ULF-1 Discussion Archive
Anonymous static archive of the former Mailman list
Anonymous static archive of the former Mailman list
Re: [ULF-1] Best Glues
I don't know . I'd asked you . On Thu, Jun 14, 2018, 2:06 AM Member 27 <[email]> wrote: > In case I might have missed something in the last fifteen years, > all of the resourscinal glues mentioned in the Forest Products Labs > "Member 60 INFO BOOK" that are the only glues that qualify as "exterior > structural" > (which is the highest rating) were completely removed from and are still > no longer > available to private users in the USA because of environmental hazards. > > Is that still correct? > > -------------------------------------------- > On Wed, 6/13/18, Member 116 <[email]> wrote: > > Subject: Re: [ULF-1] Ulf-1 Digest, Vol 70, Issue 14 > To: [email] > Date: Wednesday, June 13, 2018, 7:57 PM > > Member 67, you are > absolutely right! Flocked cotton (flox) is structural, > micro is not. Also micro is porous. If you fix a fuel leak > with micro the fuel will wick right through. I've built > two LongEZ's, ask me how I know - LOL. > On Wed, Jun 13, 2018 > at 2:03 PM, <[email]> > wrote: > Send > Ulf-1 mailing list submissions to > > [email] > > > > To subscribe or unsubscribe via the World Wide Web, visit > > http://lists.ulf-1.com/ > listinfo.cgi/ulf-1-ulf-1.com > > or, via email, send a message with subject or body > 'help' to > > [email] > > > > You can reach the person managing the list at > > [email] > > > > When replying, please edit your Subject line so it is more > specific > > than "Re: Contents of Ulf-1 digest..." > > > > > > Today's Topics: > > > > 1. Re: Epoxy bonding (Member 121) > > > > > > ------------------------------ > ------------------------------ ---------- > > > > Message: 1 > > Date: Wed, 13 Jun 2018 09:12:17 -0700 > > From: Member 121 <[email]> > > To: [email] > > Subject: Re: [ULF-1] Epoxy bonding > > Message-ID: > > <CALUQ4rd1+YpvK9Ck0+ > QsJ1dZ6tMm=4QX6ZpFFAarKzZjKi=b > [email]> > > Content-Type: text/plain; charset="utf-8" > > > > Cool . > > Did you ever hear of fiberglass drywall tape? > Wrapping struts near > > the cocpit to prevent splintering impaling effects ? But > some fiberglass > > is unravel -ish when cut into strips . Cotton linen was used > in ww1 on > > propeller tips . > > > > On Wed, Jun 13, 2018, 9:06 AM Member 72 < > [email]> > > wrote: > > > > > Hi Doug, > > > > > > All very good advice. One thing we did on our ULF-1 > build was to mix flox > > > (floculated cotton) into our T-88 glue batch when we > needed to thicken it > > > up a bit to help fill some voids in the joint, rather > than micro balloons. > > > We found flox to be structural in nature and added > strength to the joint, > > > while microballoons was more cosmetic, not adding much > strength to the > > > joint. > > > > > > Thanks, > > > Member 72 > > > > > > > > > > > > Sent from my iPad > > > > > > > On Jun 13, 2018, at 1:43 AM, Member 1 <[email]> > wrote: > > > > > > > > I'm with Bob on this. To me, there is a lot of > superstition involved in > > > peoples' beliefs about gluing Member 60. The shiny > surfaces created by blades > > > have always intuitively struck me as a deterrent to a > good glue bond. I am > > > now working as a violin-family luthier, and I am up > against the same > > > superstitions there as well. > > > > > > > > Having said that, though, I'm not sure it > makes a big difference. While > > > building an aircraft, you end up with leftover epoxy > from many small > > > batches. Grab some sticks out of your trash or scrap > pile, and do some > > > semi-scientific testing with your leftover glue. It > only takes a minute or > > > two. For example, I would cut two sticks about 10 times > as long as their > > > width/thickness, overlap them 2 or 3 times their > width/thickness, and glue > > > them together with light or moderate pressure, and then > break them after > > > curing for a couple days. The Member 60 should always fail > before the glue joint > > > does. If it does, then who cares how the joint was > prepared? > > > > > > > > Do this often, throughout your project, during > different environmental > > > conditions, and as your epoxy gets old. As soon as you > find yourself > > > airborne, your life hanging from all those glue joints > you've made, you may > > > think about those glue joints (as I did) and find > comfort in the fact that > > > they are stronger than the Member 60 itself and you've > done the best you could. > > > Then it all comes down to proper design which > doesn't allow any joints to > > > get stressed to the point that the Member 60 itself fails. > > > > > > > > To me, it is more important to not apply too much > clamping pressure to a > > > glue joint than it is to worry about cutting vs > sanding. I always let my > > > wet joints sit open either until the epoxy is > thickening a bit, or it is > > > obvious that the Member 60 is saturated and won't be > absorbing any more glue. > > > Then I'd assemble and clamp with moderate pressure. > Epoxy has several times > > > more tensile strength than hardwood, so even if > you're sloppy and end up > > > with a thick seam of glue, there should be no strength > penalty. A small > > > weight penalty perhaps, but that would be > over-nit-picking. If you join the > > > parts before the glue has stopped soaking in, and/or > apply excessive > > > clamping pressure, you are asking for a weak, > glue-starved joint. (I use > > > T-88 which is relatively thick... if you use a glue > that has a thinner > > > consistency, this attention to soak-in is even more > important.) > > > > > > > > Epoxy is really good at filling imperfections and > allowing stresses to > > > be spread out over larger areas, so a perfect fit is > not as important as it > > > was with previous glues. For large voids that can't > be easily avoided in > > > structural joints, I recommend wetting the bonded > surfaces with epoxy and > > > then making a light slurry with epoxy and > micro-balloons to fill the voids > > > with. > > > > > > > > Test your glue and your methods. Then you'll > know, and nothing anyone > > > writes will bother you. There are some photos of the > glue-starved joint > > > risk here (and other gluing tips throughout my old > AirBike building web > > > site): > > > > > > > > http://questiongravity.com/ > airbike/feb03-1.htm > > > > > > > > $0.02, > > > > > > > > Doug > > > > > > > > PS: We have 307 members! So glad to see you all > here, and thanks to all > > > who have been contributing. And thanks to Dieter for > continuing to fund the > > > domain fees to keep this service available. > > > > > > > > > > > >> On [phone]:56 AM, Member 116 wrote: > > > >> I disagree about not sanding before gluing. A > power planer of a hand > > > planer bends the fibers over and leaves a shiny > surface, not good for glue > > > penetration. I have a cabinet shop and glue stuff > together daily. For a > > > couple years I glued up 12 ply (birch and maple) > propeller blanks for a > > > prop manufacturer. All those ply's after planeing > were smooth and shiny > > > because of the bent over fibers. Before gluing (with > Resorcinol glue) I'd > > > run over them with a belt sander/80 grit across the > grain, one pass to give > > > the Member 60 some (tooth). Then use a shop vac to clean and > make those > > > (damaged) fibers stand up straight and accept more glue > penetration. > > > > > > > > ______________________________ _________________ > > > > ULF-1 discussion list -- [email] > > > > > > > > Subscribe, Unsubscribe, Preferences, List > information: > > > > http://lists.ulf-1.com/ > listinfo.cgi/ulf-1-ulf-1.com > > > > > > ______________________________ _________________ > > > ULF-1 discussion list -- [email] > > > > > > Subscribe, Unsubscribe, Preferences, List information: > > > http://lists.ulf-1.com/ > listinfo.cgi/ulf-1-ulf-1.com > > > > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: <http://lists.ulf-1.com/ > private.cgi/ulf-1-ulf-1.com/ attachments/[phone]/d5c11fed/ > attachment-0001.html> > > > > ------------------------------ > > > > Subject: Digest Footer > > > > ______________________________ _________________ > > Ulf-1 mailing list > > [email] > > http://lists.ulf-1.com/ > listinfo.cgi/ulf-1-ulf-1.com > > > > > > ------------------------------ > > > > End of Ulf-1 Digest, Vol 70, Issue 14 > > ****************************** ******* > > > > > -- > > > _______________________________________________ > ULF-1 discussion list -- [email] > > Subscribe, Unsubscribe, Preferences, List information: > http://lists.ulf-1.com/listinfo.cgi/ulf-1-ulf-1.com > -----Inline Attachment Follows----- > > > _______________________________________________ > ULF-1 discussion list -- [email] > > Subscribe, Unsubscribe, Preferences, List information: > http://lists.ulf-1.com/listinfo.cgi/ulf-1-ulf-1.com