Bottom Removal

Hey, what a great forum!  I've been eavesdropping on you guys' conversations for a couple of weeks, now, ever since I pulled my drift boat out from behind a friend's barn.

It's a 16'/54" Tatman kit that I built back in 1996.  I used it a good bit on the Hiwassee and Clinch rivers in E. Tennessee for six or eight years, but it's been sitting behind the barn ever since.  Occasionally, I'd go over and bail the water and mosquitoes out of it, and put another blue tarp on it, but you know the rest of the story.

Please forgive me, for I know that I have sinned. 

But actually, and surprisingly, it's in better shape than I had feared. However, I definitely need to replace the bottom.

So, I've removed the UHMW shoe (a real boat saver on the Hiwassee) and begun removing the 3/4" plywood which brings me to the point of this post.

During the initial build, I coated the bottom with several layers of West System epoxy before using 3M 5200 to glue it to the frames.  I also used countersunk stainless steel screws which I faired with epoxy and wood flour.

You know the question, is there an easier way to get the bottom off?

So far, I've been alternating between removing sections between the frames with a Sawzall, then working on the remaining strips of plywood with a wood chisel to remove the top ply to get to the screw.  That's going OK, it's not fun, but I guess it's part of my penance. 

However, separating the remaining plywood from the frame is a punishment that no one should have to endure.

I even broke out the old Fein Multimaster, but the blades are pretty pricey, and if I hit one screw, they're history.  Plus it's not working real well, anyway.

So I need a magic bullet, or at least moral support.  Any ideas?  Or if there's a thread, here, that I've missed, maybe you could refer me to that.

Once the bottom is off, and I have a better feel for the damage (some of the frame bottoms, for sure), I'll have a few dozen more questions.

Thanks for any help.

Jack

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Permalink Reply by John Greenleaf on March 3, 2011 at 2:57am
Hi Jack, Sounds rough- One suggestion regarding the screws when you encounter them.. (note: if there is fiberglass on the bottom, this might not work as well, but you did not mention any so here goes). Anyway, Instead of cutting and burning through blades to cut the screw heads off - I've in the past used a small soldering iron (with a standard-type screwdriver tip) and plunged it into the epoxy covering the screw. While it smells real good, it does clear the epoxy out pretty quick. In almost all cases, once the countersink hole and head of the screw is cleared out, I can back the screw out with a screwgun. Takes about 20-30 seconds. keep up the good work.  JG
Permalink Reply by Jack Rose on March 3, 2011 at 7:26am

John, excellent idea!  Yes, that was one of my problems, clearing the epoxy from the screw heads that I had so carefully filled, 15 years ago.  Removing the top ply with a chisel was working OK, but it's pretty hard on the chisel.

 

So are you using just a flat head screwdriver bit?  My screws are Phillips head, but a small enough flat head would probably work for clearing the epoxy.  Or are you saying that getting the epoxy "cap" off is be good enough to get a Phillips head bit on the screw?

 

I'm heading to the shop, now, to give it a go.

 

Thanks,

 

Jack

Permalink Reply by John Greenleaf on March 3, 2011 at 8:38am

Maybe I was a bit unclear - Use a soldering iron. - It is the soldering iron tip that looks like a screwdriver tip (real small soldering iron). It is small enough to fit into the head of the phillips screw and clean out the nooks of the screw head that have all been filled with epoxy. It should once heated up, plunge right through the epoxy. Sorry,  Hope that is a little clearer

Permalink Reply by Troy Nicolls on March 3, 2011 at 7:39am

I had a similar problem when removing the bottom on an old 16 footer I rebuilt last spring. I had to cut through the bottom right along the edge of each frame in order to chisel off part of the bottom. By bottom was nailed on mostly but with a few screws. As far as twisting out the old screws...you might try cutting a new groove into each screw using a little cutoff wheel in a dremel tool or I know Craftsman makes a screw removing bit used with a driver drill. They are basically a reversed fluted drill bit but with a biting head instead of cutting head. I have a set of three I think cost $20, but I have never used them. If they worked, it could make your life much easier. I wonder if heat will soften that 5200?

 

Don't ya hate tearing appart something you spent so much time on making perfect? Been there...

Permalink Reply by Jack Rose on March 3, 2011 at 9:18pm

John, thanks.  I ended up going a less delicate route.  Your soldering iron gave me the idea of applying heat, and after persuading myself that there was nothing about the bottom that I wanted to save, I got out a propane torch.

 

And Troy, I planned to use your suggestion, but after popping the little caps of epoxy out with a flat head screw driver and hitting the remaining residue inside the screw head itself with the propane torch, most of the epoxy went away, and all the screws came right out with a cordless screw driver.

 

I had already cut out the 1/2" plywood floor from between the frames, so now I'm down to alternating between a wood chisel and a knife blank that I'm using like a small froe to separate the remaining plywood from the frames.

 

It's fairly easy separating the plys from each other, it's removing that last ply that's bonded to the frame with 5200 that's a bit tedious.  Everything you've ever heard about the tenacity between 5200 and wood is true.  When I head back, tomorrow, I'll be taking an old draw knife and a power plane to see if either of those will speed up the process.

 

Then, the even more tedious task will be separating the chine from the sides w/o tearing up the 1/4" plywood hull.  If I have any miracle breakthroughs, I'll let you know.  And I hope you guys will do, likewise.

 

Thanks for your advice,


Jack
Permalink Reply by John Greenleaf on March 4, 2011 at 2:44am
Awsome, I love the brute force approach- probably the most appropriate in this case. That 5200 really is a monster- though it does have 2 weaknesess that I know of and that's 1) a day long soak in acetone and 2) it can be cut (like bladed cut not saw cut). The blade has to be very small; like a chisel is too big in my book.. Perhaps use a small guitar string (high E) wound around two dowels that you can hold onto. Then work it between the frames and the plywood kind of like a draw knife, but smaller. Just a thought...Keep up the good work and keep us posted. J.G.
Permalink Reply by Robb Grubb on March 4, 2011 at 12:18pm

Way to go on the brute force, I used a hack saw blade (just the blade) with gloves on, with my floor replacement, cutting through the 5200 as well as some of the screws that would not come out. I would really prefer to build a whole new boat than replace another floor and chine...

http://www.woodenboatpeople.com/forum/topics/new-bottom-and-chine-o...

Cheers, Robb

Permalink Reply by Jack Rose on March 4, 2011 at 9:52pm

Robb, yes, I've had that thought many times over the last few days.

It reminds me of my best friend's question upon first seeing the house that my wife and I have grown to love as we've fixed it up over the years, "why don't you just tear it down and build something nice?"

I'd guess that everyone on this forum knows the rebuttal to that.

Today, I rediscovered the wonders of a draw knife that I bought at a flea market sometime during my college days.  I'd highly recommend one to anyone who is thinking of separating a plywood bottom that's been bonded to an oak chine or frame with 3M 5200.

After cutting out most of the bottom up to the frames and chines with a Sawzall, I was left with just the plywood that's glued and screwed directly to the frames and chines, themselves.

I found that my old draw knife was great at removing the top ply to expose the sunken, epoxy-covered screw heads.  After backing those out with a cordless screwdriver, I had at it with the draw knife, again, all the way down to the bare frames and chines ... just like peeling the bark off a log.

By feathering the knife I was able to take off as much or little as I wanted at a time.  After one frame, I pretty much knew what I needed to know in order to do the rest of the boat.

It also helps that I'd amortized the cost of that $15 draw knife out over 30+ years as I couldn't avoid hitting a few screws.  Matter of fact, the knife even sheared the edges off some of the stainless steel screw heads.

Thanks for the link, those pictures look awfully familiar.

Next, on to replacing a couple of frame bottoms and repairing the bottom edge of the plywood sides, before putting the new chines on.

Sounds like a new thread to me.

 

Jack

Permalink Reply by justin nicola on March 5, 2011 at 5:23am

i got a tool called a "spider scraper" on impulse a few months ago from my local lumber yard.  it costs about $5, and is a scraper that fits in a sawzall.  i too know the pain of buying fein saw blades, and these are both beefier and far cheaper.  they make three different sizes.  the small one would work well for what you're doing.  good luck, doesn't sound like much fun.

 

Permalink Reply by Jack Rose on March 5, 2011 at 7:44am

Cool, I'll check them out.  It looks like they've got a whole line of products that might come in handy.

 

As for my bottom project, I think I've turned the corner and I've moved from destruction to repair.

 

Jack

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