IOMICA Forum

I have built a few hulls with balsa, 2-US1M's and 1-IOM. The balsa worked fine, and was light, but I would like to use a wood that is more durable/ prettier than balsa.
What wood do others use for planking? What are some of the good and and bad points of those woods and are there any special techniques for using them? Thanks, Rob

Mahogany is relatively easy to work, and a time-honored boat material. Basswood (a.k.a. lime) is conveniently available from hobby sources, but rather featureless, if looks are important. Cedar can be beautiful, is fairly lightweight, and fairly rot-resistant; but the dust is toxic/allergenic. Anigre is a light-colored variant in the mahogany family, I believe; but probably somewhat difficult to find in plank form (most is sliced for veneer work). There are other tropical woods with great texture and figure: satinwood, lacewood; pretty much the same story.

Check out Soeren Andresen's nice set of photos about building his Laerke hull
http://groups.msn.com/RCSailing/bouldin ... snw?Page=1
He planks structurally in balsa, and veneer-planks the outside with mahogany, and then glasses it. Looks like a good technique.

Thanks Charles, That does look like a good method. I did not see any text with the photos. I wonder what thickness mohogany he uses. I will try to contact him.
Rob

I have built a number of hulls from Cedar and a variant that is locally called 'Galician Pine' (which isn't pine by the way). It is sold here in hobby shops in 1metre x 10mm x 3mm planks and so you can just about build an IOM hull with it. I have tried with and without a fine coat of glass on the exterior...and found it isn't necessary. The wood it very beautiful, eaasy to work with and you can glue it with epoxy (I add thickener) or cyano glues and strong enough to handle the rough and tumble world of IOM sailing.
The Portuguese build some spectacular planked boats with a slightly lighter coloured wood but also very attractive, and I will try to get you some pics and find out what the wood is.

Thanks Roy, Do people who use harder woods than basla( pine, cedar, basswood, mohogany) usually cut their wood strips to size or buy them that way? I love the look of red cedar and will probably try it next. I noticed that when planking with balsa, if you get CA( instant glue) on the outside of the hull it is almost impossible to sand the hull smooth. CA is so much hrder than the balsa that it sands unevenly. Is this also a problem when using CA with harder woods like cedar?
Rob

In my experience (and it's not so great so listen to others) the problem of cyano isn't as bad with the harder woods but excess glue can leave an aesthetically unpleasing 'stain' which looks a bit ugly and is difficult to cover up. With epoxy, it's not generally so bad since that's the same as your going to use on the outside to protect the wood anyway. As the wood soaks up the glue it darkens in colour and causes the 'stains'. This is all cosmetic but a wood boat is being built partly for it's looks, no?
I add plenty of thickner (fibres etc) to epoxy to stop the wood soaking up so much resin - read the instructions carefully of the provider of the resin and fillers to get the right mix or you'll loose resin adhesion strength.
In either case, I believe the answer is don't be too heavy handed with the glue - whichever type you use. It's a lot easier to fill in a couple of small gaps bewteen planks than try to remove huge excesses and runs. Using plenty of strong rubber bands and pins on the frames to hold the planks together when they are on the frames (but being careful not to bruise the wood) - if your using that method - should ensure you don't have problems of the planks seperating. They should be a good snug fit up against each other to avoid glue pockets and this may mean champfering the edges.

If you can get hold of Cedar it certainly looks spectacular...here in Spain it's sold in pre cut planks.

Thanks again Roy , I guess there is nothing left but to find some cedar.
Rob

If Roy Thompson is talking about Spanish Cedar (cedrela odorata, not really from Spain, but imported from Brazil or elsewhere in SA) then it's not the same as Western Red Cedar (thuja plicata); not that this matters that much. The former weighs around 30 pcf, while the latter is usually lighter, say 22 pcf. Spanish cedar is the preferred material for lining cigar humidors, and making classical guitar necks.

With regard to glue, I've thought about trying the Titebond II aliphatic (for the hull I've been threatening to build), which is supposed to be waterproof, even though it's water-based. I don't like using epoxy and CA (my spouse finds them anathema), so I try to stick to more innocuous stuff when building model projects.

Sounds like you know your trees Charles. I wonder if they have simular working properties. I have used both eastern and western cedar in finsh carpentry. Eastern is more colorful and stronger smelling than western, but western is much cheaper and easier to get where I live. I have never seen either one for sale in thin strips, but I have never looked . I may have to cut my own.
Rob

I looked up eastern and western red cedar, eastern is a juniper not a cedar no wonder they look and smell so different!
Rob

Hello Robert, my local timber yard (a fairly large one) keeps in stock tounged and grooved Red Cedar used for panelling. Usually stocked in large quantities I am able to pick through and find good clean, light straight grained peices. It comes ready planed at 10mm thick just requiring to be cut into 3mm strips. If you can find this I am sure you will be delighted with it. Am I just lucky to have this on my doorstep! It glues great and looks fabulous. I finish the outside with several coats of two pack polyurethane varnish which I wet and dry down then cut back with cutting compound. The only trouble with this is the number of people that ask you how you build your formice boat!

Barry Chisam

Hi barry and thanks. I have a large lumber yard about 5 miles from me, and yes they let you pick through the wood there too.(I love that) I will check and see what woods they have for planking. You strip your own wood on a table saw? How does it come out cutting such thin strips(3mm)?do you have to sand or plane the strips before they are usable? I have never had to cut such thin usable strips.
What do you guys think of the method Charles posted about planking with balsa and then going over that with thin mohogany?
Rob

Hello Robert, Iuse a small bandsaw to strip timber down including gunwalls etc. on the Isis. Make sure you use a fairly fine blade nice and sharp, preferably new. A table saw will waste nearly as much in sawdust as you use. When the hull is finished I sand the inside down and apply a layer of 60 grams glass cloth with epoxy. I prefer to do this on the inside rather than outside as I like to keep a nice bright varnish finish on the outside.When glueing I hold the strips in place with a combination of rubber bands, clips and masking tape so as not to leave holes that show. The balsa/mahogany method sounds interesting but you will probably have to source a supply of veneers for the finish as you probably won't want more than about 1mm, difficult to strip down. You will also have to make sure of the fairing/sanding etc. at the balsa stage because with a very thin top layer it will be easy to sand through.

Barry

Barry ,Well I put my thinest, finest tooth blade on my table saw and tried cutting 1/8 strips. The thickness was consistant, but there were a few blade marks ,not perfect but usable. The wast is another matter, about 50%. I will go pick a band saw. I can use it for many other projects too.
Rob

Robert H wrote:Well I put my thinest, finest tooth blade on my table saw and tried cutting 1/8 strips. The thickness was consistant, but there were a few blade marks ,not perfect but usable. The waste is another matter, about 50%. I will go pick a band saw.

Hi Rob

I have a small table saw, and a small band saw (probably not the ones Barry has!). I can only strip wood using the table saw, with a good fence it always gives excellent consistency. The band saw wanders too much on a long run, no matter what the fence, and it just doesn't work for me. You can see the tools I use at http://www.onemetre.net/Opinion/Workshop/Workshop.htm

Micromark http://www.micromark.com sell a #80805 230 TOOTH BLADE (.020 INCH KERF, 3 INCH DIA.) http://www.ares-server.com/Ares/Ares.as ... t&ID=80805 that is as thin if not thinner than a bandsaw blade.

Wow Wish I had a workshop like Lester.

Barry

Barry Chisam wrote:Wow Wish I had a workshop like Lester

I wish I had boat-building skills like Barry! Y'all know his ISIS is a world-beater, and I'm certain he has much the better end of the deal (smile)!

Prior to buying ISIS hull No41 from Barry, I built a cedar planked Kite. I also cut down the planks myself, but not from pre-machined cladding, I managed to get a piece about 6"x4" and had a large band saw cut slabs at about 10mm thick. This meant that I had to finish at least three sides of the 3.5mm thick strips that I cut on a hobby band saw. As Lester found, the small band saw tended to wander a little bit, but if you are very carefull this can be limited to about 0.5mm. To part finish the strips I took a piece of 18mm MDF and cut it to the width of my Bosch hand planer. I then routed grooves lengthwise at 9.5mm and 9mm deep x 5mm wide and 3.25 & 3mm deep x 10mm wide. By mounting the hand planer on top of the MDF I then had a machine thicknesser. By passing the rough strips through the grooves in the appropriate order the planks were sized. Only one 9mm face had to be finished, and this was used to make the inside surface of the hull. The other rough face on the outside was to be hand finished anyway. On planking up, I used West with silica and 'fingered' the excess into the inner surface hull as I went along. It worked very well. The beauty of doing your own plank cutting is that you are not limited to quantity, and can scrap any 'errors', but watch that the strip does not kick back if you get the grain direction wrong. it hurts!

Cheers

Ralph

Lester and Ralph , thank you for the great information.
Ralph, the blade looks like the ticket, but the shaft on my saw is too large.
I am sure I can find a blade that will fit my saw, maybe not as thin, but close.
Ralph ,I like your idea of using the MDF and hand planer. I will make a wood jig and try it out.
Rob

Hi

I would like to give some insight on how I built my IOM´s, since Charles was kind enough to mention them. I would liked to answer earlier but time has not allowed me to do it.

I plank my boats over MDF frames, the frames are placed with 50 mm between them. I know that 50 mm gives a lot of frames to be cut, but since I get my brother to make them on a CNC miller, it is not a problem for my.
The reason I use 50 mm placing is to get the first layer of planks more rigid, and thereby avoiding flat-spotting the outside of the hull when sanding.

The first layer is planks made of “abachiâ€

Charles said:

If Roy Thompson is talking about Spanish Cedar (cedrela odorata, not really from Spain, but imported from Brazil or elsewhere in SA) then it's not the same as Western Red Cedar (thuja plicata)

.

1)No I am not talking about Spanish Cedar. No such common name exists here anyway - see 2.) below.

I am all in favour of scientific names (as I have worked most of my life with trees and shrubs) and think they avoid the confusion of using common names which change from place to place and often add confusion. It is important however to use the correct scientific names:

2.) No such tree with the scientific name 'Cedrela odorata' either. I guess you mean Cedrus deodara sometimes called 'Deodar'.

I know that sometimes trees/plants are reclassified and the 'old' names die slowly and that in the USA some names are different (I have had this 'argument' on a profesional level a number of times) but if we are to use the scientifIc name for clarity we must get it right.

Bye the way Soeren, excellent details of your building technique, well done and thanks!

Yes, thank you Soeren. This has been a very informative thread! I have printed it out for reference. I just hope I can do the methods justice. Soeren ,the Obechi is so light colored in the pictures I mistook it for balsa also. Rob

VCmeasurement wrote: 1)No I am not talking about Spanish Cedar. No such common name exists here anyway - see 2.) below.

I am all in favour of scientific names (as I have worked most of my life with trees and shrubs) and think they avoid the confusion of using common names which change from place to place and often add confusion. It is important however to use the correct scientific names:

2.) No such tree with the scientific name 'Cedrela odorata' either. I guess you mean Cedrus deodara sometimes called 'Deodar'.

Hmm. Google search for cedrela odorata turns up a lot of hits. As I said, it's traditional for cigar humidor construction and guitar necks. Try this link:

http://www.rngr.net/Publications/ttsm/F ... .1748/file

which seems fairly recent.

And if you're not using cedrela odorata, then what (scientific name) do you use for planking?

And if you're not using cedrela odorata, then what (scientific name) do you use for planking?

Ah my friend, if I knew that I would have put it in the post. It's a mystery which I continue to investigate. It is sold as 'Galician Pine' which may well be a type of 'pine' that has been treated and that gives it a distinctive aroma and colour - maybe for protection against termites and rot etc. However I don't think it is your 'Spanish Cedar' imported from central America, (it's quite cheap and I imagine that Spanish Cedar would be relatively expensive.)
Is there anyway you know of to identify Spanish Cedar when in thin strips (1000x10x3mm)?

And you are absolutely right Charles, I apologise, Cedrela odorata does exist.... It has a number of common names but none that I can see are 'Western Red Cedar' Thuja plicata (which is what I was searching for thinking it was a synonym)....

Your google search is very interesting since I think it serves perfectly the purpose to highlight the confusion caused by common names, at least 24 are listed for Cedrela odorata in the article you point to, including, white cedar, yellow cedar, red cedar, Mexican Cedar, Spanish cedar, Jamaican cedar, West Indies cedar, royal cedar, aromatic cedar and a number of other very local hispanic names etcetcetc... Some of these common names are also used for completely different species (eg. Yellow Cedar is also used for 'chamaecyparis nootkatensis' a 'False Cypress' from Alaska/Nootka Sound/Vancouver)
Maybe the 'Spanish Cedar' in Spain is locally called something else? (Or maybe I'm simply not asking the right people!)

Like I say, confusing eh?
If I ever find out what my mysterious 'Galician Pine' is you will be the first to know.

Has anyone tried Redwood? It is cheap here in northern California, though the days of finding really clear heartwood with no knots is over. Its a lightweight wood that is very rot resistant and has a beautiful rich red color. I have some cabinets in my garage that are 50 year old redwood heartwood and I am going to remove them. I think I will cut them up for planking.
Rob

Robert H wrote:Has anyone tried Redwood?

I did a Google search "cedar strip" and found a (USA/NH) source for stripwood to build kayaks and canoes. They can supply Western Red Cedar (Thuja plicata), Alaskan Yellow (Chamaecyparis nootkatensis), or Northern White (Thuja occidentalis L.). While they generally cut strip 1/4" x 3/4" with bead-and-cove edges, an inquiry to them received the response that 1/8" x 1/2" (3mm x 12 mm) would not be a problem. Since they're cutting from plain sawn boards, the resulting strip is vertical grain (quartered); better for sanding/shaping.

The site, and others covering wood kayak construction that it led me to, are fascinating, and the boats beautiful. Makes me wish I had a garage for a minute. Kits cost about what an IOM does!

It's Newfound Woodworks, http://www.newfound.com/strpinfo.htm
The response said $0.30 per foot for the Western Red Cedar strip, plus shipping cost. I don't know whether that's bead-and-cove or squared edges, but my guess is the latter.

Fantastic work Charles!
I see that they also export, great! (No doubt the Euopean Union will have something to say about wood exports from the USA).
I normally buy about 45 (or a few more) strips of 10x3mm (x1metre) to make an IOM, this gives me enough spare strips to choose and get a nice colour match and allow for a few mistakes.
Maybe it's worth asking around in our club/area to see if a larger order is worth while.

Thanks again Charles!