|Project by wuddoc||posted 01-16-2009 07:53 PM||10469 views||18 times favorited||18 comments|
Steam Chamber Test #2
My woodshop buddy Rick and I have been asked to make some circular attaché style cases for carrying presentation materials. To create the circular case edge we have in the past used the cross saw kerf method described and illustrated in the Bending And Laminating chapter of Cabinetmaking and Millwork ©1988 by John L. Feirer. We are looking for an easier method to bend the wood.
We are still looking for a non-disposable steam chamber and in this test we tried a 3” diameter schedule 40 plastic pipe. At the same time we used four minute J-B Weld to secure the kettles top as in the first test it leaked too much steam. Prior to sealing the lid we filled the kettle to just below the spout as seen from the inside. This came to 48 fluid ounces of water. Now we could seal the lid knowing that 48 ounces would not overfill the kettle.
All the fittings were taken from the failed chamber we had conducted in Test #1. To install the fittings each hole required was tapped. Using clear silicon for the adhesive the brass fittings were installed. The pipe was sealed at one end using a silicon adhesive on the end cap. The other end cap was attached using springs so if the steam pressure got to high the cap would loosen. A ¼” drop per foot was achieved using wood of various heights. Radiator clamps attached to the wood allowed us to secure the pipe and keep it from rolling. Finally ¼” dowel rod stock was inserted to create shelves and those in turn were sealed with silicon at the drilled dowel hole locations in the pipe.
The test was begun and after 45 minutes steam appeared. The test was allowed to run for an additional 90 minutes. The hot plate was turned off and the kettle finally cooled down after sitting overnight. The remaining water was poured into a measuring cup and we found 24 ounces remained. This tells us that we can probably run the steamer with this kettle safely for 160 minutes without damaging the kettle.
The rule of thumb on steaming hardwood is one inch of thickness to one hour of actual steam. With several pieces of wood in the chamber on the shelves each time we open the cap to remove a piece of wood considerable steam is lost. The 160 minutes allows the steam to build back up in the chamber quickly and the wood left on the shelves to stay flexible until the next piece is removed.
We did discover that gloves were needed to remove the cap and take out the hot wood in the steam. We also discovered our drain tube was not large enough for removing the condensate. There was so much water that it started coming out the elevated removable cap end. We have now installed a ¼” ID flexible clear plastic drain tube.
The plastic pipe did not get hot enough to sag but it did distort around the band clamps and they had to be retightened. Reading about plastic pipe in our ever present McMaster Carr catalog we discovered most plastic pipe has a maximum recommended temperature of 200ºF. There is a one that is labeled PDVF allows for temperatures up to280ºF but the maximum diameter is only 2” and a 5 foot length is over $330.00.