Barrier coat?

JSmith · Post by **JSmith** » Tue Nov 07, 2006 9:40 am

We have half the bottom strip down to nothing- just little quarter size areas that I'll probably run some 120 grit over as I sand it all. This is on a 1960 Alden Challenger so not looking to have a hard racing bottom- stripped mainly to find all the ghosts in the closet- quite a few minor digs into the glass that were not visible w/ 3/16" of bottom paint on her.

My question is after repairing the digs, etc. do we just lay some good old fashion bottom paint back on? What is a barrier coat?? We're putting a green back on so I don't think we'll go the ablative route, unless we can find a suitable color.

We stripped all the spars to bare wood (they were painted white) and have 8 coats of varnish on. The cabin trunk was also white & we satripped that and have 5-6 (and counting) coats of Schooner on it along with the coaming etc.

The second question is our cockpit below the seats is plywood mahogany veneer that hasn't seen varnish in a long long time- we'll never get the deep color back and how tricky is putting new on?

Thanks for the help, Jon

Jason K · Post by **Jason K** » Tue Nov 07, 2006 10:27 am

Hi Jon,

I bet the rig looks great.

A barrier coat is essentially an epoxy paint. It's purpose is to create an impermeable membrane to keep water from seeping onto the laminate and creating blisters. However, I consider a barrier coat as part of a repair process - not a normal component of a bottom paint job. If you are not experiencing a blister problem now, then there is absolutely no reason why you would need a barrier coat. In fact, some think a barrier coat used unnecessarily can trap existing water in the laminate and actually cause blisters.

You should be able to find a green ablative in any chandlery.

I'm not sure I understand the question about the veneer. If it is only veneer, I can't imagine replacing it would be all that difficult. When you say below the cockpit seats, I assume your talking about the sides of the cockpit well and not the sole?

Mark.Wilme · Post by **Mark.Wilme** » Tue Nov 07, 2006 10:39 am

How did you strip the bottom ?

chemical peel ? hand tools ? power tools ?

Duncan · Post by **Duncan** » Tue Nov 07, 2006 10:52 am

Sounds like you've got some very satisfying accomplishments under your belt now! NICE boat.

You might want to alternate colours on the bottom paint - helps next time around to know when you're through the first coat?
Very hard to say on your plywood veneer - it's a catch 22, since new varnish won't hold unless the prep's good, but it's ridiculously easy to sand through the veneer. Depends on your sense of aesthetics, but I dunno, I'd be tempted to paint it.

Figment · Post by **Figment** » Tue Nov 07, 2006 11:17 am

I'll second Duncan's suggestion on the alternating colors. It's a handy telegraph.

I also agree with Justin on the barrier coat issue. Don't do it unless the hull is REALLY dry.

JSmith · Post by **JSmith** » Tue Nov 07, 2006 5:52 pm

Thanks for the info! I def. have no blisters on the bottom. We tried every chemical know to man and settled on reg old kleen strip from Home despot. Soy strip was ok , peel-away worse but we were working w/ temps 45-55 which are chilly for all that stuff. Even went the overnight route covering w/ saran wrap or wax paper w/ no better result.

Took about 10 gal. The spars and trunk sides we did w/ a heat gun. Earlier I asked if any one had tried the silent stripper-infared- but didn't go there and glad we didn't considering the cost. The best thing we did was a hyde pull scrapper w/ the tungsten carbide blade. The blades were expensive but well worth it.

The veneer is in the cockpit well and I think we'll put new in and varnish- the rest looks too good. Eventually we will replace that plywood w/ new. Our cockpit sail locker hatches are raised- I don't think they were originally- and not at all water tight-not to mention uncomfortable. So that's the next project.

I'm tech challenged- need to reboot my RAM every morning but I'll try and post some pix of our progress.

Jason K · Post by **Jason K** » Tue Nov 07, 2006 6:29 pm

We tried every chemical know to man and settled on reg old kleen strip from Home despot.

Just a heads up - many of the strippers you'll find at Home Depot-type stores are not formulated for use on fiberglass.

Post by **Tim** » Tue Nov 07, 2006 6:58 pm

Don't barrier coat. Jason's comments above echo my own thoughts closely, so I won't bother reiterating it more.

Micron CSC has a nice green ablative; the West Marine version also has a green, though it's somewhat darker. Petit Vivid is also an ablative, and has a bright green that I used last year. A "signal coat" of a different color is a good idea for boaters who keep their boats in the water year-round and want true multi season protection, but if you haulout and repaint every year like we do in Maine, the signal color will never show through and isn't really necessary.

You can try the veneer in your cockpit; I'm sure that will help the appearance for now, but it may not last forever.

Figment · Post by **Figment** » Tue Nov 07, 2006 7:59 pm

I find that the "signal coat" is handy even for annual-haulout types... tells you when to stop sanding!

Capn_Tom · Post by **Capn_Tom** » Tue Nov 07, 2006 8:08 pm

I am curious about the condition of the vener. Most hardwood veneer plywood is not exterior grade and if it hasn't been varnished it is probably delaminating. If a small panel is well supported delamination is not always easy to detect. If it is exterior and in good shape replacing the veneer is pretty straight forward. Check oakwoodveneer.com

JSmith · Post by **JSmith** » Tue Nov 07, 2006 9:47 pm

forgot to add as soon as we strip off the paint we use a green 3m pad and thinner to wash/scrub off the stripper and then we will pressure wash the whole works.

Peter · Post by **Peter** » Tue Nov 07, 2006 11:12 pm

JSmith wrote:The best thing we did was a hyde pull scrapper w/ the tungsten carbide blade.

Can you tell us more about this scraper? width? model? etc.
My Vega sits in the boat shed awaiting a complete stripping. So far I've power-washed off a fair bit of the loose stuff, but there are areas that are still pretty tight ... and thick :-(

Post by **Tim** » Wed Nov 08, 2006 6:41 am

Figment wrote:I find that the "signal coat" is handy even for annual-haulout types... tells you when to stop sanding!

Why would you sand ablative paint? The only reason I use ablative is because it doesn't build up and threfore requires no sanding. The fall scrubdown after haulout provides more than enough "tooth" for the new coat.

Post by **Tim** » Wed Nov 08, 2006 6:44 am

Peter wrote:
JSmith wrote:The best thing we did was a hyde pull scrapper w/ the tungsten carbide blade.
Can you tell us more about this scraper? width? model? etc.
My Vega sits in the boat shed awaiting a complete stripping. So far I've power-washed off a fair bit of the loose stuff, but there are areas that are still pretty tight ... and thick :-(

I don't mean to speak for JSmith, but I have had good luck with this Bahco carbide scraper. The carbide really does make all the difference (as with most cutting tools). This one is 2-1/2", but there are other sizes, including a 1". I have two or three of these.

Carbide Scraper

CharlieJ · Post by **CharlieJ** » Wed Nov 08, 2006 9:38 am

Figment wrote:I find that the "signal coat" is handy even for annual-haulout types... tells you when to stop sanding!

I was wondering the same thing- that's one of the real beauties of ablative- no sanding. Other than continuosly showing fresh paint as it wears away.

Mines 18 months old now, in Texas waters ( read WARM) and still doing well.

When we did Tehani we stripped MANY old layers of who knows what off the hull. Found zero blisters- I wasn't really surprised at that - the older boats didn't seem to have the problems with blistering. But because of some other damage, we did a good bit of fairing with epoxy filllers, so finalized the redo with 3 coats of WEST with the 422 filler they have designed as a barrier coat additive. The cast iron keel got two coats of Coal Tar epoxy pre painting. We'll be hauling in the spring for a bottom job- we'll see how it looks then.

Figment · Post by **Figment** » Wed Nov 08, 2006 9:51 am

I guess I'm just a nut. I think bottom paint should be sanded down at least every three years. I go every other year. This keeps things fair (depending on the person holding the tool) and I also think there is benefit to getting up close and personal with the hull once in a while to be able to catch small problems before they become big problems.
Though far less critical, it's really the same logic that says you should unstep the mast every few years.

Post by **Tim** » Wed Nov 08, 2006 1:13 pm

Figment wrote:I guess I'm just a nut.

You said it, not me! hehe

Peter · Post by **Peter** » Wed Nov 08, 2006 8:31 pm

Thanks for the link, Tim. I also found this one on the same site, also a 2 1/2" Bahco. Any comments?

Post by **Tim** » Thu Nov 09, 2006 7:02 am

They call that one the "ergo" model. It has foamy-stuff on the handles for added comfort, I guess. Otherwise, it's identical.

JSmith · Post by **JSmith** » Thu Nov 09, 2006 7:27 am

Those blades look to be just the same as what we used- You can spin them around and get another edge. Lowes has them for $5-$6. There is also a small one w/ a 3 cornered- 3 sided blade around 3/4" to the side. This one was tricky to use as it loved to take a digger into the surface with absolutely no prompting on my part :)