I have decided to build a steam box.

[Osmosis]

I Know I know! I have read as many threads on plank bending as I can find. I have tried several of the methods that are outlined in those threads to varying degrees of success. Dry bending and soaking has worked for most applications up till now.

 

On the project I an currently working on the planking is 3/16" x 3/8" x 40" and the bend is predominantly on the thinner edge. Future/Larger projects will require even thicker material so I am going to give steam a try.

 

After spending a couple of evenings on google and youtube I have come up with a plan that will hopefully bring me some success at a fairly reasonable price. I have gathered all of the parts I will need and will most likely get started tomorrow as my current build is on hold until I get this worked out.

 

 

All of the plumbing parts and hardware I was able to get where I work at cost (less than $20.00) so that was a big savings. The steam generator which was used in quite a few of the videos I saw was only $65.00 on amazon and the wood parts are all left overs and scraps except for a couple of dowels which I just realized got cut off the bottom of the picture. So for less than $100.00 we shall see what we wind up with.

 

Win or lose it will be a learning experience if nothing else.

 

Until tomorrow, Best Regards.

 

 

[Jaager]

Heavy duty bending equipment suggests serious bending is contemplated.

 

I apologize for the inappropriate anthropomorphic terminology, it just is easier.

 

Wood wants to bend thru the thin dimension.

But for sharp bends pay attention to the grain,  if it is not parallel it may delaminate.

Wood does not want to bend thru the thick dimension.  It will try to spring back forever. It will tend to twist.

 

This means that for parts like rails, it is a better choice to follow prototype practice.  The method is to spill the shape from a much wider plank and assemble it in pieces.  Most kits do not supply the necessary wide stock, so a third party supplier is needed.

[Roger Pellett]

Art,

 

I hesitate to post this since you’ve already spent $100, BUT, here goes.

 

A number of years ago, I got involved rebuilding wood canvas (Old Town) canoes.  These involve a lot of steam bending.  After jury rigs outdoors I finally set up a system that would be safe to use indoors.

 

Your steam generator will work well.  I used a Wagner PowerSteamer wallpaper steamer that is the same thing that you have, just a different color scheme.

 

After trying PVC pipe as a steam box I found that it would not withstand the heat from the steam.  It sagged badly.  I replaced it with a wooden box made from  4 1”x4” boards nailed together.  With a hinged lid on one end and a block of wood capping the other.  A galvanized threaded flange was fastened to the bottom and a threaded nipple was screwed into the flange that mated with the hose from the steam generator.  A small hole was drilled into the bottom as a drain.  

 

The hinged door allowed me to quickly open the box to pull out wood.  The steam can burn you quickly so you will need some sort of tongs.  Another advantage of the wooden box is that it leaks!  This allows circulation of hot steam within the box and ensures no buildup of pressure within the system.

 

If you have adequate circulation in and out of the box, I don’t see a need for either pressure or temperature gages.  Water at atmospheric pressure boils at 212F, and you don’t want a closed system.

 

Roger

 

 

Edited January 30, 2021 by Roger Pellett

[Larry Cowden]

9 hours ago, Roger Pellett said:

Art,

 

I hesitate to post this since you’ve already spent $100, BUT, here goes.

 

A number of years ago, I got involved rebuilding wood canvas (Old Town) canoes.  These involve a lot of steam bending.  After jury rigs outdoors I finally set up a system that would be safe to use indoors.

 

Your steam generator will work well.  I used a Wagner PowerSteamer wallpaper steamer that is the same thing that you have, just a different color scheme.

 

After trying PVC pipe as a steam box I found that it would not withstand the heat from the steam.  It sagged badly.  I replaced it with a wooden box made from  4 1”x4” boards nailed together.  With a hinged lid on one end and a block of wood capping the other.  A galvanized threaded flange was fastened to the bottom and a threaded nipple was screwed into the flange that mated with the hose from the steam generator.  A small hole was drilled into the bottom as a drain.  

 

The hinged door allowed me to quickly open the box to pull out wood.  The steam can burn you quickly so you will need some sort of tongs.  Another advantage of the wooden box is that it leaks!  This allows circulation of hot steam within the box and ensures no buildup of pressure within the system.

 

If you have adequate circulation in and out of the box, I don’t see a need for either pressure or temperature gages.  Water at atmospheric pressure boils at 212F, and you don’t want a closed system.

 

Roger

 

 

Thanks for the info!

[Osmosis]

Thanks for all the interest and input. I have decided to go ahead with my original plan pretty much intact. I will try and explain my reasoning as best I can.

 

First of all I want everyone to know that I have the utmost respect for everyone on this forum and value your opinions very highly.

 

As to using PVC It is what I have at hand, and there are several examples of successful use of same on line. Even my hero Norm Abram (New Yankee Workshop) used one made from PVC. Also mine is only a very short span that is supported well so sagging should not be a real issue.

 

I have decided that Roger is right in that the gauge and thermometer are superfluous and will not be using them. My reasoning for including them in the original plan is that they we used on several examples I saw on line and the thermometer seemed handy for knowing your starting time based on the actual temp of the tube. Plus there is the coolness factor, with them you have a real contraption without them it is just a piece of pipe.

 

As for the need for the steam box itself. I will be doing the same bending as Roger just on a smaller scale. Canoes are mostly made from bent wood and some of the bends can be quite acute and on all three axis over the length of a single plank. It is what they use at full scale so why not at 1/6 scale.

 

Anyway here goes.

 

I got started on the wooden parts. The base will be a piece of 3/4 Sande Ply left over from a cabinet project. Cut to size, drilled and countersunk for SS the clamp hardware. The rails and dowels for the rack have also been ct and drilled.

 

 

After some sanding I applied a coat of wipe on poly to the base just to keep some of the moisture out of it. Then I turned my attention to the rack. I used 30 minute epoxy for the assembly. Firstly for the heat factor and secondly for the extra time to align and clamp all those dowels.

 

 

I am not all that confident in the rack holding up all that long but again I had the materials at hand. Is there a finish/sealer that will stand up to high temps like this? Next came the drilling and tapping of the PVC. I was pleasantly surprised how close my forstner bits were to the actual sizes I needed. It made really short work of that part. I applied a bead of high temp clear silicon sealant to all the threaded parts prior to assembly.

 

 

The drain will not work so well like this.

 

 

After about a minute with a hacksaw blade. That should be much better. I ran the assembled rack through the table saw with the blade tilted to about 18 degrees just to take a sliver off the bottom outside edge so that it sits a little lower in the tube.

 

 

Then some sanding and we are about done.

 

 

And here is the complete set up after only a couple of hours.

 

 

Well nothing left but to test it and see how it works. I will let you know as soon as I finish. Please wish me luck.

 

Best Regards

 

[Osmosis]

Hello again,

 

Success! It seems to have worked perfectly.

 

First I got the forms and clamps ready for the test strip.

 

 

Then I fired up the steam generator. Some on line videos stated that they had to wait an hour or so for the water to boil so I went about cleaning up a bit and was pleasantly surprised when I went back after 25 minutes to find a roiling cloud of steam issuing from the open end of my pipe.

 

Steam is not very photogenic.

 

 

So in went my two test strips and the cap was placed on just barely hand tight.

 

 

Honest there is a lot of steam coming out of that drain hose.

 

 

After about 20 minutes, I was able to reach in with my hook and pull the rack out past the danger point and retrieve one of the strips.

 

 

I am just not a good enough photographer to convey how much bend is in that strip for some reason I can't find the proper angle.

 

 

Once I got the first one clamped up I went back and got the second one.

 

 

As you can see the sliding rack allows you to stay well away from the steam.

 

 

This one I just clamped to the rack as a sort of demo. I could have bent it quit a bit further but did not have anything set up to do it.

 

 

All in all this certainly exceeded my expectations. Not just in the result but in the process also.

 

This setup could definitely be used indoors without worry. Other than a few drops while removing the cap I had absolutely no leaks whatsoever. The initial heat up time was very impressive and the amount of steam was also more than I was expecting.

 

As for the PVC holding up I did notice that when it was fully heated (after an hour or so) I could squeeze it with a gloved hand and cause it to deflect very very slightly. Certainly it was not soft enough to cause concern but I could see where it might sag if not properly supported.

 

The sliding rack worked out quite well. That was the one Idea I would take credit for. I am sure it is not original but I did not see it in any of the videos I saw. It allows you to pull the stock out past the steam without having to reach in with a pair of tongs or what ever. Also most of the ones I saw simply drilled holes across the diameter of the pipe and drove the dowels through. Allowing steam and condensate to leak out. With only two penetrations in this set up there are far fewer leak points to worry about dripping everywhere.

 

I am happy with the result and will be using this gizmo every evening for the next few weeks I am sure.

 

Thanks for looking in I hope you enjoyed it.

 

Best Regards,

 

Edited February 1, 2021 by Osmosis

[vaddoc]

On 2/1/2021 at 12:52 AM, Osmosis said:

All in all this certainly exceeded my expectations. Not just in the result but in the process also.

 

Excellent Art, your steamer seems to be working well. Now, I need to make a similar one!

I have two boats to plank, about 50 planks altogether of 2 mm beech. 

I am thinking to make a long box out of plywood, with one end closed, apart from an opening to accept the steam feed hose, the other with a loose fitting cap and a rag so steam can escape. I presume a drain hole will be needed, probably just drill a hole but attach a hose so that the condensation be directed to a bucket to avoid making a mess.

As you report things will get pretty hot in there so some caution will be needed. 

I ll post my results

 

[Charles Green]

The problem of the tube sagging from heat can be solved by using thick-wall PVC or buy using CPVC (chlorinated PVC) pipe.  The thick wall can absorb more heat before it sags and the CPVC is made for higher temperature - 140 deg. for PVC and 180deg. for CPVC.

[Don Case]

One thing I learned about wooden steam boxes is don't get silly with quality, especially if you use plywood. They delaminate after a while. Close joints are a waste of time, you need a good flow of steam anyway. The first one I made I did a primo job, all glued and nailed and tight. After a few months it was all warped and peeled.

[vaddoc]

40 minutes ago, Don Case said:

One thing I learned about wooden steam boxes is don't get silly with quality, especially if you use plywood. They delaminate after a while. Close joints are a waste of time, you need a good flow of steam anyway. The first one I made I did a primo job, all glued and nailed and tight. After a few months it was all warped and peeled.

I was thinking solid wood planks or better sacrificial plywood but maybe PVC pipe is the way forward. 

[Osmosis]

If you use PVC as I did with mine it is simply common sch 40 you can buy at H Depot just support it well and it will be fine. I have used mine several times now with the steam pot running for up to an hour and a half and had no problems at all. Mine is 54" long and supported in three places as you can see. For that matter you could strap it to a plank and it would be fully supported the entire length.

 

Good Luck

[Bob Cleek]

As fancy as you've gotten with that steam box, might I suggest that you cook up a good sour mash, let it ferment well, and put it in your steam generator. You'll be killing two birds with one stone that way.

 

[Osmosis]

Not a bad Idea. That is if you don't mind all your models smelling like the inside of a whiskey barrel. Although there are worse smells.

[Duanelaker]

On 1/31/2021 at 7:52 PM, Osmosis said:

 

 

Steam is not very photogenic.

 

Steam is not actually visible...what most people mistake for "steam" is actually the condensation that is occurring as the steam reverts from its gas state back to liquid.  Just thought i would be annoying and point that out.   Very nice steam box you created.

[vaddoc]

Well Art, I got motivated by your thread and built my version of a steam box. Dead easy to make, tried it today, huge success!

Materials (This side of the pond): 2 planned wood planks from B&Q at £9 each and a wallpaper steamer at £30 and scrap wood. I did not put a drain hole, the water drained from the (not so) closed end. The door was undersized so that steam could escape.

After 2 min of steaming, the 2.2 mm thick beech planks could be tied to a knot!

[Roger Pellett]

Perfect!

[Osmosis]

Very Nice! Glad you found my post helpful.

 

Best Regards