Rust Treatment - Steel Yacht

[FUTURE DAYS]

Hi Cruisers,

I have a 34ft steel yacht which is 30yrs old, and need some advice on rust treatment. I have been told Selleys 'Ferro pro' rust converter is good...has anyone had experience with this ?? or is there a better product available in Australia..... Cheers Harry 'Future Days'

[Boracay]

The best method depends on what's wrong. Can you post some photos?

Problem is, those who got it right don't know that they did. Me, I'm an expert in getting it wrong.

[capngeo]

We used a lot of Corroseal when I was working on the tugs

[Matt sachs]

Phosphoric acid works well also. What ever you use, you have to first scale off the big flakes and get it as clean as possible. If you have deep pitting be sure to get that last little bit out of the bottom of the pit, or the cancer will spread. Be sure to check the thickness in the bottom of the pit if its on the hull.

[CharlesFCook]

1. Chipping hammer
2. Needle Gun
3. Angle grinder with a wire brush wheel (Do Not Grind it out)
4. Ospho rust treatment (OSPHO: a formula of Phosphoric, Dichromate, and Wetting Agents)
5. Wipe with White spirits
6. Rustlock
7. Wipe with White spirits
8. Primer
9. Paint

Rinse and repeat ….

[hdra]

Depending on what the rust is like, using a 36grit flap disc on an angle grinder is often a better alternative to wire wheels - I've found that it's harder to get down to bright clean metal with a wire wheel than a sanding disc, although sometimes for deeply pitted areas a wire wheel can get in there. Another tool that is great for that stage is the little grinding cones that you can chuck into drills or dremels - they make it possible to clean out corners and deep pits a lot more cleanly.

[ViribusUnitis]

Originally Posted by hdra

Depending on what the rust is like, using a 36grit flap disc on an angle grinder is often a better alternative to wire wheels - I've found that it's harder to get down to bright clean metal with a wire wheel than a sanding disc, although sometimes for deeply pitted areas a wire wheel can get in there. Another tool that is great for that stage is the little grinding cones that you can chuck into drills or dremels - they make it possible to clean out corners and deep pits a lot more cleanly.

I would think that a disk on a angle grinder might end up removing too much metal with the rust. Most of the 30 foot size steel yachts don't use very thick metal. If you have to do several rust treatments over the life of the yacht in an area, I would think you could remove far too much metal to be safe.

A wire wheel would at least be safe from removing metal, and ONLY remove the rust, all be it somewhat more slowly than the disk.

[hpeer]

Originally Posted by CharlesFCook

1. Chipping hammer
2. Needle Gun
3. Angle grinder with a wire brush wheel (Do Not Grind it out)
4. Ospho rust treatment (OSPHO: a formula of Phosphoric, Dichromate, and Wetting Agents)
5. Wipe with White spirits
6. Rustlock
7. Wipe with White spirits
8. Primer
9. Paint

Rinse and repeat ….

8 - Primer - Ameron 2 part zinc epoxy - Dimetcote 302H(Marine/Offshore Only) http://ppgamercoatus.ppgpmc.com/products/Products.cfm
9 - Paint - Ameron 2 pary epoxy


302 info
Product Data/Applications Instructions (For Marine & Offshore use)
• Applies easier than any other inorganic zinc, using spray,brush, or roller
• Can be topcoated with most organic coatings as soon as solvent evaporates
• Low VOC
• Zinc dust is already mixed into the liquid portion
•Fast dry-to-handle
• Excellent resistance to topcoat bubbling
• Outstanding mudcrack resistance
• Excellent corrosion protection from unique formulation

Typical Uses
Dimetcote 302H Reinforced Inorganic Zinc Primer is a proven cathodic primer for protecting steel structures, tanks, equipment piping, and other surfaces exposed in the following environments:
On ships, barges and offshore structures.

Dimetcote 302H Primer is ideal for touch-up and maintenance
because of its ease of application,.wide compatibility and fast dry-to-recoat.

Recommended Topcoats
Amercoat® 370, 385 Amercoat 233H, 235,
236
Amerlock® 400, 400FD Amercoat 201, 230
PSX™ 700 Amercoat 5A

Dimetcote 302H surface must be clean and dry before topcoating. Water soluable contaminants may be washed off with water. Remove grease and similar contaminants with an emulsion type cleaner or neutral detergent. Rinse with clean water and allow to dry. Solvent wiping is not satisfactory
as contamination may only be spread and not removed. In some cases a mist coat/full coat technique may be required to prevent application bubbling.

Surface Preparation
Coating performance is proportional to the degree of surface preparation. Surface must be cleaned, dry, undamaged and free of all contaminants, including salt deposits. Round off all rough welds and sharp edges, remove all weld spatter.

Apply Dimetcote 302H as soon as possible to avoid rusting or other recontamination. Do not leave blasted steel uncoated overnight. Spot blast if needed.

Steel – New without pits or depressions – Dry abrasive blast,
SSPC-SP6 or pickle.

[hdra]

Originally Posted by ViribusUnitis

I would think that a disk on a angle grinder might end up removing too much metal with the rust. Most of the 30 foot size steel yachts don't use very thick metal. If you have to do several rust treatments over the life of the yacht in an area, I would think you could remove far too much metal to be safe.

A wire wheel would at least be safe from removing metal, and ONLY remove the rust, all be it somewhat more slowly than the disk.

Yeah, that makes sense - All of my rust busting has been on bigger steel boats where you can take a decent amount of metal out of 1/4 to 1/2 inch plates and get away with it - it's often hard to get all the little pits without grinding down pretty deep, even with a wire wheel. Depending on the age of the boat, you can sometimes find that what appears to be just a pit to be ospho'd over is actually the top of a whole pocket of rust when you grind into it - something that can be hard to do with a wire wheel. I really like using the sanding disks, but I can see how with thinner steel they could be a problem.

[capngeo]

For deep pits, a needle scaler is the way to go

[Don1500]

I'll probably get strung up on the yardarm for asking, but here goes:

What about sand blasting? There are many materials that can be used, one to suit every purpose.

[rustypirate]

Sand blasting is ideal, however it makes an awfull mess especially inside the boat. Also unless you are able to clean out ALL of the sand, it will collect moisture and increase the possibility of more rust later on.

[SabreKai]

I'm going to be sand blasting inside SD so I'll be putting up plastic sheeting to separate parts of the hull like you would see in an Asbestos removal operation. Then my 425 cubic inch turbocharged Rigid shop vac will take care of the sand. The cute little Stinger shop vac just isn't up to it.

[Sangsom]

Broken drill bits are great for getting into tight spots and wheedling out the bottoms of pits, make sure you wear eye protection though!

[TOM]

Originally Posted by FUTURE DAYS

Hi Cruisers,

I have a 34ft steel yacht which is 30yrs old, and need some advice on rust treatment. I have been told Selleys 'Ferro pro' rust converter is good...has anyone had experience with this ?? or is there a better product available in Australia..... Cheers Harry 'Future Days'

You poor thing , you will spend a large amount of time fighting rust . Steel boats are not great ..we are currently sailing around the world on one actually a very good one but no matter how good they are made and how good they are primed you will still get rust . the only way to go is AIR TOOLS .Arm yourself with a compressor and some lethel air weapons and go to war! You need Shiney steel almost white and a good epoxy primer anything less then GLEAMING WHITE STEEL is a waste of time.

TIME .....YOU can achieve in 10 minutes with air tools what will take you an hour with a wire wheel.

Good Luck.

www.byamee.com