bending a 2x4 with steam

[chris fresh]

i've watched some videos on steam bending and i'm in the process of building what i need to bend a 12ft 2x4 into a half circle.has anyone done a pine 2x4?

what i'm doing this for is to build window casing for my new house.i used 8'' log siding,wich is 2 3/4 thick in the center.i cased all my doors and windows with 2x4's that were ripped down to 3'' wide,so that i had 1/2 reveal between the siding face and the face of the door casing.

problem that i have gotten myself into is that i have a large arched window in the front,i have to keep it the same through out.so heres what i have,


i made a steam tube out of 6" pvc with a clean out on one end and a 2'' fitting on the other.i made a rack to slide into it,to keep the 2x4 in the middle of the tube.this will allow the steam to cover as much surface area as possible.

for the steam part,i'm using a 55 gallon drum,laying flat,with about 25 gallons of water in it.i'll be using a propane burner for the heat part.same like for a turkey fryer. there will be a hose connecting the drum to the tube.

tube will have a thermometer in it.from what i see,200 degree's and change seems to be the magic number.i'm thinking a 2 hours steam should do,correct me if you know something.

i built the jig today,3/4 plywood with 2x4 blocking,cut with a router and circle jig.what i plan on doing is screwing the jig down to my sub floor,putting a large strap around the 2x4 and using a come along to pull it in.

any thoughts? am i missing something? i have pics if anyone wants them.also the diameter is 67 1/4, 33 5 /8 was my center point.

 

[slopecarver]

I'd love to see you try, why not just try laminating a bunch of thin strips around a template?

 

[srmofo]

youre gonna need some c clamps for sure...and lots of them. You can use the come along to pull it in most of the way, then just attach the clamps as you go along to pull it in tight.

Should be interesting. post some pics as you go. I would like to see someone bend a 2x4 like that.

 

[chris fresh]

I'd love to see you try, why not just try laminating a bunch of thin strips around a template?

thought about it,but didn't want to layer it,or have issues down the road with it seperating.we have alot of heat and humidity here.heres a pic of the jig.pretty sure it will work out,only thing i'm not sure of is,how long to let it cook before attempting the bend.

 

[chris fresh]

and heres the window situation

 

[chris fresh]

youre gonna need some c clamps for sure...and lots of them. You can use the come along to pull it in most of the way, then just attach the clamps as you go along to pull it in tight.

Should be interesting. post some pics as you go. I would like to see someone bend a 2x4 like that.

i will have plenty of pics,shouldn't be that bad to do,just watched a vid on youtube of a guy bending a 2x6 made out of white oak.and it was on edge.i think the biggest concern right now is taking the time to find a super clean,no knots 2x4.just about all that i have bought had no knots,very clean,very straight.

a knot would be a very weak point for the bend

 

[bczygan]

thought about it,but didn't want to layer it,or have issues down the road with it seperating.we have alot of heat and humidity here.heres a pic of the jig.pretty sure it will work out,only thing i'm not sure of is,how long to let it cook before attempting the bend.

It won't separate if you use the correct glue. Heat and humidity won't be an issue. It is the way to go.

 

[shoot summ]

From what I have seen on steam bending you will need ALOT of clamps, and an extra set of hands or two. The jig looks good, you will need longer clamps though, probably need to clamp every 6 inches or so.

I agree that laminating would be WAY easier, there will be no issues with heat and humidity and the glue.

 

[willy3486]

It won't separate if you use the correct glue. Heat and humidity won't be an issue. It is the way to go.

I second that. I have done some steam bending. IF it was me I would look at some thin oak strips,bend then glue them. The thicker the wood was the more issues I had. Some people use plywood then cut groves in it along where you want to bend. If it was be I would use strips,steam them at the same time and then glue. If you try to bend a 2x4 wear safety glasses. As far as the pvc pipe they can get so hot and then warp. I have used pvc before so make sure its supported.

 

[hunter1151]

Have you allowed for spring back??? Seems like everything does but I have no formula for it in wood.

 

[hunter1151]

Aren't most 2x4's fir??

 

[GarageEnvy]

+1 for trouble coming. I've done a total of 2 steam bends so I'm not an expert but the thickest one was 1/2" and it was a wrestling match. That was for a toboggan and the radius was tighter but there is definitely spring back.

The other was for a boat keel. A much longer story but it took 4 guys and clamps every 3" and the working time was about 20 minutes or so. The steam doesn't keep it soft long and it doesn't make it into a wet noodle. I wish you the best of luck but I'd reconsider lamination. I think if you did somehow manage to apply enough force to a 2x4 to make that bend, it would break.

 

[chris fresh]

It won't separate if you use the correct glue. Heat and humidity won't be an issue. It is the way to go.

i'm thinkin that i'm going to try the steam,if it breaks,i'm out 4 bucks and i'll just lam one together,but now i'm to the point where i have to see if it's possible.

 

[chris fresh]

From what I have seen on steam bending you will need ALOT of clamps, and an extra set of hands or two. The jig looks good, you will need longer clamps though, probably need to clamp every 6 inches or so.

I agree that laminating would be WAY easier, there will be no issues with heat and humidity and the glue.

as for the clamping,i'm thinking this,i'm going to screw the jig to the floor in a million spots,no worries there. then as we pull it around i'm going to shoot blocks to the floor and drive wedges in all the way around to keep the 2x4 tight to the jig.better than clamps in my opion.

 

[chris fresh]

I second that. I have done some steam bending. IF it was me I would look at some thin oak strips,bend then glue them. The thicker the wood was the more issues I had. Some people use plywood then cut groves in it along where you want to bend. If it was be I would use strips,steam them at the same time and then glue. If you try to bend a 2x4 wear safety glasses. As far as the pvc pipe they can get so hot and then warp. I have used pvc before so make sure its supported.

can't be oak and can't be kerf cut,has to be pine and 2x4.has to match all the rest of the house.

 

[chris fresh]

I predict it won't work out. This might be the place for plastic trim boards -- cause I don't think you'll want to do it again (in wood) in ten years. In plastic, it won't bother you to do it again in ten -- or 20.

I've got some window boxes made from the cheap Lowe's plastic trim. Full, direct sun, irrigation watering 2-3x per day for 10 years... still looks great -- unpainted. You can probably take a 8' board and tie a knot in it, right off the shelf.

Chip

can't use plastic,it's getting stained.

 

[chris fresh]

+1 for trouble coming. I've done a total of 2 steam bends so I'm not an expert but the thickest one was 1/2" and it was a wrestling match. That was for a toboggan and the radius was tighter but there is definitely spring back.

The other was for a boat keel. A much longer story but it took 4 guys and clamps every 3" and the working time was about 20 minutes or so. The steam doesn't keep it soft long and it doesn't make it into a wet noodle. I wish you the best of luck but I'd reconsider lamination. I think if you did somehow manage to apply enough force to a 2x4 to make that bend, it would break.

i'll have 2 other guy's with me,i've allowed for spring back in the jig,we will all be wearing full goaly gear.and i'm definitly going to video the whole ordeal.so if it works,i can talk all that ssssshhhiiiittttt!

 

[MoonRise]

A quick web search (mostly some boatbuilding and home building references checked, circular staircases and trim and such) says pine is NOT a good choice for steam bending. YMMV.

And that is a relatively thick piece of wood, and a relatively big piece of wood, and a relatively tight radius you are trying to bend to. And you are trying to get pretty much an EXACT radius to match your window dimensions. In a wood species not generally chosen for steam bending. That's at least five (-) marks right there.

Maybe not impossible, but certainly says to me it may be darn difficult.

You'd need a long piece of stock with really-really straight and consistent grain, with no grain 'run-out', to even consider trying it. Twisted grain mean warp or twist. Grain run-out mean the piece will probably crack or shatter along the grain run-out. Etc, etc, etc.

Oh, and you want green wood, not kiln-dried or really even air-dried. The drying process changes the wood's cellular structure and makes steam-bending more difficult (for loose radius bends) or impossible (for tight radius bends).

Let's see, 2x4x12 green, straight-grained, grade "Select" or better with NO
knots, splits, checks, or what-not, pine. And you'd usually want at least 3 of those to allow for the first trial (or six) to check for springback and clamping and oop'es (split, crack, etc). Not so easy there.

Info quoted from someone else, quoting "Wood Bender's Handbook" by Zachary Taylor, indicates that pine is a 'poor' choice for bending. Minimum steam-bent radius for a 1" thick piece, strap-bent, for pine is 36 inches. As a comparison, 1" thick steam bent white oak can go to ~1" radius.

Take a look at existing arch (circle-top) window trim/framing. It's either sectional (sector) pieces then cut into the desired radius or a bent lamination.

 

[BigRed390]

I cut a bit of wood here and there, so I'll throw my $.02 in here and second what has already been said. That board is WAY too thick to bend like that. Pine is a bad wood to bend. Watch out for springback. Etc. Etc.

Ok, now here's some hopefully helpful ideas. Has to be pine? No problem. Laminate some pine as the bottom (showing) layer of a white oak bent wood lamination. It'll be stronger than steam bent anything and will resist twisting like a single board can.

Side note, I hate 2x4's with a passion. From a woodworking perspective, they are a real pain. Don't get me wrong, I like southern yellow pine, just not 2x4's. You look at them sideways and they'll warp on you. Go buy a 2x10 or a 2x12 and rip it down to an appropriate width. They don't misbehave nearly as badly, and it's usually easier to find a clear section with the grain in a more agreeable orientation.

 

[chris fresh]

I cut a bit of wood here and there, so I'll throw my $.02 in here and second what has already been said. That board is WAY too thick to bend like that. Pine is a bad wood to bend. Watch out for springback. Etc. Etc.

Ok, now here's some hopefully helpful ideas. Has to be pine? No problem. Laminate some pine as the bottom (showing) layer of a white oak bent wood lamination. It'll be stronger than steam bent anything and will resist twisting like a single board can.

Side note, I hate 2x4's with a passion. From a woodworking perspective, they are a real pain. Don't get me wrong, I like southern yellow pine, just not 2x4's. You look at them sideways and they'll warp on you. Go buy a 2x10 or a 2x12 and rip it down to an appropriate width. They don't misbehave nearly as badly, and it's usually easier to find a clear section with the grain in a more agreeable orientation.

very good point on the 2x12,i could run one through my tablesaw and get the cleanest piece possible.as i see it the hard parts done.building the jig,cooker and the steam tube took the time,now i can try a few different materials for short dough.

i would really like to at least try the 2x4 (really it is 1 1/2 x 3'') just to see.if it breaks?i' will laminate one.if i don't have to spend the money on the oak,i won't.after all it is second floor,it will be stained,and noone around me is smart enough to call me on it.

i could amaze my neighbors by folding loose leaf paper.after they see me do this arch they will all be like .

 

[GarageEnvy]

Another option would be flexible moulding. I know that this has become somewhat of a mission to see if you can do it and I totally get that. It also sounds like you've got some time but there are some products on the market that may help you out. I haven't used any of these but variations are carried at my local fine wood dealers (White Pine and Diamond Hardwoods).

http://www.resinmold.com/

http://www.spectis.com/moulding_flex.htm

http://pearlworksnews.com/PDF/Mouldings.pdf

http://www.timdunn.biz/truflex/truflex.pdf

Maybe others have used these flexible composites and can give you more first-hand knowledge

 

[Will67]

Surprised no one has suggested building it out of plywood or MDF and then putting a pine veneer on it....never would be able to tell it wasn't solid from a few feet distance

 

[chris fresh]

if i can't do it in a solid piece,then i'll laminate one together.i can't use anything plastic,pvc,synthetic,composit.i have to be able to stain it to match and the wood ages,turning darker over time.so if it's plastic and matches now,it won't in 6 month's.

i've got the tube built,the jig,and tonight i'm welding up legs on my barrel for the steamer.all i'm lacking is the clean ripped down 2x4 and a hose to connect the steamer to the pipe.were real close.my plans are to get the stuff mentioned tomorrow and have everything ready to go by saturday morning.while the water is coming up to temp,we will secure the jig and get the anchor set for the come along.first attemp will be letting the board steam for 6 hours and see what i have.if it breaks? then i know where to go,but right now i'm blind,gotta start somewhere and go from there.

 

[chris fresh]

Surprised no one has suggested building it out of plywood or MDF and then putting a pine veneer on it....never would be able to tell it wasn't solid from a few feet distance

the piece has to be 3'' wide finished.i thought about if i had to laminate one,i would make one 2 3/4,then skin the face with 1/4 so you couldn't see the layers.plywood has been considered,but no way on the mdf,if it even smelled moisture,it would blow up like a balloon.

gonna be an interesting weekend

 

[bczygan]

Another thought..........segmented pieces of solid lumber joined end to end at slight angles to form the arch, and then band sawn to an arc and routed for a profile. Will this be finished clear or painted?

 

[Milton Shaw]

I don't think you are going to bend pine like that. I think you would be better off either laminating it or cutting short segments, fingerjointing them, and then cut the radius's out with jig or band saw. Short segments cut from say 2x10 or so would give a fairly long piece of the curve, then dowel joint (or lap joint) with gorilla glue and it won't ever come apart. You could also use a router with circle guide to true the final circle up and get a good looking piece made. Pine doesn't bend the way you want it to, only the way it wants too.

 

[chris fresh]

Another thought..........segmented pieces of solid lumber joined end to end at slight angles to form the arch, and then band sawn to an arc and routed for a profile. Will this be finished clear or painted?

going to be stained

 

[grego]

I say, GO FOR IT!! You have it all thought out, have everything to try it so give it a shot. But please be careful, video has a way of making murphy's law rear it's ugly head.
I like the goalie gear idea, nice call!
Just for sh!ts and giggles, try it with the 2x4 for practice and then use the good piece of wood.
Let us know how it works out and good luck!

 

[MoonRise]

if i can't do it in a solid piece,then i'll laminate one together.i can't use anything plastic,pvc,synthetic,composit.i have to be able to stain it to match and the wood ages,turning darker over time.so if it's plastic and matches now,it won't in 6 month's.

i've got the tube built,the jig,and tonight i'm welding up legs on my barrel for the steamer.all i'm lacking is the clean ripped down 2x4 and a hose to connect the steamer to the pipe.were real close.my plans are to get the stuff mentioned tomorrow and have everything ready to go by saturday morning.while the water is coming up to temp,we will secure the jig and get the anchor set for the come along.first attemp will be letting the board steam for 6 hours and see what i have.if it breaks? then i know where to go,but right now i'm blind,gotta start somewhere and go from there.

6 hours is waaay too long.

Usual time for steam bending is 1 hour per inch of thickness, +/- 10-15 minutes or so.

And yes, you can 'oversteam' the wood.

Oh, the steamng time starts when you put the piece of wood into the already hot and steamy steam box (no putting the wood into a cold steam box and then turning on the heat).

Also, unless your come-along is somehow different than my (and every one I've ever seen) come-along, that is waaay to slow a device to apply force to the steamed piece of wood. You really have to move pretty darn fast. As in 15-30 seconds from out of the steam box to bent into shape. Then you apply the rest of the clamps to hold it all in place.

And you made that nice form, but what are you going to do about spring-back?

 

[cdent]

very good point on the 2x12,i could run one through my tablesaw and get the cleanest piece possible....

Careful trying a table saw rip that long with framing lumber. It's not some magically stable material. Chances are it'll pinch or curl apart as you make the cut and bind. Just snap a chaulk line and use the circular saw, then kick yourself because it didn't stay flat like your window.

I think this is what bending ply is for. No steam or guessing, then just trim the front edge to get the look you want. Framing lumber usually isn't considered finish/stain grade, so it shouldn't be to hard to tack segments of ripped framing lumber to the face and then run a router around to flush it up to your curve.

Good luck with it. Don't worry about the video, I think you'll have your hands full.

 

[Duker]

Some good advice in the previous posts. I am all for going against the crowd but sometimes wisdom beats out persistence and determination,

I would love to see the video as I bet it would show what I must have looked like when trying to bend a 2x6 in a radius half as tight for a doorway. My old man warned me but what did he know! I hate it when he is right...

In all seriousness, give it a shot, the knowledge and experienced gained will be priceless and I would love to show my old man a success story!

 

[Zeke]

All arched casings and moldings ever supplied to me for my door and window business have been segmented. This is how the industry does it.

Bending a 2x4 is foolish, but you only go around once, so do it fail or succeed. The grain of the wood is going to always want to go straight, remember that. So if it doesn't pull away as a whole, it just may split leaving shards pointing out after it gets some weather.

Old boat and sleigh builders went into the forest and cut bent trees.

 

[cnc-me]

I predict it won't work out. This might be the place for plastic trim boards -- cause I don't think you'll want to do it again (in wood) in ten years. In plastic, it won't bother you to do it again in ten -- or 20.

I've got some window boxes made from the cheap Lowe's plastic trim. Full, direct sun, irrigation watering 2-3x per day for 10 years... still looks great -- unpainted. You can probably take a 8' board and tie a knot in it, right off the shelf.

Chip

First choice would be plastic for exterior use.
Second Laminated wood.
And a very distant third would be solid steam bent wood
as it will likely crack or rot especially framing grade lumber like the OP is talking about using.

 

[TheGrooveking]

MAybe I a missing something here but a steam tube made out of PVC seems like a problem. Steam is 212 degrees F and above, PVC starts to melt/soften in the neighborhood of 134/138 degrees F. Am I missing something?

TheGrooveking

 

[back2class]

will never work! Even if by some miracle you get it bent, it wont stay that bent and will warp and be a dasaster. You have a pretty basic arched window frame there, just do it the way 99.99% of builders do it and don't reinvent the wheel???????

 

[Duker]

MAybe I a missing something here but a steam tube made out of PVC seems like a problem. Steam is 212 degrees F and above, PVC starts to melt/soften in the neighborhood of 134/138 degrees F. Am I missing something?

TheGrooveking

It's been awhile since I reviewed specs on pipe but I think most ASTM CPVC 40/80 pipe I believe is rated with a melting point closer to 360 degrees and a max operating temperature between 150 to 160 degrees under full pressure which if memory is correct over 200 PSI. I may have this way off as the memory is not what it once was so double check those numbers.

The current piece of CPVC pipe I use has steamed about 40 windsor and shaker style chairs parts so it's had it's fair amount of steam running through it but it's not under high pressure as it's vented. It also doesn't take that long to steam wood as too much can ruin the piece.

I think the OP would be better off laminating a piece. Correctly grain matched and you would have a hard time seeing that it was not one piece of wood and it would still take stain. It would also be stronger and easier to set in the form.

But hey sometimes we just need to try things for ourselves...

 

[bczygan]

All arched casings and moldings ever supplied to me for my door and window business have been segmented. This is how the industry does it.

Bending a 2x4 is foolish, but you only go around once, so do it fail or succeed. The grain of the wood is going to always want to go straight, remember that. So if it doesn't pull away as a whole, it just may split leaving shards pointing out after it gets some weather.

Old boat and sleigh builders went into the forest and cut bent trees.

If it was a master work that is what I would do! Out to the forest!

 

[kbs2244]

More than you ever wanted to know about bending wood.
Pay attention to the grain selection part!

http://www.leevalley.com/en/wood/pag...=1,45866,45867

 

[chris fresh]

o.k i've decided, i'm going to laminate one.now a couple of questions, i was thinking of making pieces that were 1/4 to 5/16 thick, to thick or to thin? i know thinner would be easier and probably more control while bending,but i don't want to make an 18 layer casing either.

should i still steam them? or just soak them?

and lastly, what glue? i've used tightbond for all my woodworking stuff and had very good results,or should i use gorilla?.i've never used tightbond's green bottle,i think it's there best and also for outdoor use,i could be wrong there.

what say you wisemen?

 

[Duker]

o.k i've decided, i'm going to laminate one.now a couple of questions, i was thinking of making pieces that were 1/4 to 5/16 thick, to thick or to thin? i know thinner would be easier and probably more control while bending,but i don't want to make an 18 layer casing either.

should i still steam them? or just soak them?

and lastly, what glue? i've used tightbond for all my woodworking stuff and had very good results,or should i use gorilla?.i've never used tightbond's green bottle,i think it's there best and also for outdoor use,i could be wrong there.

what say you wisemen?

Chris, I prefer 3/16" to a 1/4" max depending on the arc as it's easier to work by yourself in setting and clamping into the form. If you do briefly steam them (which will make them more pliable) then your working time with something like Gorilla glue is shortened as it reacts to the moisture in the wood to cure.

I also like titebond glues and their III product has around a 10 minute open time which would give you some time to level and "make flush" the strips while they are clamped in the jig. A roller, plenty of clamps, an extra set of hands (especially someone that doesn't mind four letter expletives when something does blows out from the clamps - maybe that just happens to me) and some cold beer waiting and your good to go.

A little advice that you probably already know... Make the strips a little wider then the finished width so that you can rip a clean edge to more easily take stain. Less stress than trying to keep glue off and easier to joint/ plane level one side and rip to final width.