Our Hull is WET! Ammonia washing???

[wingNwing]

We're redoing doing the bottom. Step 1 was to grind off the old paint down to the gelcoat and add new barrier coat. But - after being in the water year-round for the last 10 years, our inch-thick solid fiberglass (no core) hull on our 1980 CSY is, unsurprisingly, wet. It's drying, but sloooooowly. The guy doing the work suggested an "ammonia wash" of the bottom. He said this procedure will temporarily loosen the outer layer of resin to let more water evaporate.

Have any of you guys ever heard of this? Any downsides (other than cost)? He promises us that the process doesn't actually remove resin or weaken the hull, just accelerates the drying time. I haven't been able to find anything on the internet about it, my searches just keep coming up with laundry products.

BTW, we're going to be using copper-epoxy bottom paint, supposed to be good for 10 years; we anticipate the cost will quickly pay for itself (fewer haulouts!) and I'll be blogging about the process (Life Afloat Archives). Will let you know how it all goes!

[capngeo]

its wet......so? Don't worry about it, dry the spots that need repair and forget about the rest. (JMHO)

[wingNwing]

Originally Posted by capngeo

its wet......so? Don't worry about it, dry the spots that need repair and forget about the rest. (JMHO)

Normally I'd be okay with that, but, well, unfortunately, the mfg won't warrant the paint unless its applied at <10% on the moisture meter...

[DeniseO30]

Which barrier coat are you using interlux 2000E? Or will they be mixing copper powder in a epoxy like west system? Never heard of using ammonia but acetone will dry surfaces real fast. Ammonia and or vinegar with soap will remove the "blush" which is a residue that some epoxies make when they cure. If it were my boat I'd just add copper powder to the bottom paint after the epoxy coat is done.

[wingNwing]

Denise - the paint basically is just as you say, copper powder added to epoxy: Coppercoat USA

[Fiberglass1Inc]

Never heard of ammonia but it's worth a try. Fact is your hull is constantly blushing out salt and an aggressive fresh water rinse every other day will help with the drying, with or without the ammonia. I'm assuming there were no blisters.
20 years ago we applied a copper/epoxy product to several bottoms. The most informative one started out in Florida where it worked OK but needed aggressive scrubbing now and then to keep the epoxy particles exposed. It then spent several years in the Bahamas where it did not work very well. It sat in Bell Channel, Freeport where the grass grew very quickly and there were no barnacles anyway. It then came back to us and we painted a Carolina "smile" around the waterline to help curb the algae growth. Once the algae starts growing the larval stage barnacles get started. The boat then went to South Carolina where the copper/epoxy worked quite well (less algae, cooler water). The last contact I had with the boat was after 10 years and it had served three owners quite well. But don't waste your time putting it over a wet hull!

[AnchorageGuy]

I think there are two conversations going here. You talk about "paint" and "barrier coat" and these are two completely different animals. The bottom needs to dry out to 3% or less for a proper barrier coat application. This will need to be either a natural drying process or a controlled environment to speed up the process. No type of wash or anything else will do the proper job. You have two choices, let it dry properly and have the barrier coat applied, or try some "experiment" and pay to have the job done right again the next time. Applying a barrier coat over a wet hull will make additional problems that you probably did not have before. Chuck

[minaret]

Originally Posted by wingNwing

We're redoing doing the bottom. Step 1 was to grind off the old paint down to the gelcoat and add new barrier coat. But - after being in the water year-round for the last 10 years, our inch-thick solid fiberglass (no core) hull on our 1980 CSY is, unsurprisingly, wet. It's drying, but sloooooowly. The guy doing the work suggested an "ammonia wash" of the bottom. He said this procedure will temporarily loosen the outer layer of resin to let more water evaporate.

Have any of you guys ever heard of this? Any downsides (other than cost)? He promises us that the process doesn't actually remove resin or weaken the hull, just accelerates the drying time. I haven't been able to find anything on the internet about it, my searches just keep coming up with laundry products.

BTW, we're going to be using copper-epoxy bottom paint, supposed to be good for 10 years; we anticipate the cost will quickly pay for itself (fewer haulouts!) and I'll be blogging about the process (Life Afloat Archives). Will let you know how it all goes!

I've been drying bottoms for many years and have never heard of an ammonia wash. Fresh water rinse or even a soap scrub followed by rinsing is normal procedure for air-drying, but air drying a really wet hull can take a very long time. Your manufacterer requires less than 10% relative for good reason, but you may find it impossible to acheive by air drying unless you live somewhere very dry and hot. I have used most methods out there from air drying to infrared radiant, but the Hotvac is the only real cure I have found. You should do some searches on this forum, there are a great many threads on this subject. Also on the subject of copper epoxy, which you should really look into as well. The horror stories here are legion. What are your present moisture meter readings like?

[bobconnie]

I feel like Minaret on this one !! The Only copper bottom Ive seen that seemed to work even a little, was a solid copper bottom put on in England many years ago ! And it was very expensive and still needed cleaning just as offten as any other bottom paint did !! If ya can get to the Caribe, ya can get paint that works pretty well as far as lasting go's!! Just my 2 cents

[wingNwing]

Thanx guys, this is really helpful.

I'm confident that the product will work in our waters; 4 boats at our marina have it. One is a dock neighbor has had the stuff on his hull for 8 years and loves it.

I'm going to ask the guy about using the tent and space heater approach on Monday.

[delmarrey]

Just float the boat in silica gel.

[Irish rambler]

I can only speak from my own experience. When I lifted my boat and detected light blistering I placed the boat on chocks on top of a giant sheet of heavy duty plastic. I ground off the old anti foul and blistering,( a really shitty job) I then cleaned the dust & crap away, taped up the sheet all around the boat to a foot above the waterline making sure it was airtight. I cut two apertures(one at each end of the boat) to fit a dehumidifier and taped them in airtight with the exhaust outside the plastic sheet, it took 3 weeks to dry the hull and was by far the cheapest option for me.
Hope this helps someone.

[wingNwing]

Thanx everyone for the helpful suggestions, comments, and commiseration. After about 30 days drying with agressive freshwater rinse to remove any exuded salt every 2-3 days; the boat basically showed no further change in moisture meter readings. We, the marina staff, and the mfg rep (who was very responsive and helpful) agreed that it would not be profitable to wait any longer and we began painting. The process went very smoothly. I'll let you guys know how the paint performs in about a year or so. Here's a photo
and blog post:Life Afloat Archives: Oooh, Shiny!

[callmecrazy]

Good to hear!

Did you end up tenting and heating it? Or any other method to hep the drying process, not counting the freshwater rinse you already mentioned?

[lancelot9898]

I have a couple of questions about some of the comments made here. One is the frequency for the fresh water rinse. 2 or 3 days seems to be suffiecient however I'm unable to be at the boat for that time frame and so I'm considering a fresh water rinse with scrubbing twice a day for a week. This is after the yard peels the gelkote from the bottom. Or during that time I could just rinse it several times letting it dry out 2 to 3 days between rinsing?? Seems like the more rinses the better??

The other question concerned removing blush from freshly applied epoxy. I was going to just use soap and water and scrub the epoxy however someone mentioned adding vinagar to the soap?