planking a hull

Rcsailing.net Technology Discussions
1

ok so i started planking my hull… i forgot to put masking tape or sumthing down[:-banghead]half of its planked, not nearly as easy as i thought it would be, the bow is almost impossible and the headache i have from the ca glue is rediculous. now i planked from the bottom and than from the top. the middle is now not planked and i don’t have shadows to start the plank on. should i keep planking and just make this a male mold? or is there hope for my hull yet?

i love tinkering with these boats it takes up time i’m sure my girfreind is going to hate it soon

2

if this thing isn’t goin to work i think i may just buy a hull to work off of, if it comes to that anyone know where i can get one for cheap?

i love tinkering with these boats it takes up time i’m sure my girfreind is going to hate it soon

3

I’m not quite sure how you’re doing your hull but I am sure that if you’re going to use CA then wear a respirator-not a dust mask!!! That stuff is flat dangerous! If used properly it can speed up a planking job. A tip you may already know is that if you have a gap you can fill with baking soda and then drip CA on it-makes a rock hard fillet.(gets very hot-don’t get baking soda on your skin and then get CA on it)
But again-wear a respirator!!
Can you post a picture of what you’ve done so far?

Doug Lord
–High Technology Sailing/Racing

4

yeah i know now to wear a respirator that ca is horrid, i was messed up all night. i’ll know for next time. um and i can try to get a picture of it.

i love tinkering with these boats it takes up time i’m sure my girfreind is going to hate it soon

5

Sorry I’m new in all this building stuff. I made my hull with balsa and UHU Hart model glue, and finished it with epoxy. Where does CA stand for? And what kind of wood are you guys using?

Folkert

6

CA is cyanoacrylic glue. It is an “instant” bonding glue that I use(in combination with baking soda) to bond balsa planks to balsa frames to build a plug(form an exact shape of hull and/or deck etc.in order to make a mold).
Planking is my preferred method to build plugs and the cyano makes it a little less tedious.
The downside is insidious fumes-you absolutely MUST invest in a respirator or you will have serious discomfort and could seriously injure yourself.

Doug Lord
–High Technology Sailing/Racing

7

Don’t worry about how whether the planks start or stop on a frame. I used a hot glue gun. Use as little as you can and don’t try to wipe the excess while it’s soft. Wait till it’s set up and then peel it off. When you are finished the hull try to get the hull and frames off the building board in one piece. Then coat the inside between the frames with epoxy. That will hold it all in one piece. It’s a little late to tell you this but I attach the frames to the building board with screws from the back. When I finish planking I undo the screws and the whole thing comes off easy as pie.

Thanks
Don
Vancouver Island

Edit- You’d be surprized how much easier the second one is!

8

<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by 1mtrklasse

Sorry I’m new in all this building stuff. What does CA stand for? <hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>

Super Glue (Cyanoacrylate)

<u>How To Use Cyanoacrylates:</u>

Heat and moisture will decrease the shelf life of CAs. Unopened bottles can be stored in a freezer or refrigerator, but allow them to reach room temperature before using. Keep your bottles in a cool place that won?t be exposed to direct sunlight and store away from bottles of accelerators. Depending on the freshness of some CAs, their shelf life can be up to 12 months. Check for “Use By” dates often included by manufacturers! When paying per ounce for CA glue, it is nice to know it will remain fresh for a period of time while working on your project.

With all CAs, the closer the parts fit together, the stronger the bond

For the initial opening of the top, loosen and retighten the entire top first to relieve internal pressure, then hold the bottle against a near vertical surface and cut off the top 1/32" with a knife or razor blade without squeezing the bottle. To prevent clogging, do not let the tip of the nozzle touch a surface that has been sprayed with a fast accelerator, used to reduce drying times. Before replacing the colored cap, set the bottle down hard to knock the remaining CA back into the bottle before squeezing it in an upright position to blow air through the nozzle, then wipe the tip clean. By squeezing the bottle in a vertical (up) position, you are removing any excess air inside the bottle and extending shelf life of the glue.

With all CAs, the closer the parts fit together, the stronger they bond. Always hold the bonding surfaces together as tightly as possible. Any rough spots on the mating surfaces should be smoothed out. Although CAs will hold objects together with considerable strength within seconds, the full strength of the bond is not reached for several hours. Allow for this before subjecting parts to maximum stress. Also, CAs are generally a little less brittle and have higher strength when they are allowed to cure on their own.

Super glues come in a variety of kinds and from many manufacturers. Generally, they are pretty expensive and come in small amounts per bottle or tube. They can be very thin to allow them to run between joints of close fitting parts, or they can be a gel that will span small gaps. Give consideration to purchasing the smaller tubes of Super Glue (under various names) from home centers. Often you can find a two tube pack for about $1.00 (U.S.) which makes it less costly if the tube dries or breaks. I would suggest having purchased (and on hand and available), a thinner to use should you get the CA on your fingers. Remember, some grades of this stuff are used in medical surgery to bond human skin! If you do get some on your fingers, keep the fingers from touching each other and let the CA dry. Warm water and a bit of scrubbing will generally remove the dried glue. Kind of like the old styrene plastic airplane cement.

Also, CA glue gives off a “smell” and can cause respiratory or eye irritation for some who may be sensitive to the glues. A small table fan can be used to blow across the project and move the fumes away from you.

Some have used CA glue to “coat” parts to waterproof, but discussion has indicated, exposure to water or moisture over time can (possibly) cause the glued joint to fail. I am experimenting with using CA glue for attaching sail panels at their seams. Place wax paper under the seam to prevent the cloth from sticking to your workbench. I also use CA to “tack-bond” small parts in place so I can reinforce with fiberglass tapes or thickened epoxy because of the glue’s fast dry/cure time (5 to 15 seconds on average).
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<center><font color=“brown”><font size=“1”>Used with permission from the F-48 Discussion Forum. </font id=“size1”></font id=“brown”>
http://formula48.proboards13.com/</center>

9

As pointed out in the excelent post Dick presented don’t use CA in area’s where it will directly contact water.It’s ok for planking hulls as long as the finished hull is coated with epoxy inside and out.
I’ve had experience with using CA in structural applications where it failed after contact with water.

Doug Lord
–High Technology Sailing/Racing

10

e27: check out this site for excellent pictures of the planking of a hull:
http://home.iprimus.com.au/vizible/Gary’s%20boat.htm

Doug Lord
–High Technology Sailing/Racing

11

wow his boat is getting planked 50 times better than mines going, and thats no joke his bow planks sit flat mine are all over the place i was just hoping to sand them down… well if this doesn’t work i still have my vic, but i want this to work!!!

i love tinkering with these boats it takes up time i’m sure my girfreind is going to hate it soon

12

Try and keep it in mind that the planked hull can be considered a permanent plug.It doesn’t really have to provide any strength(although it’s nice if it does) as the glass will do that. If you think about it the only reason the hull has no holes in it is to keep the water out. If I wasn’t for that engineers would have the hull full of holes for lightness.

Thanks
Don
Vancouver Island

13

Well it’s always possible to sand your planks down… But when you’re using very thin material it’s almost impossible to create a nice and smooth plug. It’s just a thing I experienced with my first hull. But I’m now thinking of shaping a hull out of Polyurethane foam, does anyone have experience with this material?

Folkert

And by the way thanks for the info about CA.

14

My experience with polyurethane foam isthat it is a real drag to work with. You have to wear goggles becuseit hurts more than aything I’ve ever gotten in my eye!And the shop must be 100% freeof the dust before you remove the goggles. And ,of course, a dustmask is required.
For the balsa plugs I build I use 1/4" (6.3mm) planks; their thickness stiffens the plug considerably making a stiff sanding surface.

Doug Lord
–High Technology Sailing/Racing

15

Here’s someone who has built a plug using foam.

http://www.helsinki.fi/~awallin/1m/01nov.html

16

I disagree with a previous post regarding the problems with using extruded poly foam for a plug material and would encourage you to try the process.

If you have pre-cut most of your sections, there is little if any sanding required. You can use a bandsaw with a fine blade or even a hand held hacksaw blade.

Better yet, consider building a simple home-made hot-wire foam cutter, and use your cross sections and templates. Simply run the hot wire along the template on each side to remove excess foam. Make a “Y” shaped wooden handle. Stretch stainless steel wire across the top of the “Y” and attach a piece of insulated wire to each side. Run those wires to a small electric train transformer and test for appropriate voltage. You want the heat to be just enough to allow the wire to "Cut’ the foam without excessive melting. If the temperature is correct and you move the wire through the foam at the right speed, you will see a shiny, smooth almost factory finish in the area cut.

Once you have shaped the foam, a small amount of sanding may be necessary, but only for fairing. If you are using a power planer, and belt sander and grinding discs, you need to change your method of initial shaping.

Once you have your foam to final shape, use a warm/hot clothes iron to go over the surface to “seal” the foam - eliminates a lot of weight from epoxy sealing the foam surface.

Download Attachment: [ smMulti1meterside.jpg](http://www.rcsailing.net/forum1/data/F-48 multihulls/200433110236_smMulti1meterside.jpg)
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As can be seen in this photo, each section of the hull was hot-wire cut independant of the others. I used thin aluminum for templates, because I want to build more of these size hulls.

Download Attachment: [ smImpulseplug.jpg](http://www.rcsailing.net/forum1/data/F-48 multihulls/200433110715_smImpulseplug.jpg)
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This photo illustrates, how you can simply glue each of the sections together to for the hull. I used joint compound for wallboard to fill and fair the hulls.

Of course, safety eyewear is a necessity for any shop work, but the only negative part of using foam is the tendency to build up static electricty and the stuff sticks to your clothes. A soft shop brush gets rid of it and once on the floor is can be swept up with a broom. I would caution you not to do this process inside a house. Better in a garage or workshop. I find it no worse than having balsa dust all over after sanding.

Using foam is a method that has been proven to be fast, cost effective and a viable way to build plugs or forms. A few hundred thousand sailboarders and surfers can’t be wrong.

17

Caution!!! DO NOT CUT POLYURETHANE FOAM WITH A HOT WIRE!!!
Polystyrene foam can be cut with a hot wire with excellent results whether large cell or small cell but polyurethane, Last-a-Foam, and Divinicell should NEVER be cut with a hot wire!!!
For reference refer to page 36 of the Aircraft Spruce and Specialty catalog.
IMPORTANT additional info: the original post in this thread specifically requested info about POLYURETHANE foam; the previous post mentioned only"POLY" ; this info is posted because there is a BIG difference betweenn POLYurethane and POLYstyrene!!! I’ve built plugs from both materials; polystyrene is much more user friendly than polyurethane. I prefer, when I have the time, to balsa plank a plug but when in a hurry small cell styrofoam(polystyrene) makes a quick plug but can only be covered with epoxy. Polyurethane can be covered with polyester , vinylester or epoxy but should not be hotwired and sanding is nasty.

edt:sp/ad info
Doug Lord
–High Technology Sailing/Racing

18

I use regular yellow wood glue for planking. I think its called Tite-bond. No fumes. Works fine. I then coat the whole business with thin epoxy inside and out. I’m sure you already thought of this. Another thing I do at the bow is to make a hollow balsa block for the part thats too hard to plank. I call it a “Chin-block” You know like whare the tapered planks are so thin at the bow you can’t work with them. TO hold the planks in place while the Titebond dries I use a rubber band secured to the building surface and a piece of string which goes around the plank and gets then tied somewhare on the building surface again outside the hull. There are variations on this Idea, you get the Idea. I usulally have permanent frames instead of removable shadows which makes it stronger and about the same weight if you don’t coat it with gallons of glue and fabric which, in my opinion, you don’t really need. A little bit is good for those times when you get “t boned” Permanent frames save you the step of adding fabric.

19

Styrofoam is NOT a suitable product for forming a plug. Also from the Aircraft Spruce Catalog previously referenced: “The compressive strength of polystyrene is too low”.

Extruded polystyrene foam IS suitable for making plugs. (versus “Expanded” - which is picnic cooler type stuff)

As to PolyURETHANE products, I would offer the following - available on a quick search of the internet:
<hr noshade size=“1”>
Fire properties
Like all organic building materials - wood, paper, plastics, paints - rigid polyurethane foam is combustible, although its ignitability and rate of burning can be modified to suit a variety of building applications and it can be formulated to meet the relevant national regulations.
Rigid polyurethane foams are usually used at lower thicknesses than other insulants, which means that their heat or fuel contribution to a fire is low compared to other, thicker insulating materials. The overall fire performance of an insulation panel can be significantly enhanced by the material that is used to face the panel - for example, steel.
Independently monitored, large-scale tests of buildings incorporating rigid polyurethane and polyisocyanurate (PIR) foam insulation carried out in the USA and Europe have concluded that, properly used, these materials do not add to the severity or serious hazard of fires.
<hr noshade size=“1”>
Since hot-wire cutting seldom reaches (or exceeds 250 degrees, the likelyhood of combustion is rather low).
<hr noshade size=“1”>
Topic: Composite Materials

Expert:Steve Olson
Date:12/17/2003
Subject:Hot wire foam

Question
Is it true that polyurethane foam cannot be cut using a hot wire cutting machine? I know EPS foam is cut all the time with hot wire. If true,do you know why?

Answer
Dear Marc,

I know why it is more difficult to cut PU foam, it is because this foam is made from a thermoset material as opposed to the EPS or PP foam which is made from a thermoplastic material that can be re-melted. However, you can heat the wire very hot and it may still do the job by burning the PU foam. (look out for the fumes). Or also a sharp wire might cut the foam by the cutting force, it depends on the size, foam density, etc.

Best way is to treat the PU foam like wood and cut it with a saw.

PS. The PU foam has many advantages over PP and EPS foams: Usually harder and more compression strength, easier to form and cut with wood processes like sanding, etc. And also more solvent resistant.

Hope this helps, good luck,

Sincerely,
Steve Olson
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20

In the interests of geting the right info out this is a direct quote from the Aircraft Spruce and specialty catalog 2002-2003 edition page 36: “Styrofoam FB, 2lb. cu.ft.: tight closed cell structure leaves no voids between the cells. The result is high compressive strength and unequaled resistance to water penetration”.
I have actually used this stuff as well as the large cell stryrofoam to shape many plugs and it works very well as long as it is coated with epoxy. The large cell stuff doesn’t sand as well because the cells tend to pop loose leaving voids.
I’ve also worked with polyurethane for countless hours to build custom ice boxes for fishing boats as well as some plugs and it is nasty to work with and should never ,ever, be cut with a hot wire!

Doug Lord
–High Technology Sailing/Racing