How to fix hairline crack - pics up

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scianna54

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I am trying to fix 2 hairline cracks on my wooden stock. I read about epoxy etc. but the cracks are very fine at the end of my stock.

I heard about Loctite 420 but it is not available in Canada I believe. Any ideas?
 
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Depends how nice the stock is.

For a run of the mill wooden stock, carefully opening up the crack, working a very liquid glue into it, then lightly clamping it (if you clamp too tight you risk forcing all the glue out).

If the cracks grow, pinning is another solution, depending on how you want it to look afterwards.

Pins usually bridge the gap between the crack by drilling across it, putting glue into the crack and drilled hole, then pushing a piece of wooden pin or threading a brass screw through an undersized hole to create a mechanical bond.

IE: http://www.ehow.com/how_4690624_repair-cracked-broken-shotgun-stock.html

http://www.ehow.com/how_5024531_repair-cracked-rifle-stock.html
 
i have a browning blr ( lever action ) , where the butt stock meets the reciever it has fine cracks running back towards the butpad . ( a horse rolled over when the rifle was in a scabbard) .
i was going to open up the inside of the stock where the cracks where with a die grinder ( careful work with a dremel tool , or a drill / drill bit would work too ) .
i don't want to disturb the outside finish at all .

once i had opened up the insides of the cracks enough , i was going to use a product called " panel bonding adhesive " by 3m to glue the whole mess solid again , then when that has set up solid and cleaned up , bed the butstock to the reciever using the same product again .
 
scianna54 said:
I am trying to fix 2 hairline cracks on my wooden stock. I read about epoxy etc. but the cracks are very fine at the end of my stock.

I heard about Loctite 420 but it is not available in Canada I believe. Any ideas?
Click to expand...

"LOCTITE® 420 is a general purpose cyanoacrylate instant
adhesive."

From http://www.loctitehf.com/assets/tds/420-EN.pdf

Get some Zap or Hot Stuff CA glue from a Hobby Shop that deals in model airplanes or trains, etc..

If you can get some real epoxy glue, as in, not the crap from the grocery store beside the till, you can use that. I've used a fair bit of West System Epoxy for stuff like airplane ribs and boat parts and it is thin, sets clear, and takes a bit of time to set (Good! Allows it to wick into cracks!) and best of all, it sands well, when cured.
Know anyone that has built a strip canoe, or works on wooden boats? If you go out on the scrounge to a boat shop, bring some small clean containers. Pick up some hypodermic syringes for measuring the correct qty's of the two parts.
Thinning epoxy makes it weaker, and is generally a bad idea. Sometimes it works, sometimes you get a sticky mess where your glue was supposed to harden.

There are several other good epoxies out there. The hobby shop stuff that sets in an hour or more is worth checking out, if you can get small size qty's.


A heat source like a blow dryer or heat lamp, even a 100 watt bulb in a light fixture, can be used to preheat the area, which will allow the epoxy to flow better, as well as speed the cure. Mainly the 'flow better', is what we want.

Cheers
Trev
 
Without seeing it, it's hard to say for sure. But I would try to carefully open up the crack just a little (without making the crack run further) by sliding a knife blade or some other thin metal into the crack. Then force wood glue into the crack using a chisel or a knife blade. Once the glue is well into the crack, let the wood come back together. Then clamp with a couple of suitable clamps. Protect the wood from damage by the clamps by using a couple of soft wooden blocks or cardboard. Wipe off the excess glue while the glue is still wet.

Bond Fast is a cheap and effective wood glue, although it will work better with some types of wood than others. Weld Bond is more highly rated and may be better. I probably wouldn't use epoxy or a "super glue" for wood.
 
It is from a Ruger Mini 14, factory wooden stock, here are the pics, thanks for the input so far:


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i would use Hot Stuff and a syringe (not the thin insulin type - a little larger one) from the drugstore - done in 5 minutes flat. The needle gets in there - a little squit and it will bleed all through the crack. Easy - no mixing

get some Hot Stuff cleaner from Lee Valley at the same time as you will likely need it to clean up some of the bleed over.
 
Save some coin and buy acetone nail polish remover. Or borrow some from girlfriend/sister/mom/the hot cougar next door/whoever. Same end result as the bottle of remover from the hobby store.

I'd use the thin Hot Stuff or Zap CA glue on that, and not think too hard about it. It will wick all the way through the cracked area, and if it's not oil soaked, it will fill and bond the area fine. If you are concerned about the gaps, grab a half Oz. bottle each of the thin (for wicking in deep, and securing the areas that are close together) and the thicker, gap filling CA glues (for filling in the gap, naturally) after the thin glue has been wicked in.
Unless your hobby store is really out of line, a half Oz. bottle should run about $5 or less.

Handy stuff to have around!

Cheers
Trev


How worried about looks, as opposed to making it solid? If you want it to vanish when repaired, it's gonna take more work than just wicking glue into it
 
I have to check out where to find that stuff you guys recommended. Not too concerned about looks right now as the side folder covers up most anyway and I wanted to refinish the stock anyway.
 
From the size of the cracks in the photo, I would pry the cracks open and not worry if you crack any more. You can then then use some epoxy and get it deep into the crack. Once you bind it back together (clamps, tight rope, etc) you will have a good bond.
I don't see any point in trying to finesse some glue into cracks that size.
 
Regardless of which glue you finally go with you will want to flush the cracks out with a few good shots of brake cleaner first. There's very likely at least SOME gun oil in the cracks from the look of the way they have a blackish color in the cracks. You need to get that oil out of the wood before any of the glues will properly stick the wood back together. Wear glasses as the brake cleaner will be shooting all over the place and you do NOT want any of it in your eyes. In fact using lacquer thinner in a pot to swich the end with the cracks in to soak out the oil would not be a bad option either. But in some manner you will want to get the cracks cleaned of any signs of gun lubricating oil first.

A hearty PLUS ONE on the use of epoxy thinned with a heat source. Heating the epoxy makes it runny like water and it'll soak into those cracks really well. Acriglas, being a resin that won't shrink, would also be a good option. Just depends on what you have.

CA would also work well IF the cracks are moving easily to close them tight. But if the cracks occured due to shrinking stresses then you're better off to use an epoxy, Acriglas or other resin that won't shrink.

Devcon 30 minute or 2 hour cure epoxies are fine for something like this. Just avoid any of the 5 minute quick options since they do not give you enough working time before hardening up.

If the cracks flex closed easily then another option is the thin CA glue (Crazy glue is only one brand of CA glue) Get the thin formula from any number of hobby stores dealing with model airplanes or trains.

DO NOT wedge it open with anything other than perhaps some finger pressure to aid in "pumping" the heat thinned epoxy into the cracks. If you stick anything at all in there it will bruise the wood and then it won't fit cleanly back together. Also heat thinned epoxy is about as runny as water. You'll need to dam up parts of the cracks and flow the epoxy in from the areas left. Flexing the crack with hand pressure will aid in pumping out the trapped air and get the epoxy further into the cracks. Because you'll need to dam up the low sides you'll likely want to do only one crack at a time, let cure and then do another. If you use epoxy and end up clamping the cracks closed do NOT use a lot of pressure. Unlike wood working glues epoxy needs at least a small joint thickness to keep it's strength. So only light pressure with any of the resins if you use any pressure at all. CA and carpenter's wood glues don't have this issue.
 
The wood is walnut and there is no way to move the cracks apart or getting into them without force. It looks as if they are stress cracks being in the mount area of the Mini 14 factory folder. The whole area is very small (the pics are blown up)
 
RR said:
Instead of brake cleaner I use a hot stuff accelerant , this helps bond oily surfaces together.spray it on first and then use the glue.
Click to expand...

The accelerant will cause the CA glue to go off and polymerize but oil in the wood will compromise the joint strength between the wood and the glue "wedge" that forms when it hardens. Also from having used the accelerant on many occasions if you use it as you suggest then the glue will harden before it soaks very far into cracks such as scianna showed. Far better to degrease, fully dry until you can't smell the solvent anymore and then introduce the glue to the crack first, let soak in for a few seconds and then spritz on a light coat of the accelerant if it's not hardening.

Degreasing (actually deoiling in this case but it's a generic term) is definetly a first step before any adhesive is introduced.
 
I my experience using it a lot with my model airplanes and other woodworking it won't matter. The dry accelerant treatment will still cause the liquid to kick off before the joint and the surrounding wood has a chance to let the glue soak into the grain. If it's working for you then great. But my experiences over the years of using CA's and accelerants suggests that it's best for this sort of crack to flow the glue in let sit for a few seconds to ensure good filling and absorbtion into the wood grain as much as possible and then, if needed, apply the accellerant to the outside to kick off the cure if it doesn't go on it's own.

Anyhow, degreasing the cracks with a solvent and letting it dry fully isn't a big job. And if it cleans out and opens up the wood grain to better accept the glue so it keys to the wood better than oil clogged and accelerant coated grain then the joint strength is just obviously going to be all that much the better.
 
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