HELP Need The Best Bonding Agent To Repair Cracked Grip On High Standard Model 100?

[albayo]

I have buddy with a High-Standard M100 pistol with a cracked grip.

The grip is manufactured with a Bakelite material, no metal in it, its manufactured with solid Bakelite.

What is the best bonding agent to repair the crack?

 

[josquin]

Others will hopefully chip in, but I'd think epoxy would work. Is it possible to spread the crack at all? (Dangerous...). Epoxy can't really be chemically thinned but warming it a little (mix in a small plastic or metal cup and put in warm water) will thin it out and allow it to get into small crevices better. Mask off the area around the crack and apply with a toothpick.

Another alternative would be one of the industrial cyanoacrylates. I say "industrial" because they are availale in various viscosities. The really thin stuff is like water and will wick into a crack quite well. There are some made specifically for plastics. Might be good to e-mail the mfr. and ask about Bakelite.

I should add that if the crack goes all the way through and the grip is in, or nearly in. 2 pieces, you'll almost certainly have to reinforce the back.

Addendum- I just remembered that I have a .pdf of an article from Rifle Magazine Issue 251 on "Saving Horn Buttplates and Trigger Guards", which might be applicable here since he says that not all "horn" pieces are actually genuine horn, but sometimes early plastics. PM me your e-mail and I'll send it to you.

Stuart

 

[Fargone4sure]

Assuming that Bakelight is just a plastic, it can be plastic welded. I've done grips this way where you can't even see the cracked. You use a good powered soldering gun. You can Google for more info on it.

 

[trevj]

Assuming that Bakelight is just a plastic, it can be plastic welded. I've done grips this way where you can't even see the cracked. You use a good powered soldering gun. You can Google for more info on it.

You should look in to the differences between thermosetting plastics and thermoforming ones.

FWIW, my go-to for a fine split that is not broken, is cyanoacrylate (probably spelled wrong) thin grade glue, also known as CA glue or Super Glue. Super Glue from the grocery store rack will do if you can stomach the price, but pretty much any wood working or Hobby store will sell you anywhere from a 1/2 ounce bottle on up, for the same money as the couple drops you get from the Grocery store.

Good epoxy is OK too, you need to be able to clamp your parts down and let them sit while the stuff cures. Use the longest cure time epoxy you can get, and use a heat source, like a lamp, even a regular reading lamp will do, if it has an incandescent bulb. You want the temperature of the part to stay just a bit over body temperature, under being too hot to touch.

Cheers
Trev

 

[josquin]

You should look in to the differences between thermosetting plastics and thermoforming ones.

FWIW, my go-to for a fine split that is not broken, is cyanoacrylate (probably spelled wrong) thin grade glue, also known as CA glue or Super Glue. ...

I used thin CA glue (from KMS Tools here, I think) to repair a crack in the wrist of my Marlin 45-70 years ago. I removed any oils in the wood with lacquer thinner first. Isopropanol would be better on plastic if there is any hint of oil in the crack. CA glues do have a shelf life, though, so it's best not to buy any more than you need. I think you can store them in the fridge to increase the shelf life but it's still limited to about 18 mos. max.

 

[trevj]

I used thin CA glue (from KMS Tools here, I think) to repair a crack in the wrist of my Marlin 45-70 years ago. I removed any oils in the wood with lacquer thinner first. Isopropanol would be better on plastic if there is any hint of oil in the crack. CA glues do have a shelf life, though, so it's best not to buy any more than you need. I think you can store them in the fridge to increase the shelf life but it's still limited to about 18 mos. max.

The stuff kicks from humidity, and it doesn't take very much to set it on the road to being wasted.

Keeping it in the freezer puts it into a really dry environment, but it also causes the moisture to condense on the outside, where you really need it to come up to room temp before you even think about opening it,so it's kinda a draw whether it will save any life span for later, at least, from what I have been able to tell. I usually try to keep at least one bottle of thin and one bottle of gap filling formula around for various purposes, ranging from sticking stuff down, to closing up small cuts on my fingers when I am making parts.

Pretty much any solvent that will flash off and not leave a residue will work, some WILL eat the finish that is already there. Test before use, eh?

Cheers
Trev

 

[sahara]

Others will hopefully chip in, but I'd think epoxy would work. Is it possible to spread the crack at all? (Dangerous...). Epoxy can't really be chemically thinned but warming it a little (mix in a small plastic or metal cup and put in warm water) will thin it out and allow it to get into small crevices better. Mask off the area around the crack and apply with a toothpick.

I thin epoxy all the time. I'm a pro painter and get Benjamin Moore Epoxy thinner. It's toxic beyond what most home owners comprehend, though. I don't recommend heating epoxy to thin it, that generally speeds it setting up.

 

[josquin]

The stuff kicks from humidity, and it doesn't take very much to set it on the road to being wasted....

Yup. I'd forgotten about that side of it. Letting any adhesive come up to room temp is a good idea in any case.

 

[josquin]

I thin epoxy all the time. I'm a pro painter and get Benjamin Moore Epoxy thinner. It's toxic beyond what most home owners comprehend, though. I don't recommend heating epoxy to thin it, that generally speeds it setting up.

I'd be curious to know what's in that thinner.*** Years ago when I worked for a big graphic arts supply place in Vanc. we sold epoxy screen printing inks, which were mostly used on nylon jackets and sails etc. I can't remember if there was a thinner for them (MEK?) but isopropanol was used for cleanup. In any case, the thinner you get from BM probably isn't available to consumers anyway. We used to also sell One Shot Lettering Enamel, which was (and still is, I think) lead-based, which gave it excellent covering capacity and hence its name. I don't think it's available to consumers in Canada any more.

Yes, heating epoxy will speed up setting but if you're all prepared beforehand it can work as long as you don't heat it too much! (Don't ask me how I know this...)


***Corotech V704? 2-Butanone, Toluene & n-Butyl alcohol. Probably not good as aftershave.

 

[bearhunter]

JB weld will hold the two pieces together well enough to use. Its color can be died to match with cheap cloth die. It goes on thin and is almost un noticeable when cured. Good stuff and easy to use.

Acra glass resin or Gel can be forced into the crack if it isn't already broken as well. Just make sure to flush the crack or area to be joined with pure alcohol or some other cleaner.

 

[oneadam12]

Assuming that Bakelight is just a plastic, it can be plastic welded. I've done grips this way where you can't even see the cracked. You use a good powered soldering gun. You can Google for more info on it.

I would not try plastic welding for this application or material. The right epoxy is the way to go. If you have to finish the break to get the best coverage, do it.

 

[Porschemann]

Bakelite cannot be plastic welded as its claim to fame is that it is heat resistant. There is not way to melt this product back together. That said I have had very good luck using a Wurth product called Klebfest. It is an industrial super glue. I will flow into your crack from the backside and holds very well. The key is to degrease the cracked part. No bonding agent will work if there is grease or oils on the material (including from your hand).
This product is incredible. It will glue anything together, yes that includes fingers! I've used it on glass, metal, rubber, plastic and yes even Bakelite.

 

[josquin]

...I have had very good luck using a Wurth product called Klebfest. It is an industrial super glue. I will flow into your crack from the backside and holds very well. The key is to degrease the cracked part. No bonding agent will work if there is grease or oils on the material (including from your hand).
This product is incredible. It will glue anything together, yes that includes fingers! I've used it on glass, metal, rubber, plastic and yes even Bakelite.

"Klebfest" translates as "sticks strongly" or perhaps more idiomatically "High strength." Sounds like Wurth's brand of cyanoacrylate. My millwright buddy up the street is familiar with the Wurth brand. Loctite/Henkel also makes similar products; vastly more than what you see on the shelf of your local hardware store. So many industrial products out there that we consumers know nothing about

 

[trevj]

Bakelite cannot be plastic welded as its claim to fame is that it is heat resistant. There is not way to melt this product back together. That said I have had very good luck using a Wurth product called Klebfest. It is an industrial super glue. I will flow into your crack from the backside and holds very well. The key is to degrease the cracked part. No bonding agent will work if there is grease or oils on the material (including from your hand).
This product is incredible. It will glue anything together, yes that includes fingers! I've used it on glass, metal, rubber, plastic and yes even Bakelite.

Winner winner, chicken dinner! Someone understands thermosetting plastics!

I thin epoxy all the time. I'm a pro painter and get Benjamin Moore Epoxy thinner. It's toxic beyond what most home owners comprehend, though. I don't recommend heating epoxy to thin it, that generally speeds it setting up.

Which is why the recommendation for the longer setting time epoxy formulation, aside from that the strength is higher. The heat allows the epoxy to flow into finer cracks and areas it would not otherwise reach. It also will allow the epoxy to set up fully, in far less time than it otherwise would, so that you will be able to sand it or scrape it smooth without having to wait a day or two for it to no longer be gummy, depending on the epoxy used, of course, some are workable sooner than others.

Thinning epoxy is a calculated risk. If the layer is thin enough to allow the solvent to flash off before the epoxy cures, it won't affect the strength of the bond much. Otherwise, there is not much good to be said about it, from a strength standpoint. Early on in dealing with composite structure, we were taught that in no uncertain terms, thinning epoxy was to be avoided. This is because of the way epoxy chemically cures, rather than drying. Putting a solvent in the mix can interfere with the pair-bonding on the two components of the epoxy.

JB Weld is simply cheap epoxy with a metal powder filler in it. You can do better, using 45 minute or 1 hour epoxy, and adding a small qty of micro-ballons or other inert filler (sanded powder from whatever material you are fixing works well to color match, if you can) and going with that. It ain't the worst stuff out there, and if all you need is a little bit... Lee valley stocks dye powder that can be used to color match to the grips or wood you are using. Micro-balloons are little glass bubbles that can be bought at most hobby shops that deal with model airplanes, or from places that deal in fiberglass supplies. They weigh almost nothing, and can be mixed in with epoxy or resin to make a lighter weight fillet or make a badly fitted joint much stronger. You DO want to wear a dust mask or better, a respirator, when sanding, though, as it is glass. Should anyway.

Cheers
Trev

 

[josquin]

...Which is why the recommendation for the longer setting time epoxy formulation, aside from that the strength is higher...

Any recommendstions for long- cure epoxies? The stuff I've been getting form KMS Tools is "30 Min. Slow-Cure" from Bob Smith Industries in Calif. Dries to the touch pretty well in 30mins. or so but they recommend overnight. I've always got good results with it but it's always good to know if there's a better product.

As to thinning epoxies, your comment reminded me of something one of our screen-printing salesmen at Behnsen Graphic Supplies said about thinning- that too much will "break the back of the ink."

 

[BCRider]

When bakelite cracks or snaps in two the joint tends to be very fine. It's much like a broken glass or china plate. So the glue used should be the sort that won't pry a joint apart. And leaves out epoxies with fillers such as JBWeld.

I've fixed bakelite parts with both thin CA (I have it around all the time as I also build and fly model airplanes) and the clear styles of epoxy. Both work very well and need only a very slight dab of the stuff along the edge or applied to the crack.

Sahara is right about heating to thin the epoxy also speeding up the cure. But if the heat is applied to thin it and the epoxy worked into the crack with careful flexing quickly enough then the reduced working time is a fair tradeoff. I use this trick a lot to get the epoxy to flow into cracks where if I tried to thin the mix it would never cure due to trapping the solvent inside with the glue where it can't evaporate.

Here in BC we also have a place in Burnaby called Fiber-tek that markets a line of epoxies and polyester resins. They have a few different "2 hour" slow cure epoxies that work well.

But really that 30 minute stuff that KMS sells is just fine. It's got a long enough working time that it'll let you heat it up with a hair dryer without curing before your eyes and it's plenty strong enough for this sort of repair.

KMS also handles a line of CA glue and last time I looked the thin stuff was there. Take note that if you go with the thin CA that "less is more" and "too much makes a big mess". You want the crack to be neatly closed and held that way and then you apply a small drop to the crack and then use a small wire such as a straightened out paper clip to tease the excess of the drop along the crack. You need to work quick with this. Might even want to apply the SINGLE drop with one hand and then instantly wipe it along the crack with the other hand holding the paper clip. Needless to say this is being done on the inside face of the grip since it will leave a track of glue behind.

The thin CA soaks into just about any opening. I've literally glued myself to balsa while holding the wood up to as far as a full centimeter from a joint when the thin CA wicked along the end grain and came out on the surface where my skin was sitting. So hold the crack fully together and apply while it's held that way.

 

[VictoryXC]

check out ZAP CA. It is available in three different viscosity.

 

[BigUglyMan]

Any recommendstions for long- cure epoxies? The stuff I've been getting form KMS Tools is "30 Min. Slow-Cure" from Bob Smith Industries in Calif. Dries to the touch pretty well in 30mins. or so but they recommend overnight. I've always got good results with it but it's always good to know if there's a better product.

As to thinning epoxies, your comment reminded me of something one of our screen-printing salesmen at Behnsen Graphic Supplies said about thinning- that too much will "break the back of the ink."

West System and G2 are popular with knifemakers who are often trying to bond dissimilar materials. I use G2 but may try west System because I have a dealer connection. G2 is available from lee Valley and West System may be as well. Failing that a place like Mermaid Marine or Stright-McKay (or likely a gighillion places between Mission and Van City).

 

[josquin]

West System and G2 are popular with knifemakers who are often trying to bond dissimilar materials. I use G2 but may try west System because I have a dealer connection. G2 is available from lee Valley and West System may be as well. Failing that a place like Mermaid Marine or Stright-McKay (or likely a gighillion places between Mission and Van City).

Thanks, BUM. I'd forgotten about those.

 

[J_K_S]

I have been using Lock Tite Super Bonder for all my plastic bonding. It's great stuff and sets in under a cpl of minutes if steady pressure is applied. The only downside is its around $30.00 a 1 oz bottle. Best of luck