removing varnish from a clinker dinghy

[Werona]

The material used on this dinghy is ply. I've used a burred scraper on her starboard side, to hasten the job I'm toying with the idea of using chemicals or a heat gun. Is it a good idea to use heat on ply? would it affect the glues near the surface of the ply? Should I stick with the scraper and a bit of elbow grease?

[JimConlin]

Wood is a good insulator, so it's unlikely that using heat to soften a finish will affect glues at the structural level.

[Wooden Boat Fittings]

I once stripped a ply forehatch of epoxy and dynel with a heat gun, and without damaging the ply.

Mike

[Jay Greer]

Get your self a gallon of Star 10 or Interlux 299E Stripper. With the boat inverted on horses lay on a thick coat with a junk brush. Do not back stroke. Go have a beer or a coffee. Take a look and see if the remover is working. If it is, then lay on another coat and have anorther beer or coffee. Come back and check again. If the firnish is lifting and looking a bit dry, lay on another coat. You may or may not want another beer. Even so, wait a half an hour. Put on some rubber gloves and protective glasses. Using a medium 3m pad and a high pressure hose scrub and blow off the finish. If any material is left, use a scraper. Time and materials required are an hour and a half plus two to three beers or lattes.
Jay

[mike hanyi]

heat gun, heat gun, stay away from chemicals, when you are done with heat gun-your done, start sanding and putting on a new coat.
chemicals taka a long time to go away,washing,uggg!

[Thorne]

Interior or exterior? If the former, how complex is the structure - lots of bent ribs, breasthooks & knees, or thwart supports creating nooks and crannies?

I'd say for a complex interior structure, apply the chemical stripper several times, then move to small scrapers. It will still be a beast of a job, but the more you get off with the scrapers the less you'll have to hand-sand.

[Rich Jones]

When I re-built my 1959 PennYan runabout, I used a heat gun to remove the paint on the outside of the lapstrake, marine ply hull. I had no problem with delamination. Interior, I just touch sanded and slopped a few coats of varnish because I covered the whole interior with ceiling planks.

[Werona]

Thanks for the advice folks, Thorne, I'll be concentrating on the outside of the hull initially. The insides can wait for another day. Jay, I'm thinking of a latte in the morning,then once the sun is over the yard arm it's time for a beer/stout etc. I think both techniques are worth a try,when I do get around to the inside of the hull maybe the stripper followed by a pressure wash might work. I'll suck it and see .
Cheers

[Tom Freeman]

On a hull, I would use a heat gun and scraper(s). Unless it was a really small hull. Then I would use Soy Gel. The heat gun shouldn't bother your ply. With the Soy Gel you won't need to do multiple applications, and it cleans up nicely with water.

[Werona]

It's a 12 ft dinghy, Tom, soy gel ?? hmmm I think I'll stick with a beer no chaser. I can't help myself, what is soy gel ?

[Dave Katt]

I spent the winter stripping a 14 ft. cold molded plywood runabout. I shouldn't say all Winter as it didn't take that long stripping. I would guess all the stripping which included the hull, deck and the whole interior removed to be stripped, probably took a total of 2 weeks. I used Zip Strip and tried Citrus Strip. Both worked well. I would slather on a coat of stripper and after about 15 min. use a putty knife to remove the old finish. I had to do this about 3 times total The last time I used #4 steel wool and the hull is now naked as the day it was born. Hopefully tonight, all the finish sanding of the wood will be done and I can start laying varnish.

[Thorne]

Dave - clean or even better sand that hull before you paint or varnish! If it will ever be anywhere near salt water, or towed on salted roads, you really don't want all those tiny little rusty bits of steel wool anywhere near the hull. Don't ask me how I know this...

[Jay.]

Hi Werona / Guys

My first post been lurking for a while but thought id like to contribute to a fantastic forum.

Iv stripped quite a few ply hulls with both methods, I personaly like the heat gun method, a bit cleaner and therapeutic on larger surfaces, the problem I have encountered depending on quality of ply used for contruction is voids in the ply, if there are any moisture/air pockets the heat can cause them to expand and bubble, not really a bad thing as at least you now know they are there, depending on severity they might need cutting out and repairing, I have had success depending on the moisture content injecting glues or epoxy into the void which will keep the Aesthetics intact for varnishing.

[skuthorp]

I'm working on a planked dinghy with about 1/4" of what I presume is lead paint and red lead as an undercoat. No heat gun, disposable overalls and outside on a big old blue tarp that I can throw away. Good breather mask as well. I bought a chisel at a flea market and made a tool for the job, tapping it with a sculptors mallet and workig very slowly. It might take me all winter I think. I don't have much varnish on the Mac.n

[Dave Gray]

I like Jay Greer's approach. I can see a lot to recommend it, mainly, beer!

[Lew Barrett]

Soy Strip (http://www.greenboatstuff.com/frsoystmacor1.html?productid=frsoystmacor1&channelid=FROOG) is a great product. This is one case where the new, non-toxic miracle goo really does meet it's claims in almost all applications. If I were you I'd buy a quart, available through Rockler or online at Amazon and give it a try. It is non-toxic and as Tom says can be washed off with water. How you treat the actual "scrapings (a scraper is necessary as it is with all chemicals) is a question of the paint base,but because it is soy based itself, it is much easier to deal with than most MEK based strippers. It's been discussed here many times. For most paints and substrates, I find it works virtually as well as airplane stripper and it is simultaneously not as caustic nor is the price out of line. It does cost more, but you can justify that by thinking of how many fewer fumes you are inhaling, how eco-friendly you are, etc. It works about as well on varnish as it does on most paints, but my experience is with long oil varnishes where it is almost foolproof. You really don't need a mask when working with this stuff.

I'd try the heat gun first ( if I had one and was stuck on the process) but I find chemical stripping goes a lot faster. Dry scraping only gets you so far and is very much harder to master as a skill. I rarely start there with any major project. You can still enjoy a coffee or beer (or three) as part of the Soy regimen, as it is otherwise frequently not to Jay's instructions and process.

[artif]

As a kid I used to strip the varnish of my grandads ply dinghy using bits of glass as scrapers, no heat, no chemicals just a bit of elbow grease. He had piles of old glass left from an old greenhouse, so we would break a bit off and go at it. Still do it now.

[Lew Barrett]

As a kid I used to strip the varnish of my grandads ply dinghy using bits of glass as scrapers, no heat, no chemicals just a bit of elbow grease. He had piles of old glass left from an old greenhouse, so we would break a bit off and go at it. Still do it now.

I suspect here are easier, less time consuming and more comfortable ways though.

[Jay Greer]

I like Jay Greer's approach. I can see a lot to recommend it, mainly, beer!
When you are in the business to make a profit, the fastest and easiest method is my choice. Yes one can use heat, but this is a clinker built boat! Heat drys out planking and scraping the laps with a heat gun and hook scrapter is a ticket to doing rough work and also damaging the wood. Just consider the possibility of hooking a bit of run off grain on a lap and yanking out a sliver! Then, when using heat, there is always the possibilty of getting a plank or its edge too hot and leaving dark spots! Plus, inhaling burnt paint or varnish fumes is not all that pleasant! I swear by Star 10 stripper as it is friendly to the skin and nose. Designed for stripping commercial aircraft it is one heck of a fast and efficient product~!
Jay

[Tom Freeman]

It's a 12 ft dinghy, Tom, soy gel ?? hmmm I think I'll stick with a beer no chaser. I can't help myself, what is soy gel ?

Lew referred to the product as Soy Strip. I think we are talking about the same thing. It turns varnish into butter-like goop in one application with about a 30 minute set time.

http://www.rockler.com/product.cfm?page=17402&filter=SoyGel

[John P Lebens]

Here's my short take based on many hours of stripping in the past year:

Use the green stuff when you can - Soy and Citrus Strip work extremely well. The advantage to Citrus Strip is it is widely available in retail outlets. Soy Strip is a great performer. Even if you aren't too concerned about the general environmental effects, the toxicity of some chemical strippers can be a very serious personal health issue. The green stuff might take longer, but I have found that by putting it on thick, it will sit and work longer before drying out. Jay is right that Star 10 works well - but I did find it dries out fairly fast, and it uses some nasty solvents.

Temperature, in my experience, seems to be the biggest single performance variable. All of these strippers seem to work more slowly in cooler temperatures. In warmer temperatures they tend to dry out. Covering them with plastic wrap can keep them working longer.

When it comes to epoxy, it's time to get serious and buy the highly toxic and effective Jasco.

(those of you who advocate using penetrating epoxy as a sealer should be assigned to spend a week or so trying to wood the surface afterward. Penetrating epoxy under a finish is a bear to remove by any means.)

[Thorne]

(those of you who advocate using penetrating epoxy as a sealer should be assigned to spend a week or so trying to wood the surface afterward. Penetrating epoxy under a finish is a bear to remove by any means.)

I've experienced a similar problem with deeply-applied boat soup under varnish on Doug Fir -- it makes it much harder to sand the wood down past scratches / dents / dings.

So these products like CPES and boat soup that are used to protect the wood really do end up protecting the wood - from our refinishing efforts as well as damage of other sorts. Go figure! (grin)

[Yeadon]

Third vote for Soy Strip. I used it recently to strip the varnish off my oars. It's great stuff. A clear, jelly-like goop. You mush it on, wait a while, scrape it off.

[Jay Greer]

Whether you use Soy or one of the many other strippers that are designed to turn paint and varnish into a "jelly-like goop", it is important to re-apply the remover in multiple coats, waiting for a space of time maybe one beer or latte, until the remover has thoroughly penetrated the finish down to the wood and one sees large amounts of finish actually lifting and almost falling off. At this time, a high pressure hose and 3m pad will, usually remove, 90% or more of the finish. Stubborn spots can be re-soaked and spot scraped. Where many people make a federal case out of stripping a hull or spar, I have found this method to be the fastest way of getting the job done.
Jay

[Dave Katt]

Thorne, no problem with the steel wool. I have used bronze wool on other projects, but found the way I do it, I have never had a problem. But, it is a very wise caution! I have done this so many times, I forget how many times. But, I always scrub the wood with water and a good brush when done stripping and then of course sand the whole hull down as now the wood, because it was wet, needs whiskered. Not to step on this thread, I just applied the 2nd coat in 24hrs. to the mahogany hull. It is almost spell binding to watch the wood look almost iridescent as the Ephianes is laid on and you change your angle of looking at it. I can't wait for another 24hrs. for the next coat.

[kbowen]

Beware of a heat gun on old varnish: it can basically drive the varnish further into the wood. Though there are those who would argue that this is better than leaving stripper residue in the wood (and your lungs). Stripping lapstrake is a bear anyway you cut it, I have done two 17' Rangleys, inside and out, and have found no "good" way. One tip, though: get an old handsaw and snap the blade into pieces, then grind and sharpen the pieces for all the various contours you will need to scrape. See any one of several WB articles on sharpening scrapers. May the force be with you.