I need an epoxy that will act as a filler as well as an adhesive. I don't even want to get into the problem I've created. Will Rod Bond or Ultimate Gel work? Or, are they only going to work from surface to surface?
Thanks for any help.
Todd

I would suggest Rod Bond use as much as you need, stays where you put it. You may want to tell us the problem you created, as there may be other fixes.

Without knowing what you are trying to fill, that is a difficult question. Rodbond and other epoxies will of course fill but the end results are drastically different accross types and brands. If you don't mind the "fill" being flexible and slightly soft, Rodbond will work. If you are looking for something you can sand out and that will be rigid, 5min, 15min, or another type of epoxy will more than likely fit the bill. For the ultimate in hardness, you could even use JB Weld products. One thing that is a fact across all of those I mentioned; they are by design an adhesive and will stick very well to any properly prepped surface.

Ultimate Gel will also work.
If your needing some extra strength in it you might cut up some fiberglass cloth into one inch pieces pull the threads apart and mix them in with the gel. for added strength.

Micro balloons are a filler that is mixed with any epoxy where ever epoxy is needed as a filler. You can get it from any model airplane builders supply like Hobby Lobby or Tower Hobbies. Micro balloons add little weight ... Bob.

Most epoxies have fairly good cohesive strength. I have no idea what you're trying to do or fix, but unless you're talking about filling a very large area or void, you can probably find an epoxy that will make do in a pinch.

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A few years ago I got a great deal on 2 gallons of high strength epoxy. One thing though, the material was in liquid form not paste.

Purchased a quantity "colloidal silica" on an online @#$%& and used it to thicken the epoxy into a smooth paste as I mixed it. It worked great.

Look around colloidal silica is widely available. BTW, there is booklet available by "The Gougeon Brothers " that describes many epoxies and related materials and their uses.

Lou

Hi Tod,

It's very hard to give a correct answer without knowing what you are trying to glue. Maybe Gorella glue might work for you as it swells like foam once you activate it with water. If you told us what you were glueing and the gap size you're trying to fill someone here will give you the correct answer.

As somewhat of an 'expert' on using epoxy, I second what many here have already said. Just a few considerations:

(1) fumed or colloidal silica ("Cab-O-Sil") when mixed with normal viscosity epoxy will produce a thickened putty with a Vaseline-like consistency that resists sagging. The downside, and it's significant, is that the mix is rock hard and VERY hard to sand. So if you use it make sure it's in the form you want before you let it set up firmly. It can be worked a little in its gel-like state before it's become rock-hard, but, depending on the base epoxy mix, you may have only have an hour or two.

By the way, I'm pretty sure Rod-Bond is simply a proprietary blend of thickened epoxy, with the primary thickener being fumed silica.

(2) Low-density fillers are what you want if structural strength isn't important but later sanding/shaping is. Micro-balloons work great, but can be a little pricey; talc is a cheaper alternative. The more you mix in the lighter, stiffer, and easier to sand the mixture becomes--however, the strength also decreases.

(3) A moderate-density filler can be made by simply mixing sanding dust or fine sawdust with the epoxy. This may be what you want if you're filling cork or wood.

(4) Some experts recommending first wetting out the surfaces of the materials to be bonded with unthickened epoxy prior to bonding. In other words, you first lay on a thin coat of epoxy, then mix in your filler, and then apply the thickened filler. I've found this isn't always necessary, especially if the mixture is kind of 'wet'. If you're using a very stiff or 'dry' mixture, I'd recommend it--especially if adhesion is important.

Good luck!



Edited 1 time(s). Last edit at 12/16/2007 06:54PM by Tom Juster.

One method of thickening epoxy or polyester resin that I have often used is with a very sharp razor blade cut some approx. 1/8 inch strips of fiberglass mat. It can be seperated by stirring it (dry) in a container leaving you with very thin fibers that can be mixed into your resin. This can also be done with nylon masons twine.

If you have unassembled parts to put together with mismatched ID and OD you can take some fiberglass cloth and pull out one strand from the edge and wrap it like a loose guide wrap around the OD. If filling a large gap make additional passes back and forth. You may have to apply some epoxy every couple of passes if it is a large gap. This also can be done with the masons twine.

This is pretty much speculation, not knowing what your dilema is, or what you are trying to acheive.

Remember that if you add fillers or micro-balloons, those don't make the epoxy stronger (they actually make it weaker) but it keeps you from having to use so much epoxy.


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Tom, I'd like to pick your brain about the effect of fillers on the strength of epoxy. I am thinking that the filler medium does not cause any chemical change reducing the adhesive properties of the resin, but that what happens is that the filler can reduce the contact area between the resin and the object that it is applied to. Also it would reduce the mass of the resin that is in place.

If that reasoning is correct, what I am pondering is since most applications in rod building involve basically cylindrical shapes, and if the medium used for a filler is spherical or cylindrical in shape, if applied on an OD then the contact area being opposing radiuses it would seem like minimal loss of contact area. When applied on an ID the dimensional differences between the radiuses would also tend to minimize the loss of contact area. I am wondering how much loss of strength should we expect to have.

I guess my question is how much is too much and how little is too little. If my reasoning, above is incorrect, I suppose that the question is moot.

Your first paragraph is on the money.

The forces we deal with on most fishing rods means that most epoxies, even those with filler, aren't likely to be compromised to the point where an adhesive failure will result. It's not a big deal. Generally, unless you're using the epoxy as a gap filler, there isn't any reason to use the fillers or micro-balloons other than to perhaps save some money (then you have to pay for the filler, though) on epoxy and make it go farther per the amount purchased.

I really don't know if it would be suitable for what Todd is doing. I just don't know enough about his project.

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