From the Boatshop
by Ron Magen

"Things “THEY” Don’t Tell You About First, When They Really Should"

We’ve all seen it in the movies, where the hero has to disarm the bomb and his sidekick is reading the directions;
" ... cut the YELLOW wire and pull the lever. ... ".
"O.K., what’s next?".
"... be sure and ground the GREEN wire FIRST !".
DOUBLE TAKE and etc., etc., etc.

In the REAL WORLD they would make copies of the instructions. Read them thoroughly, several times. Highlight specific points and make notes. HOWEVER ---


Take NOBODY’s word as the absolute best and only way to do anything! Least of all my word. I’ve tried to illustrate that as much by my errors as by what went perfectly. READ and get several opinions. Then think over, repeatedly, what you are going to do. FLASHES of inspiration do happen !

aniline dyes -
Commonly available through wood workers mail order catalogs. May be available where you live in a "high end" paint, or artists supply, store. Usually available as a WATER SOLUBLE or ALCOHOL SOLUBLE powder. Go with the ALCOHOL; it will dissolve in both. MAKE TESTS - MAKE TESTS - MAKE TESTS !!

Cleaning Fluids -
A way to keep your epoxy application tools "going" is to have a container of DENATURED ALCOHOL & VINEGAR mix handy. Keep several tools at hand. As a tool gets sticky or too messy to comfortably work with, WHILE THE MIX IS SOFT toss it into the container. {A cut up water or milk jug works great & costs nothing} The solution will further soften the un-set epoxy and keep it from gelling. At the end of the work session you can clean the tools with no panic about timing. "FAST ORANGE", and similar "no-water" hand cleaners work very well, are relatively inexpensive in gallon quantities, and are HARMLESS compared to acetone and other highly volatile chemical cleaners. DO NOT WAIT OVERNIGHT. I say this because I’ve had long sessions or put a lot of tools & brushes into the container, created a fairly saturated solution, and had the epoxy "set-up" at the bottom.

Fillers -
The wider the variety of fillers you have on hand the more situations you are prepared for. There are basically TWO general types of ‘fillets’ & fillers - STRUCTURAL and COSMETIC.

  • Structural -
    • The fillet that is going to replace the traditional ‘chine log’ and both hold the side to the bottom and give stiffness to the hull shape; the fillet that holds a frame to the bottom and sides, etc. When cured should be strong, hard, resilient, and not necessarily easy to sand
  • Cosmetic -
    • The fillet on the external seam at the turn of the bilge that will be under several layers of cloth; the transition fill at the edges of the taped seam; the external topside transition seam, the filler used for fairing before glassing over the hull, or rudder, or keel, etc. This is basically to ‘take up space’ under another covering. Similar to spackling a hole in a wall before painting or papering, or putting on extra socks to pad your feet to make an odd size shoe fit better. Should definitely be easy to sand or otherwise shape.
  • NOTE - these can be combined . . . as an easily sanded cosmetic fillet over a structurally filleted and taped ‘chine seam’.

Although they are readily available in ‘blister pacs’ at any number of marine or hardware outlets, the qualities (WEST SYSTEM products excepted) and quantities are more for "touch-up" and spot repair than "production" work. Also, I have never seen either WOOD FLOUR or TALC on any store shelves. The prices are usually high as well; partially due to the small quantity packaging.

There are any number of catalog sources for your materials - prices vary -- shop around. [RAKA Marine advertises in MAIB - Larry is a good source; Thank You, David Goodchild] Remember to look out for "minimum orders" and "shipping & handling" charges.

  • Colloidal Silica -
    • THIXOTROPIC or STIFFENING agent. When used as a resin filler sets up rock hard. When used as an additive it gives a solidifying effect to mixtures; stiff and non- sagging.
  • Wood Flour -
    • EXACTLY what it says it is and my basic filler. Not only is it a filler but a thixotropic agent as well. When "wet out" it looks like wet or darkened wood. RELATIVELY HARD. Often add one or two of the other fillers to modify it’s properties.
  • Q-Cell -
    • A finer material than 3M Glass Bubbles or Balloons. Not many sources. Try "MicroBeads" or "MicroBalloons". RELATIVELY SOFT - easy sanding. Leaves a somewhat course / open surface.
  • Phenolic Microballoons -
    • If you like Purple - this is the stuff for you!! A fairly fine and relatively easy to sand thickening agent. It’s dark color, when wet out, is a good indicator when you need a ‘flag’. You can definitely see when a rough seam or low spot is filled. Also if you are trying to imitate a ‘Traditional’ pitch seam - you won’t need to add so much black pigment .
  • PLASTIC Mini Fibers -
    • Have found one source. They are the equivalent of a PREMIUM (HIGH COST) brand of lightweight FAIRING
  • Talc -
    • White, powdery, highly dense material. Relatively soft & easy sanding. Helps make a smoother putty. Price varies WIDELY from source to source
    • Chopped Fibers and Milled Fibers (glass fibers) - for a really tough but rough {chopped) or ‘liquid glass’ {milled} effect.

While these are the better known materials, don’t be afraid to experiment - BUT do it BEFORE you use it in YOUR boat.

Glass Cloth-
From the experience of building NYMPH, and the samples from RAKA Marine, cloth schedules can be modified. With 3/4 inch material for transoms cloth is NOT needed for STRENGTH, only surface protection. If rough use is expected then a strong, smooth surface would be provided by a TIGHT WEAVE. For light to "normal" use a light regular weave should do (2.75 oz.). Probably hold true for ½ inch ply as well.

A bottom would be well protected, with less resin required, with a tight weave. The side panels with a light weave. Bilge panels are a toss-up.

Limber Holes -
These are openings in frames to allow water to collect at low points for easy bailing, or cleaning. In "hard chined" designs, which "Tack-N-Tape" or "Stitch-N-Glue" usually are, they are typically at the "knuckle" of the chine. In these designs it is also usual to set the frames and place the "skin" around them with internal epoxy/filler/tape fillets. Plans may either skip detailed discussions on timing, or talk about them when discussing the frames {remember the hero and the bomb ?}. In the case of "Nymph" the shape of the holes is also to allow placement of the fillets & tape on the longitudinal seams. The frame shapes are on the plans and it is implied to cut them (the limber holes) when the frames are cut out. HOWEVER, because they ARE at the point of the chine they remove the support of the change of angle between panels. NOT a STRUCTURAL problem, just a headache hanging and aligning the panels. In later books/designs this was corrected by instructions to mark and cut out most of the hole, but leave a "tab" intact. This piece would be cut with a keyhole saw, and the hole cleared after assembly.

Another, not as elegant but easier, method is to not mark the opening and install the frame whole. After assembly cut a circular opening with a HOLE SAW chucked in a drill. YOU choose the size; either fillet only in this area or simply use a few narrower pieces of tape.

Putty Knives-
AGAIN - CHEAP is GOOD. Shop around. Epoxy does stick to metal !! They are going to get covered with the stuff. The set resin can be sanded off and metal does resist the sand paper. The plastic ones are also very inexpensive and flexible. The plastic can be cut to shape but do wear away when sanded clean.

You can also get some 1/8 inch ply and make your own shapes. [I used a 1/8 inch hardboard template so I can keep making identical ones] If they are coated & sealed with epoxy they are then impervious to chemicals. {see "Cleaning Fluids"}

"Sheetrock" or "Drywall" Screws -
Not just for walls anymore. Their reputation for snapping off is most likely due to the material of the usual interior grade construction screw. With the usual CONSTRUCTION DUTY electric driver set at a high clutch setting {efficient for, "We’re burning daylight; you guy’s are paid by the hour", construction jobs}, you can twist the turret off a tank !! I have a $30.oo Ryobi electric (not cordless) with 6 clutch settings; some heavy duty, 12 volt battery powered units have 12.

By using long ones at places like the transoms and frames, they can be "backed-out" half way to allow the joint to be "spread". After the epoxy adhesive / filleting material is inserted, they are then re-tightened to clamp the joint. Waxing (NOT soap) screws always them easier to drive and in this case will prevent ANY CHANCE of them getting stuck in the epoxy.

Styrofoam Cups -
"They" say not to use them to mix epoxy. Like everything else it’s a case of knowing your materials. CARELESSNESS is the lowest common denominator. IF you let a quantity (the "typical" 300 grams), of mixed epoxy "go off", the exothermic reaction will MELT the cup. You WILL have a potentially dangerous mess on your hands. HOWEVER, if you PAY ATTENTION to what your doing, make up smaller batches, and get to know the characteristics of YOUR "mix", the insulating properties of Styrofoam cups can help during COLD WEATHER operations. Plus, if the cups are USED you will be re-cycling as well.

Other Mixing Containers-
DON’T USE WAXED containers; plain paper are O.K. Metal food cans are good, all around useful and universally re-cycled .. EVEN AFTER you’re done with them.

"Power Disk Sander", etc. -
For any number of reasons you want to sand as little as possible. However, when working with resins there are times you’ve got to SAND. When epoxy/wood flour structural fillets set up they are rock hard. [Dave Carnell recommends using agricultural limestone as a filler material ... he was a chemist (?) and has been building boats for years. I still say - WHY !!? That’s making hi-tech ROCKS !!]

I’m a firm believer in fine tools. Sometimes the "fine tool" is too much tool. The shipwrights of yore had NOTHING BUT hand tools and time. Today it’s LASER guided cutters. If you are making your living building boats, you’re probably NOT reading THIS. IF you’re thinking of building a dream, a small one - not a circumnavigator, then this could help you get started.

BUY TOOLS APPROPRIATE for the job. Also THINK and READ -- CONSTANTLY. Just because a tool is typically used for operation X in industry Y does not mean it can’t be used for something else.

Professional builders like Devlin use Milwaukee and De Walt tools. A 4½ inch angle grinder can cost more than $200.oo. Mine is from Sears - $39.oo on sale. Not only is epoxy tough, it makes abrasive dust. It is going to eventually "eat" the insides of air cooled tools. Devlin’s probably sooner than yours, but he can amortize. Put the METAL CUTTING DISK AWAY and get a KLINGSPOR SANDING CATALOG sanding disk or two; the "flat" style in course and medium grit. WEAR A MASK and GOGGLES.

This tool & disk makes faster work of the task {sometimes VERY FAST - PRACTICE a LIGHT touch}. It is also a nice setup for scarfing & beveling. It’s handy size, small shape/heavy weight for in situ work. {Oh, S___! I forgot to bevel that frame. etc., etc.}


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