Rust Removal


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Living in Hawaii, things rust fast...... super fast. Trivia, and surprise, when I was living in Oahu things rusted much faster than here on the big Island. About a year ago I bought a piece of 1/4" steel for making a sanding disc. I decided not use it as I thought it would be too heavy for the motor and opted for aluminum instead. Anyway, I left in storage and it rusted (as shown in pix 1)

So, I cleaned it with about 72 grams of 99% pure citric acid mixed in a gallon of water.

Attached are the pixs of the piece before and after

After 3-4 hours in the acid, I washed it off and green scrubbed clean. Then sanded the top with 150 for about 1-2 min a side and then cleaned with rubbing alcohol and primed.

Personally, I think the phosphoric acid is more effective, but this is what I had.

All the other things I de-rustred cleaned up nicely. I think that was due to the better alloy steel.



Corporate Member
Thanks - why do you think phosphoric acid is more effective and do or did you have any examples?

I was REALLY curious that you said "... in Oahu things rusted much faster than here on the big Island"
Is there a reason you know of?
Is it scientific "fact" or just your opinion?

It seems the exposure to the salt water of the islands would be the same on any island - they only think I can think of that is different is "active volcanic activity" on the big island, which in my mind would potentially be MORE atmospherically acidic???
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Phosphoric acid in the past worked faster, that could be from the dilution percentage factor but, what I like is it leaves the surface with a natural inhibitor because of the reaction. The citric acid does not. The recommendation was 50 grams per gallon, but I used 72. The citric acid did work good on the tools

Being around a salty environment everything rusts faster. I think from a factual basis because I live on the Hilo side of the big Island it rains more. I think that is one big contributor, if you live on the Kona side you get the Volcano smog (VOG) this contains sulfur dioxide (really harsh on ppl and metal) which is constant as long as the winds move towards the west. It also only gets about 40% of the rain we get on this side. Useless fact: When we install HVAC equipment in Guam even when treated with BYGOL rust treatment (considered the best today) the coils only last 3-7 years vs here in Hawaii 10-15 vs say North Carolina or California 20 years. But, Guam is basically a flat table island much like Florida. Lots of Stainless hardware sold here.
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Marshall islands, Guam, Saipan & Hawaii

It's Military related. I no longer go there other younger and more enthusiastic do so.

I would love to go to the Galapagos to go diving

That's quite a service area you have there. Hawaii to Guam. Do you cover the Galapagos, too?

Roy G


Be VERY mindful of the fumes from either phosphoric or muriatic acid. Strip as much as you can mechanically first.

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