Just one man's opinion:

I tried Marine Tex and I thought it sucked...Big-Time.

I have a degree in chemistry from UT Austin. Many use Marine Tex because it has a very high concentration of steel in it. Well, Devcon Plastic Steel Liquid does too. Tell me...what happens to finely divided steel when exposed to moisture? It oxidizes... it rusts. What happens to it's volume? It increases. Take a ton of iron...2000 lbs. Add oxygen and oxidize it to Ferric Oxide = Fe2O3 = rust. It now weighs 2,860 lbs. and it's larger in volume too. Just a guess, but that doesn't sound like a very good filler to be using in a bedding compound to me. I've popped a bunch of actions out of their stocks and seen where the bedding is rusty on the surface. That tells me that the mating surface is changing...that can't be a good thing when a thousandth of an inch in this area is HUGE.

And another thing, I don't think many have a background in corrosion chemistry like I do either. Tell me...what happens when you put two metals in contact and add some water with some CO2 dissolved in it? It forms a "battery" or a galvanic or electrochemical cell. One metal will be the cathode and the other will be the anode. If the metal in the action is the less "noble" metal, it will be the anode and it will pit. You get the same thing happening in the same piece of metal where one crystal of the metal is the cathode and the x-tal next to it forms the anode...all within the same piece of steel...that's how corrosion works...that's exactly what causes metal to pit.

I don't know how many chrome-moly "blued" actions I've seen that were bedded in steel impregnated bedding like Marine-Tex or Devcon that were spotted or speckled where the bluing was missing where it contacted the bedding because of this galvanic corrosion. If that's what other rifle builders want to do with a customer's action, fine with me.

Basically, epoxy is epoxy. There's a pretty short list of resins and hardeners that you can mix together and they polymerize and presto, you have an epoxy...no big deal. What the epoxy does is to hold and bind the various fillers together...that's it, nothing more, nothing less...it's the glue. The key component is the filler. The pro bed 2000 idea was to take and use an inert filler...something that wouldn't rust or oxidize and change size and chemistry. Sounds like a good start to me from a chemical standpoint. Then let's use a little common sense and let's see if we can select a filler that we can dense pack together and let the filler support the filler and not the filler support the epoxy and the epoxy support the filler.

Let me explain it this way to make it a little more understandable. Take a swimming pool...fill it full of beach balls...then fill the space between the beach balls with say, softballs...then fill the space between the softballs with golf balls...then fill that space with marbles...and on down smaller and smaller, etc., etc. See how you can get some really dense packing there? Anyway, there's a mathematical formula for the % of each size sphere in the mixture to achieve the desired packing. Making sense here? OK...what kind of "balls" are we going to use? How about inert etched solid glass micro-spheres of the correct % of each size to form this dense packing. The etching on their surface lets the epoxy get a "bite" on the balls but all it does is hold things together and the spheres themselves sit directly on each other forming a non-compressible compound. A non-compressible inert bedding compound...wow, who'd of thunk it possible. I don't know about you but I kind of like the common sense in that approach and thinking.

quote:

Originally posted by Doc:
Just one man's opinion:

I tried Marine Tex and I thought it sucked...Big-Time.
Many use Marine Tex because it has a very high concentration of steel in it.

Doc,
that's is incorrect
There is NO METAL at all in marinetex grey -- None --

quote:

Are there metal fillers in Gray Marine-Tex?
No, Gray Marine-Tex contains no metal fillers.

http://www.marinetex.com/Marin...#Anchor-Marine-44867

here's the MSDS
http://www.actiocms.com/VIEW_M...1F7-902011BCE0B5CAF2

I don't mind a differing opinion -- but when it starts out incorrect, then the common sense approach can't work -- as its not reasoning fact based. All speculation of what metal does, well, doesn't apply

all exopies aren't the same .. and all fillers aren't either.

I have NEVER seen a professional product remove actual bluing (one exception -- and it was room temp black oxide) ..


however, must people use vinegar to remove the slop.. and that WILL remove bluing.

Doc, i've only bedded about 100 rifles, with everything from "megastick" to jb weld, to acra glas, gel, steel bad, marine tex grey and white, 2 or 3 (i forget) different devcons -- in a pinch, i did one in 20 minute epoxy (which is too brittle for anything with a decent amount of recoil) 3 different "a+b" industrials, and even a couple automotive "bovina" type materials ..

its HARD to beat marine tex grey, for any application in gun bedding, that will not "show" or can be painted ..

as for the "constantly smaller filler" we've all done the reduction in size increases fill rate experiment .. and marine tex has dolomite in it to fill the tiny spaces .. as well as powder silica .. its hard to get much smaller AND be rigid ..

dolomite has a moh's hardness of 3.5-4 -- right between copper and iron .. pretty hard stuff

That's good to know...so the titanium is of no concern?

quote:

Originally posted by Doc:
That's good to know...so the titanium is of no concern?

except there no titanium in it -- there Titanium dioxide, which is THE most common idustrial white pigment on the planet.

and it occurs in most "none-puss colored" epoxies.. you put it on yourself when you put on sunscreen, in MOST cosmetics, paints, and toothpastes ..

So, no, not a concern

The link you had is for white. Here's the link for gray. (spelled grey on their site).

Doc,

No offense, but no way you have ever used Marine Tex if you think it rusted. There is no metal in it.

Are you sure you didn't use Steel Bed?

Just asking, because it seems odd to me that you claim a degree in Chemistry yet you didn't notice that the product you were working with didn't contain any metal (unless you added it of course).

I'm not arguing that Marine Tex is the best product on earth, but I know for damn sure that it doesn't contain steel.

Lest you think I am full of it, her is MArine Tex's website. Read for yourself and see if you can find where they include steel. Pay particular attention to the part where they say:

quote:

Are there metal fillers in Gray Marine-Tex?
No, Gray Marine-Tex contains no metal fillers.

no no no....you didn't interpret my post correctly. sorry about that. I don't do gun work. What I posted was from a trusted builder I've used before. Just HIS opinion.

My goal is to find out what builders are using and why, and who thinks what is best and why.

Not trying to stir a pot but share reasonable info. That's all. I do like the explanation though as to why not to use a compound with metal in it. I don't know much about those things. Not my specialty. I'm a healthcare guy.

Ok, good to know.

With regards to the fellow who wrote the opinion, I'd not put much stock in a person's opinion when that person can't even get the most basic details correct.

I use and like Marine Tex. I also use and like several Devcon products.

In my experience, so long as someone chooses a high quality epoxy, the prep work and quality of the bedding work mean more than the actual substance used.

I'm finding lots of builders like marine tex. I have 2 rifles bedded with Devcon Steel. Should I be worried if either ever get wet on a rainy day of hunting?

quote:

Originally posted by Doc:
I'm finding lots of builders like marine tex. I have 2 rifles bedded with Devcon Steel. Should I be worried if either ever get wet on a rainy day of hunting?

If you're worried, take them out of the stock and apply a couple coats of Johnsons paste wax to the metal and put 'em back together. Might as well put some wax on the bedding too while they're apart.

When in doubt check the specs ; I have to laugh when I read some postings as too what's best and what's not .

Thanks for entertaining me !.

http://www.marinetex.com/marinetexepoxyputty.html

Titanium putty ; http://www.devcon.com/prodfiles/pdfs/fam_tds_124.pdf

http://www.devcon.com/prodfiles/pdfs/sku_msds_53.pdf

Aluminum Putty ; http://www.devcon.com/prodfiles/pdfs/fam_tds_107.pdf

Stainless Steel Putty ; http://www.devcon.com/prodfiles/pdfs/fam_tds_105.pdf

http://en.wikipedia.org/wiki/Titanium_dioxide is used for many things yet bulk filler in putty is no

longer one of them , try talc . http://en.wikipedia.org/wiki/Titanium_powder is used in Devcon as well as

Cotronics products weight varies by application and product .


If any of you have need of TIO2/ Rutile TiO in .02-.04 micron size

I have somewhere near 900 lb , or ? I'd be happy to part with .

http://www2.dupont.com/Titaniu...oatings_Brochure.pdf

Been a while since I've seen so much incorrect info (I am too polite to call it BS) as was in the original post.

"What I posted was from a trusted builder I've used before. Just HIS opinion." -- Doc, you need to find a more knowledgeable builder to trust.

I too say thanks for the entertainment though!

John

FWIW, I like Pro Bed 2000, but I live right next to Albuquerque and I know Charlie Robertson who makes it. Pro Bed 2000 works very well and is my first choice for bedding compounds, second is Acra Glas Gel.

Doc
Re-read your original post.

Misinterpreted??? We are not reading the bible here...

When someone starts off a post with "I've tried Marine tex and it sucks" well you have to think they are not talking in the third party nor did they used "quotes" to imply someone else's statement so it must be theirs.

As you can see a small misstatement draws a lot of fire. A rant like that warrants air support

I truly enjoy these show an tell discussions and have the utmost respect for people who do it themselves .

As do I have for professional Smiths there are several products on the market which are more than adequate

for bedding a rifle stock ( some are better than others an when you learn to read specs of products YOU

may decide for yourselves which you prefer ) . Personally I see NO Reason to go beyond an Aluminum bedding

epoxy putty for strength , as it surpasses the object in which it's being embedded into ; be that wood or

synthetic stock material .

Now with that said here's an article which contradicts my thinking ,an I'm OK with that !.

http://www.6mmbr.com/pillarbedding.html

As everyone one knows I'm not a professional Gunsmith yet I do know epoxies and it still doesn't

make me right or this person right or wrong .

It's a PERSONAL PREFERENCE in what one has used and can rely on .

That being said I wouldn't use MarineTex as a bedding compound there are SO MANY BETTER PRODUCTS too use !.

Check the specs on Devcon Aluminum now on steel now on SS ,It's Tensile and compressive

values are what you're after ; If the epoxy matrix fails it doesn't make a tinkers dam what metal filler

is in it ; I'm willing to trade a bit of compressive strength for Tensile ANY TIME for bedding purposes .

While others purchase Putty I use Epoxy an add my filler, this allows me too regulate adhesion

better than a Putty would in synthetics it becomes a NICE added bonus .


There is NOTHING wrong with ProBed 2000 or Acraglas an I would use the recommendation of

those professionals Folks, such as John ,Jim , Duane ,James , Westpac and several others !

JB Weld and ordinary grease for a release. It works, not complicated and cheap. Also readily available. I have used it for years and have found no reason to change.

I've lost all respect for UT Austin.

I wouldn't be so judgemental, Forrest. Several of my high school class got excellent educations there. Best 7 year degree in the country!