The beads or lack thereof is a technique (art?) issue. I use Ray Harlan's boron applicator tool. I also have one I made myself but Ray's is a bit easier to use because he has a steeper cone at the bottom of the cup to help guide the fiber into the small hole.
One needs to experiment with both the viscosity of the glue and the speed at which the fiber is drawn though the applicator. When things are just right, the beads disappear just about everywhere. Ray's instructions recommend that thinned Ambroid be used and others say only Duco should be used. I have used both to the same effect. One thing to look out for is that the fiber can be drawn through too slowly. There are no beads but there is too much glue. I usually weigh my fibers (for light, weight critical planes like F1D) after the glue has dried to make sure the correct amount of glue was applied. If not, I wipe the glue of with acetone on a paper towel and apply the glue again.
I have tried pregluing a bunch of full length fibers (24" as I get mine from Ray) for later use. However, I think that the glue tends to come off near the area where I cut the fiber. Also, if the fiber is used a few minutes after the glue is applied (the glued fiber no longer sticks to a piece of paper), the glue has not yet cured. Then the application of acetone dissolves the glue much faster with less acetone, too. I still will take preglued fibers to contests as it makes for faster repairs.
Finally, some people just glue the fibers on using a thin brush for the glue. This works for them but I think it takes too long. I do not know if their fibers stick better, but from the weights they provide, I think the brush on and applicator methods provide for the same final, finished weights so neither method is really better than the other weight-wise.
I would think that hypo tubing of the right ID would work as well as Ray's applicator. I would add experiments varying the length of the tubing in addition to the viscosity and draw speed tests.
Leo
--- In Indoor_Construction_at_yahoogroups.com, "Mark F1diddler" wrote:
>
>
>
> --- In Indoor_Construction_at_yahoogroups.com, "John Berryman" wrote:
> >
> > Never worked with boron, but this discussion prompts a question:
> >
> >
> >
> > Is it possible that the boron, as it is extruded (?), spun (?), or drawn
> > through a die (?) is coated with some sort of lubricant, and that it needs
> > to be degreased (detergent?, acetone?, mineral spirits?) to prevent the glue
> > from "beading?"
>
>
> JB,
> I always try to clean boron with acetone before use. I have also tried sanding it to roughen up. Can't tell if either one does any good, but I still pretend acetone wipe does help.
>
> Neil, I'll try that. I once had okay results by pulling through a glue-soaked napkin, but full strength glue. Tended to grab too much glue, but at least it wasn't a series of beads.
> thanks,
> MB
>
Received on Thu Jan 24 2013 - 17:14:04 CET
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:47 CET