Glass bedding vs. "Steel bedding"

[ptbobdemaria]

Hi guys. I think I'm going to new gunsmith to have my bear hunter rifle pillar bedded into a laminate stock I had made for it since the gunsmith I sent everything to hasn't even began to work the rifle in six weeks since he received everything. The new gunsmith suggested I do a steel bedding as aposed to a glass bedding as glass bedding is susceptible to "crush" over time which was simply explained to me as glass bedding crushing overtime due to air bubbles or something. I have not found too much research regarding pros and cons of both so I've decided to post to the professionals as many of you have schooled me on the unknown before.... and always appreciated. I am pillar bedding a 300 win mag. Am I better off with steel or glass bed? Does steel bed corrode (humidity... I live I NY) And a little off topic... has anyone heard of Parker gunsmith in Danbury CT.? That is who I may have do the gunsmithing now. Thanks guys. Any and all comments appreciated

[FW Conch]

Steel bedding a rifle action is simply using an Epoxy glue material that has steel dust in it. These products were made to do repairs to machinery, etc. I bed with JB Weld, which has steel in it. If you were to strip out a bolt hole, you could fill it with JB Weld, etc., drill and tap it and have an acceptable repair, to a certain extent. People have filled cracked engine blocks with it , and other remarkable things. I have bedded with plain Epoxy glue with good success, but I also always pillar bed. If you have steel bed and your rifle gets wet and you don't dry it, the steel bed will rust. I have heard of people putting a sealer on it. When your smith says he steel beds, he is likely using a good product, but to me it is the pillars that do the bulk of the job.

Good Luck-Good Shooting ... Jim :-)

[BlueDog]

Bob, I think this all boils down to semantics. Glass bedding and steel bedding for all intents and purposes is the same. The real strength in either is the epoxy. I have used everything from Acraglas, Marinetex and JB Weld. All work more than fine, but I will say my last few I've used good Ol'JB. (It's the cheapest!) Some discount it as too runny, but I mix it and let it sit awhile, then bed as usual. Like Jim said, pillars will do the heavy work and will keep anything from "crushing". My opinion is I suspect your new gunsmith is pushing for whatever kind of bedding he has on hand.

[Texas10]

Devcon 10110 is steel filled epoxy and probably what your 'smith is referring to. "Glass" refers to fiberglass reinforced resin, usually some kind of polyester or vinyl ester resin. The issues with that old technology is that moisture will find it's way along the fiberglass and gradually break up the plastic base, which also shrinks with age. Another issue is that catalysts such as MEKP (A.K.A. fiberglass hardener) are not used up in the 'curing cycle' and migrate out, causing problems later with metal and wood. Filled epoxies use finer particles and harder, more resilient resins, and contain no catalysts.

Epoxies need to be proportioned accurately and mixed thoroughly for best cure and strength. I use a gram scale. I also keep the project warm throughout the work. Adding more "hardener" to an epoxy like you add catalyst to polyester resin is a common mistake that yields poor results. Epoxies cure hard only when there are the right amount of part A and part B molecules.

It's really not hard to do correctly. Just sounds hard. Follow directions closely and use a good mold release.

I hope this helps.

[DrThunder88]

I've never seen a reference to glass bedding using anything other than epoxy as the substrate. People certainly could have used other resins, but I would suggest that they weren't doing things correctly. Perhaps that was a holdover from the dinosaur days when rifles were "glass bedded" with pieces of fiberglass fabric? Since that technique and material have fallen by the wayside, I imagine those other resins have too.

I used to be an AcraGlas guy, but I've switched over to Devcon, mostly for the convenience but also for the higher viscosity. Devcon makes a 1oz tube kit of plastic steel that's handy for bedding projects. I like it a bit more than JB Weld, but it does smell a little funkier.

[BillPa]

Perhaps that was a holdover from the dinosaur days when rifles were "glass bedded" with pieces of fiberglass fabric?

Actually the term 'glass' bedding came about with the introduction of Brownell's AcraGLAS.

Its darn good thing they didn't call it AcraPOOP?:p

Bill