JB Weld

[AZRedhawk44]

JB Weld typically takes about 24 hours to reach maximum curing hardness, right?

Can heat accelerate that?  If so, how much heat?

[zahc]

It seems to me that most epoxies give off heat when they cure. According to thermodynamic reasoning, any epoxy that gives off heat while curing should cure faster at cooler temperatures. I'm not entirely sure this applies here though.

Consider JB Kwik. It's a lot like JB weld and sets up in about 15 minutes. Alas, according to TANSSAAFL reasoning, it's not quite as strong either.

[Nick1911]

Yea, heat helps jb weld.  Don't apply heat until after an hour of setup time, or it could become thin enough to run.

[AZRedhawk44]

According to wikipedia, JB Weld cures more quickly when exposed to heat.

http://en.wikipedia.org/wiki/JB_Weld

J-B WELD works faster when used in an area with a temperature above 50 °F (10 °C).[4] After J-B WELD has cured for the first six hours, a heat lamp or lightbulb placed near the weld will speed the drying time.[2][4] An application might sag or drip before 4-6 hours, at which time it has hardened.

The whole article appears to be nothing but references to JB Weld instructions, so I think I trust it.

My new Colt 1991 is abusive to brass and bullet jackets in the same way as my lemon Sig GSR.  Argh.

I put some JB Weld on the top ledge of the magazine catch... about 0.020" worth of thickness.  The problem with the last one (and this one exhibits the same problem) was that the magazine dropped too low when free-hanging in the mag well.  My Colt LW Commander is flawless in magazine orientation and is baby-gentle on brass, and feeds any hollowpoints you choose to put into it with complete reliability.

I'm going shooting tomorrow AM and want the thing cured to maximum hardness.  I just put it in the oven since I was warming up some pizza from last night, so it got 15 minutes at 350*, and it's still in there as the oven cools.  Probably gonna get a good 2 hours of 150 degree or higher heat.  I applied the JB Weld to it around 12:30 or 1pm today, so it had about 5 hours to set up before I put it in the oven.

In the meantime, I do have a spare mag catch that is unmodified.  If I ruin this one, no big loss.

In the event the JB Weld temporarily fixes the problem, I'm gonna order one of these:

http://egw-guns.com/store/index.php?main_page=product_info&cPath=34_48&products_id=239

It's a mag catch designed to increase the magazine height in relationship to the frame by 0.020".  By my half-assed measurements this Colt doesn't sag as bad as the Sig (the sig was off by 0.050, and the Colt is only off by about 0.035), but it's still enough to put some nasty cuts in the bullet jacket or scratches in the brass case.

We'll see how it holds up to 100 rounds tomorrow.  I'll take a micrometer measurement of the seated thickness before firing and after to see if it compresses much from the abuse.

[zahc]

I'll be surprised if it doesn't just separate from the mag catch. JB weld is tough but its adhesive properties are usually what get you in my experience, unless you can form it to encapsulate some 3-d features and 'lock in'.

[Gewehr98]

I don't think that JB weld "fix" will hold up.

I've used it before, and even machined the stuff, but when I've subjected it to that kind of shear stress, it gave out quickly.

[Nick1911]

I don't think that JB weld "fix" will hold up.

I've used it before, and even machined the stuff, but when I've subjected it to that kind of shear stress, it gave out quickly.

Ditto.  Although, it did hold up reasonably well when threaded and used with threaded fasteners.  Much better then I expected, to be honest.

[AZRedhawk44]

OK... that was my suspicion... that it wouldn't hold up long term.

But it should last long enough to tell me if an additional 0.020" in catch height will cure my feed woes with this gun.

As long as I don't have to shove out $30 + shipping to find out, I'm happy.