Rifle Scopes Bedding Scope Base?

[Mike McBride]

I have never bedded a scope base, but have read a couple of “how to” threads. I still have some questions:

1-What type of epoxy? For general applications I usually rely on the slow setting JB Weld, but it does tend to run. I am also unsure of its thermal expansion properties. What is the best to use for staying in place while making a strong pad?

2-What is the best release agent? I see shoe polish, car wax, and floor wax but what gives reliable release with the thinnest coat?

3-On the end to be bedded is there any good reason not to use over-length screws with the heads cut off as studs rather than the actual mounting screws? It seems one would be less likely to accidently turn epoxy into the screw holes if the base were installed over studs that are not moved.

4-Is there a good material to prevent epoxy from getting into the screw area and leaving small voids around the screws? I figure a good pad of epoxy is enough and this may lessen risk.

5-Has anyone tried smearing release agent over most of the base so that the epoxy could be removed once set? It seems like drilling a couple of small blind holes for the epoxy to grab but using release agent over the rest of the surface would make the whole thing reversible. These little rails are expensive.

Are there any thoughts on the above questions from folks who have done this? If one never screws up, he doesn’t do much, however it is better to learn from the mistakes of others. I know it is hard to admit that you have done something really stupid, but I am really stupid and would very much appreciate any insight on what NOT to do as well as what to do.
Thanks

 

[Willyz_54]

Re: Bedding Scope Base?

I used red loctite when I bedded my Badger rail to my Model 70 long action.
1. Mock up the rail to ensure that it fits and screw holes align.
2. Used rubbing alcohol and a cotton ball to ensure both surfaces were free of any debris or fibers.
3. Ran a thin bead of loctite around the base of the rail.
4. Attached the screws with loctite on the threads and torqued to spec.
5. Used a Q-Tip to remove any extra loctite
It is my understanding that a small amount of heat will release the loctite, but I have not had occasion to un mount my rail.

Hope this helps.

 

[308Shooter1911]

Re: Bedding Scope Base?

Check this link...LoneWolfUSMC does an excellent job of demonstrating and explaining...

http://www.youtube.com/watch?v=aoW5bHQqgis&sns=em

 

[Mike McBride]

Re: Bedding Scope Base?

Willyz54,

I can see where your method will hold the base securely, but do not see how it prevents the rail from bending when the front and rear mounting holes are not exactly level to one another. You would have to go ahead and crank down the screws because Loctite will not cure if there is much of an air gap.

The red loctite will go liquid at about 450 or 500F.

308shooter1911

Thanks--that video was very well done.

 

[Mike McBride]

Re: Bedding Scope Base?

Has anyone tried measuring the gap and using shim stock instead of bedding?

 

[Redman797]

Re: Bedding Scope Base?

How necessary is bedding a scope base? I've heard of it but never tried it.

 

[10rounds]

Re: Bedding Scope Base?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308Shooter1911</div><div class="ubbcode-body">Check this link...LoneWolfUSMC does an excellent job of demonstrating and explaining...

http://www.youtube.com/watch?v=aoW5bHQqgis&sns=em </div></div>

I used this video to learn how to bed the base.

 

[kill_goose]

Re: Bedding Scope Base?

I use devcon. Bedding material becomes permanent to the rail.

 

[10rounds]

Re: Bedding Scope Base?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: moredots</div><div class="ubbcode-body">How necessary is bedding a scope base? I've heard of it but never tried it. </div></div>

When I was doing a test fit of the base to the receiver by screwing on the two front screws, there were gaps in the rear of the base. The gaps were gone after bedding the rear part of the base only (did not bed the front part of the base).

I found out about bedding the base when a viewer commented on a Youtube video about lapping the scope rings. The viewer mentioned that bedding was a "better" option. I'm sure there could be a debate on whether lapping is better than bedding or vice versa. I'm happy with the route I took.

 

[10rounds]

Re: Bedding Scope Base?

Learning from the video:

Started with degreasing the base bottom & the receiver with acetone. I waxed (neutral shoe polish wax; cleaner to work with) the area & side (safety measure) of the receiver that was to receive the base & plugged the two rear holes on the receiver with some clay. I attached the base after applying the epoxy & screwed on the two front screws.

Used some Q-Tips sprayed with WD40 to clean up the epoxy that was running out on the side of the base & on the receiver. I used dry Q-Tips in the two rear holes to soak up the excess epoxy.

After 5-6 hours, I pulled off the base & cleaned up the two rear holes on the base by turning a drill bit by hand on them. Trimmed the epoxy around the two screw holes. The clay plugs got yanked out when I pulled off the base. I attached the base back to the receiver with the two front screws & let it cure overnight.

Pretty happy with the result.

 

[wchartz]

Re: Bedding Scope Base?

When I bed mine I put a heavy coat of past wax on the screws and in the receiver screw holes. In fact I fill the holes up solid with wax. You will not have a problem with the screws being stuck if you do this. I also put a coat of past wax on the receiver and buff it down. You want a hard setting epoxy not some of the cheap stuff that gets semi hard and "creeps" over time. Acura Glass Gel and Devcon are two that I have had good luck with. Do not use a liquid type such as regular Acura Glass. Before you apply the epoxy dry fit the base or bases using a machinist's steel straight edge sitting on top of the base or bases running parallel to the bore. Hold a light behind the straight edge on one side and see if you can see any light between the straight edge and top of the base. Tighten the screws gently and see if you see more or less light between the straight edge and the base. The base does not have to fit tight to the receiver at this point, the epoxy will fill the gap if there is one. Your goal is to vary the screw torque so as to get as flat a surface as possible from the rear of the back base to the front of the foward base or in the case of a one piece base just plain flat. Once this is done you can apply the epoxy and just as above vary the screw torque until you get the flattest surface possible by using the straight edge and light. Tighten the screws slowly as it takes a few seconds for the high viscosity epoxy to squeeze out fully. Clean off the excess as has been described elsewhere. You can clean out the wax and apply locktite later if you want to.

 

[CohenJ87]

Re: Bedding Scope Base?

I never even realized people did this, I still have so much to learn when it comes to long range and accuracy.

 

[LanceS4803]

Re: Bedding Scope Base?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ed-209</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 308Shooter1911</div><div class="ubbcode-body">Check this link...LoneWolfUSMC does an excellent job of demonstrating and explaining...

http://www.youtube.com/watch?v=aoW5bHQqgis&sns=em </div></div>

I used this video to learn how to bed the base. </div></div>

Same here, as I had never done this before. My thought was to just do it right the first time, and never have to worry about it again. (Seekins 1 piece base on Rem 700 receiver.)
Had the laptop set up on the bench and just followed along. Turned out PERFECTLY.
My only tip would be to mix more JB Weld than you think you might need. Better to not use it all, than have to try and mix up more in a hurry.

 

[northern50]

Re: Bedding Scope Base?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CohenJ87</div><div class="ubbcode-body">I never even realized people did this, I still have so much to learn when it comes to long range and accuracy. </div></div>

And the best part of it all is.... Learn to read the wind and you will trump a lot of little things.
Honestly there's a few things I've learned over the years.
Shooting a .223ai In f class with the big boys and their 6.5's has made me be better shooter because I had to pay attention to the wind. Shooting bmg's in the Nebraska wind at 1k has tought me a lot about wind and what uneven land will do to a bullet on the way to a target. Use the wind and weather to your advantage and you will out shoot a lot of others.

 

[beretta_man11]

Re: Bedding Scope Base?

I bedded my base earlier this week. I wasn't extremely confident in my skills so I took a more unconventional way of doing it. I didn't have any shoe polish or any of the other release agents mentioned so I used scotch tape on the bottom of the base and on the rear action bridge so I wouldn't permanently stick the JB weld where I didn't want it. It actually turned out really well. I thought the tape or JB weld may not stick well but I've got everything torqued down and I don't think it's going anywhere. I put my straight edge on the rail, it seems to be straight now so I'll be mounting the scope this weekend.

 

[Mike McBride]

Re: Bedding Scope Base?

Hey Baretta Man,

I assume you never lifted the rail after the epoxy set. How did you ensure clean screw holes? How did you trim the tape without scratching the finish on the reciever?

Tape is a novel approach that I haven't seen. It seems an elgant solution in that the process is reversable and the thickness of the release agent is a nonissue. I believe that if Kapton tape were used, the amount of compression would be completely insignificant. Of course if your rail is straight with Scotch tape, then that ought to be good enough.

 

[beretta_man11]

Re: Bedding Scope Base?

basically the JB weld is sandwiched bewteen the tape so if i screwed up, i wouldn't have an issue with scraping the first run and trying again because the epoxy does not touch the metal. the tape covered the holes in the receiver as well as the scope base so i didn't get any in them. when the JB weld set, i took a small drill bit and drilled through the weld.

 

[Mike McBride]

Re: Bedding Scope Base?

Beretta Man,

I have been looking around the net on this subject and yours looks like the most ingenious as well as unique method to cross my path. I salute your resourcefulness and appreciate your post.

By the way; who are your favorite gunsmiths?

 

[beretta_man11]

Re: Bedding Scope Base?

HAHA- Thanks!

Chuck Macintosh of Mac's Gunworks of Gillette, WY
Karl Feldcamp of Kampfeld Customs.

Both do excellent work-Great prices-Great turnarounds!