Steam Bending

[jthornton]

I'm fixing to steam bend some air dried white oak in a pretty small radius I hope. Reading the Veritas instructions they say the moisture content should be 25% going into the steam box. My white oak is ~8% how do you get it back up to 25%? I saw in one video the chap had his wood in a vertical pvc pipe full of water.

 

I'm shooting for a 1/4" thickness and 1 1/2" wide with a 2" radius on the inside of the bend. The part will be U shaped and it's to hold Sweet German Baloney in the fridge lol.

 

I've been pretty distracted from wood working for the last few months...

 

JT

Edited December 1, 2023 by jthornton

[DAB]

to hold baloney?

 

that's a new goal.

 

as for your design, i know nothing about steam bending, but i do know that if a project calls for a technique i can't do, i either pick another project, or I design another way to get the end result desired.  like blocks of wood cut with a hole saw.

[lew]

I’ve done a little. That’s a pretty tight bend and will definitely need support on the outside of the bend. As for increasing the moisture content, soaking in hot water is probably a good way or maybe steam for a very long time. 

[Gene Howe]

While oak is gonna be tough. Though, your thickness will make it a bit easier. My method for bending wood is a bit unorthodox but, it doesn't require a steam box or steam. I use a length of black PVC sewer pipe with caps for each end. No glue, though. The wood is inserted in the pipe and partially filled with water. To which is added a generous amount of Calgon liquid water softener. In AZ, the sun heats it adequately but, you might consider heating your water before pouring it in the pipe. I usually give it an hour or so to brew.

I've had excellent results with strips of walnut as thick as 1/2" and 4" wide. 

Edited December 2, 2023 by Gene Howe

[Cal]

15 hours ago, jthornton said:

 

I've been pretty distracted from wood working for the last few months...

 

Glad to see you back JT. 

[Grandpadave52]

Glad you found your way back JT. I knew those donut crumbs would work.

IIRC, @John Morrisbuilt a steam box for some chairs/rockers??? Hopefully he can weigh in with his experiences and suggestions.

 

[4DThinker]

I've helped a few dozen students steam bend parts for their projects.   Lessons learned include to make sure the grain runs straight down the wood strip(s).  You can reduce likelihood to split by added a compress strap on the outside of the curve. Sheet metal hooked on both ends so it can't slide.   Last lesson: Prepare for failure.  Have backup pieces ready to steam if the first one fails.  

4D

[jthornton]

@4DThinker Thanks, I plan on using my Veritas steam bending strap as it has the adjustable compression on one end. I know from watching Engels Coach Shop videos on steam bending that you can't allow the wood to expand along the grain. Thinking of soaking a couple of test pieces in water overnight and allowing them to air dry and see what the moisture level is.

 

JT

[lew]

5 hours ago, jthornton said:

Thinking of soaking a couple of test pieces in water overnight and allowing them to air dry and see what the moisture level is.

You could probably put the directly into your steam box. My guess is they would be even more flexible.

[jthornton]

I did do an overnight soak on a piece of white oak and it raised the moisture by 2% and surprising to me it stained the water. It was just a test while I build the steam box.

 

JT

[Grandpadave52]

3 hours ago, jthornton said:

I did do an overnight soak on a piece of white oak and it raised the moisture by 2% and surprising to me it stained the water. It was just a test while I build the steam box.

 

JT

Just curious JT. Did you use tap water to soak or distilled water. If tap water, depending on your source (well, utilities or??) guessing the minerals or additives reacted with the tannic acid in the white oak staining the water.

[jthornton]

1 hour ago, Grandpadave52 said:

Just curious JT. Did you use tap water to soak or distilled water. If tap water, depending on your source (well, utilities or??) guessing the minerals or additives reacted with the tannic acid in the white oak staining the water.

 

I used softened well water, I didn't think of using distilled water for this. I'll try another sample with distilled water to see.

 

Thanks

JT

[kmealy]

2 hours ago, Grandpadave52 said:

Just curious JT. Did you use tap water to soak or distilled water. If tap water, depending on your source (well, utilities or??) guessing the minerals or additives reacted with the tannic acid in the white oak staining the water.

They use white oak for bourbon barrels to add a golden color to the distilled colorless alcohol.

I have made a bunch of Shaker oval boxes.  I have a tray that I put in water bring it to a near boil and soak the wood for a few minutes.  The smallest boxes are about 1/16" thick and the largest I've made were close to 1/8".    I have typically used cherry or maple, though.  Just another data point.

[Danl]

An other data point. 

I made shaker berry boxes a few yrs back and they had 1/8" x 1" wide maple handles.  The wood I had available had been KD, so I put the handle pieces in a small Rubbermaid tub and let them soak in hot/warm for a few hours. Then I bent the handle piece around a jig, clamped with 3 clamps and let the set for 12+ hours.  The jig was made from 2X material.  Next time, I will use cauls under the clamps to eliminate small clamp impressions under the clamp pads.  The bend radius was 2-3/4".  See link for more details and pics.

Danl

[jthornton]

Thanks so much for all the replies, I finally got started making the steamer box. The plan is to use a turkey cooker as the steam source and have the steam box on top of it so no hoses involved.

 

JT

[aaronc]

On 12/7/2023 at 9:50 AM, Grandpadave52 said:

Just curious JT. Did you use tap water to soak or distilled water. If tap water, depending on your source (well, utilities or??) guessing the minerals or additives reacted with the tannic acid in the white oak staining the water.

 

I can't help with the steam bending but Dave beat me to it on the tannic acid. That would be my guess on the water darkening. 

[jthornton]

I managed to get the adapter finished for the steam box. I still have to seal it with something... thinking of using fiberglass resin.

 

The adapter sits on top of my turkey cooker and that will be the source of steam.

 

Working on the actual steam box now and that will sit on top of the adapter.

 

JT

[jthornton]

Got a bit more done on the steam box, just need a lid and some water proofing and I'm ready to test it out.

 

 

JT

[John Morris]

Great looking set up there JT, never thought of that design. I am sure ya know, but not to sealed, the steam needs to escape.

Do you need a thermometer? I did, I had to wait for the temp to rise to a point before I inserted my pieces into the box. I remember it had to be at least 180degrees but I think around 220 was more preferable, again, you know all this already since you been building yours, just thought I'd throw it out there though.

 

 

[4DThinker]

Yep.  Without a vent you've got a pressure cooker. I have a vague memory though about a couple of chair makers I met in Iowa who found that putting the parts under steam pressure made them much more flexible/twistable.  They used them to make chair arms that twisted up to make the back rail of the chairs.  One continuous piece. 

4D

 

I little research and they may have been using ammonia: