Looking for homemade or cheap solution for heating & soaking planks

[Capella]

I'm working on my first ship and a big source of frustration is soaking the planks in warm water.

 

Currently I'm using a 12in x 6in shallow plastic bin and getting hot water from the sink, but obviously I have to keep replacing the water. 

 

I was looking at immersible heaters on Amazon, running around $25 - $30 - and I think that might work. I've found a few that can be used in plastic.

 

But before I bought one of those I thought I'd check here to see what others are using. 

[No Idea]

When I have had to use water I just use a metal tray and stick some water in it and put it on the stove.  You can heat the wood for as long as you like and then just take the whole lot to where your working.  I must be honest though I prefer hot air now for bending as waiting for the planks to dry on the hull just took too long.

[davyboy]

Hi there,

 

A normal hair drier or variable temperature hot air gun will do the job perfectly well. No need for hot water at all.

 

Dave.

[vaddoc]

I like large scale models so my planks are also large, 2 mm thick and up to 70+cm long. I tried lots of methods but really just very hot water from the tap is enough.

After I cut the plank to proper shape, I take the model to the kitchen. I hold the plank with a clamp for 30 secs under the hot water and then immediately put on the model. The plank will take even very acute angles but must be bent immediately.

For steam bent frames, I through them in a pot of boiling water, fish them out one by one and immediately secure on model.

Steam is not really needed for the dimensions we work with, although a steam box will work very well.

I do not like dry heat for planks. I do use the curly hair women machine sometimes to bend strips prior to laminating

[Jaager]

From the point of view of a home sawyer and saw miller, much time is involved in getting water out of wood and getting it equilibrate with atmospheric water concentration.  Soaking a plank is undoing all that, if you even could get water deep into the interior.  The natural glue that holds wood fiber together is not soluble in water in any case.  It is heat that loosens the bond enough to allow the fibers to slide as individuals and then rebond when the heat as dissipated,  Steam is more efficient than air at heat transfer. The hotter the steam the faster is the transfer.  Liquid water does not exceed 100 degrees.  It is probably a bad thing to actually cook the wood.

 

There are more than a few threads here concerning the various methods and devices used to bend planking.

 

[Jim Rogers]

Sous Vide Immersion pump keeps the water hot all day, although I use a mini steam cleaner or iron.

 

 

Edited January 23, 2021 by Jim Rogers

[kurtvd19]

I have an old Champaign bottle - nice and heavy.  Fill it with water and soak plank for 2-3 minutes and if it needs more to bend use a hair dryer to heat it - clamp in place and glue down when dry. 

[Jim Lad]

If you're working in smaller scales, an old cordless kettle works really well,  I simply put my planks in and boil them up in the kettle - job done.

 

John

[AON]

Presently I am using a discarded kitchen rice steamer (the wife wanted a new one so I snagged the old one).

 

 

 

[Bob Cleek]

3 hours ago, No Idea said:

I must be honest though I prefer hot air now for bending as waiting for the planks to dry on the hull just took too long.

 

3 hours ago, davyboy said:

A normal hair drier or variable temperature hot air gun will do the job perfectly well. No need for hot water at all.

 

2 hours ago, Jaager said:

From the point of view of a home sawyer and saw miller, much time is involved in getting water out of wood and getting it equilibrate with atmospheric water concentration.  Soaking a plank is undoing all that, if you even could get water deep into the interior.  The natural glue that holds wood fiber together is not soluble in water in any case.  It is heat that loosens the bond enough to allow the fibers to slide as individuals and then rebond when the heat as dissipated,  Steam is more efficient than air at heat transfer. The hotter the steam the faster is the transfer.  Liquid water does not exceed 100 degrees.  It is probably a bad thing to actually cook the wood.

 

2 hours ago, kurtvd19 said:

if it needs more to bend use a hair dryer to heat it - clamp in place and glue down when dry. 

 

Defying all attempts to dispel it, the myth that hot water or steam is required to bend wood in modeling sizes refuses to die. As Jaager explained, it is heat that softens the lignin and allows the bending. In full-sized construction, wood is steamed in a steam box because, given traditional technology, steam is a good way to transmit heat to the piece to be heated. Moisture has no effect on the process of "steam bending," which should  properly be called "heat bending," I suppose. It is beyond me why, in this day and age, modelers are still trying to soak wood in water in order to bend it! Do it however one wishes. It's your model, as the saying goes, but there's simply no point to it.

 

Very simply, here's how bending wood works: Think of a bundle of long straws stuck together with wax. The bundle is hard to bend. If you melt the wax holding the straws together all the way through the bundle, the bundle is easy to bend because the individual straws can slide against each other to accommodate the differing radii inside and outside the curve created by the bend. If you melt the wax, bend the bundle of straws, and then hold them in place so that the wax hardens again, the bend stays in place and the bundle has the new curved shape you've given it. Now, you could melt the wax by throwing the bundle in a pot of boiling water or you could simply blow hot air on it from a hair dryer or heat gun, or apply heat from contact with a soldering iron or clothes iron, or by even putting it in a microwave. The choice is yours, I suppose, but there's an awful lot of bandwidth being consumed by discussions about the problems people have trying to bend wood with hot water or steam. It would be a kindness to put them out of their misery once and for all, but I suppose that's not to be.

 

Read Chuck Passaro's excellent planking tutorials and learn how to do it correctly. You'll be glad you did! They are the best tutorial on planking ever done.  https://modelshipworld.com/forum/98-planking-downloads-and-tutorials-and-videos/

Edited January 23, 2021 by Bob Cleek

[mtaylor]

I agree with Bob on Chuck's method.  Not messy.  No fussing.   I dip the plank for a few seconds in water (improve heat conduction) and then clamp it to board in shape I need.  About 30 seconds or maybe a minute with a heat gun and the water is gone.  Let it cool still clamped and the plank is ready to be installed. 

[vaddoc]

 A few years ago I did my research on wood bending, indeed Bob is right, it is heat that does the job by releasing the lignin or however it is called so that fibers can slip. Then when it cools, it locks the shape. The temperature needed to achieve this is more than 100 C, so steam is needed as, being gas, it can reach higher temperatures but also is easier to heat the wood.

Still, my experience is that even lower temperatures will work. I have bent a lot of beech and maple and even leaving under running very hot water for 30 secs will dramatically increase their bending potential, even at 2 mm, a thickness where the strips are pretty solid.

I am not concerned for the wood getting wet, thin strips will reach an equilibrium with the environment in no time. 

Even wood that is just wet for some reason will make bending a bit easier. In my last boat I used close to 100 beech ribs 2 x 4 mm which had to take a bit of extreme bending. Immediately out of the pot with boiling water, they would take any shape. A few seconds later, they would snap.

I personally do not like using dry heat but it does work, at least for very thin strips.

The above should not really work but they do, at least for me and the scale I like working at. Maybe the very thin strips we use behave differently to full scale planks.

In all honesty I would much prefer to have a steam box and I though of making one but in my current set up it is just too difficult. Having said that, I now need to plank two boats so that will be about 70 planks, each 70 cm long, so may need to revisit this!

[Stevinne]

I went to the neighborhood thrift store and picked up an old plug-in percolator-type coffee pot. I believe that's what Frank Mastini recommended in "Ship Modeling Simplified." The only thing I have to do is make sure it's unplugged when I'm done using it.

 

[allanyed]

Heat is the key as very well explained above, but I do like to soak some of the problem planks a bit before bending and ironing them as explained in Chuck Passaro's write up.  To do the soaking I have a couple pieces of 1/2 inch ID plastic pipe that I cut to a few different lengths with a cap  glued on one end of each. Cheap and easy to find in any hardware store.  Small, uses little water, keeps the water warm longer if you want to use hot water. Larger diameters are of course readily available.     The long pieces of wood tend to rise (float) for a while so I loosely cap the other end as well to keep them submersed.  You will know they are thoroughly wet when they do not bob up after the loose cap is removed.    MOST of the time I forgo the water and just use dry heat with no issues.

Allan 

[Roger Pellett]

Steam Temperature:  Water at standard atmospheric pressure boils at 212F (100C).  If you live at a high elevation like Denver, Colorado the boiling point is less.  There are two ways to increase steam temperature both used in power plants but impractical for ship model builders:

 

Increase the pressure at which the water boils.  That’s how a pressure cooker works.

 

Heat the steam after leaving the pot that it boils in.  This is called superheating.  

 

That’s it, you can’t fool Mother Nature.

 

Steam coming out of a pot of boiling water contains more heat energy per unit mass than the steam water mix still in the pot but the temperature of the boiling water in the pot and the steam coming out of it are the same.  Heat transfer is driven by temperature difference, and conductivity.  Water has better conductivity than steam.  A small piece of wood in a pot of boiling water will heat faster than one held in a jet of steam.

 

Roger

 

 

Edited January 26, 2021 by Roger Pellett

[vaddoc]

1 hour ago, Roger Pellett said:

That’s it, you can’t fool Mother Nature.

 

This is very interesting Roger. So the ship builders heating those massive planks with steam actually only achieve 100 degrees C at best. 

 

I did a bit of googling and found some info:

 

"Softening temperatures of lignins ranged from 127-193°C. Birch xylan and pine glucomannan softened at 167° and 181’C, respectively. Sorption of water by lignin and hemicellulose caused pronounced decrease of the softening temperature-in some cases, to as low as 54°C." 

https://bioresources.cnr.ncsu.edu/resources/thermal-softening-adhesive-properties-and-glass-transitions-in-lignin-hemicellulose-and-cellulose/

 

"The structure of lignin is rich in phenolic hydroxyl and it offers the possibility to create intermolecular hydrogen bonds. Water molecules can break these hydrogen bonds and segmental motion can occur easily. The T_g of lignin decreases with increasing moisture content until the wood or the lignin reaches its water saturated point. The number of hydroxyl groups influences the amount of water bound to lignin"

https://link.springer.com/article/10.1007/s00107-020-01637-3

 

This is completely out of my areas of expertise but it seems that while heat does the job, moisture helps a lot. 

 

Vaddoc

[Roger Pellett]

Yes,  industrial and hospital applications use autoclaves to contain pressure above atmospheric thereby raising steam temperature.  Simple steam boxes do not do this.

 

The temperature difference between dry and moistened wood is also striking.

Edited January 26, 2021 by Roger Pellett

[Phil Babb]

Hi.

Not a very good idea to put wood into any sort of water or moisture,  we all tend to get the driest condition to store wood prior to use in any applications , especially model work.

The method I was taught and always use is an domestic iron, wrench it from the wife or buy your own, not a steam one obviously,  and depending on type of timber, adjust the heat and iron away, pearwood responds beautifully to this.

 

[Snug Harbor Johnny]

I have a small hobby 'heat sealing' iron - the kind that can be used to set (or loosen) seams in wallpaper, and is also used for shrinking plastic skin over RC model airplane wings and fuselages.  It has a temperature control knob, and should work for heat-softening planking wood for model ships !  I suppose a slight moistening before ironing wouldn't hurt, since the heat will drive most of it off - the wood isn't 'soaked' for any length of time.  I have to confess that when I did the planking on the Wasa (quite a few years ago), the curvature of the bow was the hardest to contend with ... so I put the end of the plank in my mouth where warm saliva and the action of tongue, palate and teeth caused enough bend to make the plank cooperate for a significant bend.  There was a 'knack' for telling how far to 'push' the plank and avoid breakage.  I'd let the wood dry and the bend would set before I glued it in place.

[Dziadeczek]

Check out this link :

Anyone using electric plank bender? - Modeling tools and Workshop Equipment - Model Ship World™

Edited January 27, 2021 by Dziadeczek

[Decoyman]

I'm thinking of getting one of these, with the strap:

 

https://luthiers-bench.com/products/bending-iron

 

This is because I might build a lute, but also because I can see the use for shipbuilding.

 

Rob

[kurtvd19]

One of our club members purchased one when he built a violin and he continues to use if for model ship building.  He's very happy with the one he purchased.

[Bob Cleek]

On 1/24/2021 at 6:53 AM, vaddoc said:

Maybe the very thin strips we use behave differently to full scale planks.

This is very true. Keeping in mind the example of the "bundle of straws bound together with wax," an effective transfer of heat throughout the entire piece of wood is essential to successful bending. Heating a piece "through and through" requires subjecting the piece to external heat for long enough that the heat is transferred to the center of the piece. In full size construction, the rule of thumb for heating wood before bending is one hour per inch of thickness. Thus a full size one inch thick plank must be heated for at least an hour and then quickly bent before the temperature drops and the lignin in the piece begins to harden as the temperature drops. A steam box is commonly employed to steam larger pieces of wood because it is a practical way to heat a full size plank evenly for the required length of time. Indeed, in earlier times, it was the only way to accomplish the job. (In some instances, however, short sections of a long plank can be heated sufficiently by wrapping the section to bent in rags and continuously pouring boiling water on the rags, or, as has long been the practice in the construction of Venetian gondolas, by heating the section of the plank to be bent over an open fire, a technique that takes care and expertise to avoid burning the plank.) With the very small sized thicknesses of wood encountered in modeling, the application of dry heat effectively heats the piece "through and through," obviating the need for steaming or boiling.

 

On 1/26/2021 at 8:27 AM, vaddoc said:

"Softening temperatures of lignins ranged from 127-193°C. Birch xylan and pine glucomannan softened at 167° and 181’C, respectively. Sorption of water by lignin and hemicellulose caused pronounced decrease of the softening temperature-in some cases, to as low as 54°C." 

https://bioresources.cnr.ncsu.edu/resources/thermal-softening-adhesive-properties-and-glass-transitions-in-lignin-hemicellulose-and-cellulose/

 

"The structure of lignin is rich in phenolic hydroxyl and it offers the possibility to create intermolecular hydrogen bonds. Water molecules can break these hydrogen bonds and segmental motion can occur easily. The T_g of lignin decreases with increasing moisture content until the wood or the lignin reaches its water saturated point. The number of hydroxyl groups influences the amount of water bound to lignin"

https://link.springer.com/article/10.1007/s00107-020-01637-3

 

It is true that hot water will be absorbed by the lignin itself and thus cause softening of the lignin at lower temperatures. Heat transfers far more readily through moist wood than through drier wood. In full scale boat building, the best wood to be bent, particularly for frames, is "green wood," i.e. wood which has not been fully dried. The higher the moisture content of the bending stock, the easier it is to heat effectively and, thus, the easier it is to bend and the less likely it is to fracture when bent.  The critical factor, however, is getting the moisture into the wood. While absorption rates vary depending upon the properties of various species of wood, in any event it takes a considerable amount of time, relatively speaking, for the moisture content of wood to change. Air-drying a cut piece of stock to a usable moisture content requires one year of drying time for each inch of the stock's smallest dimension. A one inch plank should air-dry for a year before being considered sufficiently stable for it to be suitable for fitting. Even at the small dimensions encountered in modeling, increasing the moisture content of a small piece of wood throughout its entire thickness will take a surprising amount of time. Here again, the "bundle of straws stuck together in wax" analogy applies. There's not much, if any, benefit to getting just the outer surface of piece wet because the moisture isn't going to penetrate the whole piece unless it's soaked for a good bit of time. Applying the "year of air drying for each inch of thickness" to a 1/32" model plank, equals about eleven and a half days for that model plank to reach equilibrium with the ambient humidity, so the small amount of temperature reduction advantage gained by increased moisture content really isn't worth the trouble, since increasing the heat is so easily accomplished. On the other hand, using "green wood" in full size steaming jobs is advantageous because the higher moisture content makes thorough heating of the piece much more efficient owing to the more efficient transfer of heat through the wood with greater moisture content.

 

(Full disclosure disclaimer: "I'm not really a dendrologist, I just play one on the internet.  )

[Bob Cleek]

1 hour ago, Decoyman said:

I'm thinking of getting one of these, with the strap:

 

https://luthiers-bench.com/products/bending-iron

 

This is because I might build a lute, but also because I can see the use for shipbuilding.

 

Rob

While this example appears to be the "Rolls Royce" of bending irons and is priced accordingly, In my experience, bending small pieces of wood over a curved hot iron is a particularly good method. The iron supplies the heat and each side of the piece can be offered up to the iron alternately, speeding up the initial heating of the piece. Thereafter, shaping is accomplished by bending the piece directly on the iron. No heat is lost between the heat source and the bending and heated wood loses its flexibility quite rapidly as it cools. If the wood resists the bend, one need only slow the rate of bending, i.e. apply less force, and let the heat increase to permit flexing to a sharper curve, thus avoiding much of the risk of breaking the piece. Given the cost of this appliance, since most of us won't be bending the sides of a cello, the side of a soldering iron will suffice.

[hornet]

I use a length of polypipe with endcaps cut into a trough and mounted on a wooden base. A tap on the end allow most of the water to be drained when finished 

[Decoyman]

12 hours ago, Bob Cleek said:

While this example appears to be the "Rolls Royce" of bending irons and is priced accordingly, In my experience, bending small pieces of wood over a curved hot iron is a particularly good method. The iron supplies the heat and each side of the piece can be offered up to the iron alternately, speeding up the initial heating of the piece. Thereafter, shaping is accomplished by bending the piece directly on the iron. No heat is lost between the heat source and the bending and heated wood loses its flexibility quite rapidly as it cools. If the wood resists the bend, one need only slow the rate of bending, i.e. apply less force, and let the heat increase to permit flexing to a sharper curve, thus avoiding much of the risk of breaking the piece. Given the cost of this appliance, since most of us won't be bending the sides of a cello, the side of a soldering iron will suffice.

I should try the hot (soldering?) iron trick. Up until now I have assumed that the small contact area would be disadvantageous, but, on the other hand, the associated cost is essentially zero, if you already have an iron. Thanks for the suggestion.

[Bob Cleek]

24 minutes ago, Decoyman said:

I should try the hot (soldering?) iron trick. Up until now I have assumed that the small contact area would be disadvantageous, but, on the other hand, the associated cost is essentially zero, if you already have an iron. Thanks for the suggestion.

The trick is to keep the wood moving so it doesn't scorch. On most electric soldering irons, the lower shaft, rather than the tip end, is just about the right temperature.  If you have a clothes iron or a ladies hair curling iron, those may work well also.