What adheres to fiberglass/polymer really well?

[dyl]

I have a project pistol I never liked the grip of. It's a Polymer 80 Glock lower. The front strap of the grip is dead flat. As in 90 degrees to the side panels of the grip, not oval. This makes for a very restrictive grip where your hand needs to rotated on the grip to a very specific position or it's uncomfortable. I'd like to build up the front so it's an oval.

What material could I add and then sand down that would bind to polymer / fiberglass? It would have to stay adhered even with the grip being squeezed/flexing. Bondo? Epoxy? If I made a wooden panel to adhere, I'd run into the same problem, what adhesive would bind to fiberglass despite flexing?

[Onward Allusion]

JB Weld - Plastic Weld.

[T. O'Heir]

Try a set of Pachmayr grip gloves.
JB Weld is epoxy based putty. It's biggest advantage is that it's easy to find and doesn't cost a ton of money.
"...bind to polymer/fiberglass..." Those are different things, but just about anything sticks to both.

[4V50 Gary]

AcraGlass

[Scorch]

Most glues do not adhere to thermoplastics very well because thermoplastics have mold release agents in their formulation to allow them to be released from molds easily in the manufacturing process. Best adhesives for thermoplastics include sticky adhesives (like acrylic adhesive, 100 MPH tape, Gorilla Glue, etc) or solvents in their formulation to dissolve or soften the plastic's surface and allow deeper penetration by the adhesive into the plastic itself. Epoxies bond at the surface, so any wax, oil, silicone, PFA, ESO, or other non-stick materials will inhibit a bond.

As far as fiberglass (or micarta, G10, resin, polyester, etc), epoxy is the adhesive of choice since those materials use epoxy or polyester resin in their construction.

[pete2]

You ever handled an M&P???? Just sayin'........................

[Geezerbiker]

There's an epoxy made for artist called Magic Sculpt. It seems to stick to everything. I've used it as filler in plastic hand guards and stocks to stiffen them up. I would suggest scuffing up the area where you plan to add the epoxy first... It's non toxic and works like clay. Wet your fingers a little and it molds very easy. When hardened, it sands like wood.

The sell it in black but I've always bought the gray because it's cheaper then painted it afterwards. I wouldn't count on it matching the frame color.

Tony

[dakota.potts]

I've bedded many a fiberglass rifle stock with Marine Tex epoxy. Of course there should be far less flex in a thick fiberglass rifle stock than a pistol frame, but it basically becomes one with the fiberglass. Absolute nightmare to remove it if you glass something in wrong

[10-96]

Another vote for Marine-Tex. However, for building up the front of a grip area, you may want something with a thicker consistency. But for stayputtedness- Marine-Tex stays put.

[Steve in Allentown,]

I agree with Scorch.

I bedded a Ruger 10/22 in a Magpul stock. The epoxy wouldn't reliably bond with the slick plastic stock. So I had to drill multiple small holes through the plastic stock where I wanted the epoxy bedding to be. This created a mechanical lock with the stock. I also used a pointed tip on a soldering iron to supplement the drilled holes.

[Slopemeno]

E6000.

[Unclenick]

The problem with epoxies is adhesion is hard to obtain after they finish hardening. This is why epoxy paint says you have to apply a second coat within a time limit, or it won't bond.

I don't know what is in the polymer frames. If it's epoxy glass, you may have to treat the surface with a pre-paint surface softener to get good adhesion.

If it is polyester resin fiberglass, you may need to use a polyester resin-based filler, like Bondo to get good adhesion.

If it is an FRP (fiber reinforced plastic), you may have to heat the surface to get good adhesion.

You could call the maker and ask what they recommend.

[HiBC]

Its a complex subject. We start with not having a clue what the base polymer is.
There are commodity resins which may be relatively cheap. Polyethylene,polypropylene,ABS,PVC come to mind.

You can take a polyethylene or polypropylene bowl and mix epoxy in it,pour out most of it (so heat doesn't build up) come back the next day,flex he bowl,and the epoxy will crack off . You can use the bowl again. Pretty much,nothing sticks.

ABS and PVC can be solvent bonded.Styrene is another.Solvent melts the plastic. It sort of welds together. Plumbing and model airplanes.I don't know of gun applications.

Delrin/acetal...Might give you the illusion epoxy/superglue sort of sticks.It will fail.

Acrylic/plexiglass solvent bonds.And there are 2 part catalyzed specalty glues that work pretty well. But guns don't have plexiglas stocks

Polycarbonate! Tough stuff!! Long carbon chain molecules.Amazng,at normal
tapping speeds,even hand tapping,those carbon chains get broken,and release heat.The threads will easily melt. Look very close,you will see suspended black flecks of free carbon. Polycarb can take impact an shock. It does not like sustained stress. Polycarb can be solvent bonded. Solvent polished,too.But as the solvent evaporates,it leaves a stressed layer.
Ever get a glass marble hot and throw it in cold water? It will crackle and craze.Polycarbonate is susceptible to solvent stressing and crazing.

There are urethanes and other exotics... I've been out of it for 20 years. New stuff.

Many polymers are filled with something else. Glass,graphite,talc.corn starch,etc. You might get glue to stick to the filler.

With a porous material like wood,glue can penetrate and mingle with the wood fibers. You might tear wood out before the glue lets go.

Not so much with polymers.

I'm not a chemist,its been over 20 years,but polymer molecules look like spaghetti noodles. There are different ways the molecules bond. I forget which is which,but there are Brownian,Covalent,and Vanderwahls bonds.
Someplace in all of that science will be your adhesion answers.

I don't know what a Choate or a Ram-line stock is made like,but I'll describe a process of co-injection that a stock COULD be made of.The way plastic flows through a mold,it sort of rolls within itself. Ther is little,if any friction between the mold and the skin of the polymer. By friction,I mean movement.The polymer skin gives up its heat to the mold and solidifies. The mold continues to fill within this shell.

With some molding machines,its possible to begin filling the mold wth one resin which will form the skin,then switch to another resin that will form the core. So your part ends up like chocolate covered cherry. Now,you can think a little bit like case hardening. You can have a relatively expensive outer skin of engineering resin,with a cheaper core fill.
Now,here is where it gets fun!!

Maybe nylon 6/6 will get a graphite /fibergass fill.That enhances the characteristics of the nylon. There is more. Polymers shrink when they solidify. Nylon? Ballpark .007 to .009 per in. Polyethylene/polypropylene? You might get .020 or .022 per inch. That causes problems with snks,warps,etc. Internal stresses. But now,when we add fill,the fill is not subject to shrink . So,if your nylon has 40% fill,you might cut your shrink to .004 per in. There is another trick! A blowing agent,like baking soda an be a polymer additive.It makes the polymer foam.
So you could shoot a part with a hard skin of Graphite glass nylon 66 with a foamed core of polypropylene.

I'm not saying thats what they do,but you would have an accurately molded,servicable relatively cheap stock. And glue,epoxy,etc would not stick worth a darn.

That stock is a whole different ballgame from a composite stock,such as a McMillan,which is laid up of epoxy glass,kevlar,graphite with a foam core.

You can get epoxy to stick to epoxy


Note to Unclenick I'm not an epoxy expert,but there is something about a volatile solvent in the catalyst..like maybe acetone or methylene chloride.
Its a problem if it evaporates too fast. So the magic is,some kind of wax floats up and forms a protective skin over the curing resin.
Thats why the timing thing on recoat.
You can get good adhesion on a recoat after the time,but you need to sand or otherwise remove the wax film.

Now,a little knowledge is a dangerous thing,and thats what I have. I'm sure my explaination is at least partly wrong, but certainly I will be corrected!

[jfruser]

1. Ask the majufacturer
2. Think about material removal
3. Welder brand contact adhesive sticks to things that others dont. Like kydex. Good stuff

Sent from my SM-N900P using Tapatalk

[FrankenMauser]

Devcon plastic steel putty is what I would go for.
But you still have to count on a mechanical bond (rough that frame up), rather than molecular.

[HiBC]

Kydex is an Acrylic/PVC alloy. It should solvent bond. Try plumber's plastic pipe cement and primer.
I'm saying "should work" . I have not tested.

[Pahoo]

Unless I really don't understand the problem, here is what I suggest.
If I want to increase the grip on a slick area, I buy stair-tread stick-on material. Not the black gritty material but the Grey rubbery stick-ons. 3M makes them, in a pack. I trace around the contour, cut with heavy scissors, peel off the protective paper and just stick it on. So far, I have not found any material that this stuff doesn't stick to. ????? ,,,,,

Be Safe !!!