steelbed?
Acrcaglass?
devcon?
snot?

jeffe

I use Marine Tex from Brownells...But I doubt it makes a bit of difference if the truth were known.

jeffeoso, they are all just epoxy with additives, usually in the form of aluminum, steel and even titanium. The strength comes from the epoxy resin, that is the matrix that holds it together and gives it the strength. The additives allow them (or they think) to charge more money and does nothing for the final product. It may make it conductive, not sure of that, but would bet that the resistance was high.

I use Epoxy Mend from Goop Industries, look for it at Lowes or Home Depot.

[ 05-19-2003, 07:17: Message edited by: Customstox ]

Any Tile Setters on the forum?

I recently installed ceramic tile in a shower, using epoxy grout for the joints.

This is a two part mixture, and a fine high density sand is added as the epoxy is mixed.

I poured the excess in some paper cups, and let it cure for a week or so.

This cured mixture is very tough, hard to shatter with a hammer, does not appear to shrink and even bonds to the plastic buckets I was using. I have another cured sample I will drill and tap to see what gives. It is a lot stronger than Acra Glass, and also stronger & harder to break than Steel Bed. Plus it is super waterproof.

Been thinking about trying a batch of it around the recoil lugs of a 458 Lott. Might be as good as the old sliced bread thing. I have an ample supply of the unmixed kit left.

Chic is right about the additive thing. Its all just Epoxy with additives.

John, what do you do to get the mold out and the ring around the recoil lug, lol.

Gentlemen
I've bedded 4 or 5 rifles using Accraglas with good result. Keep in mind this was 15 or 20 years ago. I think some of the Accraglas came with glass fibers for adding to the mix.
I've never used any of the epoxies that have additives like steel. I should think that mixing the steel in epoxy would be like putting the aggregate in concrete.
The products by Bisonite with Aluminum, steel, etc. is a waste? I really don't know and have no experience, so I have to rely your experience and knowledge.
Thanks
Jim

John Ricks,

I'd be interested to hear some more about the tile gout. If it bonds to plastic it might be good to use on plastic stocks.

Rob

Ditto what recoil Rob said, John. "Tell me more, tell me more..." - Dan

Jeffeosso, contrary to Customstox comments, the filler type and size has a dramatic effect on the strength of the epoxy. In my experience Devcon Titanium epoxy putty is one of the toughest and stongest commercially available. This would be followed by steel and/or carbon fiber reinforced epoxies. JBWeld sells a steel reinforced product. I am not sure if you can get a carbon fiber resin commercially.

If you believe Customstox comments just buy the cheap 5 minute epoxy it has no filler added to the matrix. BTW, this is the stuff Winchester uses in their M70! Moves around like silly putty, but doesn't seem to "break".

Axel

Axel--

Chic is right, you are wrong, and Winchester uses hot glue as a "bedding agent", not epoxy. Other than that........good post.

More important than the agent is dual recoil lugs, and dual cross bolts. The bedding agent simply takes up the slop between the cross bolts and the recoil lugs. Without the bolts and double lugs, the bedding agent will simply shear out a portion of the stock.

I agree with Chic when it comes to things like Devcon Steel and Aluminium and they are mainly for colour differences. Some fillers I think are for wear resistance.

However Devcon Titanium is different altogether. Whent it has been heat cured it is far harder than Devcon steel or aluminium. If you get some cured Devcon Steel and Devcon Titanium a bit into a small cube and then try crush them in pliers you will you see the difference between the two. I have used Devcon Titanium for bedding scope mounts but it would not be very good for rifle bedding as it would be too hard to use. Also its specifications show a much larger shrinkage on curing than Devcon Steel or Aluminium.

My general understanding is that epoxies for the building industry are lower quality than for metal trades. Also epoxies that use a straight 50/50 mix are lower in performance.

Mike

I am not going to argue this with any of you! Follow these links to get the MANUFACTURER'S specifications for the materials:

Devcon Titanium Putty Specifications Devcon

JB Weld - Marine Weld Specifications

Devcon "5 Minute Epoxy" Specifications

The KEY parameters to look at are:
1.) Impact Strength
2.) Compressive Strength
3.) Thermal Stability
4.) Shrink rate

You decide which is best.

If Chic is right, why do we have FIBERGLASS? The orientation that Infosponge refers to only applies to composite laminates! The size and type of the reinforcing "fibers" determines the strength of the individual layers. Thus short and long cut FIBERGLASS. Guess which one is stronger, even though they are bonded with the same "epoxy", actually it is polyester. This is also why carbon fiber is stronger than fiber glass. Since the carbon fibers are MUCH smaller than the glass fibers! Same principle applies to sintered carbides, which are more commonly refered to simply as CARBIDE tools. The carbide particle, often only a micron in diameter, are GLUED together with a metallic bonding agent. This agent is typically an iron/cobalt mixture. Of course everything I say may be WRONG so just believe what is written in the technical specs from the above links!

Axel

[ 05-21-2003, 06:12: Message edited by: Axel ]

Jeffe- To answer your question without getting into hypothetical arguments of little value, Use Steelbed! It works just fine! I've also had alot of success with accraglass/ powdered tungsten mixes.-Rob

This may be one of the most ridiculas threads I have ever read..For the purpose of glass bedding a stock almost any bedding compound will work including proper inletting without glass on most calibers....Devcon, Brownells, Marine Tex etc. they all do the job...The original pure glass by Brownell without enough binder tended to craze within a few years, but most today have a binder...

Anyway one is as good as the other as steel and tungston etc. are not particularly necessary for the job at hand..Pick your product by how user freindly it is is my suggestion....

So...
Devcon is cool...

But I *KNOW* steelbed... and it was me that had the bedding failure, but I expect that was material limits...

I am adding an additional recoil lug (and thinking of 2) and will go with the steelbed...

thanks rob
jeffe

KmuleinAK, there is a formula to use, but it is engineering. You must calculate the total area of of the lug(s) and you must calculate the impact energy of the recoil event. You must have enough stock material in direct contact with the lug(s) so that you are loading the stock material below's it's impact strength. Actually, you need a good safety factor too so I would suggest that you load the stock material to only 1/2 or 1/3 of it's impact strength.

The biggest problem I think you will find is that the impact strength of wood VARIES greatly even within the same tree!!! You should be able to find these equations in any descent mechanical engineering "Strength of Materials" text book. You may also want to look at machine design text books or maybe "Machinery's Handbook". Enjoy yourself. As with many things, the experience Gunsmiths just do as their mentors did, or as their experience tells them. Sometimes they are right sometimes they aren't. They often cannot tell why, since they do not know the load conditions.

Axel

[ 05-22-2003, 00:37: Message edited by: Axel ]

When glass bedding regardless of the brand of material I mix enough to do the entire job, then reserve enough of the mix needed for the recoil lug area and mix Brownells glass flock in it.

Through some rather primitive tests in my shop I have determined that the strongest additive is carbon fiber, then fiberglass, and last the differant powders. The glass flock is the most practical form of fiberglass to use even though the fiberglass cloth is stronger.

I think you can compare epoxy with the differant powders to particle board and epoxy with glass flock to wafer board. Of course the wafer board is much stronger.

For big bores I would mix ordinary Acraglass to wet the recoil area, then lay down a piece of thin aircraft type glass cloth, then wet the cloth with more Acraglass, then mix more Acraglass with glass flock to complete the bedding area. If you will layer the glass cloth accross the areas prone to cracking or splitting, it will act as a very strong girder.

If you use super hard glass it will be more prone to resisting compression totally or failing. Where you use slightly flexible glass it will have tensile strength. Sort of like cast iron will not give at all untill it breaks. Steel on the other hand will give and return to it's original form.

While we are on the subject of epoxy(s) and wood... I use plain old devcon with VERY fine sawdust to fix some cracks. They sand up well and dont shrink or look like crap (like some "woodfillers" putty). Always turned out well for me. Maybe some others with more experiance can comment.

[ 05-22-2003, 12:00: Message edited by: smallfry ]

Info sponge,

I don't believe that any big bore is going to trash out a properly glass bedded rifle stock, unless the mix is bad, the person didn't understand big bores, or it was improperly bedded to start with.....

A big bore (458 Lott and up) should have double recoil lugs, two cross-bolts to stop the spreading of the magazine box area, has nothing to do with the glass, it is the nature of the design that causes the problems...Below that caliber any good reliable glass compound will hold up for many years...

I have big bore rifles all over the country and never has one failed to hold up once it left here...

I'd like to see broken glass from a big bores recoil, and after personal inspection I'll bet money the problem was mix or other than the product...