Favorite bedding compounds

[Alex Wheeler]

The type of epoxy is way down the list compared to the method used to bed in the first place. Many of the commonly used epoxies are up to the job, and they all shrink. There are some methods used to try to maintain even contact throughout the bedding job after shrinkage but the main goal is to not have any stress. A good looking job comes down to buffing off your release agent very well and how you mix and apply the epoxy to avoid air bubbles. But how it shoots will come down to the fit. So pick any one you want but test your process with dial indicators at the forend when breaking screws loose. .001" movement or less is your goal.

 

[ntsqd]

Your posts are what I was referring to in my post above. It was a great help and showed me what to look for in doing my own research. Like I said, after researching it was between Devcon Aluminum and Brownells Steel-Bed, which has stainless steel in it.

Thanks @ntsqd

You're welcome.

I really wanted to include the same set of specs for Marine-Tex and any of the other compounds commonly used for bedding, but I could not find them listed anywhere. Perhaps if that info can be found or the various products are scientifically tested to get those results we can get a sticky made?

It is outside of the OP's scope of the thread, but I agree that technique or process is important. That can and has been a huge thread all by itself.

 

[Alex Wheeler]

A small difference in shrinkage rate is not really worth worrying about. I have measured differences in shrinkage rates within the same product, in fact I quit using one because of it. If your action is sitting on top of pillars and the epoxy shrinks .0002" or .0004" whats the difference? Its either touching the action or its not. This is something that will not show up with a dial indicator, that will only pick up on bind or stress. The key in my opinion is to try to maintain an even thickness of epoxy so the shrinkage rate is as consistent as possible across the whole job.

 

[Susquatch]

Over the years, I've used most of the epoxy compounds out there a time or two. Some are better than others. I've had consistent success with Devcon and I use the liquid for skim bedding and the putty for most regular bedding now.

I have not had any major shelf life issues. Even after a major health issue that stopped me from doing any bedding work for several years, all it took was some serious mixing and kneeding to soften up the resin. The hardner never has a problem.

From an Engineer's perspective, all these shrinkage concerns are much to do about nothing. One must keep in mind that the ratings are in inches per inch. For a 1" thick layer, the manufacturer claims the change is only 0.0006 inches - just a bit over 1/2 a thou. HOWEVER, I don't know anybody who uses an inch of bedding. A tenth of an inch is probably more than most bedding jobs. So the actual shrinkage is more like a half of a tenth of a thou. Conventional measuring tools cannot even measure it.

In other words, shrinkage for Devcon Steel Epoxy is a zero issue.

It's also important to recognize that synthetic stocks also shrink because they are also resin based. Wood stocks are far worse and I won't even begin to cover the issues.

 

[Ranger Rick]

thank you for the compliments guys. every single one looks like that when it leaves the shop. I take and post pics of the inside of every rifle and post those along with the outside pics. Probably only a handful of other builders out there take pics of the inside. My thoughts are anyone can make the outside pretty with a can of paint. But the inside is what matters. I can also send pics to customers of their chambers if they wish. The Haas setup Im using cuts the most beautiful threads and perfect chambers. Pin gauges are used to ensure the back of the chamber isn't oversized and then the chamber, throat and 1" forward is measured to ensure there is zero runout. I can record the timing of each action and its headspace. Then I can time even a fluted barrel and chamber it without the action in hand. That is handy for my fclass customers who don't want to send their actions in during the middle of the shooting season for new barrels to get chambered up. The problem is very few actions time up the same. Ive even seen some Defiance actions that timed up 90 degrees apart. Being able to record the actions timing solves that issue and allows the timing and headspace to be perfect everytime. I have a tool that I made up and sell to other gunsmiths so they can do that as well. The tool is only like $50 per thread size.

Mr. Pierce, you and your work deserve every kudo. When I saw your picture, I thought WOW (all caps) Your explanation adds to your A+ Quality Work.

 

[rpierce]

Mr. Pierce, you and your work deserve every kudo. When I saw your picture, I thought WOW (all caps) Your explanation adds to your A+ Quality Work.

Thank you for the kind words.

 

[Eagel Builder]

With epoxy any thoughts of heating the wood or synthetic stock before applying . Helps for bonding and set up time. Not to much heat.

 

[ntsqd]

I don't know if it is true of all epoxies, or just those that I've used (recently that is J-B, Devcon AL putty, M-S 907), but those that I have used were all exothermic to some degree or other. In a warm climate I doubt that heating the stock would do much for you. In a cold climate I think that it is a good idea.

Alex Wheeler & Susquatch have me thinking that I need to revise my procedure and to the pillars last. At least with round bottom receivers. Or machine flats on the action for the pillars to sit on and not bother with bedding the action at all.