Speed Strip tongue-and-groove strip planking

rectangular strips with biscuits

I have seen a boat built using rectangular cedar strips and biscuits using the standard cabinet makers biscuit machine. This will flush the strips well inbetween the frames. They are in the strip edges with one or two inbetween each of the jig frames. Can possibly save money on pre-made cove/bead strips and also adds strength. Each strip is dry fitted to mark and cut the biscuit slots which is a little extra work but one bonus is that once the strips are glued they will stay in place by just knocking them on with your hand and hammer, then fasten to the frames.

 

I have been following the posts above and find them to be very helpful. Is there any reason that instead of clamping the strips as there applied that a person cannot just shoot monel staples at specified intervals along the plank length? They will not rust and they cannot back out with the preceeding plank over the top. Seems like this would accelarate the process drastically. I also posted a new thread looking for a strip plank boat plan that is a planning hull, approx 25' long with a beam of no greater than 8.5' that has similar accomadations as the C-Dory 25', minus the exterior appearance, as I am looking for something with traditional lines that is seaworthy and that two people can comfortably cruise on. I just finished building a 64' by 30' shop with 12' ceilings to facilitate this project...all set to start except a good set of plans. Any help would be appreciated.

Thomas

 

Monel staples are fine...but why.....
if you are using bead and cove or tongue and groove speed strip metal fasteners aren't needed, are extra cost and weight. Check the adverts in the back of Woodenboat Magazine (not pictoral advertising) Under "TOOLS" and there's a fellow that sells special clamps that attach to the frames and push down on each strip as it's installed. Use an epoxy like T-88 without fillers as the adhesive. You can then clean/longboard the hull and apply veneers or xynole fabric, just epoxy coat the inside...epoxy coat all surfaces as you work..

 

Strip planking, if it is thicker than 1/2", makes sense with square edges and fastened with nails or staples. The speed of construction balances the extra time and money to cut the lumber into strips. Fitting every plank or, even worse, fitting and then routing the cove, defeats its purpose. If the hull gets laminated with fiberglass, galvanized nails are fine.

 

I'd have to agree with using square stock. Bead and cove is nice, but I don't know that it is worth the time and effort to do it yourself or the expense of having someone else to mill it. Ultimately, it boils down to personal preference.

I think the monel (or galvanised depending on the application) staple idea is a good one. The staples will have greater holding power, as opposed to other power nailer fasteners. I assume we are talking about a power equipment here. They also remove the requirement for clamps in most cases. I see the need for an alignment tool to hold the strips flush while being stapled. (Save your fingers if you get too close and you get a fastener break out.) The greatest drawback to a power stapler is that it's a one shot deal. With hand nailing, you can feel if your nail is going to stray and you can pull it and start again. Savings in materials (bead and cove strips) and tools (special clamps) might even send you a long ways down the road to purchasing the stapler and compressor. The time savings on a power fastener will be tremendous.

Stripped hull have been around a long time. Originally, the strip to strip fasteners would lend a great amount of cross-grain strength to these hulls. With the modern coverings that we have, I see these fasteners being a little redundant if the the hull is fabric covered on the inside and outside since the fabric is positioned more appropriately to carry cross grain loading. (At least when hull flexing is concerned.) Ultimately, you'll end up with a strong, though likely heavy, hull.

 

Done plenty of strip plank boats in the past and seen lots of diferent methods used.

Have used speed strip and while it works in some areas you still end up with a lot of the tongue and groove on the floor and the cost of the machining can cost almost as much per m2 as the material itself. Waste

Galvinised nails etc do rust eventualy as they will get sanded prior to glassing, and I have repaired rotten ply decks that were done this way with the owners using the same arguments posted earlier.

My favourite way at the moment is to dry stack the planks using a thick paint scraper as a spacer and using plastic strips and a battery drill and chipboard screws to fix, I read above someone useing pre drilled holes and timber dowels as a method, bloody hell sound's way labour intensive.

Once everything is in position and lined up we roll unmodified epoxy over the hull pushing it in and watching it pull through with capillary attraction. then use a rubber squeegee to wipe it in from both sides.

Sure, a bit of resin gets wasted on the floor, on my current 50ft cat we probably dropped about 3 to 5 litres, but much faster than glueing individual planks.

Any bigger gaps get a sloppy epoxy filler mix wiped into them while the first lot is still green, making sure to clean up the runs as you go.

Let dry, pull out screws, peel strips off and fill holes that are left.
Let dry and sand with a 2 speed sander with 36 grit, give a quick fair up with a long hand plane where needed, scuff these areas again and glass.

This method works for me and many other builders in Oz and we think it is the fastest and most cost effective way to do a strip plank hull to date.

The timber core used here is Kiri, lighter and in my opinion better than cedar http://www.highpointtimber.com.au/

Dave

 

Dave, just came across this and I'm intrigued by your method of dry stacking. When you say a 'thick paint scraper' I take it that you mean 1 - 2mm. How do you close this gap after applying the epoxy - or don't you?

Also, I assume you are in QLD (building under a tent and all!) how's the freight on getting your Kiri from WA?

 

Closer to the 1mm gap, and dont close it as the planks are screwed to the frames and lined up with the plastic strip's in the pic.

Any that may have a bigger gap get a west 411 type filler wth resin pushed through as the original brew kick's

Transport from WA for me was only a couple of hundred by train to Bris. and then by truck to my door.

Takes a couple of week's, but at the time being one of the first users in OZ, we got the Kiri for about 50% of the cost of WRC .

Oh yeah, I am in QLD.

Dave

 

My experience was pretty much identical to Nero's except max. width I could deal with was 40mm. I really enjoyed the strip plank process. Ya get a lot for your effort.

I will try Daves method next time. Gotta be easier than trowelling goop on top of the unthickened epoxy, on strip edges.

 

Dave - how do you make certain that you have completely filled the gaps between strips? I know that you said that capillary action does this, but how can you be sure that it is indeed completely filled?
On the face of it, I like the idea - but I'd have to be positive that the bonding was effective as necessary....
Also, given that you've rolled epoxy, not only into the gaps, but also all the outside surfaces, how does this effect sanding back for fairing?

 

When rolling it in from one side you can see in a lot of areas it comes out the other.

When going over it with a squeegee if forces it through the spot's that havent had it come through.

Samples of cut out's show that the void is mostly filled, and only occasionally have we found very small void's maybe 20mm long at most and maybe 3mm across on a 16mm plank.

Robin Chamberlain and Jeff Mcdavit have been using this technique for year's with no problems on his ocean going catamarans

It is not 100%, but probably 99%, and more than strong enough

After looking at a lot of samples from production boats built to survey, I found many more larger void's in contour foam/balsa layups.

Sanding is best done within day's as the resin does go hard, but I use Norton Blue Magnum 36 grit disc's, and they make short work of it, and last up to 4 times longer than the white ones.

Dave

Just a further note on the spacer, we saw a cat done where he did not believe that a thick scraper was enough of a gap between planks and used a jig saw blade instead.

he had lots of resin run out and had a lot of back fill work to do later after the resin had reached cure, so would have possible secondary bonding issues, though in reality, I don't think it would be a problem.

 

planking joint strength and grinding

I have done and continue to do simple break tests as the strip planking continues on my project. Catmando2 has a lot of wisdom in his post.

At the start of my project, I would wet out both edges of a plank and then scrape on a thickened epoxy mix, before screwing the plank back on to the forms. All samples broke in the wood grain. Stripping this way takes a lot of time.

Then I started to put the thickened epoxy directly on the plank edge and wet out the last plank edge with thin epoxy. All samples broke in the wood grain. Still too much time needed.

Next I tried using only thickened epoxy (silica in all cases). Same results in breaking. A lot less runout and mess to clean up. Progress is at an acceptable pace

Tried the dry method and found the clean up to be way to much time. For me this method would be ideal for a team. There would be enough time for all the work to be done before the epoxy kicks.

Second part of wisdom from catmando2 is finding a fast way to remove resin from wood ... and being able to control the removal. I use a $30 Coleman air sander with 4.5 or 5 inch, 36 and 50 grit blue discs. The discs need to have a backing disc or other support to hold shape. The red paper discs sold with the grinder are worthless. As soon as they get the condensation off the grinder they also loose shape. My solution is to coat the backside of each grinding disc with epoxy and 10 oz biaxel glass. This has to be done with the glass and resin laying on a plastic sheet and the disc layed on top with a paint can and weight to flatten it out. This way the resin doesn't get on to the working side of the disc.

The result is these discs come out with a slight dish shape that lessens the chance of gouging the wood. They last at least 20 times longer than an orbital sander disc. There is a Canadian supplier online that has cheap prices and $5 shipping.

Down side to using air sanders is the need for a big compressor (with a continuous service rating)

 

This is the supplier I use for the discs

http://www.onlineindustrialsupply.c...conia-fibre-backed-discs-5-inch-diameter.html

fast shipping and quality product

 

Catmando2,

Just wondering how well you think your method would work with Vacuum infusion rather than hand. Do you think it would be possible to have the resin pulled from one side of the hull to the other through the gaps.

Just think this may speed up the process and give minimal amount of cleanup.

 

Hi Dave

I just spoken to Port Phillip Plantation Shutters who are supposed to have taken over the WA Kiri distributors.

The prices I was quoted seem to be over $AU4000 per cubic metre.

Did you do better in pricing than that ?