Hi, following some previous posts, I would ask your current advices about gluing a front ramp. The barrel is too thin to thread and soldering would be a secondary option. I'm planning to use Loctite 638, because it let a couple of minutes to carefully position the ramp, unlike other faster glues. Thanks.

Personally I'd braze it but to each there own.
And what do you mean it's to thin to thread. What caliber and outside diameter??

I'm aware that brazing would be a safer option, but...; outside diam. is 0.642 inches and cal. is 375 H&H. Unfortunately, the front ramp has been brazed slightly crooked (at the factory) and I'm trying to repair it.

That's more than enough barrel to drill & tap.

That said, if you chose not to Drill & tap, I'd soft solder it on using silver bearing solder rather than brazing.

The 638 won't be hard for 48 hours

don't braze, solder..

quote:

Originally posted by jeffeosso:
The 638 won't be hard for 48 hours..

Jeffe, I'm not sure; are you saying that the 638 will take 48 hours to completely bond?

If you can fit a band type sight, then Loc-Tite 680 would be perfect. It is removable with less heat than solder requires and without damaging the bluing. On the other hand, epoxies can be very strong on a curved surface but if the surface is not large enough or the curve insufficient, can be broken with a sharp 'crack'. It's hard to imagine how such a sharp crack would be delivered to a front sight! (I have a glued on scope mount that has lasted many, many years and is still good).

pull down the spec sheet on the glue.. it is like 50% in an hour, and 100% in 48 hours,,,,

there's even a lockite that doesn't get fully had unless it sees an HOUR at 300f -- bluing salts harden it!

I use Loctite 380. You will have to use a big hammer to knock mine off.
Butch

Butch, how many seconds one has to position the ramp, before the 380 starts to bond?

quote:

Originally posted by butchlambert:
I use Loctite 380. You will have to use a big hammer to knock mine off.
Butch

Butch, Are you talking about a ramp or a banded sight?

Not very long. I set mine up in the mill first and did a trial fit. I made a couple reference marks on both the sight and barrel. I glued it up and tapped it on.
Butch

Yes,
I was talking banded ramp. I did use the 380 to bond a small piece of steel to a mandrell and made some light cuts on it in the lathe. Didn't have guts enough to take more than .010 on an interrupted cut.
Butch

I guess I used the wrong term But Brazing in my book is anything that melts around 900 degrees.
Yes silver bearing solder would be a good choice.
But I still call high temp silver solder "Silver braze"

quote:

Originally posted by kcstott:
I guess I used the wrong term But Brazing in my book is anything that melts around 900 degrees.
Yes silver bearing solder would be a good choice.
But I still call high temp silver solder "Silver braze"

to me, brazing denotes brass or bronze as the adhesive; soldering, silver/lead/tin.

Wildboar,
I think that if I were doing it, I would use a screw and the Blackmax380. Plenty of barrel as you only need about 2-3 threads. A 6-40 or 8-40 would work great.
Butch

quote:

to me, brazing denotes brass or bronze as the adhesive; soldering, silver/lead/tin.

I know but I was taught to either silver solder something meaning low temp or to silver braze something meaning high temp. It's all semantics

That's the slightly crooked ramp that I should unsolder; It would be a test so, if the glue will not resist in the long term, that's not a problem. I would try to do the job myself, for fun. Do you believe that a propane torch would be enough to unsolder it? How should I act to avoid any damage using the torch? Thanks.

I read somewhere long ago about putting a wood dowel in the bore. That is supposed to burn the wood instead of oxidizing the bore while heating the barrel. The idea was the vapor from the charring wood would displace oxygen in the bore. Anybody out there got more on this?

Sounds like a good idea Mike.
Butch

Flood the bore with argon or some other inert gas to eliminate the problem of scaling.

Tape one eye of gnewt to your forehead and run clockwise around the project 3 times. Or is it counter clockwise. or, "anti-clockwise" as the Chinese say. I forget which. Never mind!

Brownell's heat control paste works pretty good. I have wrapped small parts in brown paper and foil during heat treating to reduce scaling. Similar principle as Mike suggests.

quote:

Originally posted by Westpac:
Tape one eye of gnewt to your forehead and run clockwise around the project 3 times. Or is it counter clockwise. or, "anti-clockwise" as the Chinese say. I forget which. Never mind!

X-2

quote:

I guess I used the wrong term But Brazing in my book is anything that melts around 900 degrees.

You used the correct term - it's the rest of us that use the wrong term. Brazing is joining two close fitting metal components by holding them together and heating them util a joiner metal/alloy melts and flows between them by capillary action, thus forming a bond. We say brazing when we mean 'bronze welding'!

wildboar, that ramp sight would hold real solid with a good epoxy glue.

There is a point not mentioned so far and that is the distorting effect heat has on steel. By the time scaling temp has been reached, crystaline changes will have taken place in the steel, sometimes hardening it, often softening it, most likely distorting it. Stress relieving can also take place but likely as not it can be induced. Soft solder is cool enough not to damage the structure of steel. Silver solder is pushing your luck - getting real close to localized over-heat. Just something to be careful of.

Wildboar ; Click the link if you don't like this product rest your cursor on the

column too the left side of web page click adhesives or solder or what ever product

you wish to view . It's a multi conglomerate of epoxies adhesives sealants ALL Types of useful

products some of the finest commercially available .


http://www.ellsworth.com/displ...tid=936&Tab=Products

quote:

Originally posted by 303Guy:

quote:

I guess I used the wrong term But Brazing in my book is anything that melts around 900 degrees.

You used the correct term - it's the rest of us that use the wrong term. Brazing is joining two close fitting metal components by holding them together and heating them util a joiner metal/alloy melts and flows between them by capillary action, thus forming a bond. We say brazing when we mean 'bronze welding'!

Well there you go then.

Wildboar
Proper heat control and you won't need anything in the barrel or any heat stop paste at all. but if you feel that you don't have the experience to get away without heat protection then i'd say use some heat paste and pack some in the bore too.
I've performed quite a bit of silver brazing in my time. On some very delicate stuff. a rifle barrel is not hard to do. One thing we did was find out what the flux would look like at the melting temp of the solder. The flux we used is the same stuff Brownell's sells for there high temp silver solder the 56% stuff. When used it would look like a paste then as heated it would boil off the water that was mixed with it and turn to a clear solid with a little more heat added it would then go liquid again and at that point the part was at the correct temp to apply the solder. It would flow exactly where the flux was so proper control of where you put the flux is critical. The old say "a little dab will do ya" has never been more correct.

And personally I'd stay away from a propane torch. The flame is too large and heat is too low. If you're careful it will work but you are exposing the barrel to heat longer.
I use a oxy/acetylene torch with a 00 tip and just tickle the part with the flame.
Get a couple of pieces of scrap and practice it will help on the barrel.

quote:

Originally posted by kcstott:
Proper heat control and you won't need anything in the barrel or any heat stop paste at all.

Just to keep things clear for the folks, a person "may" get away without the need of bore protection when using the low temp stuff. Provided they have the experience and skill to pull it off. But I would recommend the "in the bore" use anyway for those rare instances when one accidentally exceeds the working temperature of the solder. It's cheap insurance.