welding on a scope rail

[zackyholdem]

i purchased a steel scope rail for my tracker II 12 gauge and would like to permanently weld it on. are there any problems that can arise from welding on a scope rail. Can any damage occur to the chamber? I am going to have it professionally welded by my neighbor w/ 40ys experience. also what kind of steel are the shotgun barrels made of? and has anyone welded on a scope rail before?

thanks for all the help?

[Goatwhiskers]

 Don't do it.  If it's too thin to drill & tap it's too thin to weld,  too much chance of warping the barrel or weakening it.  Besides, no one likes a bubba'ed gun.  Goatwhiskers the Elder

[thejanitor]

I am no gun smith, in fact I am not any kind of a smith.... But the chamber is the part than handles the highest pressure, Welding will change the characteristics  charectoristics Properties of the metal thus changing the strongest part of the barrel to an unknown. Could work forever, might blow up on the 23rd shot. Once you change it you don't know. And no one in their right mind would buy it from you. This is just my opinion, but I wouldn't do it.
And your neighbor may be an excellent welder, my negative idea of how this may turn out has nothing to do with his welding ability, I just worry that you would have a very strong weld, but a very weak barrel. And a long or short game of Russian roulette.
Good LUCK,  thejanitor

[Dinny]

Why not J-B Weld it instead?

Thanks, DInny

[max1138]

dont do it,

the barrel  is a specific type of steel specifically heat treated for purpose.
any welding WILL, not maybe or might weaken it. it WILL weaken the barrel.
 if heated and cooled from welding temps the crystalline structure of the steel will reform into larger weaker crystals that will crack.
microscopically at first then growing larger  then propagating into adjacent areas till the steel is cracked all the way thru and your weapon fails.

may not fail on the first shot  or the hundredth but sooner or later it will fail.

[quickdtoo]

Shotgun barrels are 1137 mild steel, I wouldn't weld the rail on, soldering is too easy, you can get good low heat(<500º) 6% silver ribbon solder on Ebay for less than $18 shipped.

Tim

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330378666406

http://www.brownells.com/userdocs/learn/Inst-345.pdf

[trotterlg]

Not to confuse the issure, but remember that H&R welds the underlug on these barrels, and I have never heard of a shotgun problem with the welded on lugs.  My personal choice would be to silver the mount on, H&R used to silver the under lug on and that worked for years.  I have also had H&R's that had scope base screw holes drilled through into the chamber area and still functioned fine, but I would say this is probably not a proper thing to do.  I would drill and tap it first, silver it on second and weld it on third, but then I am just an old guy who is not a gunsmith.  Larry

[Spanky]

If you are dead set on welding have it TIG welded. MAKE SURE your welder knows what the hell he is doing. Run a very fine bead at the front and rear of the mount... do not run a long bead down the full length of the mount... it'll build up too much heat and you don't need that much weld to hold it. Make sure he uses heat sink on the surrounding metal too.

Now with that being said... I WOULDN'T WELD IT ON. I would do as some of the guys said and silver it on. Silver solder is easy and it won't ever come off.

As far as drilling and tapping it... I have a 12 gauge that is drilled through into the chamber and the screws were ground perfectly flush with the inside of the chamber. The chamber was polished after that and you can't tell where the screws are now. I've shot everything from low brass loads to 3" slugs out of it and haven't had any problems. In fact is shoots pretty darn good for a smoothbore shorty.

You have a few options to choose from.
I would go by the following with 1 being my first choice and 3 being the last.

1. silver solder
2. drill and tap
3. (a distant 3rd at that) welding



Spanky

[Slenk]

Just because someone is a welder doesn't mean they are a gunsmith.
I have been a welder most of my adult life (70yrs.)
I also do some smithing on my own guns.
 
 1. silver solder
2. drill and tap
3. (a distant 3rd at that) welding
I vote no on welding.

[gcrank1]

If you calculate the breech pressure in the chamber that will act upon the tip of a #6 or 8x48 screw holding the mount on you might have more understanding of your options. Remember, this is radial pressure, not breech thrust.

[woodchukhntr]

Soldering is the best way to go, but if you do decide to weld, I think that plug welding is a good option.  Have the welder drill out the screw holes to the diameter that he thinks is appropriate and have him plug weld the base to the barrel.  It will look better than welding along the ends or sides of the mount, when the scope is on you won't be able to tell.  It sould be a good idea to cool the barrel between welds.  Trotterlg is right about the welded-on lug, it is on all of their rifle and shotgun barrels.

I have glued scope bases on .45-70 Handi's with JB Weld with great success.  I have put the mounts in the "scout" position after removing the rear sight.  Since there is one thrreaded hole in the barrel for the sight, I did use it to align the base.

[gcrank1]

I know several have done the 'glue-on' with success, even on some heavy kickers, but for me the sound of a scope bouncing off the gun and ground is a sound I dont want to hear.

[mannyrock]

   For goodness sakes, if you are not happy with your gun, then go buy another one.  Don't ruin your current one on a lark, or worse, create a disaster for you or someone else down the road.  Is this worth losing an eye over???

Mannyrock

[Spanky]

If you calculate the breech pressure in the chamber that will act upon the tip of a #6 or 8x48 screw holding the mount on you might have more understanding of your options. Remember, this is radial pressure, not breech thrust.

How much pressure is there?
Whatever the number is it hasn't caused any problems on my 12 gauge.



Spanky

[gcrank1]

I expect we have someone on the forum who is more the mathmatician than I, and/or knows their way around the I-net well enough to find the type of tech site to be able to verify and quote.
For my part, I have, somewhere in the distant past, read a short article on just such an application, but cant recall where just now. I wish I could........It satisfied me that properly done min. 70ish% threads that were flush to the innerwall of the chamber (so brass has no chance of expanding into a void) for at least moderate rifle cartridge pressures is not a problem. The author did some sample calc. to show the radial pressure upon that small a screw tip square area to be quite small. As I recall, the radial pressure is much less than the breech thrust to start with.
FWIW, I would do it like you did Spanky and not be worried.

[S.E.Ak]

Max pressure in a shotgun happens between nine and thirteen inches down the bore. I would not weld but don't see a problem drilling and tapping to take four or five threads plus silver solder or loctite. Solder holds on ribs and barrels together on SxS's

[zackyholdem]

thanks for all the info guys, after reading all of the responses I will NOT be welding on a scope base, the chamber is too thin to drill and tap and i did not think that using silver solder would hold but after reading your responses i will give silver solder a try. how should i go about attaching the rail to the barrel, should i solder the two sides or the front or rear, or alll sides??

thanks for not letting me blow my face off, Zack

[quickdtoo]

I would make a full contact joint, clean and tin both surfaces per the Brownell's instructions, mate them up with a heavy spring clamp to hold the rail in place, heat with a propane torch and when gets hot enough to seat in place, remove the heat. One way to make sure the rail goes on where you want it precisely on top of the barrel, drill and tap one hole just deep enough to engage a few threads, then use a screw to align the rail where you want it, the contour of the rail will self align to the barrel once the solder flows. I've only worked with silver soldering shims and the spring clamp works well, but maybe someone with more actual smithing experience like gcrank1 can help with more details.  

Tim

[moorepower]

If you lap the mount to the barrel for 100% fit before you start, just drill and tap a couple of screws and use the GREEN Loctite and it will never move. The green loctite will make it a solid piece unless you heat it up. Silver soldier is great stuff, but the green loctite is another solution. Just make sure you lap to fit before you start .

[trotterlg]

Well, a good 6-48 screw has a stress area of less than .014 sq inches and a tensil strength of about 800 pounds.  If you do the math, at 12,000psi for a shotgun, the pressure on the screw is less than 170 pounds, so you will have a safety margin of over 4 to one.  Someone else can do the math to check up on me.  Plus, a screw in comprssion should be even stronger than it is in tension.  Larry

[gcrank1]

Thanx, that seems similar to what Ive been trying to get at. I find the comment that it is too thin to D/T curious.
The depth of threads required is only that of the diameter of the screw. At that, surely the chamber wall thickness is more than enough?

[Rustyinfla]

  I also read not long ago about BLACK Loctite. It isn't listed as a thread locker but is considered a permanent adhesive.

[S.E.Ak]

The chamber on my barrel is plenty and every plain barrel shotgun I have ever seen with just a bead is threaded completely through the barrel wall