Bending cross-grain bulwark rail?

[johngee]

Hi All,

I have posted this in a facebook group and received a few replies.

However, I am after a few more ideas/suggestions.

I have to bend a cross-grain thick-ish plank as the top rail of the ships bulwark - it also needs to be bent to meet the ships natural curvature from bow to stern (so it needs to be bent across 2 axis)

Suggestions I've received include: 1) use a steam box (I'd have to build/design one first)  2) Won't be able to bend it so cut/join the plank so it fits 

Does anyone else have any ideas - pics below

[Jaager]

The angles at the bow are far from as bad as they could be and most commonly are.

1. Do not try to use one piece to be the rail.  Outside of Redwoods et al. normal trees do not grow that tall, that clear and straight.  The joins were not a straight butt either. The scarph is more involved.  By using pieces, with the curves sawn, instead of bent, no spring back will occur.  The wood will not "want" to return to its natural shape.

2. Given the curve in question, you may get by using the kit supplied material.  For a serious curve, a wider piece of stock ( at least for a buff bow ) is used and the actual rail is spilled from it.  Alternatively,  a wider piece of wood of an appropriate species (Maple, Cherry, Pear, etc.) that is the needed thickness would be bought.  It would surprise me if your kit supplied species takes to scraping the outboard OoGee or whatever pattern into it.  The harder, tighter species do this much better.  The color can be adjusted by using a wood dye.

 

Bending:  wet heat works best.  The water - steam transfers heat to the interior faster and more efficiently than dry. 

No matter what you read, no sort of ammonia that you can access will aid in bending wood.  What did that was anhydrous ammonia, commercial only, explosive, toxic,dangerous and it would probably dissolve you if you got on you.  The household ammonia cleaner will only discolor and deform the surface fibers of wood. 

[Dziadeczek]

Watch the video in the link (it is of lousy quality and in German, but you'll get the idea). Water+ heat + lots of patience.

https://modelshipworld.com/topic/18868-anyone-using-electric-plank-bender/?tab=comments#comment-579808

[wefalck]

I would take a board and draw onto it the shape of the hull in the correct dimensions, i.e. to the inside of the rail. Put lots of nails to the inside of that curve and gently coerce the hot, wet plank unto this shape, while holding it down to the board, so that it does not twist. Work from one end to the other and fix the shaped part with more nails and the occasional little wood strip nailed down to hold it flat. You may not be able to do this in one session, because the wood will dry and cool down. Leave it in the jig to completely dry and then steam only the unbent part before putting it back into the jig to continue.

[allanyed]

Hello John,   Welcome to MSW.  Please consider starting a build log on your model, it will avail you to thousands of helpers here if you run into any other questions or problems.   Looking at the photo you posted, I would go with a two, or even better, a three piece rail on each side, scarphed together.  You can get various sheet wood at local hobby shops or on line, depending on the type of wood you want to use.  CLOSE grained is best, such as pear or Castello and quite a few others you will see discussed in the Wood Discussion forum here.    

Allan

 

[Jaager]

Rather than balance the rail on a knife edge and have a problem with its horizontal orientation,  I would probably fix the timber heads first.   If they are timber heads in the original construction, My shipyard would have left the sides perpendicular to the centerline.  Check the plans for the shape.  If cant frames were used ( probably fore only )  they would likely have the angle of the cant. 

The rail would have a 3 point base and a significantly more secure bond.

[johngee]

Thank you all for your great thoughts and ideas 🙂
Pinning/nailing the railing may be better if the surface was flat, but with the ships curvature, I think scarphing sounds like a better solution - I'll prep some drawings off the plans.

Thanks Allan for the offer of a build log - that sounds like a great idea too . . . . . mind you, I started this ship about 25 years ago and recommenced it's build in Jan 2020 with a commitment to finish it this year.

 

[mtaylor]

I don't have a steam box but have had much success with soaking the timbers for a couple of hours and then using a curling iron.  I work the timber where the bend is needed by holding on the iron and moving it back and forth.  It takes some practice but so far so good.   I also do what others have recommended and that's cut the rails (or planking or beams) into pieces per Allan is an excellant idea.

 

If you use decide to use the curling iron, I suggest you buy the admiral a new one and then take hers.    Seems to work better with keeping them happy than just going out and buying one for yourself.