Seeking advice on how to edge bend 0.6x5mm sapelli for second planking

[Esap]

Hi all, I am on my first build, trying to do the right things for planking, and have read the tutorials and in particular watched Chuck Passaro's planking videos. The bending station idea and edge-bending technique to get a great flat-on-bulkhead fit makes total sense, especially with kits like the one I have where the plank wood supplied is not wide enough for spiling.

I found success on the first layer of planking, as the thicker strips were more manageable, and I believe the strip in Chuck's video is very similar. However, attempting the same on the second planking material is proving difficult to say the least. The material is 0.6x5mm sapelli, and being extremely thin I just can't get it to edge bend, even after extended soaking in hot water. It has a very strong tendency to curl/rise up as my image hopefully shows. Having the hold-down in the middle to attempt to hold it flat worked great for thicker strips, but hasn't worked well for strips this thin, as it just curls, quite significantly, to the sides of that instead.

I have found posts that do talk about it being harder with certain types of wood when it is this thin, but haven't found any detail on how to truly manage it, other than that it seems people have succeeded, somehow. Would anybody be kind enough to help shed some light on how beginners should be approaching this? Should I just plonk the iron down anyway to flatten it despite not really having achieved a nice curve? I want to do planking the best way possible, but I can see why so many beginners fall back to less 'proper' methods!

[vossy]

Hi, from what your photo is showing it appears that you are trying to bend the plank against the grain. This is wrong. The planks should lay flat against the first planking layer. To achieve the slight upwards curve on the finished model it is necessary to taper the planks as you go ie. remove small amounts from the top edge of the fore and possibly aft section of each plank. Unless your model is a bluff bowed vessel such as the Victory, Endeavour, Bounty etc. with second layer planking as thin as yours, 0.6mm you probably wont have to use any plank bender on the vessel. But you will have to taper as you go.

 

Chris.

 

[Esap]

Hi Chris. Thanks for your fast response! I was planning to taper out of necessity as the bow of the ship has less space available than the middle, but wasn't aware that tapering would be sufficient to get it to lie flat against the hull? I figured I was going to run into the issue of the strip being unwilling to bend in the 3-dimensions necessary to lie properly on the hull unless I did manage to edge-bend it somewhat.
With thicker strips you run into a clinker looking effect if you don't edge bend as it doesn't sit smoothly against the bulkhead. But with these ultra thin strips its not really a clinker effect, it just doesn't lie flat properly without that slight edge-curve... or so I thought. Have I misunderstood what Chuck's video series was demonstrating? This one talks of the specific issue I was trying to solve: 

It did work great with my thicker strips, I just can't seem to do it with these ultra thin ones. My attempt at a bending station can't get it to bend.

[Dziadeczek]

 

At about 3:15 min. into the video, he starts edge bending with his hot bending iron (you can use an ordinary soldering iron with a heat control).

[Dr PR]

Esap,

 

With the thin planks you are working with it will be very difficult to get much curvature across the thick dimension. It is like trying to bend a strip of paper - it will fold before it bends. There just isn't enough thickness in your 0.6 mm planks to allow much bending.

 

I built several plank on bulkhead models years ago before the Internet and without books telling me how to do it "right." I didn't know anything about soaking, heating and bending wood. For these I just tapered the planks. After one plank was glued in place I placed another against it and marked it at each bulkhead the amount needed to be removed. Then I trimmed the plank edge with a hobby knife and sandpaper. It took two or three passes to get a good fit all along the length. I did end up with very narrow pointed planks at the bow - less that 1/3 the original plank width in some places. Where the gap between planks opened up I just cut triangular stealers to fill the gaps. I wouldn't say the results were beautiful, but I was planning to seal the wood and paint the hulls anyway.

 

Perhaps the most important step comes with the shaping of the garboard plank - the first plank outboard the keel. If this is tapered to a point at the bow where the stem just starts curving upward you won't have to trim as much from the subsequent planks.

 

A more elegant technique would be to trim the planks similar to what is shown in this picture from zu Mondfeld's "Historic Ship Models."

 

 

I understand what you say about the planks not being wide enough to do the "hooking" as shown on the right where the hook is wider than the rest of the plank. But maybe you don't have to make it any wider than the plank and cut the notch behind the hook only half the thickness of the plank. Just taper the garboard plank to the place where the plank is half the width of the original plank width and attach it to the hull. Then taper the next plank the same way then notch it to fit over the end of the garboard plank, and so on.

 

I confess I haven't tried this, but it seems to me it should work with either the "pointed" version (English) on the left in the picture or the "hooked" version (Dutch) on the right. And if you want to leave the wood unpainted it would be a bit more elegant than the extreme tapering i mentioned above.

 

 

Edited November 19, 2022 by Dr PR

[Jaager]

I am not a wood products scientist,  I have not done the experiments to back this up.  The available evidence seems to support:

 

A strip of wood that is rectangular in cross section, does not "want" to bend in the thick plane.  It will twist instead.

 

The solution is to spill the plank.  Start with a wide board and trace out the "S" shape of the plank shape needed on it.  It is then cut out and the rest is spilled / spoiled in Cockney(?)  -wasted.

The wood species that you are using is a poor choice.  The stock that you have is not wide enough to do its job.

 

To bend wood, the lignin binder needs weaken its hold.  Lignin is insoluble in water.  What weakens its hold temporarily is heat.  With a thick piece of wood, steam is an efficient way to get heat into the interior.  At model plank scale, steam is usually not necessary.  Heat alone will do the job.  Water just swells the fibers and messes up a smooth surface.  

Soaking a plank may refill the cellulose tubes with water.  What that does is undo all the time spent in seasoning (drying) it.  Water will not reanimate it.  It was actually dead while it was a part of a living tree.   Wood will equilibrate   with the water concentration in its atmosphere. Humidity varies with the weather. So does the water content in lumber but with a significant lag.  It will not get drier than this, unless forced.   Old brittle wood is just wood that has always been brittle.  It was crap to begin with.

 

Wood fibers are cellulose tubes.  They really do not slide along each other all that much.  They stretch and pull apart on one side and crush and kink on the other with a bend - if it is still growing the new layers  can adapt.   Some species are more forgiving in how much bending that they will allow.  There is a limit for any species.

[allanyed]

If you need to use the pre-cut strips, you can probably succeed using Chuck's method instead of what you show in your photo.    What you show does not follow his method.  After lining out the bulkheads and subsequently tapering the width of the plank follow part three where you can see that there is a hold down for the plank so it does not ride up and a former piece with the curve that is needed.   

Allan

)  

Edited November 20, 2022 by allanyed

[mtaylor]

I find that I need quite a few clamps to hold the wood into position. I use Chucks method of soak, mount to a board in the shape I want and them clamp with more than a couple clamps especially at the center of the bend.  Then hit it with the heat source.  I try to get as much of the moisture out of the wood with the heat and then let it cool before removing it.   Haven't had a problem bending yet.

[Esap]

allanyed sorry I wasn't more clear there, I did have a hold down in the middle but it would just warp to either side of it, my photo above was to the left of the hold down, I should have showcased the whole thing but was trying to get a close up of the twist/warped bit. I think with strips this thin a single hold-down just doesn't cut it.

Thanks everybody for your advice and feedback. You have inspired me to keep trying with this method and with heat, and I have found a way to follow the method while keeping the wood pinned down. I am using drawing pins on a pinboard, and progressively add more as I work my way along the strip with the iron. I wet the strip, move the far right pin down a bit until there is some warp in the middle, but not too much, and then just plonk the iron down on it anyway and flatten it out with heat. I then add additional pins to hold that area secure, and repeat. It seems to be working - the pins are helpful but really the trick was just having the confidence to plonk the iron onto the wood even when it wasn't very flat. When it is this thin the iron seems to just flatten it anyway without damaging it as long as the deformation isn't too large.

[allanyed]

No matter how you do the hold down, pins or clamps I have found that the best way to go about the heating process (at least for me) is to use a heat gun.   A hair dryer will work, but it was frowned upon by the admiral when I did that.  An industrial heat gun is easily adjustable plus had higher temperature limits and was cheaper than a hair dryer.  It is sometimes hard to maneuver a heating iron around the clamps and pins where as the gun gets heat to all points.

 

Allan

[glbarlow]

Chuck’s method does not involve any soaking, it is heat from a travel iron or hot air on dry wood.  It is easy to bend wood against its grain using his method, I do it all the time and often twist it after I’ve bent it for stern planks. One point is that you “bend the wrong way” by bending the wood down for it to then curve up on the bow. You absolutely need to taper the wood, every strake should run from the bow to the stern,. So I use a metal ruler and a #11 blade to taper following the lining of the hull or simple math of how many full planks fit midships and the height available at the bow.  You need a bending station and the method Allan provided in Chuck’s video, push pins won’t work. First soaking the wood is just asking it to warp and curl.

 

All that said I don’t know sapelli or its characteristics. I have bent 1mm Boxwood, Alaskan Yellow Cedar, and even kit walnut planks that were closer to .5 - 75mm but your wood looks very thin, as someone mentioned like bending paper.  One option is to replace that wood with something more common and thicker. The small cost of doing that may be worth the frustration of what you’re experiencing.

 

Good work on learning to do it right. Planking is a skill learned only through experience. There are so many opinions and variations on techniques and what can and can’t be done, it is easy to get mentally twisted on trying to sort out what to do. I used to soak and force planks into place, I’m now fully a disciple of Chuck’s dry heat bending method. My build logs show how I’ve applied it to my models. Every plank it’s own project. The thin sapelli is one thing, choosing one technique and sticking with it is the most important step, then sticking with it. It pays off for a lifetime of modelling, so hang in there, it will come. 

[allanyed]

Glenn brings up an important point.  Sapelli or the "walnut"  found in some kit boxes are not appropriate woods for ship models in most cases.  It is porous with a lot of visible grain and often brittle thus difficult to work.  A tight grain should be a major consideration.   Consider buying a good quality wood and replace the sapelli.  Boxwood, Alaskan cedar, basswood, Swiss pear, and other species folks here can recommend.  

 

Dry bending works, but there is nothing wrong with soaking a strip before shaping as it often makes it easier to shape plank around the bending piece as seen in post 7.  Both methods have worked well for many members.

 

Allan

Edited November 21, 2022 by allanyed

[OllieS]

I get around the problem by using shorter planks. Using Sappelli for the second planking on my OcCre revenge (I have not reached the modelling level of replacing everything in a kit yet ) I cut the strips into 7.5 cm lengths which is 1/8 of a strip which scales to 18 feet. 

Using contact glue you can then make a close enough fit to the next row of planks adjusting the cut ends slightly to fit. Also tapering where needed.

In effect you can make Jaager's S shaped plank out of several short sections even though you don't have the width to cut the shape out of one plank.

It looks like this

Edited November 22, 2022 by OllieS
adding a link

[No Idea]

If you look at Chucks video the point that the plank touches his jig has a larger surface area. This would help spread the forces away from a very small focal area when bending. 
 

Using a pin would make the contact point tiny and therefore increase the forces in that tiny area. It’s got to go somewhere so the wood will start to lift instead of bend. 
 

l had this problem until I made a better jig to bend the planks on and allowed the plank to be bent with less pressure in a very small area. So try making a jig and also make the hold down the same gap as the plank is thick. 
 

Cheers Mark