Type of Locktite for barrel liner?

[precision tools]

The method described by James Keefer is used for the best jobs. A close fitting liner in a reamed barrel using one of the Loc Tite products will produce an excellent fit. There are a couple of Loc Tite products that will handle larger clearances, but most require a rather close fit. Look through their site for the required clearances.

Probably the second best method is using an epoxy to retain the liner. Epoxy will allow lining a barrel with larger clearances. Accraglass is a good product, but the kits are expensive, and for barrel liners most epoxies will work equally as well as the Accraglass resin. I use JB Weld, it is good to 600*F and will withstand hot bluing. There are coloring agents that can be added to epoxies, black is readily available and a few drops in the mix will make it invisible.

In the days before Loc Tite and epoxies, liners were soft soldered in place. It requires care in cleaning and tinning of the liner and barrel and maintaning both pieces at soldering temperatures while installing the liner. I have done this on a pistol barrel and certainly would not recommend it since much simpler and better methods are now available.

I have never heard of either silver soldering or heat shrinking barrel liners in. Silver solder would require heating both parts to red heat and maintaining that temperature while installing the liner. This is a sure way to induce stresses in the finished product if you managed to accomplish it.

Similarly, expecting to gain enough expansion with the small diameters involved places shrinking a barrel liner in place is well outside of the normal shop abilities. It might be employed with artillery pieces, but I see no way it would work with a rifle or pistol barrel. I have never seen it recommended in any gunsmithing book I have ever read.

 

[jockofthelowveld]

Hello Joe;
Saw your question and decided to respond....It's a subject of great interest to me... I specialize in precision .22 target pistols. I prepare my liner first.. between centers to approx. .325 O.D. I strive for zero run out and taper. It's difficult to get that with a tool bit, but I can get very close...I then use a tool post grinder to get it perfect...When perfect, the diameter is what it is, and it is much easier then, to drill and reamer the barrel to to the clearance I need to match that liner.. I use 680 or 620 loctite.. Either one works very well. The 620 will withstand over 300 degrees, so bluing will not effect it. I talked with the Loctite engineers, and even though 680 is rated slightly lower at 290 degrees, they felt bluing temps would not harm it. I have blued numerous barrels with 680 secured liners with no ill results. As far as shrink fitting being the best, with out being disrepectful to the poster, that would be impossible. The stresses imparted to the liner would be very detrimental to accuracy. The Loctite method is completely stress free, and properly lined barrels out perfom orginals by a large margin..
Good luck, and hope this assists you..

Jerry

Jerry;

Would you mind describing how you set your follow rest and what type/shape turning tool you are using on your lathe for the primary cutting of the liner--before you use the follow rest. Any other info on how to accurate cut such a thin tube will be helpful to me and others.

Best Regards;
Steve, aka Jock

 

[homemade]

The Loctite method is completely stress free, and properly lined barrels out perfom orginals by a large margin..

Not challenging the assertion, why do you think this is so?

 

[SmithSolar]

In some cases a shink fit barrel liner is not the best try aluminum barrels with steel liner
I have read where a MFG try aluminum barrels did not work out as aluminum will expand greater than steel.
FYI
On the other hand a cast iron gear box use a steel liner for ball bearings work the best. Using epoxy or JB for gear box this will fail.

As far as gunsmithing loctite, epoxy or JB is a good chose for its location.

Dave

The method described by James Keefer is used for the best jobs. A close fitting liner in a reamed barrel using one of the Loc Tite products will produce an excellent fit. There are a couple of Loc Tite products that will handle larger clearances, but most require a rather close fit. Look through their site for the required clearances.

Probably the second best method is using an epoxy to retain the liner. Epoxy will allow lining a barrel with larger clearances. Accraglass is a good product, but the kits are expensive, and for barrel liners most epoxies will work equally as well as the Accraglass resin. I use JB Weld, it is good to 600*F and will withstand hot bluing. There are coloring agents that can be added to epoxies, black is readily available and a few drops in the mix will make it invisible.

In the days before Loc Tite and epoxies, liners were soft soldered in place. It requires care in cleaning and tinning of the liner and barrel and maintaning both pieces at soldering temperatures while installing the liner. I have done this on a pistol barrel and certainly would not recommend it since much simpler and better methods are now available.

I have never heard of either silver soldering or heat shrinking barrel liners in. Silver solder would require heating both parts to red heat and maintaining that temperature while installing the liner. This is a sure way to induce stresses in the finished product if you managed to accomplish it.

Similarly, expecting to gain enough expansion with the small diameters involved places shrinking a barrel liner in place is well outside of the normal shop abilities. It might be employed with artillery pieces, but I see no way it would work with a rifle or pistol barrel. I have never seen it recommended in any gunsmithing book I have ever read.

 

[gunsmither]

Thanks!

Thanks to everyone for all the interesting information. I've ordered some #620 Loctite from McMaster. It has a 30 minute working range, and is good to 450F, so that gives plenty of time to work it in, and hot bluing should be no problem.

One fellow on another board, who does a lot of re-lining, says he has used medium strength #262 for years with no problems.

I have only done a few liners in years past, and used Acraglass. Works great, but it's pretty sticky/ messy. Loctite should be easier to use, with less mess.

Thanks again to all! Safe and happy shooting! Joe

 

[jabezkin]

Thanks to everyone for all the interesting information. I've ordered some #620 Loctite from McMaster. It has a 30 minute working range, and is good to 450F, so that gives plenty of time to work it in, and hot bluing should be no problem.

One fellow on another board, who does a lot of re-lining, says he has used medium strength #262 for years with no problems.

I have only done a few liners in years past, and used Acraglass. Works great, but it's pretty sticky/ messy. Loctite should be easier to use, with less mess.

Thanks again to all! Safe and happy shooting! Joe

You might have a rude awakening if you use 262 as a "medium strength" in another job. It is 242 for medium.................don't ask..........:-)

 

[James Keefer]

Not challenging the assertion, why do you think this is so?

Homemade:
The liner is a slip fit into the barrel.
It is under zero tension in any direction, a desirable condition which contributes greatly to accuracy.
A factory, mass produced, production barrel cannot be expected to produce record performance.
I use only the very best match grade barrels/liners available..

Jerry

 

[homemade]

The liner is a slip fit into the barrel.

Is this similar to the theory that a barrel in a barrel shroud, tensioned by various methods lengthwise is more accurate? I have an old Dan Wesson and it is very accurate "right out of the box"?

 

[James Keefer]

Jerry;

Would you mind describing how you set your follow rest and what type/shape turning tool you are using on your lathe for the primary cutting of the liner--before you use the follow rest. Any other info on how to accurate cut such a thin tube will be helpful to me and others.

Best Regards;
Steve, aka Jock

Hello Steve;
I don't use a follow rest. I use small miniture carbide boring bars by Accupro or Circle.
I reshape the radius and angle. I constantly monitor the cuts for taper and adjust accordingly. As I approach finish size, I take lighter cuts to reduce the push in the center of the liner. Many times I can get to within .001/.002
I then finish with the tool post grinder which will remove any variation. I don't care what the finish size is. (within reason of course) I then drill and ream the barrel to size to allow a clearance of approx. .0015/.002.
When drilling/reaming, the barrel is held in a spider to align both axis'. The reason for such care, is to prevent high spots/low spots/voids, etc. I also want the bore C/L to be in line and concentric with the breechface, and I want the liner completely tension free.
The loctites I mentioned are designed for securing cylindrical parts. 620 has a shear strength of 3500 lbs. psi and 680 has a shear psi of 4000 lbs. I would be reluctant, as in never, to use thread lockers as mentioned..
I have renewed liners from time to time and they are quite tough to remove..

Take care
Jerry

 

[kendog]

Who makes, and where to get the best liners?
Thanks

 

[James Keefer]

Who makes, and where to get the best liners?
Thanks

I've had good results from Lilja, Shilen and Douglas...I order the smallest diameter possible/available to minimize the amount of O.D. removal.
I have had super great results from Lothar Walther...
If you are lining someone's old family .22 rifle, the regular commercially available liners will be servicable, and more economical.

Good luck

Jerry

 

[Tweak]

LocTite 648 Cylindrical Locking. Put hundreds of SS Simunitions (9mmP chamber, .30" bore) liners into steel sleeves for M16 barrels. Took a 10 lb sledge, nearly red hot temp and constant application of a oxy/acet torch to drive out the liner using a steel dowel with the sleeve locked in a bench vise.

 

[Claude Wright]

I use J/B Weld to bond liners.
I drill out with extension drills and finish ream with barrel dialed in with a four jaw and steady rest.

J/w will hold .32-20 liner in.
CEW

 

[SmithSolar]

Here is a list of hight temp Epoxy from McMaster-Carr
I like the ideal of JB as its cheep and I can get from a local store

Dave

High-Temperature Adhesives and Repair Putties

Epoxy— This two-part electrically insulating epoxy resists high temperatures and acids. 1-pt. epoxy has 1-pt. jar of resin and 3-oz. jar of hardener; 1-gal. epoxy has 1-gal. jar of resin and 1-pt. jar of hardener. Mix ratio for both is 100:8. These products are VOC compliant in all 50 states as of October 1, 2008.
Repair Epoxy— Permanently repair leaks in valves, fittings, and shafts. This aluminum-filled two-part epoxy resists corrosion and at full strength can easily be machined, tapped, and drilled. Bonds bronze, copper, stainless steel, ABS, acrylic, polycarbonate, PVC, ceramic, fiberglass (FRP), and glass. 1-lb. epoxy includes a 0.9-lb. jar of resin and a 0.1-lb. bottle of hardener. Mix ratio is 100:11. Kit includes 1-oz. syringe of aluminum-filled epoxy resin, 1/2-oz. syringe of epoxy hardener, sandpaper, reinforcement screen, and mixing sticks. Mix ratio is 2:1.
Adhesive for Insulating Materials— Bond porous insulating materials such as calcium-silicate insulation with this silicate-based adhesive.
Repair Putty for Cast Aluminum— Also known as Pyro-Putty, this two-part adhesive seals cracks, holes, and pits in metals exposed to extremely high temperatures. Machinable at full strength. Includes a powder and a liquid that forms a ceramic- and aluminum-filled thick putty. Apply up to 1/2" thick. Mix ratio is 2:1.
Repair Putty for Cast Iron, Stainless Steel, and Steel— Also known as Pyro-Putty, this ceramic- and stainless steel-filled one-part putty seals cracks, holes, and pits in metals exposed to extremely high temperatures. Machinable at full strength. Apply up to 3/8" thick. 8-oz. size includes 4 oz. of thinner so you can change the viscosity.
Gasket-Sealing Silicate Adhesive— A thick adhesive for sealing fiberglass (FRP) gaskets into stove doors, sealing cracks in metal, and for filling gaps.
Gasket Cement Silicate Adhesive— Easy-flow adhesive for bonding fiberglass (FRP) gaskets to steel and cast iron stoves.
Ceramic Adhesives— Get excellent electrical insulation and bond strength. Bond ceramic, iron, lead, and steel. Use on diesel engines, exhaust systems, and gas turbines. Can also be used with silica gasketing and to coat furnace linings. Resist oil, gasoline, acids, and alkalies.
Ceramic Putty— Adheres to all porous surfaces and can be used as thermal insulation on brick, mortar, burner blocks, furnace holders, and thermocouples.
Zirconia Adhesive— This paste forms a hard surface and resists rapid temperature changes, molten metals, and most chemicals. Bonds ceramic, glass, metals, and graphite. It also serves as a corrosion-resistant coating for graphite, ceramic, and thermocouples.
Withstands Begins to Reaches Full
Size† Temp. Up To Harden Strength Color Each

Epoxy
1-pt. Jar 500° F 25 min. 16-24 hrs. Black 7563A24 $78.05

1-gal. Jar 500° F 25 min. 16-24 hrs. Black 7563A26 285.96

Repair Epoxy
1 lb. 500° F 20-30 min. 12-24 hrs. Gray/Black 75325A2 52.02

Kit 500° F 20-30 min. 12-24 hrs. Gray/Black 75325A1 31.79

Adhesive for Insulating Materials
1-gal. Bucket 1000° F 15 sec. 90 min. Off-White 93630A22 34.42

Repair Putty for Cast Aluminum
12-oz. Can 1400° F 2-4 hrs. 24 hrs. Lt. Gray 7356A32 33.81

1 1/2-pt. Can 1400° F 2-4 hrs. 24 hrs. Lt. Gray 7356A34 71.86

Repair Putty for Cast Iron, Stainless Steel, and Steel
8-oz. Bottle 2000° F 5-7 hrs. 24 hrs. Dk. Gray 7356A33 37.65

1-pt. Bottle 2000° F 5-7 hrs. 24 hrs. Dk. Gray 7356A35 71.86

Gasket-Sealing Silicate Adhesive
2.7-oz. Tube 2000° F 1-12 hrs. 2-3 hrs.• Black 7573A63 6.57

10.3-oz. Cartridge 2000° F 1-12 hrs. 2-3 hrs.• Black 7573A65 7.06

Gasket Cement Silicate Adhesive
2.7-oz. Tube 2000° F 1-12 hrs. 2-3 hrs.• Black 7573A29 6.56

10.3-oz. Cartridge 2000° F 1-12 hrs. 2-3 hrs.• Black 7573A31 7.06

Low-Viscosity Ceramic Adhesive— Apply with a brush.
0.5-pt. Can 2300° F 30 min. 24-48 hrs.* Gray 7482A11 39.98

Standard-Viscosity Ceramic Adhesive— Apply with a brush.
0.5-pt. Can 2300° F 30 min. 24-48 hrs.* Gray 7482A21 39.98

0.5-gal. Can 2300° F 30 min. 24-48 hrs.* Gray 7482A22 105.35

High-Viscosity Ceramic Adhesive— Apply with a trowel.
0.5-pt. Can 2300° F 30 min. 24-48 hrs.* Gray 7482A31 39.98

0.5-gal. Can 2300° F 30 min. 24-48 hrs.* Gray 7482A32 105.35

Ceramic Putty
4-oz. Tube 2300° F 30 min. 24 hrs.º Off-White 7551A23 13.53

11-oz. Cartridge 2300° F 30 min. 24 hrs.º Off-White 7551A24 22.21

1-gal. Bucket 2300° F 30 min. 24 hrs.º Off-White 7551A26 106.90

Zirconia Adhesive
1-pt. Jar 4000° F 30 min. 5-6 hrs.º Lt. Tan 7564A11 77.88

1-qt. Jar 4000° F 30 min. 5-6 hrs.º Lt. Tan 7564A12 129.81

†Cartridges fit a standard caulk gun; see page 3398 for guns.

 

[gunsmither]

620 Loctite worked great

I used the 620 on two reline jobs with zero problems. No mixing, no mess, and it flowed into the barrel perfectly. I won't be using Acraglas in the future.

I drilled the barrels out from the breech end using an extension on a piloted bit, with oil pumped thru the barrel from the muzzle end via rotary union. Using the power feed and oil pump on my Hardinge lathe, drilling them out was easy, and the oil flushed out the chips, with minimal clearing of the bit. I stopped just short of the muzzle, feeding the drill the last few thou's by hand while watching the bit come out, to be able to hide the liner.

I did manage to get cutting oil all over the floor though, when I forgot to shut the pump off to withdraw the bit! Finally put a plastic funnel over the bit to stop the oil from flying all over. Worked great!

I highly recommend the Loctite over epoxy for ease of use in my experience.

Thanks again to everyone for the info. Joe