James Combs
06-18-2011, 9:25 PM
Test results of vacuum processing my overly spalted maple noted in my earlier thread. http://www.sawmillcreek.org/showthread.php?167816-Vacuum-Chamber-Prototype
For the first trial item I decided to use something small to avoid wasting the wood if it failed. I had some corner pieces cut off of a birdhouse blank that were just big enough to make pen blanks out of so that is what I tried first. I was so anxious to turned a spalted item treated with my new vacuum process that I shortchanged it as much I could as follows:
- held the vacuum for only ~5-10 minutes till it stopped bubbling - mfr recommends 30+
- released vacuum and drain off excess - mfr recommends let soak another 30min.
I immediately cut one of the two trial blanks in half. It appeared to be wet all the way through so I wrapped the two of them up in some aluminum foil, popped them into our toaster oven for 45min at 225*. As soon as the bell rang I grab them and ran back to the shop, drilled the already cut one, tubed it, squared it, threw it on a mandrel and in about 10 minutes I had this:
198441
No tear out although it was surprisingly dusty but the surface was almost ready to finish right from the finishing gouge cut. I hit it a few passes with some 320g then went straight to my CA finishing process using up to 1800g between coats. One of the fastest pens I have made outside of commercial stabilized blanks.
BTW I trialed the vacuum process in a quickie made 6" PVC vacuum chamber. I capped the ends with some scrap 1/8" Lexan. You should have seen the sunken bow form in that:eek:
Can't wait till I get the 3/8" polycarb for the big one. After seeing the bow pulled into the 6" diameter 1/8" Lexan I am concerned that maybe the 3/8" may not be heavy enough at 10" diameter.:o I will let everyone know how it goes. The polycarb will be here Monday or Tuesday.
For the first trial item I decided to use something small to avoid wasting the wood if it failed. I had some corner pieces cut off of a birdhouse blank that were just big enough to make pen blanks out of so that is what I tried first. I was so anxious to turned a spalted item treated with my new vacuum process that I shortchanged it as much I could as follows:
- held the vacuum for only ~5-10 minutes till it stopped bubbling - mfr recommends 30+
- released vacuum and drain off excess - mfr recommends let soak another 30min.
I immediately cut one of the two trial blanks in half. It appeared to be wet all the way through so I wrapped the two of them up in some aluminum foil, popped them into our toaster oven for 45min at 225*. As soon as the bell rang I grab them and ran back to the shop, drilled the already cut one, tubed it, squared it, threw it on a mandrel and in about 10 minutes I had this:
198441
No tear out although it was surprisingly dusty but the surface was almost ready to finish right from the finishing gouge cut. I hit it a few passes with some 320g then went straight to my CA finishing process using up to 1800g between coats. One of the fastest pens I have made outside of commercial stabilized blanks.
BTW I trialed the vacuum process in a quickie made 6" PVC vacuum chamber. I capped the ends with some scrap 1/8" Lexan. You should have seen the sunken bow form in that:eek:
Can't wait till I get the 3/8" polycarb for the big one. After seeing the bow pulled into the 6" diameter 1/8" Lexan I am concerned that maybe the 3/8" may not be heavy enough at 10" diameter.:o I will let everyone know how it goes. The polycarb will be here Monday or Tuesday.