Sounds like finger tip depressions from handling the core. I have experienced this before "and" after the bagging process...
Quoting Harley Michaelis <[EMAIL PROTECTED]>: > I'm puzzled about the random, shallow depressions that sometimes form after > bagging and wondering if others experienced in bagging know the cause and > how to prevent it. > > My inquiry is prompted by the worst case I've ever seen in some 14 years of > bagging wings.There are no less than 60 of the depressions in a 48" > panel.There are about 20 on the bottom skin and the rest on the top. All are > > behind the spar that runs about 2-1/2" back from the LE on a 10" chord > slightly tapered panel. The depressions are 1/100" or less in depth and most > > are 3/8" to 1/2" in diameter. > > The cores were cut from Dow High Load 60 and looked perfect. The epoxy used > was fresh West 105 with fresh slower 206 hardener. The carriers had been > waxed and polished with 3 coats of Meguires #26 paste wax and painted with > common Krylon. The layup was 1.4 oz. glass on a bias and the 4.7 oz. ACP > 80/20 unidirectional CF cloth. > > The epoxy was rolled on to thoroughly wet all out. Toilet tissue was then > rolled out on the work and a roller used to pick up excess. The work was > folded in 3 mil drop cloth with breather attached to it and then left in the > > bag at room temperature for 36 hours. Toilet tissue used to pick up epoxy > and saved to judge cure in the bag was well cured.The vacuum was set to > cycle from 15 to 10 hg's. The Gast pump setup was running 5-6 seconds every > 16 minutes. Paint transfer was perfect. TE's are straight, true and rigid. > > All the above is in keeping with techniques used for years on many dozens of > > panels. Most came out normally. A few had some depressions. > > Have any of you had the same experience? Confirmed the cause? Preventative > medicine? Have any of you suspected moisture content in the foam cores? > Would its release be more likely to cause bubbles rather than depressions? > Have any of you placed a core panel by itself in the bag to see if any of > the depressions would appear before actually applying the layup? Did they? > Did you fill the depressions before bagging? Did new ones still appear? > > Please give us all the benefit of your experience. > > > > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and > "unsubscribe" requests to [EMAIL PROTECTED] Please note that > subscribe and unsubscribe messages must be sent in text only format with MIME > turned off. Email sent from web based email such as Hotmail and AOL are > generally NOT in text format > Simon Van Leeuwen PnP Systems - The E-Harness of Choice Radius Systems Cogito Ergo Zoom RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
