" . . . not sure which acid it is, but it may be worth a try.

You can find Iron Out at many hardware stores.

EDIT: another thing you could try is 'descaler' (Barnacle Buster, etc) I believe it is phosphoric acid, it dissolves lime/calcium scale