Solved glues u can use on fiber glass
- Thread starter JetCrafts
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Hot glue, white glue like Elmer’s, CA, GG or other polyurethane, they all work for reinforcing smaller areas.
Minwax polyurethane is my favorite for larger areas, like covering a wing.
Inq
Elite member
Any reason you rule out epoxy? It is the gold standard. Full size planes are made with fiberglass epoxy. The second choice is polyester resin. You won't see it on real airplanes but most all fiberglass boats use it or vinyl ester resin which is slightly better than polyester.
@Tench745 is right it depends on the application. If you are sure that it will always be in tension, just about anything will do. Say... if you are sure you'll never pull negative G's, the bottom skin could be stuck with anything. In compression, however, the resin is critical. The resin is what keeps the individual filaments (~ 10µm) from buckling. Thus the strength of the laminate is largely dependent on wetting every filament. When laying up fiberglass with epoxy or polyester, if it looks hazy, it's not wetted. If totally clear where you could read through it, it is wetted properly. Every filament is being supported laterally so they don't buckle and thus contribute to the ultimate compressive strength of the laminate (layer) you're applying.
@Tench745 is right it depends on the application. If you are sure that it will always be in tension, just about anything will do. Say... if you are sure you'll never pull negative G's, the bottom skin could be stuck with anything. In compression, however, the resin is critical. The resin is what keeps the individual filaments (~ 10µm) from buckling. Thus the strength of the laminate is largely dependent on wetting every filament. When laying up fiberglass with epoxy or polyester, if it looks hazy, it's not wetted. If totally clear where you could read through it, it is wetted properly. Every filament is being supported laterally so they don't buckle and thus contribute to the ultimate compressive strength of the laminate (layer) you're applying.
I agree here also. If you don't want to start over, you might find scuffing it up with sandpaper might help (might not). But only if you are willing to use epoxy. Epoxy works mainly by mechanically gripping on to things, not chemically fusing. If you give it something to grip (sanding) it might stay on better. Polyester or vinyl ester resins are NOT good for mechanically connecting. But as @quorneg, said having the glue of choice seep into the paper surface would give the ultimate strength.
Tench745
Master member
Packing tape is often used on temporary moulds to keep fiberglass from sticking. You're going to have a hard time laying epoxy over tape and getting it to stick with just about anything.
Inq is right that epoxy is the standard for laying glass on foam. Polyester resin will eat bare foam and I would personally avoid it.
I have used water-based polyurethane to apply glass before and it works okay, but doesn't stiffen the glass the way resin does so it is not really structural.
White glue may be a good a middle of the road solution; stiffer than WBPU but still water-based and easier to work with than resin.
Inq is right that epoxy is the standard for laying glass on foam. Polyester resin will eat bare foam and I would personally avoid it.
I have used water-based polyurethane to apply glass before and it works okay, but doesn't stiffen the glass the way resin does so it is not really structural.
White glue may be a good a middle of the road solution; stiffer than WBPU but still water-based and easier to work with than resin.
Inq
Elite member
Not that it will help the O.P. as it doesn't stick to anything else... but I've been experimenting with using acetone thinned ABS plastic as a matrix instead of epoxy to fiberglass and carbon tow for spars. Actually the properties are pretty similar to epoxy with the added advantage of better impact toughness and is thermoplastic instead of a thermosetting resin. Since I was using it on an ABS printed plane it fuses into the structure just fine.
Inq
Elite member
As said above by several, packing tape isn't your friend if you want to do something subsequently. I'm all out of ideas on glue. I've tried hot glue, and several kinds of Gorilla glue (foaming and non-foaming). Nothing really stuck that I'd call structurally sound.
Although I never did it... it's quite common for the guys doing hot-wire cutting of foam wing to just fiberglass/epoxy strait to the foam. That is also what they do with some homebuilt aircraft. If you're using DTFB, you might be able to just peel off the paper backing with the packing tape.
Also, if you give more details about the piece you're wanting to cover and why, you might trigger some better feedback.
JetCrafts
Active member
I think ill just by some fiberglass and epoxy and do some tests
cyclone3350
Master member
I've done some experimenting to alternatives to epoxy & so far I've had good results with only 2. The first one is EZE Kote by Deluxe Materials. It is actually sold as a 1 part WB formula for light fiberglassing. It does have it's limitations. It works best on light cloth, .75oz/yd2 or aprox 25gm/m2. It is also pricey @ 26.00 USD per bottle. I did this 56" WS pattern pattern plane with it using pink foam & .75oz cloth. The other is Modge Podge hard coat. It has to be thinned & water won't do it. I've found this mix of =parts of distilled water, denatured alcohol & clear ammonia free glass cleaner & found it to work out very well. I've tried it over this pink foam mold for a cowling using 2oz cloth.(aprox 75gm/m2) It stuck amazingly well & it was hard. The big draw back is, that is hard & takes some effort to sand but, it will sand out to a nice finish. It is also a bit on the heavy side.
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Tench745
Master member
EZE Kote is just a water-based polyurethane. I'm told sanding sealer is also the same and cheaper than even WBPU.
cyclone3350
Master member
I've tried the Varuthane Poly & found that it doesn't have the adhesive & fiber binding qualities that the EZE K had. On pink foam, it sticks, but there is a definite difference as to how much effort it takes to peel it off. Is it enough of a difference to justify $15 a quart vs $26 a pint is hard to say. However, I did use the Poly, mixed a some light weight spackle, as a weave filler on the pattern bird before I put an acrylic paint job on it. I haven't tried sanding sealer, but I'll give a try just to see how that goes.
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