Almost-A-SCAMP Progress Report #7A

[Charles Brennan]

I'll admit it:
I'm a little apprehensive (OK! Scared!) of working with epoxy resins, since I have no experience with them.
As a result, I've been dragging my feet and doing all kinds of interim mini-projects, so that this project wouldn't COMPLETELY, stall out. 
Like lofting/printing out the skegs.
Same trick as before:   
Scan the outline off the prints and make a .jpg file.
Insert the .jpg file into a drawing program.
Keep scaling the image larger and larger, until the lofting dimension offsets match the ruler scale on the drawing program.
Save the file (immediately!).
Reposition the huge image to the printable area of the printer on the drawing program and print out a portion of the image, a page at a time.
Align the pages by lining up lofting lines from one page, to the other page.
Scotch tape it all together.
You cannot view this attachment.

Use spray adhesive to stick the taped-together pages onto some stiffer construction paper.
You cannot view this attachment.
See?  EASY!! 

Here's what they look like on the bottom of a hull (not mine, since I'm nowhere near this stage of progress).
You cannot view this attachment.

Another project that's been making me nervous, is the centerboard pivot bushings inside the hull.   
This step is fraught with myriad ways to screw up.
Royally. 
Get the holes slanted horizontally and the centerboard can bind up in the centerboard trunk and jam.
Get the holes slanted vertically and you have the same problem, PLUS it rattles inside the trunk on any given tack.
In the SCAMP Camps, they make the trunk and trunk doublers early on and drill all four holes in a stack on a drill press, to make sure everything is 90º
My hull came with the trunk already installed, but the holes were missing.
No actually, it looks like someone tried to put in the holes and got it wrong, realized their mistake and filled the erroneous hole with epoxy.

Pencil intersection is the actual measurement.
You cannot view this attachment.

The other issues are mounting the centerboard pin and dealing with leaks.
There are all manner of approaches to installing a a ½-inch S-S pin into ½-inch i.d. bronze bushings glued in the CB trunk.
You cannot view this attachment.

They occasionally leak, as the O-ring on the pin below, shows.
You cannot view this attachment.

One attempt uses the same bronze hardware as the water ballast drain plug.
You cannot view this attachment.

I looked at several of these methods and they all seemed to me, to be too unnecessarily complicated.
I decided to simply use a bronze NPT pipe coupler with a ½-inch i.d. and some bronze pipe caps and a rubber washer in the cap to deal with leaks and hold the pin.
You cannot view this attachment.

But first, I needed a way to epoxy it into the trunk where it wouldn't unscrew itself, the first time I tried to remove the caps.
I used a Dremel tool with a cut-off wheel, to cut slots in the threads
The black line is where the pipe cap goes.
You cannot view this attachment.

All those jagged cuts along the threads ought to hold the epoxy glue nicely.
You cannot view this attachment.

Pipe caps screwed down.  They will have a rubber washer inside for water-tightness.
Might even use Teflon pipe tape, haven't decided yet.   
You cannot view this attachment.

Next, I needed a hole big enough for the bushings, plus room for epoxy glue, to ensure a solid joint.
Used a 1" hole saw.
You cannot view this attachment.

But, how to get an accurate right angle hole, using a hand-held drill, on a trunk that is already installed?   
I haven't had all that much luck drilling, by means of "eye-ball" engineering.   
So, after some thought, I made a 90º block that was square in two planes and used it as a guide to hold the hole saw square against the trunk sides.
You cannot view this attachment.

Here is the bushing and cap temporarily inserted for fit.
You cannot view this attachment.

But, how square is it?   
I used the tube from my splicing kit, since it was very close to the hole diameter
This is another one of those camera fore-shortening effects; it really is more square than it appears.
You cannot view this attachment.

See?!?   
You cannot view this attachment.

Since the outboard hole was not quite 2 mm out of square, I decided to oval the holes with a rasp on both sides a little, to allow me to align the bushings when it comes time to glue them in.
You cannot view this attachment.

I will wrap this ½-inch pipe with packing tape (so the epoxy doesn't stick) and use it to hold the bushings in-line and square and plumb, on the trunk.
I can use some stiff wire wrapped around one side of the pipe and run over the top of the trunk and run down and wrapped on the other side of the pipe for vertical alignment, and duct tape and a combination square, for horizontal alignment until the glue sets up.
You cannot view this attachment.

Next, I elected to work on making portholes for the dead lights. I had all sorts of scraps to use, from cutting in hatches.
Dusted off the scroll saw and had at it.
You cannot view this attachment.

Then I bolted them all together and sanded the edges, uniform and smooth.
Cut out the center holes (not shown here) next.
You cannot view this attachment.
They'll need a round-over from a router, but that's a project for another day.
Like, the day after I clean up and organize the garage good enough, that I can even GET to my table router!   

Finally decided I had done all the make-work projects I could, to delay opening up the epoxy jugs and therefore: Today's the Day. 
Started with the centerboard halves.
You cannot view this attachment.

Ok, not so scary after all; kind of like a cross between polyester fiber-glassing and varnishing.
I could do this.   
You cannot view this attachment.

Even have the same issues as varnishing!   
You cannot view this attachment.

Guess if the epoxy is good enough to hold down a bug that big, then 22lb of lead are probably OK, too.
You cannot view this attachment.

While waiting to see if the epoxy would actually set up, I made some screw "washers" for holding pieces of wood to the hull where clamps won't reach, while the epoxy sets.
They are wrapped with packing tape to keep from inadvertently becoming part of the boat, since the packing tape won't stick to the epoxy.
You cannot view this attachment.

The screw length was chosen to go through the 9mm wooden pieces and into the 9mm hull, but not completely through it.
You cannot view this attachment.

One of the problems encountered by the early SCAMP builders, was the cockpit seats sagging a little, when trying to rely solely on the seat/hull fillets.  Now they recommend cleats along the hull to reinforce the seats.
Since the hull is curved, the 9mm plywood seat-edge strips need a little "convincing" to conform to the shape of the hull. 
Now that I've gotten my feet wet, (or at least, my fingers sticky!) I think I'm going to be making a lot more progress on the SCAMP build.   

Charles Brennan

[Riley Smith]

I knew it was something! Working with epoxy is relatively easy as you have found out. There are some pitfalls which mostly involve curing time in the summer. (Too quick!) And clamping pressure (too much). Great work so far. Mmmm...be sure those bushings are actual bronze, which looks a whole lot like brass and is two totally different animals. Which is available if you know where to go (Fergusons plumbing supply and expensive). Keep plugging away and soon enough you'll be sailing! I kept having trouble daydreaming and staring at curves once the hull was done. That daydreaming is actually a form of bonding though 

[Frank B.]

I share your concern about working with epoxy.  I built a stitch and glue epoxy composite skiff.  If I had it to do all over again I would build a ply on frame skiff with more actual woodworking and less epoxy work.  I did four months worth of work over two years.  I learned that in the heat of the summer forget it.  I learned that in the cold of the winter forget it. I will only build again if the ratio of skilled work such as woodworking, metal working, plumbing and electrical is much greater than epoxy work.  Just an opinion.......

[Noemi - Ensenada 20]

Charles, what CAD program are you using?  More importantly, what format are the drawings in?  If they're .dwg, .dxf, .dws, .dwf, .dws, or .dwt, I could help with that sizing.  It's easy in the CAD program I use to size something so that it is exactly the size you want. 

Let me know if I can help.

[Wayne Howard]

I've gotten to the stage in life where I know my limitations. It's too hot, it's too cold, it's a nice day, let's go sailing! So projects stall. So I have taken the advice from another sailing friend. Throw cash particles at the problem. (Let someone who knows what they're doing do it)

[Charles Brennan]

Chica, Went right down the rabbit hole, I did!   
Rasterized or pixellated images don't maintain finite element vectors, so it's tough for a scanned image to have that info for a CAD program. 
Which is why I used a drawing program and played games with the scaling.

After reading your suggestion:
Firstly, I tried to see if there were some way I could get my scanner to save scanned image files as .dxf or .dwg files.
No luck, there. (Not that I really expected it.)
Perusing on-line, I discovered an application called Inkscape (which I've had on my desktop for years, using it for something else) WILL convert a .jpg file into a .dxf file.
Whoa!!   
Promptly loaded my rudder .jpg into Inkscape and saved it as a .DXF file.
It whirred and churned and eventually spit out Rudder.DXF.
Kewl. 

So THEN, I opened up LibreCAD and opened rudder.DXF.
Nada.
Explored on-line some and discovered everybody else has problems using .DXF files in LibreCAD.
(My CAD program of choice these days, on account of it's FREE!) 
Hmmm . . . . .
Updating the app didn't help and converting from .DXF back into .JPG in Inkscape worked fine, so it's not Inkscape, or a corrupted .DXF with screwed-up poly-lines, or something.

Started with AutoCad in 1987, using Release 9, on DOS.
Used to have a copy of AutoCad 14 from way back when, so I loaded that.
Won't work on Windows 11.
Hmmm . . . . .
Started up VirtualBox and loaded up a copy of Windows XP and installed AutoCad 14.
Got it running . . . . . eventually.
Been a minute, huh, Charles?    Geeze!! I used to KNOW this stuff!   
Copied over the Rudder.DXF file  . . . . . .
a n n n d d d d  . . . . . AutoCad 14 doesn't recognize the current .DXF revision.
   ARGGGGHHHHHH!!! 

Anyway, now I'm intrigued about the possibilities of getting honest-to-goodness .DXF files from a .JPG
There's an on-line conversion website called Convertio, that purportedly converts .JPG or .PDF files to .DXF or .DWG.  So I'm going to play with that next, to see if maybe their .DXF files or .DWG files will load in to LibreCAD.

Thanks for killing my WHOLE DAY, Chica!! 
Just Kidding!! 
The best thing about this board is not just the advice and stories, but how one suggestion can spark another (even though different) idea.

Thanks, Noemi,
Charles Brennan

[Charles Brennan]

Wayne, Channeling a little Dirty Harry, here: "A man's got to know his limitations" . . . .
Which has always been a problem for me. 
I always figured I was as good as the next guy, so I rarely considered that I might even HAVE limitations, when I wanted to do something.
As a result, I've done a great many things.  (Not all of them, well; racing in the CDCR comes to mind.) 
I also believe you should try everything at least once and the Fun Stuff, TWICE!! 
 
The other issue is, having cash particles to throw at the problem.

Believe me, I'd LOVE to just order a pre-fab SCAMP from Gig Harbor Boatworks and go sailing, but it's just not in the budget.
Nor am I inclined to swallow the anchor, just yet.
So I toil away, and with any luck at all, I'll have another boat to sail and maybe even, before I'm too old to sail it!!   

Charles Brennan

[Charles Brennan]

Riley, I made SURE McMaster-Carr was selling me bronze hardware, instead of brass.
Most everything I do is in salt water, so I can't fool around with easily corrodable metals.
I do concede it's not Silicon Bronze, but it was the best bronze I could get my hands on and NOT brass.

I have this recurring nightmare: (especially on hot nights)
I awaken from some nautical accident.
The boat is fairly trashed and the storm that trashed it must have knocked me unconscious for a while.
I have jury-rigged a mast from the boom, and am flying a jib rigged as a loose-footed main.
Just when I figure I have a fighting chance to make it, all my hardware starts failing on me.

Ever seen a heaping spoonful of sugar dropped into a cup of hot tea?
Turns grey and then dissolves?
That's what all the cleats and turnbuckles and shackles are doing, in my nightmare.
Every time I fix one thing, or fashion some mickey-mouse workaround, something ELSE crumbles into flecks of metal and washes over the side.  It's like I can't keep anything together long enough for something to work.

BIG Fan of Noble Metals, my Man.
Charles Brennan

[Riley Smith]

Well, currently I'm out of epoxy, so I hope nothing on the boat breaks! I was SO scared of epoxy, I didn't use it! I glued everything with resorcinol and overlaid the glass with polyester reisin. I really like the resorcinol because the working time is much greater and it is less toxic. But epoxy is quicker and actually easier to work with. I did have one problem with the mast once when it cracked during extremely cold weather. The base wood cracked, not the glue line. I cut the crack out and installed a replacement half section and it has been fine ever since. Luckily that crack was in the section below the deck when stepped, so it isn't even visible and was a relatively easy fix. Had it been in anywhere else I probably would have rebuilt the whole mast. Relax CB. You have modern chemistry to protect you  when you are miles from safety in shark infested waters 

[Frank B.]

I should elaborate a bit on my distaste for working epoxy.  As mentioned I built a Stitch and glue skiff.  Because stitch and glue construction is kinda like unibody construction in the car world, the primary strength comes from the box construction and the integrity of the seams.  Consequently all the seams are reinforced with multiple overlapping layers of tape prior to the glass fabric being laid on and wet in.  As a result there is a great deal of fairing that has to be done to blend the seams.  It is that part I hate the most.  Sand, fair, sand, fair, sand fair, guide coat, sand, fair.............

Although I've never built a ply on frame, I get the impression it is much less of that not so good thing.

[Riley Smith]

Fairing....oh man. That's where 3/4 of the work building a boat comes in! Getting it to fit and look GOOD. Your eye can see the tiniest of mistakes and it takes lots of work to get it right. I only managed to do that about 75% of the time too. The rest was figuring out how to make it acceptable and remedying my inadequacies.

 S R Cat was faired with polyester and a filling compound mixed in, to make the filets around the frames and elsewhere. I seem to remember thinning it all with a dollop of acetone but I don't ever want to do that whole process again. And all those fillets were overlaid with tape while wet, so in effect, it becomes a composite intersection of wood and opposing forces to make a joint.

 And yes, I was stumbling around in the dark in my ignorance. I've often wished I could rebuild the boat once more, because I'd do so many things differently, including using epoxy. Despite ALL THAT, she has given reliable and safe passage for a quarter of a century. With today's resources, it is easier and very safe structurally, as well as producing a product much different than a vanilla production hull. Back then I was stumbling around on the internet trying to find out how to do some particular something. That's actually how I stumbled on this place, and wound up getting in touch with CJ. Nothing was precut and I started with a pile of plywood and lumber and somehow came out with a boat in the end.

 Man, time sure flies doesn't it?

 SO...fare well CB. Or is it fair??? It'll be good. Nothing is ever perfect, believe me. There is a range from unacceptable to the best, and the best can make you THINK it is perfect, but trust me. It isn't. I've built so many things in my life and have never managed yet to accomplish that. I've even seen one of those machinists make a part on a lathe with those microscopic tolerances and say to myself, I'd have done that specific action differently. Live and learn. You never stop and you constantly learn, but just because you would do it differently later doesn't necessarily make the original grossly inferior. (Well, except in MY case )

[Captain Kidd]

Man, you're really going after it!

Just a note. Seems like a lot of trouble scaling your skeg drawings. That would scare me. Why not rough out your skeg, scribe the hulls curve and presto!

You cannot view this attachment.

You cannot view this attachment.

You cannot view this attachment.

[Noemi - Ensenada 20]

Charles, I do believe I can import .pdf files into my CAD program.  Also .jpgs, but you can't do much else with those.  I have imported a pdf, drawn OVER it in CAD, then scaled the drawn part.  Had to decide what part of the line to draw over - inside, outside, center?  But it worked out.

[Norm L.]

What a great thread.
If only all of the non specific boat work tips given over the last 20 years could be put into a How-To book
The Captain of this ship could abandon us and with the book profits sail off to Tahiti. Or Put-in-Bay.

[Charles Brennan]

Noemi, I tried out that file format conversion web site (Convertio) and input Rudder.JPG and the only CAD output option was .DXF (which had failed in Inkscape) and then loaded it into LibreCAD:
You cannot view this attachment.

SUCCESS!!! 
I have recently discovered I am missing the transom cap piece from the collection of plywood pieces I bought last December, so this newly discovered process will be getting a workout in the coming months.
While I am grateful for your generous offer of help, I am even more grateful that you pointed me towards an idea for a solution that I can do for myself.
"No Man Is An Island" but I've always considered myself a peninsula! 
Just too independent, I guess.

Thanks, Chica,
Charles Brennan