Thread: Steam Box From A Bond Form-ply

PVC "rigid" pipe is not a great option as it is a "thermo plastic" and will soften below 100 C and start to deform, depending upon the purpose and class of PVC pipe used.

There are different classes of PVC plumbing and drainage pipe that contain various proportions, (percentage) of plasticizer added to the PVC.

PVC is used to manufacture numerous products from rigid and very durable drainage and pressure class pipes, right through to gloves, toys, "cling wraps", even very flexible soft bodied fishing lures.

Best option for PVC pipe probably would be the higher pressure class water pipes, or storm water pipes. You may be able to pick up shorts from a local plumber or even the council, recycle yards etc.

Metal down pipes work well, however if zinc / galv you have to be very careful not stain timbers that react to iron i.e. most eucs, oak etc.

an afterthought,

Look at the DIY construction of timber drying kilns, for recommendations on materials. Many use A-bond plys that are coated, and prove to be pretty durable. Kiln temps typically don't get to 100 C however some reach near 75 C for "pest control" cycles, though 60 C is more typical.

I have not used a steambox for over ten years, Thumsucker. A plastic bag is so much more effective and so much more versatile.

There are a few posts on this Forum about it, and heaps of YouTube videos.

@GraemeCook how to you do multiple items at the same time.

If I am bending six items at a time how do I stop them from touching if I use the bag method?

Also do you use the bag once then throw it away? This seemds wasteful.

Originally Posted by thumbsucker

@GraemeCook how to you do multiple items at the same time.

If I am bending six items at a time how do I stop them from touching if I use the bag method?

Also do you use the bag once then throw it away? This seemds wasteful.

The plastic get stiffer after multiple uses - usually I get six or eight uses out of each tube. And much less broken timber. I would rather "waste" plastic than timber - also cheaper.

Why do you want to stop them from touching? If I am doing laminates then I just put them in the bag and bend them together. Otherwise just do them sequentially. Use multiple bags.

Because you keep the full steam supply for the total time of the bending process you can bend in tighter radii. You can also flex the timber in both directions and actually make it more flexible. It just does not start to harden until you have decided that you have finished the bending operation and disconnected the steam supply.

From were do you buy your bags?

Originally Posted by thumbsucker

From were do you buy your bags?

One option may be "temporary downpipe." - Just a moment...

Originally Posted by thumbsucker

From were do you buy your bags?

Cannot remember. I have Duraplas brand in 150 and 300 mm widths. Have used both 100µ and 200µ thicknesses - 100µis fine - next time I will try 75µ .

Here are 2 possible sources.
Poly Tubing, Clear Plastic Tubing , Packaging Poly Tube, Duraplas Tubing, Duraplas Smeaton Grange,
Poly Tube. Continuous Bag On A Roll - UPAC

I use a length of layflat hose. Comes in a wide range of diameters, suitable fittings available (connectors and end clamps.) Disassemble and roll up when finished, easy storage. Irrigation suppliers will have what you need.

Originally Posted by rustynail

I use a length of layflat hose. Comes in a wide range of diameters, suitable fittings available (connectors and end clamps.) Disassemble and roll up when finished, easy storage. Irrigation suppliers will have what you need.

The first time that I saw the technique was a shipwright steam bending a full length toe rail for a 40 foot yacht. He used a length of canvas fire hose.

Later I saw polythene lay flat tubing being used - it is clear which seems advantageous.

I do not use any end clamps or connectors - just fold the ends over a couple of times and then staple them.

Whatever works for you.

The end clamp is simple enough to make from a bit of R10 round reo bar welded to form an E. The layflat hose is just bent back over the bottom leg and woven through the other two legs. No damage to the hose. Quick and easy to reposition or remove.