InterProtect 2000e Surface Prep - Interlux Help Unable To Help

[zstine]

To Intelux Help....
"I stripped my keel b/c blisters had formed due to galvanic corrosion (lost all my zinc for a while). The keel has some areas of 'rust' spots that are like little worm holes that penetrate maybe 1/4 inch into the lead. I stripped with 40 grit sandpaper to lead, but there's no way I can get down 1/4 inch into the lead to remove all the corrosion holes. Is there a chemical such as phosphoric or oxalic acid (sometimes used for rust removal on steel) that you recommend for treating the corrosion or is it OK to leave some corrosion spots untreated? Thanks Zach"
Interlux Reply ....
"The corrosion areas need to be addressed because they will continue to corrode. I don’t know if the products you suggested will work or not and cannot recommend them. "

Interlux says I must address, but doesn't say how. What do you CF people think I should do for surface prep for epoxy coat 2000e? I attached a picture of the corrosion. Ignore the pink filler, the corrosion is the small brown spots.

[minaret]

Blast it bare (near white as per ASTM standard) and coat it within 45 minutes of blasting, while ensuring the substrate (lead) stays 15 degrees F above current dew point.


DIY recipe is roll on two coats of epoxy resin neat, catching the bond window. Then trowel on epoxy thickened to mayo consistency with 407, also catching the bond window. Board fair. Then barrier coat with Interlux.


When you roll on the first coat, wet sand with coarse emery paper while the epoxy is still dead wet, or scrub it with a stiff wire brush. Then reroll it to make it nice again.

[s/v Jedi]

Originally Posted by minaret

Blast it bare (near white as per ASTM standard) and coat it within 45 minutes of blasting, while ensuring the substrate (lead) stays 15 degrees F above current dew point.


DIY recipe is roll on two coats of epoxy resin neat, catching the bond window. Then trowel on epoxy thickened to mayo consistency with 407, also catching the bond window. Board fair. Then barrier coat with Interlux.


When you roll on the first coat, wet sand with coarse emery paper while the epoxy is still dead wet, or scrub it with a stiff wire brush. Then reroll it to make it nice again.

Perfect! In my case I didn't have access to a sandblaster (but you can buy $30 ones that will work for those small pockets) and used a stainless wire wheel on an angle grinder to clean them out. The rest exactly like Minaret writes, I used a 2" wide stanless steel hand brush first, concentrating on those pockets and followed up with 60-grit emery paper to touch everything. The wet epoxy combines with the lead sand dust and the fresh surface that appears with the sanding never gets in contact with air

[zstine]

Originally Posted by minaret

Blast it bare (near white as per ASTM standard) and coat it within 45 minutes of blasting, while ensuring the substrate (lead) stays 15 degrees F above current dew point.


DIY recipe is roll on two coats of epoxy resin neat, catching the bond window. Then trowel on epoxy thickened to mayo consistency with 407, also catching the bond window. Board fair. Then barrier coat with Interlux.


When you roll on the first coat, wet sand with coarse emery paper while the epoxy is still dead wet, or scrub it with a stiff wire brush. Then reroll it to make it nice again.

I talked to a guy about blasting my keel. $550!!

Interesting that you say to apply the fairing compound, then barrier coat. Interlux specifically says the reverse, barrier coat on bright metal, then fair over the barrier. Why do you recommend fairing first, under the 2000e?

[zstine]

Originally Posted by s/v Jedi

Perfect! In my case I didn't have access to a sandblaster (but you can buy $30 ones that will work for those small pockets) and used a stainless wire wheel on an angle grinder to clean them out. The rest exactly like Minaret writes, I used a 2" wide stanless steel hand brush first, concentrating on those pockets and followed up with 60-grit emery paper to touch everything. The wet epoxy combines with the lead sand dust and the fresh surface that appears with the sanding never gets in contact with air

Okay, I see these little 21oz gravity feed hopper guns at harbor freight for like $20. It will be pushing my air compressor, but I guess I can blast a minute, stop and wait for the air compressor for a min and repeat since it is a small area. What type of blasting grit? Can I catch the grit and reuse? Is there laws for how I do this, since I'm blasting Lead?

[s/v Jedi]

Originally Posted by zstine

Okay, I see these little 21oz gravity feed hopper guns at harbor freight for like $20. It will be pushing my air compressor, but I guess I can blast a minute, stop and wait for the air compressor for a min and repeat since it is a small area. What type of blasting grit? Can I catch the grit and reuse? Is there laws for how I do this, since I'm blasting Lead?

I take no risks and use cartridge respirators with all work like this. There are no laws that I know for this where I am but this is a 3rd world country and it sounds you are in the US so check it. Take the coursest grit that the gun can pass. I believe Tractor Supply has it as well as HF.

On what minaret wrote about fairing before the Interprotect: He first uses epoxy which is what is brushed and sanded into the lead and the fairing after that. Interprotect instructions don't consider that option but it's better because there is absolutely no need for mica plates to adhere to lead and epoxy is just epoxy

The blast media can be so cheap and you have so little to do that I think you don't need to recycle it.

[minaret]

Originally Posted by zstine

I talked to a guy about blasting my keel. $550!!

Interesting that you say to apply the fairing compound, then barrier coat. Interlux specifically says the reverse, barrier coat on bright metal, then fair over the barrier. Why do you recommend fairing first, under the 2000e?

Because you shouldn't attempt to chemical bond fairing compound to Interlux 2000, whereas it will chemical bond easily with neat resin of the same system. Also, 2000 dries too fast for wet sanding or wire brushing on the first coat. Use epoxy with a medium or slow hardener, depending on temps.

[lancelot9898]

Several years ago I went through the process of blister repair with a peeling of the gelkote. Interlux products were used and after much discussion I used the neat epoxy resin and as was next going to use the watertite filler material, Interlux suggested that better adhesion would be achieved if one layer of barrier coat be put down prior to the filler material. After that numerous layers of barrier could be added. The thought was that the neat epoxy required a lot of prep prior to putting additional material onto it while the barrier coat did not require the prep. The neat epoxy still required prep either way so putting the watertite filler next would have been Ok too, I suppose, but I followed Interlux's suggestion.

[s/v Jedi]

I saw a boat use a lot of that Watertite fairing epoxy and was surprised it actually worked well. They sprayed the Interprotect and that result surprised me as well but I still think rolling it is better because it's all about thickness of the coating.

[minaret]

Spraying provides substantially more millage per coat over rolling. However, 2000 and most anti fouling must be sprayed from an airless rig, and forced air respirator is absolutely required as the cure cycle consumes ambient oxygen. Spraying a bottom should only be done by certified operators using many thousands of dollars worth of equipment. If you spray, go to Tuff Stuff instead of 2000. It's much thicker, the required millage can be hit in two coats sprayed. But damn it's nasty!