How to bond: glass to glass, glass to wood...
 

Composite materials have several little tricks that need to be learned to use them successfully. One of them is bonding, bonding them together, or bonding them to other materials.

If you need to install a plywood former, firewall etc,
here is a successful way to achieve a good bond:

After making sure the part/s fit correctly:

First, clean surfaces are your friends. Clean from ANY and every type of contaminents, including your grimey little fingerprints.
Put on some gloves and clean the surface using Acetone and a new rag and thouroughly wipe down the area.

Next, with gloves still on, scuff the mating surface with 80 or 120 grit sandpaper, and the wood part/s also. You want a scuffed surface everywhere the Epoxy will be.

Again repeat the cleaning process. after everything is cleaned, You need to do what is called a "hot coat". A hot coat is when you brush on some Epoxy to the mating surface with no thickener {Cab-O-Sil or Colloidial silica} added yet. The Idea is that the thinner epoxy will penetrate all of the pores and scratches left from the scuffing up step. This step is especially inportant for parts that are porous{wood, foam etc}.

Now mix the epoxy with the Cab-O-Sil. You just want enough thickener so that it does not run from the mixing stick, A mixture in beteween mayonnaise and peanut butter thick. Do NOT add Microspheres or Microballons or glass bubbles or what ever name you want to use for these into this mixture, These were not designed to use to thicken resin for bonding. You can however if you want the ultimate strength, although usually not necessary, is add some Milled fibers or kevlar pulp.

If you are using the Aeropoxy style glue, the hotcoat still applies.

Position your part/s next and then try and make a nice fillet wherever you can. I say try because it takes some patience to get a nice looking fillet for a bulkhead or whatever the part is.

After you clean up thats it! very easy but sometimes these steps are overlooked. One of the drawbacks of improperly done composite bonds is that it will appear to hold well, then all of a sudden in will break totally free. Not a good thing for a flying machine!

Good luck and have fun

Glass bubbles
 

Here is an interesting thing I herd about glass bubbles, aka Microspheres.

They were originally developed to use for flotation on deep submergence vessels. The idea is that they needed something that would have bouyancy, but would not crush under the extreme pressures of deep sea diving like foam would. so they would cast these billets of "foam" with resin and glass bubbles.

Pretty cool idea.

How to bond: glass to glass, glass to wood...
 

Waht r Micro Balloons ?

REgards.

arjun

How to bond: glass to glass, glass to wood...
 

Microscopic Glass Spheres that are hollow.

Parts in glass fuselages
 

This comment is not to disagree, but to suggest another option for installing formers and other items in composite fuselages. (I've used the method above with success too.)

One of my favorite adhesives for the interior of a composite fuselage is silicone. (or it's hobby variants, like the Zap "Goo")

After sanding and cleaning the parts, you can encapsulate a firewall or other former in the fuselage with a fillet of silicone, and it not only holds securely, but adds vibration damping as well. The other bonus is that the silicone can be cut away to remove the part later, if needed.... Not so easy with milled glass and epoxy!

Just be sure and keep an eye on the arts to insure alignment, while the silicone begins to cure.

How to bond: glass to glass, glass to wood...
 

That sounds like an idea, I'll have to try it.

How to bond: glass to glass, glass to wood...
 

Waht r Micro Ballons Used for ?

Where can one purchase it ?

Regards.

Arjun

How to bond: glass to glass, glass to wood...
 

Microballoons are hollow glass spheres. The material looks like a white powder. I have seen brown. The material is used as a sanding filler. It is mixed with epoxy or polyester resin to create fillets. Addition of the material to the resin makes a past that can be used to fill holes, create fillets and use generally where a filler is used. The more microballoons in the resin the easier it will be to sand. However if the mix is too dry it may not adhere too well. Microballoons do not add strength to the resin. It is a lot lighter than automobile body filler.

Hobby stores carry it in small amounts. I believe SIG markets it. I purchase mine from a Fibreglass products store. It cost me $15 CDN for a four litre container.

Ed S

How to bond: glass to glass, glass to wood...
 

what kind of silicone?

Silicone
 

I honestly don't think the brand of silicone matters much. I've used a variety of brands over the years, from ZAP "Goo" to common "Goop" from the hardware store. There may be subtle differences that someone else here can point out, but I haven't seen a practical difference with the varieties I've used.

silicone
 

and I can use it on a firewall with a pumped and piped 60?

Silicone
 

I've used it on a plane I designed, which had a YS .61LS and pipe, and had no problems. (Fiberglass fuselage, prepped inside with sandpaper, and cleaned with a dab of acetone on a rag)

To be clear, the method of firewall mounting that I used was to encapsulate the firewall on both sides, with a small fillet of silicone, smoothed with the rounded end of a popsicle stick.

That experience in particular is the one that convinced me that silicone-type adhesives were good for this application. I especially like it that if you want to, you can later remove the part, by carefull cutting it with an X-acto knife and peeling it off. I've been a little surprised that others haven't used this in lieu of the (much harder to remove, and much more rigid) epoxy and milled glass.

Firewalls
 

For a 41 cc gas motor, could you tack the firewall in using silicone, and then glass over that for more strength?

Don't know
 

I can't give you a definitive answer about that engine size, as I've only used silicone on firewalls up to and including .91 4-strokes.

How to bond: glass to glass, glass to wood...
 

When using Goop products to instal, say, a firewall (I've done this with 140 pattern birds), a couple of points are worth considering: 1) a non-porous surface on the firewall area to be adhered seems to increase the bond strength - this is accomplished by fingering some five-minute around the edges of the firewall. Also, the firewall needn't fit zero-zero inside the fuse; a slight gap allows for a stronger bond; 2) fingering a large fillet of Goop only adds weight and the shrinkage of this product will put some suck on glass fuses creating a slight trough on the outside of the skin.

silicone
 

well I'm going to try a window sealent silicone. it says 100% silicone great for vinal windows and other building materials. If this is a bad choice,SOMEONE PLEASE STOP ME. THANKS ...SEAN

How to bond: glass to glass, glass to wood...
 

I'm thinking Goop may be silicone based, but is quite different.
I don't know how they get different properties from silicone with them being all 100 % . High heat, automotive, marine goop, etc.

How to bond: glass to glass, glass to wood...
 

wood to wood(strustural)=pro bond
wood to wood(cosmetic/sheetin)=any good wood glue
wood to glass=Hysol 9462

wood glue takes longer to build, but much easier to sand than CA



IMO

How to bond: glass to glass, glass to wood...
 

what is hysol and where do i get it?

How to bond: glass to glass, glass to wood...
 

Description Hysol 9462 is a toughened, two component epoxy adhesive formulated for
a good balance of shear and peel properties in an easy to use, smooth paste.

http://www.watkins-associates.com/Na...%20Numbers.htm

How to bond: glass to glass, glass to wood...
 

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How to bond: glass to glass, glass to wood...
 

Aluminum to glass also works well with Goop.I have an aluminum channel shaped tank mount in deadly Yellow Cap 'er' Snap 10 . Pranged it. Full tank and bracket never moved. Iwould'nt use the window silicon for glasswork as it wasn't meant for high strength. Goop and glass meant for each other. Ply formers were also gooped in. Nothing moved!