Darryl Keil Last Activity 2025-05-12 11:03 AM
2 replies, 1581 viewings
 
back
Navigate threads:
< Previous Thread :: Next Thread >
 
^ Top
jkh

Posts: 5

Joined: 2005-05-13
Location: Bozeman, MT

User Profile 
Subject : vacuum bag chemical compatibility
Posted : 2005-05-13 12:56 AM
Post #32193
I need new vac system for arch door jambsets and curved stair stringers. Am also interested in anhydrous ammonia bending technique and am contemplating experimenting with a vacuum system rather than (positive pressure) Are these bags compatible with anhydrous ammonia? does anyone have any experience in this area?


 
^ Top
Larry Root

 
Subject : RE: vacuum bag chemical compatibility
Posted : 2005-05-13 7:01 AM
Post #32197 - In reply to #32193
Ages ago, Fine Woodworking had a *brief* article on anhydrous ammonia bending. I looked into it but concluded that I wasn't willing to take the very real risks involved in handling it, nor was I willing to make the financial investment into the equipment to use it. It's NOT common cleaning ammonia; it's NOT a simple fuming process like you'd use for a mission finish.

I have no idea what anhydrous ammonia would do to either the bags or the pumps in a vacuum system. As I recall, after processing, the wood was bent into shape and held until the ammonia off-gassed -- the wood didn't need to be forced: The image that piqued my interest was of a batten literally tied into an overhand knot.

If you don't want to use bent laminations, look into steam bending.



 
^ Top
jkh

Posts: 5

Joined: 2005-05-13
Location: Bozeman, MT

User Profile 
Subject : RE: vacuum bag chemical compatibility
Posted : 2005-05-13 11:43 AM
Post #32200 - In reply to #32197
Anhydrous ammonia can be obtained through farm co-ops... It is pretty nasty stuff, but with precautions carefully observed and strictly followed, I don't see why the method would be out of the question. By the way, Anydrous Ammonia "offgases" with the introduction of water. And the apparatus I have used for my preliminary small scale experiments is a (pressure tested) welded stainless steel vessel with a screw on end cap and various fittings for ammonia / pressure / water / etc... It works amazingly well, but I need to refine a simpler cost effective means so that I can attempt a full size staircase handrail. I am considering the industrial pump and stair veneering bag, but would prefer the bag to be a bit longer.

Does anyone here build curved stairs? I'm wondering how well the bag works for veneering stringers? I currently iron on my veneer. -very time consuming and probably far less consistent than vac pressing
back
Navigate threads:
< Previous Thread :: Next Thread >
Legend      Notification  
Administrator
Forum Moderator
Registered User
Unregistered User
 Toggle e-mail notification


Logo by MAZY
Running MegaBBS ASP Forum Software v1.5.14b public beta