Hi, was hoping someone had a new idea on how to keep an inch thick honeycomb core from lifting on a large concave surface if film adhesive is not very tacky? Have considered thermoforming core first but investment in tooling would be required. i have also tried various glues/foam pastes for spliced areas but still lifting occurs eventually. Even de-bulking fails after a couple of hours at ambient. Heat guns are employed initially but the stress on the core makes it want to naturally revert back to original shape.Would appreciate some ideas on this please, thanks
Few idea’s/bodges but all dependant on what you can get away with where you are
Presume you lay up instructions detail core orientation ? You able to turn core to the more flexible plain
Bag up 60deg in the oven for 15 mins an leave to cool under vac over night
Redux212 cut strips 1" wide an lay on the laminate surface at strategic points,that holds most things !
You don’t say what grade core your using ? Not possible to use a softer core
Use some flex core or OX core ?
Pictures an dimensions of the job might help
Hi, thanks for your reply. I have de-bulked overnight but have been trying to reduce time so tried without with little success. Haven;t tried a warm de-bulk though. Have tried spots of adhesive in strategic areas but not Redux 212 strips so that might be worth a try. Currently using a different foaming paste but was considering switching to Redux 212 as feel its a superior product. I will try the strategic strip theory next as have also tried different orientations of the core itself and feel i have it correct at this time. would appreciate any other ideas that come to mind mate as this is an ongoing issue, thanks
another option is to do a two step process, where you cure the core to A laminate, then laminate and cure B laminate. This isn’t uncommon, not ideal as it can add cost, but it can be necessary in some cases. You could also ask your supplier if they can increase the tack level of the film adhesive. I have used some film adhesives in the past that are extremely tacky.
Never had any trouble with mta240 or fm87 what film are you using ?
What weight film glue are you using .3 or .6 ?
What grade core have you got ?
Core is stiffest in the ribbon direction so 90deg to your ribbon direction is your most “flexible” direction
At the minute, the materials are the materials and are not likely to change just yet as commitments are in place. i am hoping to increase the film adhesive tack at a later date and the process is a two step process where the skin is cured first then the core cured second stage. Because of print through concerns, this is not likely to change. The main success has been with an overnight de-bulk but with the size of the part being very large, i was hoping to eventually not have to do this as this adds time and cost. A trick of the trade is what i am after really, something that i haven’t already tried and probably something not generally known? Thanks for your thoughts on this, much appreciated.
Got any pictures of the item or is it secret ?
Never heard off being able to alter film glue tack level,you can sometimes get a better tack with an unsupported version but then they are a sod to put down
Sorry cannot provide pictures, nda etc but think of a generic inverted glass washing machine door and turn inside out and enlargen to car size and you will be close to the size. Are looking into possibly increasing core size as joins on curved areas giving most trounle where lifting concerned!