Other methods of bond honeycomb to CF

General Composites Discussions Composites Talk
#1

Obviously I have used film adhesive to bond CF to my Carbon Fiber panels. But, this all requires an oven at the least.
I have a huge flat panel of carbon fiber that I am bonding 1.5in thick honeycomb too.

I have already cured the two “skins” of carbon fiber. Now, i need to figure out a way to bond everything together.

I was thinking of using gel coat resin to bond the honey comb directly to the sanded side of the carbon fiber. I am going to use a heavy layer spread over the sheet. Then vacuum bag the panel to the honey comb with wood planks ontop of the honey comb.

My buddy was telling me to use standard resin and add some Cabosil to it, to raise the viscosity.

Are there any other products or methods for bonding the honeycomb to the CF panel?

#2

I think you want the best shear strength epoxy, and do what you mentioned. Spread a thin later, and weight it down. Don’t think you will need to vac bag it. You can even place the other plate on the top, to spread out the weight pressure more evenly.

speaking of…CRAP! forgot I had resin degassing.

#3

[QUOTE=BigmansM;25280]
I was thinking of using gel coat resin to bond the honey comb directly to the sanded side of the carbon fiber. QUOTE]

I’m not sure what your gel resin is but I wouldn’t use poly. I think most honeycomb is sised for epoxy. I would use a thickener as you suggest. Also, you could apply a consistent resin layer with a grooved rod tool which I can’t recall the name of. Or just use a threaded rod to pull over the wetted surface.

#4

[quote=“AMAC,post:3,topic:34569”]

I do have a grooved rod tool and u call it. I know exactly what u are talking about. I just need to find it in my mess of a garage.

I was going to use the vacuum bag to hold the honeycomb down. But now that you mentioned it. I don’t think I will need to bag it. Thats just a waste of time and material.

#5

[quote=“BigmansM,post:4,topic:34569”]

If you don’t at least use vacuum, how will you apply any “real” pressure to the part to ensure a good bond strength? Pile up cinder blocks?:rolleyes:

#6

You dont need pressure though. As long as you have contact from the honeycomb to the glue to the panel, you are good to go. There is no need to consolidate the layers more than that. A vacuum I think, would also suck the resin into the cells more than you need. As long as the layer of adhesive (whatever you use) is an even coat that doesn’t bead up, i think you are good to go. Also, make sure the pressure IS even, so you don’t have anything lifting up out of the adhesive, or not contacting the panel you are bonding it too.

#7

I don’t think i would use gel coat to bond anything. No offense so please don’t take it that way. Gel coat is too brittle and not a very good “glue”. Maybe use some type of bonding-gluing epoxy.

I’m kinda in the same boat… i want to build car body parts that need bonding and i don’t want the skins flying off the car at high speed.

Maybe run partial vacuum… 10hg or so?

Either that or get a heavy thick metal plate/sheet to lay on top.

#8

speaking of…CRAP! forgot I had resin degassing.[/QUOTE]

DOH! I hate it when that happens lol:D

#9

5 minute epoxy?

i dunno how big the part you re working on is, but its great. 1:1 ratio, very thick, doesnt drip, and in 5 minutes you are go!

smells aweful though.

oh and it heats up A LOT.

#10

The panel I am making is about 6ft long and 2.5ft wide. So I wouldn’t want to use any small tubes of epoxy, but if I could find a quart of any type of epoxy that would probably do the job.

Fastrr: I agree with you. I think gel coat is too brittle. I made a test piece but I think my gelcoat has gone bad. I’m gonna try something else.

#11

if you vacuum bag the whole thing together, external skin, honeycomb and inner layer, would the honeycomb suck much resin? or its just about the imprint that the core leaves on the external surface?

#12

I tried a mixture of two types of glue. A rubber cemet type compound that it says works on metal and vinyl materials.

Then I also used some Gorilla glue. I’m going to check everything tonight and Ill report back, hopefully with good news

#13

Well, rubber cement will shear like crazy. Should be interesting to see how it debonds/fails. Gorilla glue, I don’t know what it is.

#14

The rubber cemeter I bought was the “gel” form.
Everything worked out great.
I hate half assing stuff, but its not a very structural piece.