Has anyone steam bent wood on this forum?

[Richard Kassner]

Hello All,

I was thinking of steam bending 1/2 or 3/4 inch thick Quarter-swan White Oak planks over a boat's hull to add a keel and strakes to that boat. The planks maybe as much as 1 1/2 inches wide. I was planning to use epoxy to attach the plank to the boat's hull. I have never done this before.

I have watched some videos of people steam bending wood but not in the way that I think I can do so on this hull.

My question is as follows:

Is it feasible to tighten ratchet straps over a boat's hull with thin steamed wood planks so as to bend those steamed wood planks to conform to the surface of a boat's hull WITHOUT screwing the steamed wood planks into the hull?

Below is a picture of the boat's hull. (The gray color is NOT primer or paint but colorant added to protective epoxy barrier coats.)



Below is a picture of the ratchet straps I was planning to use to compress the steamed wood plank over the hull.


The general curve of the hull is rather gradual; however, one of the challenges is a hump or bulb at the bow that creates a sharpish curve. (I gather this hump or bulb was done to protect the rest of the hull when beaching the boat.) Therefore, I will probably have to cut away part of the plank so that the end of the plank meets the top of the hump or bulb.


I would use epoxy and fairing compound to make everything appear uniform at the hump or bulb. I would use epoxy to fasten the wooden plank ( the keel and hull strakes) to the hull. I would use ratchet straps to hold these steam bent pieces of wood to the hull while the epoxy cures.

In sum, I would use the ratchet straps to bend the steamed wood and then use the ratchet straps to hold the bent wood onto the hull while the epoxy cured.

Again, is this idea feasible or will the force to bend the steamed wood be too great for ratchet straps to achieve?

Will the wood want to spring back some after bending it so that attempting to epoxy curved wood under the pressure of the ratchet straps be unfeasible?

I am reluctant to screw the wood planks into the hull because of potential leaks. Moreover, the hull is only 5/16ths of the an inch thick. This brings another question to mind.

Would such a hull be strong enough to accommodate the force of tightening down the ratchet straps to bend 1/2 to 3/4 inch thick White Oak?

I believe I have to use wood that has not been kiln dried and I have access to non kiln dried wood.

If it is an unreasonable to steam bend wood with ratchet straps that is O.K.. As I said I have never done this before.

Any insights would be most welcome.

 

[RM Anderson]

White oak for cockpit combing. Gentle curves such as you describe the use uf a heat gun is sufficient. I think using screws would induce less localized stress than using straps or lead shot bags. Maybe drilling a larger hole, filling it with epoxy and tapping it later for the desired screw would be a better idea. Richard

 

[Eric Patterson]

I have not steam bent but I have made bent laminations. Looking at your hull I think you can dry bend as the curves are long and gentle. If you want to bend the nose area one solution is to make the keelson in two pieces. One shorter one for the tight radius, until it eases into the flatter part of the hull, and scarf joint it to the rest of the other keelson. I'd use a scribe and copy the bow shape onto a 2x or plywood doubled up and bandsaw it to match and then bend and clamp your steamed wood (or use bent lamination technique) to it to create the needed piece. Then epoxy to mate the rest of the keelson. When you clamp you want more downward force than the ratchet straps will bring you coming in tangent to the hull. Place 1x's on end, say 1' long, and run the straps over them. This will impart a lot more downward pressure. Also, do the keelson first and then the strakes. You can cut strips and place perpendicular between the strakes and keelson to get the strakes perfectly parallel to the keel this way.

My 2 cents. Like Mike Tyson said, everyone has a fight plan until they get punched in the face.

 

[Richard Lathrop]

Richard,

I have steam bent white oak. What you are describing is doable. Rule of thumb is 1 hour steam per inch of thickness.

Lou on Tales of a Shipwright has some good videos on steam bending.

I built a steam box and used a turkey fryer to generate the steam for bending in the keelson on a garvey. Main issue is having everything lined up and ready to go when the oak comes out of the box and keeping the pot topped off with water. It helps to have assistance.

Rick

 

[Matt Mahoney]

That doesn't look like much of a bend to me. I would first try strapping the piece on without steaming. You may find that steaming is unnecassary. If you decide to steam, you will need a long steam box. Alternatively, you could use the poly sleeve method of steaming in-place. Go to the Wooden Canoe Heritage Assoc forum (www.wcha.org) and search for threads about steaming gunwales in place using polyethelene sleeves. Lots of information there about this method, and about steaming in general.

 

[Steve Sanford]

Richard~

As these longitudinals are merely protective and not structural, I would be tempted to use PVC "lumber" (Azek or the like). It comes "pre-steamed" - with as much rigidity as angelhair pasta....

I'd mill the pieces on the table saw to whatever section(s) makes sense, then use the ratchet straps (with some fine tuning via duct tape) to put them where they need to go - with either thickened epoxy or 3M 5200. Once cured, I'd protect them with 1708 (6-inch wide is available) or whatever skin you prefer.



Hardly traditional - but no rot and no fastenings through the lovely finish.

All the best,

SJS

 

[Richard Kassner]

White oak for cockpit combing. Gentle curves such as you describe the use uf a heat gun is sufficient. I think using screws would induce less localized stress than using straps or lead shot bags. Maybe drilling a larger hole, filling it with epoxy and tapping it later for the desired screw would be a better idea. Richard

Thanks for the reply. If I wasn't so concerned about water egress, I would use screws as you suggest. The bending of the combing you did in the picture looks incredible. Nice work!

 

[Richard Kassner]

Richard,

I have steam bent white oak. What you are describing is doable. Rule of thumb is 1 hour steam per inch of thickness.

Lou on Tales of a Shipwright has some good videos on steam bending.

I built a steam box and used a turkey fryer to generate the steam for bending in the keelson on a garvey. Main issue is having everything lined up and ready to go when the oak comes out of the box and keeping the pot topped off with water. It helps to have assistance.

Rick

Thanks Rick. I am glad to read that you think this is doable.

I have watched Lou on Tales of a Shipwright.

In fact, I got the idea on making my skeg from him on "Building the TotalBoat Sport Dory: Episode 33 - Making the Skeg." I used Quarter-Sawn White Oak because of Lou's recommendation. I bought Polysulfide in an attempt to copy Lou in sealing the Skeg to the hull and I even bought screws to fasten the Skeg to the hull because that is what Lou did.




In fact, I book marked that video.

I saw the video where Lou steam bends mahogany and he used a plastic bag. I have book marked that video too.

That man has so much experience.

Thanks again,

Rick

 

[Richard Kassner]

That doesn't look like much of a bend to me. I would first try strapping the piece on without steaming. You may find that steaming is unnecassary. If you decide to steam, you will need a long steam box. Alternatively, you could use the poly sleeve method of steaming in-place. Go to the Wooden Canoe Heritage Assoc forum (www.wcha.org) and search for threads about steaming gunwales in place using polyethelene sleeves. Lots of information there about this method, and about steaming in general.

Hello Matt,

Thanks for the tip.

I will try dry fitting the plank before steaming to see if it works.

Thanks for the link. I will check out Wooden Canoe Heritage Association forum and search for threads on steaming gunwales using polyethylene sleeves. I can learn too much information.

Cheers

 

[Richard Kassner]

I have not steam bent but I have made bent laminations. Looking at your hull I think you can dry bend as the curves are long and gentle. If you want to bend the nose area one solution is to make the keelson in two pieces. One shorter one for the tight radius, until it eases into the flatter part of the hull, and scarf joint it to the rest of the other keelson. I'd use a scribe and copy the bow shape onto a 2x or plywood doubled up and bandsaw it to match and then bend and clamp your steamed wood (or use bent lamination technique) to it to create the needed piece. Then epoxy to mate the rest of the keelson. When you clamp you want more downward force than the ratchet straps will bring you coming in tangent to the hull. Place 1x's on end, say 1' long, and run the straps over them. This will impart a lot more downward pressure. Also, do the keelson first and then the strakes. You can cut strips and place perpendicular between the strakes and keelson to get the strakes perfectly parallel to the keel this way.

My 2 cents. Like Mike Tyson said, everyone has a fight plan until they get punched in the face.

Hello Eric,

I think I follow you. I can simulate the curve at the bow using an angle finding tool my wife bought me some years ago. I didn't think of that.


Also, I looked at your boat build on this forum and saw how you used bungee chords with blocks in your "Installing Keelsons" post. Thanks.

 

[Richard Kassner]

Richard~

As these longitudinals are merely protective and not structural, I would be tempted to use PVC "lumber" (Azek or the like). It comes "pre-steamed" - with as much rigidity as angelhair pasta....

I'd mill the pieces on the table saw to whatever section(s) makes sense, then use the ratchet straps (with some fine tuning via duct tape) to put them where they need to go - with either thickened epoxy or 3M 5200. Once cured, I'd protect them with 1708 (6-inch wide is available) or whatever skin you prefer.

View attachment 61145

Hardly traditional - but no rot and no fastenings through the lovely finish.

All the best,

SJS

 

[Richard Kassner]

Hello Steve,

That sounds like a good idea using the Azek. I still have some in the garage from a home repair but not enough to make a keel or hull strakes.


As I recall the stuff I bought was super flexible as you say. I will look into that and see how thin I can get it. Thanks for your advice.

 

[Steve Sanford]

Richard~

I bought it in 3/4" (finished thickness) for a house project this summer. My lumber yard only sells full lengths - which is 18 feet. I bought one 1x6 - but quickly added a 16-foot 2x4 to my order because the Azek drooped so much I could not keep it from hitting my hood - or the road - for the trip home. The 2x4 was just the stiffener to get it home.

Because it doesn't take on moisture and has no grain to split, I use Azek for several small projects - like the chocks for this gun rest. So, you can get your money's work from the 18-footer if you put the cut-offs to good use.



BTW: I, too, am a fan of Lou Sauzzede (sp?).

All the best,

SJS

 

[Eric Patterson]

Richard

I said "use a scribe" but what I meant was use carpenter's dividers to scribe a line that follows the curve. I wasn't clear enough in my wording. Yes, you got the bungee cord usage like I meant.

 

[tod osier]

Richard

I said "use a scribe" but what I meant was use carpenter's dividers to scribe a line that follows the curve. I wasn't clear enough in my wording. Yes, you got the bungee cord usage like I meant.

He can also just measure offsets from a string by the foot (or the inch in more complex areas). With a small filet of epoxy down each side of the keel hiding any issues with the joint that would work well to get it done quickly and nicely.

There isn't a chance I'd consider steam bending in this case. For one, the wood is dry, to steam bend it will saturate it and then it woudl have to dry before being sealed.

 

[Richard Kassner]

Richard~

I bought it in 3/4" (finished thickness) for a house project this summer. My lumber yard only sells full lengths - which is 18 feet. I bought one 1x6 - but quickly added a 16-foot 2x4 to my order because the Azek drooped so much I could not keep it from hitting my hood - or the road - for the trip home. The 2x4 was just the stiffener to get it home.

Because it doesn't take on moisture and has no grain to split, I use Azek for several small projects - like the chocks for this gun rest. So, you can get your money's work from the 18-footer if you put the cut-offs to good use.

View attachment 61174

BTW: I, too, am a fan of Lou Sauzzede (sp?).

All the best,

SJS

Hello Steve,

I had a similar experience with the Azek.

I had to have the board cut in half at the building supply store -I was using the Azek to replace risers for steps.

Thanks for sharing about using the 2x4 to aid in transporting the Azek for I could not think of a way to bring an intact piece of Azek home.

Cheers

 

[Richard Kassner]

Richard

I said "use a scribe" but what I meant was use carpenter's dividers to scribe a line that follows the curve. I wasn't clear enough in my wording. Yes, you got the bungee cord usage like I meant.

Hello Eric,

I am unfamiliar with a carpenter's divider. I recall using a compass in school. I might have my son's compass floating around the house. Is this what you mean? Below is a Pittsburg 12 inch Locking Wind Divider at Harbor Freight in stock at my local store and there is a 30% off coupon.


Thanks

 

[Eric Patterson]

Richard, that's it. You can trace the curve onto an adjacent board with it.

 

[Richard Kassner]

He can also just measure offsets from a string by the foot (or the inch in more complex areas). With a small filet of epoxy down each side of the keel hiding any issues with the joint that would work well to get it done quickly and nicely.

There isn't a chance I'd consider steam bending in this case. For one, the wood is dry, to steam bend it will saturate it and then it woudl have to dry before being sealed.

Hello Tod,

I do realize you were responding to Eric instead of me; however, if I were to steam bend the White Oak, I would wait until the wood dried before I glued the wood to the hull with epoxy.

My chief concern would be "spring back" that wood may have after steam bending.

Some video's I have watched on this process suggest that wood flexis back a little bit toward its original shape after the wood has dried after steam bending.

I do not know if "spring sack" makes using ratchet straps insufficient for pressing the keel and strakes to the hull in order to apply the epoxy.

I will not do the project if I have to use screws to attach the keel and hull strakes.

Regards

 

[tod osier]

Hello Tod,

I do realize you were responding to Eric instead of me; however, if I were to steam bend the White Oak, I would wait until the wood dried before I glued the wood to the hull with epoxy.

My chief concern would be "spring back" that wood may have after steam bending.

Some video's I have watched on this process suggest that wood flexis back a little bit toward its original shape after the wood has dried after steam bending.

I do not know if "spring sack" makes using ratchet straps insufficient for pressing the keel and strakes to the hull in order to apply the epoxy.

I will not do the project if I have to use screws to attach the keel and hull strakes.

Regards

All good.

Seems like there are multiple concerns with steam bending, not to mention just the effort to do it.

Either scribe it or take the measurements from a string or laser level (my favorite new toy to deploy whether needed or not) and cut the line with a jig saw (or similar). I think you will be surprised how nicely that can me done (and you have the benefit of not dealing with bending or forcing a bend and holding a bend until the glue dries).