Fiberglass over Kevlar?

[swiftdrivr]

I bought some new sides from CE Composites, which are Kevlar fabric on one side, and probably resin on the smooth, shiny side. I need to attach some extenders for mounting at the upper forward rollbar on my DB-1, and so I made some metal tabs from hose clamp metal, but I'm not sure if I can fiberglass these to the "fabric" side of the body work. Has anyone got any experience with this issue? The piece lays against the frame / rollbar, and the nose fits over it, so clearance is too tight for bolts, or even rivets.

[Rick Kirchner]

pictures....

[provamo]

sure

[SEComposites]

You should be fine. I'm sure the CE Composites (not to be confused with SE Composites!) use polyester resin so as long as you lightly key up the area you'll be laminating onto you'll be fine. Kevlar is not a nice material to work with and will fluff up if you're too aggressive with it. Not necessarily a problem but it doesn't look nice.

We always make sure that any Kevlar components we make have carbon or glass around the edges and in any areas that will become holes.

[swiftdrivr]

here is what it looks like. I had intended to attach the metal tab to the bottom [fabric] side, but maybe it would be best to attach to the resin / smooth side.

Actually. I have to work on the nap side to secure the locator pins on the other end. Will that work?

[Rick Kirchner]

you could extend the panel forward and thus get the surface away from the roll bar so you could use screws or rivets.

What about bonding #4 or #6 tinnerman washers to the back side so you can use flush rivets and not have them pull through the panel?

also could "hook" the tab and go over and 90 deg to pick up the other surface of the panel and get out of the plane of the rollbar.

[SEComposites]

I might have misunderstood what you are aiming to do.
I would extend the Kevlar flange at that point. Bend up a piece of aluminum that is the same shape as the bodywork in that area. You could simply tape that in place (on the outside molded surface) having released it and laminate on an extension with fiber glass.

[S Lathrop]

The trick to bonding to a composite panel of any type is to prepare the surface. The best way is to sand the surface you want to bond to until you have removed all of the original surface. You only need a few thousands of an inch.

Some resins contain materials to inhibit oxidation and these materials will coat the surface of the composite.

[Steve Demeter]

If you are trying to bond to Polyester resin, make darn sure to prep it thoroughly.

Sand as suggested above and I always give it an acetone wipe to remove and traces of the stuff built into poly laminating resins that makes them hard to stick to.

[924RACR]

Apologies if you're already aware, but... when bonding fasteners onto bodywork, using a filler material in your resin goes a long way to adding in strength, while maintaining consistency... as mine is all epoxy, much of that West Systems, I just go by West Marine and pick up some West Systems (no relation) filler, I wanna say the #404 High Adhesive stuff, and mix in to mayonnaise consistency... the panel will delaminate before those tabs tear off...


https://www.westmarine.com/buy/west-...5?recordNum=48

[Brian]

Whenever I need to add to or repair polyester resin composite, I use epoxy resin and prep with 80 grit. Ditto on wiping with acetone to remove any wax, whether mold release wax or residue from the resin itself. I use west systems stuff, too.

[swiftdrivr]

Thanks for the suggestions. I haven't used filler before. Will have to try it.

[924RACR]

It's impressive stuff, once you're using an epoxy... mix in different strengths, and using different fillers, you can do all kinds of stuff... from Microlite (for smoothing bodywork - basically making your own bondo, but uber-light) to these ones... bond in wood, or metal, or plastics, etc... endless options...