Honeycomb edge treatment
Honeycomb edge treatment
(OP)
Can anybody give me some good ideas on how to fill in a beveled edge on on honeycomb core? I normally use a Polyurethane Foam (last-a-foam) as my core in a sandwich construction.
I have heard Kelvar pulp mixed with epoxy makes a good filler.
I have heard Kelvar pulp mixed with epoxy makes a good filler.





RE: Honeycomb edge treatment
When you say beveled edge, has the honeycomb been machined to a bevel? Or do you wish to create a bevel with a filler paste.
In the first case no filler is needed although some people pot the reduced height cores with a paste of micro balloons and resin before laying on the skins.
In the second case any short fiber filler mixed into your laminating resin with a little silica ( Cabosil or Aerosil)to make a filler paste will do.
I am presuming that you are laminating your own skins, that you are not using prefabricated sandwich.
B.E.
RE: Honeycomb edge treatment
Thanks for the reply. Yes, I am laminating my own skins.
My normal lay up is Fiberglass - P.U. Core - Fiberglass that is then vacuumbagged.
During the lay up my core is completely encased within the fiberglass skins. I want to switch my core material to honeycomb. The honeycomb core will be machined to a 45 degree bevel. I am worried an untreated beveled edge on the honycomb will not give me a nice smooth edge I am looking for after vacuumbagging my layup.
PG
RE: Honeycomb edge treatment
It is also sometimes possible to simply press a low density foam into the honeycomb. You would do this before beveling.
RE: Honeycomb edge treatment
A co-cured face on almost any honeycomb core is going to look quite a bit worse than one on foam. A caul plate may be a low cost way to preserve flatness and prevent visible telegraphing.
This assumes it's aesthetics that matter. A bit of edge crush never did anyone any harm structurally. (To my knowledge - any disaster stories attributed to bobbly/dished in ramps?)