Today in the Shop "Building a steam box"

[reible]

Today I decided to give it another shot. I've added a thermometer so I had a better idea of when to time from, always a good idea even if I don't know what I'm doing at least I can learn from the experience.

I also added many more screws to tighten up the box. Added some gasket material to the fixed end of the box as well. Enlarged the drain hole for better run off.

I wanted to try a different wood, so I had a piece of oak to try. I went with the length it was, just under 15" long and then cut it in to 1/8" thick strips. While on the subject I thought I might show you all I cut the strips.

I started with a piece of scrap pine and ripped off some damaged areas and made it parallel to the rip fence which it might or might not have been before. Then I screwed on another scrap piece of wood like this:

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I then moved the rip fence out another 1/8". So with the jig against the fence and the work piece against the jig and held my the tail hook I was ready to make the strips.

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After the first cut the "tail hook" has been sized along with the work piece. It looks like this:

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The rip fence doesn't have to move any more, just keep feeding the stock through and getting the 1/8" strips. Now normally I just stop when the stock gets thin but today I wanted to get a couple more out of it. When the stock gets to narrow then it wants to lift as you cut and there is nothing but the stiffness of the wood to keep it down. It starts chattering so to speak so to prevent this I use some double sided tape. Yes the tape makes the strips a bit narrower but you can either live with it or adjust the rip fence. For this project I don't think the thickness of the tape will make any difference...... Now this has some risks and if you don't feel safe making those last couple of cuts then don't. Just get another wider piece to cut more strips from.

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Anyway it take only a short time to do the strips and in this case I made a half dozen.

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With my strips cut I then set up the steamer. Plugged in in at:

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Thermometer reading at the start:

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And I'll be back to finish this story in a short while.

Ed

[reible]

So it takes a while for the steam to get going and heat up the box. But time passes:

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At this point the temperature had reached saturation or what I use for that temperature.

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In this case I then waited one hour before starting the twisting. The temperature did get a degree or two higher but that was about it.

The good news is that all three twisted just fine without cracking! So out of this sample it looks like I can proceed with my project. I will have to add some more dowels so I can do more at a time but other then that I think I'm happy.

Results:

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I think this ends the build and testing phase. If I were to make another box despite the plans calling for solid wood or plywood I'd spend the extra money and make it out of plywood, I think it would be both easier and it would take less effort to get a good seal. Of course I can't say for sure as I've never built a plywood version....

Ed

[JPG]

Gotta wonder how the plywood laminate glue will hold up to the heat/MOISTURE?

BTW 'goodies' arrived. Thanks

[Dansmith]

Those look good, Ed. Success!

[masonsailor2]

Good post Ed ! Perseverance is the hallmark of success someone once said. If the box ever does decompose you can use a 6",8" or 10" diameter piece of pvc pipe which works well. I have used one in a boat yard years ago and it worked very well. It was a very crude version of a steam generator but it worked. The pot was an old aluminum pressure cooker with holes drilled in it and copper fittings and tubing connected to the piece of pvc. They had the pot sitting on an old propane burner. They were bending teak so the wood was in there a while but it worked. I can't wait to see what you make next !
Paul

[reible]

Just a few more comments while I'm thinking about the subject.

The Rockler plans are here:

http://go.rockler.com/tech/42826-Steam-Box.pdf

One issue that I did not mention is that the knots are leaking sap.... got some on my shirt yesterday and you can see it oozing out....... So that is another reason I'd not go back to a pine box.

Volume is one of those things that has to be taken in to consideration. The larger the box the more steam you need and the longer you steam the more water is used. If the box gets too big then you will need two steam generators.... if the length of steam time exceeds the amount of water the steamer has then you will need two steamers, one to run and a second to take over when the first one runs out of steam.

In the description they said the temperature in the box would reach 212 degrees, now were I'm measuring I don't get that warm. The max I've seen is 191 degrees. Perhaps where you measure is a detail or perhaps the box would require insulation to get that warm??

The temperature raise is pretty quick when it starts out then slows to hardly moving at about 188 degrees. The last couple of degrees above that takes an hour. So from say 75 degrees ambient to 188 degrees is about 35 to 40 minutes the rest is really slow. The times are approximate as I'm not standing over the box watching it every minute and depending on when I get back depends on my time estimates.

At some point I would like to make a fixture to hold the wood after twisting. I think that might be my next step before doing the 13 or so pieces for the project.

I'm also thinking it might be fun to do some more conventional bending but I have not decided on just what I want to try.

Ed

[Hobbyman2]

I have seen these steam boxes made from stove pipe , even pvc ,,,I assume they ll have their issues ,,,any opinions as to the wooden box as being better then other materials?

[reible]

I have seen these steam boxes made from stove pipe , even pvc ,,,I assume they ll have their issues ,,,any opinions as to the wooden box as being better then other materials?

Metal stove pipe will loose heat like crazy, that is not a good thing. Like wise with temperatures inside and outside getting to effectively the same temperature that means you could burn yourself pretty easy.... The wood box got to 135 degrees outside, warm yes but not as warm as the 190 degrees inside. Now if you had dual or triple wall that would be a different story.

PVC should work. Keep in mind that you have round rather then square shape so you might well want to look at what you want to steam and see if the shape effects the number of parts you can steam at one time..... It would also be harder to do the dowels at anything but the center line. Perhaps some sort of carrier that slides in and out for the work pieces to ride on would be better suited?

Anyway as a first go round I wanted to stay near the instructions. After playing with this box for a while I will either lose interest or explore some more designs. Right now I think exterior or perhaps marine plywood might be my choice for a second build, that could change as time goes on.

Ed

[Hobbyman2]

Thanks..


Great thinking points.

[reible]

I did two short videos of the heating, the first is after the steamer is plugged in and the steam starts arriving in the box:

https://youtu.be/-12On91NwqY

The second one shows the rate farther along in the heating process.

https://youtu.be/WsZsmUiMc3I

It slows down the warmer it gets as was expected.

Ed