Thread: Steaming big and long bits of wood

Now that was smart thinking Daddles..... see what a young mind can conjur up...... just sad I didn't think of it first so I could brag.......

The steam box is ready. One 8' section plus a 4' section that plugs onto it to give me 12'. Racks for two planks. Radiator hose provides a flexible joint to the boiler.

I've even made a wooden plug for the bottom end of the box How much can I expect that plug to swell? I'd hate to be unable to get the rotten thing out when I want to remove the timber (I guess that's a bit like asking the price of a Rolls Royce - if I need to ask, I need to take more off the plug). Rags at the top end and I should be right.

Richard

Come on mate... one thing to talk about it....
Let's see the photos.....

Then I know what I'm getting myself into on the weekend and if I need full body armour and a hard hat for when that plug fires out the end ?

Originally Posted by Aberdeen

Then I know what I'm getting myself into on the weekend and will I need full body armour and a hard hat for when that plug fires out the end ?

Just bring thick gloves, lots of clamps and rum, lots of rum

Richard

Photos? Photos? Not yet, though I am hoping to manage a test cook up tomorrow

Hey Daddles
Just be careful the neighbours don't see you doing the 'cook up' -
They might think you are up to something illegal - wouldn't want the boys and girls in Blue to rock up with the S.W.A.T. team....

Been a bit of that sort of stuff happening your way of late....

I'm not scared of the cops turning up on Saturday ... I've got my DAD coming

Richard

crusty old scottish sergeants are nowhere near as scary as 'helpful' fathers

I actually did have the local sheriff show up the first time I cooked some lumber at our new house. We're well back in the woods on a dead end road, so little traffic, but someone driving home saw a shiny metal canon looking thing propped up on a ladder, at a menacing angle and called the cops. We all got a laugh, though he did get out of the car with his hand on his holster. He had to figure I was the dumbest canon user or the leaking steam was an indication of something else. His only real comment after learning about steaming wood, was why did it smell like wet dog poop. I explained that live oak smells like that when it's getting cooked and why the one who must be obeyed will not let me use the oven any more nor the micro wave, (yep, tried it and I now have a scar).

Stayed tuned for Daddles' wrap of todays adventure with steam.....
A big learning experience that will stick with him for a while......
plus his able bodied observers

Well, a fun day was had ... by the dog

It's all that bloody scottish copper's fault

No it wasn't, but he's a convenient target

Saturday was busy and went well. Fun time had by all. Pity the results were more firewood than boat parts

I was able to get everything set up in the morning. The only thing missing from the mix was a pipe from the gas bottle to the burner, but an early dash to Mitre10 fixed that ... more on that anon.

As you can see from the attachment, having the boiler sitting on top of an old barbie made everything a little high. However, by the time you factor in the drop in the backyard and the height of the shed slab, the timbers came out at a nice height for working - I'll be using that system again.

Just after taking this photo, I fired up the burner. Hmm, gas barbies aren't supposed to have that wild orange flame are they? Thinking it was just muck or something in the burner and that it'd clear itself, I let it burn.

Eventually, and after some frantic discussions with my father, the water came to the boil, still with that yellow flame. Boiling water = steam
Nope
Oh, there was steam alright but ...

As it happened, there were four of us on duty - my father (David), Glen (Aberdeen), Mike (m2c1Iw) and myself.

Water boiled again. Steam filled the box. I popped both bits of timber into the steamer, plugged one end with rags, fitted the wooden lid (sealed with another rag) into the other and we went off to drink coffee and tell lies.

Half an hour later, I took a deep breath, popped the bottom end and slid out the first plank.

Huh? Isn't it supposed to be floppy?
This plank wasn't.
Much creative swearing and use of clamps later, the rotten thing was coerced into fitting the boat. This was NOT what I'd been led to expect.
That bit of timber was basically cold fitted into place and the clamp pressures required were enormous - my much used wooden clamps just weren't up to it, we needed steel F clamps to do the job.

Meanwhile, the water's boiling and steam's coming out, but not as much as we'd really expected.

We popped the box again and slid out the other plank.
Hang on, the rotten thing's only wet on the top

Meanwhile steam wafts out of the box.

Something was wrong.

What was wrong was the flame. It was nowhere near hot enough. Sure, the water was boiling and giving off steam, but not the great gushes of superheated steam you need. The flame continued to be that pathetic yellow thing, not the nice blue of a proper gas flame.

That's when Glen had the inspiration.

You see, the barbie is an old Companion and those of you familiar with them will know that the gas pipe has two holes in the fitting that attaches to the burner to allow oxygen to mix with the gas.
Well, I didn't know ... but I do now.

The bloke at Mitre10 had sold me a normal gas pipe, one with the normal style of burner fitting that doesn't have the extra holes drilled to allow in the extra oxygen. Net result, dud flame. A quick trip to the hardware store, back with the correct pipe and guess what, a nice, hot, blue flame

We hadn't even tried to fit the second plank - there's no way it was going to do anything. So we fired up the boiler and popped the second plank back in again to steam.

It got it's half hour in the steam, but came out like the other - stiff and recalcitrant but we managed to force it onto the boat. I suspect now that its first spell in the steamer had cooked it, not steamed it.

I left both planks for a couple of days. Pulled them off last night. They sprang back to nearly normal shape - a bit of horizontal curve, a slight vertical curve, nothing like what is needed. I cut one to length and could force it to clamp to the inwale as required, but pulling the vertical curve into it forces the centre to bow outwards and that can't be pulled in.

So I have two bits of timber that won't be used on the boat. They'll get used for something, just not coamings.

So what went wrong?
Not enough steam and heat basically, thanks to the flame. Had I been able to steam them properly, the first plank might have indeed come out floppy and pliable.
The second plank had been cooked and hardened by it's first stint in the box - clearly the box was only half full of steam and the top of the plank got the treatment while the bottom of the plank just got hot. This negated the effects of the second steaming (which I know you're not supposed to do but it was worth the experiment).

What to do next? Well, I will look at getting another couple of planks. Not kapur, it's too heavy. Whatever I get will be soaked for a couple of days first - we've worked out how to do that now, just buy a 12' length of PVC pipe If I can't get suitable planks, I'll do the coamings out of plywood.

Must dash - have to take the lad to soccer, so this hasn't been proof read. Please forgive the typos and I hope it makes sense.

Richard

Originally Posted by Daddles

So I have two bits of timber that won't be used on the boat. They'll get used for something, just not coamings.

So what went wrong?
Not enough steam and heat basically, thanks to the flame. Had I been able to steam them properly, the first plank might have indeed come out floppy and pliable.

Well sorry to hear that although I guess we sort of expected a less than successful outcome interesting play though.

I think a lot....I mean a lot more BTUs are required in fact a heat shield around the boiler perhaps less water and a really big burner is the go.

A question to the experienced, just how pliable should the wood get. You can see in Daddles avitar the sheer required. When successful steaming occurs should the board conform to the curve in both directions without a lot of effort then clamping is only required to hold the shape?

I'm on for take 2 Daddles, I'll dig around for an old 60lt drum to cut down for a heat shield just name the day.

Mike

Richard, I've broken or other wise ruined many hundreds of dollars in lumber, on one occasion a $180 piece in one bend attempt.

Some questions: What was the species? What was it's moisture content before going in? Did you soak the wood? How was it initially dried? What's the specific gravity of the species used? Was this a dense or less so example for the particular species? Were the bits of lumber placed in side the box (on a rack, blocked up, close to the bottom, etc.)? How much steam did you get, a steady column around a foot in diameter rising from the upper door (I always load from the higher end) or occasional wisps and small finger lick types of escaping steam?

The wood should be placed near the top of the box (the steam rising thingie) on a rack or some sort of light supports. I use welding rod drilled through the sides of the box, so I can change levels with the dimensions of the lumber. I always stand the lumber up on it's shortest dimension inside the box.

Steam should be pouring out of the box and you should feel guilty about how much you're losing to the air. If the box is tight, it'll explode or at least blow open the door, so some leaking is normal and a good indication of how big a head you have built up.

The wood should looked soaked when pulled from the box. In fact it should drip boiling water. If not, make more steam and put it back in the box. If it looks dry, it is.

One of the indicators I use to check a piece as it comes out is it's flexibility. It will sag under it's own weight some what and feel quite limp. This is wood that's ready. If it's not this way, it's not ready.

The hour per inch of thickness is just a very general guide. Woods that have a lot of resin or tannins need more time or should be nearly saturated, before going in.

Not very long ago I replaced the oak frames in a old lapstake cruiser. 38 frames, each bent over station specific molds flat on a table. The owner forced me to use the stuff he provided which was pretty, straight grained and clear, but kiln dried. I cut 60 frame blanks and started steaming. I need to cut 3 additional blanks to get all 38, meaning I broke about 40% (some cracked, other split, etc.). He was livid, but I warned him about using the cheaper kiln dried stuff. Had he gotten the air dried, reasonably fresh stuff, the breakage rate would have been 10 to 15% and cheaper in the long run. He started to pay closer attention after this incident and didn't give me quite as much guff about things.

Mike, only tight radiuses need some determined force. On a sheer , most of the difficulty will be incorporating the twist as it bends down and out to follow the deck line. On the frames I mentioned, the "turn of the bilge", near the stern of this boat required 6" radius, which broke may pieces. It was about 1" square stock. The other bends went in with little difficulty, just hand pressure to hold it to the form and slide a clamp or wedge in place. To answer your question, they will feel very limber, but not like over cooked pasta. A bit like a good fly fishing rod. It'll stand out under it's own weight, but it clearly is bending some and requires very little effort to bend further.

Originally Posted by PAR

Richard, I've broken or other wise ruined many hundreds of dollars in lumber, on one occasion a $180 piece in one bend attempt.

And as a pro builder, did you cover that cost yourself or charge the client? I'm interested to know because the risk factors in this exercise put it beyond the 'if you're competent you won't get it wrong' argument.

Some questions: What was the species?

Kapur - a Malaysian plantation grown hardwood. The bits used were decking planks with the ridges machined down. A darned useful source of hardwood actually.

What was it's moisture content before going in? Did you soak the wood?

I hadn't soaked it because I hadn't worked out how to make a bath that long. I'm renting so digging a trench wasn't on. However, half way through the afternoon, a collective light went on in the group and we realised that a length of PVC pipe will make a nice bath. All future pieces WILL be soaked

How was it initially dried? What's the specific gravity of the species used? Was this a dense or less so example for the particular species?

The planks themselves were probably kiln dried but I don't know and the hardware store certainly wasn't going to. The second plank was an unusually dense version of the norm, the first was about 'normal'.

Were the bits of lumber placed in side the box (on a rack, blocked up, close to the bottom, etc.)?

There are two racks in that box. The planks sit flat and are spaced equally through the box. There is plenty of room around the sides

How much steam did you get, a steady column around a foot in diameter rising from the upper door (I always load from the higher end) or occasional wisps and small finger lick types of escaping steam?

This is where we fell down, we had nowhere near enough steam coming out of the system. Initially because the flame wasn't up to it. Once we got the new pipe, there was plenty of steam in the system but nothing like you describe.

The wood should looked soaked when pulled from the box. In fact it should drip boiling water. If not, make more steam and put it back in the box. If it looks dry, it is.

It looked wet but not soaked.

We had nothing like the flexibility you describe, which is why I describe what we do as 'cold moulded with a bit of help'. The timber was easier to use than when dry and cold, but you were still coercing it into place.

Thanks for the input PAR. We were trying to do the right things and largely were, but fell down on the amount of steam.

My father is keen to make a stand for the burner and boiler - he's retired and wants something to do boys, I'm not taking this project from him. On that front, we'll probably revisit the plumbing too - I used 1" fittings because that's what Glen had on his boiler but when we build mine I'm going to try to get larger.

This is turning into a hell of a lot of mucking about for two bits of timber Ah well, others will be able to use the set up and you never know, I might just steam some ribs into that rowboat whether she needs them or not

Richard

Turn the stock on edge and place them at the top of the box for steaming. Steam gathers at the top of the box, filling it from top to bottom.

I've blown open the door to my steamer on a few occasions, trying to keep steam in the box. I use a 1/4" vent hole, drilled in the lower end plate to prevent this now. The hole is at the bottom lower end plate, so relief comes only when the box is full of steam. There still should be steam weeping around the edges of the door on the upper end.

The denser stock will need a little more time. My records show Karur to be a species with hard mineral deposits (probably silica or calcium) which not only dulls tools quickly can resist steam bending. The density of the wood suggests it should be steamed for an hour and 15 minutes for each 1" of thickness (at least) and that denser examples possibly 20% more. My wood data base also suggests that it will need a longer soak then other hard woods, so a few days in the drink will be helpful.

My boiler will burn though a 5 gallon can of water in about an hour, which should give you an idea how much steam you'll be generating. I add about a quart of water heater hot water every 15 minutes or so, though a bottom mounted fitting in the boiler can. This permits the boil at the surface of the can to continue, but keeps up with the lose of water as steam leaves the can for the box. I also have a return line from the bottom of the box to the top of the boiler can, so the condensed steam can return to the boil can, rather then just stain my driveway.

My first bending efforts were a mix bag of results. Breaks were logical, now that I look back, with stock selection being the biggest problem, as well as not steaming the stock long enough.

No, I didn't eat the 22' x 9" x 3" piece of fancy hardwood that broke on the occasion I mentioned. It was to form a curved top custom double door jamb. The jamb was a single piece and it broke just a few inches away from being locked down in the form. Grain run out was the culprit and I knew it was a questionable piece, with the grain in that location on the bend, but the radius wasn't, very tight so I thought it would make it. The second piece went in without issue. With lumber this size you're really stretching the abilities of steam to do it's magic and the ability of workers to get the piece in the form and dogged down in a couple of minutes. When it broke, it sounded like a shot gun blast inside the shop. It spent 3 hours and 20 miniutes in the box.

Mik? Which of Adelaide's timber merchants is most likely to know what I'm talking about if I went in and asked for a plank suitable to be steamed?

Bone Bros are closest to me but in the past I've got most sense out of Ottos. Never been to LeMesurier and last time I heard, they weren't selling to us plebs anyway.

Richard