bedding compound

H

highseas

Guest
Allways on the lookout for a better product. just about every one Ive run into uses Marine Tex or a close variant of such for bedding an action. I ve also heard that some suspect there is shrinkage over time. In the Marine industry we use a product called Belzona. Pretty indestructable stuff. The machinist we use pretty much say its the best for building up eroded or deteriated metal in high stress applications (shafts and such) and the machining characteristics are desirable. In the applications we have used it it hasnt failed. So as I was talking to the local rep, i got to talking about its shrinkage characteristics, as in fractions of a thousands. He stated this product has NO shrinkage that could be measured. Anyone ever use this for a bedding job? Better yet, ant of you machinists work with it? in particular the the 1111 or 1311 products?
 
I have never worked with Belzona. However, on the ship I served on in the Navy, it was occasionally (and illegally) used to repair small cuts (caused by the steam) in the joints beween segments of main steam pipes. Conditions inside such a line are (IIRC) ~660 psig @ 910 *F - this is a dangerous combination. I never heard of such a repair failing. (Then again, I knew better than to ask.) Durable enough for your needs?

I mentioned above that using Belzona to repair damage in main steam line joints is illegal. This is because the "book" answer is welding over all cuts, followed by X-ray inspecting each weld. Get caught doing otherwise, and expect to be court martialed. It's that serious.

Trivia question - how do you locate such small leaks in a main steam line? (NOTE: steam under such conditions is invisible.)
 
I have an EDGE prototype that was bedded at McMillan. It was bedded using Marine-Tex, and glued in with JB weld. There has never been a problem. When using epoxy bedding cpompounds shrinkage issues , that occur due to the depth of the pour (principally with poured pillars, a good system) are usually handled by bedding in multiple stages, with a final skim coat. Wood or fiberglass stocks are generally not of the same materials as marine shafting or high pressure steam piping. I usually don't pick a sledge hammer to swat a fly. Of course you could make concrete form stakes out of fancy steel, but what would you gain? To be less sarcastic, and more helpful, I tend to stay away from Microbed, and Acraglas, for most bedding chores. I have had good results with clear epoxy for gluing in aluminum pillars (that have been properly prepped) and Devcon plastic aluminum for the rest of the job. There is a long list of what will work and do a good job. One technique that escaped my previous jobs, that I plan to use on my next one, it to butter the action and stock with bedding compound before putting them together. I don't think that small air bubbles hurt a thing, but the look of a job that has none can be impressive.
 
lefty o said:
broom is the correct answer, unless you dont mind losing fingers.
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correct Boyd, one of our ships has a steam plant and turbines. Ive never seen it used, but the chiefs keep em around.

Asa, its tough stuff for sure. not sure i would use it on HP steam, but in a pich i can. be a well marked no travel zone.
 
Boyd Allen said:
I have an EDGE prototype that was bedded at McMillan. It was bedded using Marine-Tex, and glued in with JB weld. There has never been a problem. When using epoxy bedding cpompounds shrinkage issues , that occur due to the depth of the pour (principally with poured pillars, a good system) are usually handled by bedding in multiple stages, with a final skim coat. Wood or fiberglass stocks are generally not of the same materials as marine shafting or high pressure steam piping. I usually don't pick a sledge hammer to swat a fly. Of course you could make concrete form stakes out of fancy steel, but what would you gain? To be less sarcastic, and more helpful, I tend to stay away from Microbed, and Acraglas, for most bedding chores. I have had good results with clear epoxy for gluing in aluminum pillars (that have been properly prepped) and Devcon plastic aluminum for the rest of the job. There is a long list of what will work and do a good job. One technique that escaped my previous jobs, that I plan to use on my next one, it to butter the action and stock with bedding compound before putting them together. I don't think that small air bubbles hurt a thing, but the look of a job that has none can be impressive.
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Good points Boyd, is a little bit on the sledge hammer side. I might have to try it though, got this free 1 kilo sample burning up a spot on m desk. :) and if that rifle doesnt start grouping a little better, the barrel might end up as a concret form stake.
 
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Asa Yam said:
I have never worked with Belzona. However, on the ship I served on in the Navy, it was occasionally (and illegally) used to repair small cuts (caused by the steam) in the joints beween segments of main steam pipes. Conditions inside such a line are (IIRC) ~660 psig @ 910 *F - this is a dangerous combination. I never heard of such a repair failing. (Then again, I knew better than to ask.) Durable enough for your needs?
Click to expand...

So, if this stuff is so tough, and it takes 900f, how do you get it apart should your release agent fail to release? With all due respect, it doesn't sound like a perfect match for the req's of bedding. JB Weld can be easily removed if you need, just by heating it up. And, you don't need to go to a temp where you are altering the metal to get it apart.
 
I've found Araldite K138 to be a pretty good all round bedding compound. I started using it on the advice of Phil Mastin (maker of the prone rifle stocks). It was impervious to the cleaning products we used back in the eighties, but I haven't challenged it with the more recent stuff. It's fluid rather than putty like, but not enough to be a pain in the butt. It's also relatively quite economical.
 
I've had good experience with Devcon 10110. So far I've bedded ~20 rifles with it. Easy to mix, stays where you put it, plenty of time to clean up, releases beautifully using lightly buffed clear shoe polish as the release agent. I don't shoot shoulder cannons, but the stuff has excellent mechanical properties and seems to be immune to deterioration from any cleaning solvents I've used.

Fitch
 
John, not sure Iam good enough to work with a more fluid bedding compound, but that being said, Iam looking into it.

Fitch, seems Devcon and Marine tex have about the same following. chuckling, I do like my shoulder mounted artillery though. thanks for the imput, I may try it, I just have a really cheap source of both marine tex and belzona, free and they are sitting on my desk.

""So, if this stuff is so tough, and it takes 900f, how do you get it apart should your release agent fail to release? With all due respect, it doesn't sound like a perfect match for the req's of bedding. JB Weld can be easily removed if you need, just by heating it up. And, you don't need to go to a temp where you are altering the metal to get it apart""

4mesh thats the rub, if I screw up, i screw up big time and its in there permenantly. If i screw around with it (belzona), It will be on one of my older budget rifles first. Though Im rather fond of them and will be hugely disapointed in myself if I screw one of them up. I havent been a very big fan of JB in the past(industrial applications). Mostly bond failures, and Im not sure if it wasnt my fault for useing it beyond its intended capabilities.

Thanks all for the good solid imput.

Ethan
 
I have used West Systems Epoxy with slow hardener and colloidal silica as a thickener. You can tint it any color you want and it's as tough as woodpecker lips.
I've used it for years. Google Gougeon Bros. and you can get it from them.
 
MColeman said:
I have used West Systems Epoxy with slow hardener and colloidal silica as a thickener. You can tint it any color you want and it's as tough as woodpecker lips.
I've used it for years. Google Gougeon Bros. and you can get it from them.
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Thanks, what are you useing for tints/color? standard epoxy pigments?
 
Oatey Fix-it Stick works well for my .22 applications. It is a 2 part, steel filled, non-shrinking epoxy that comes in a 7/8" diameter stick about 7" long. I slice off an appropriate amount and knead it to a consistent light grey color. You have about 3 to 5 minutes to work with it and it sets up in about an hour. I undercut the stock to provide a mechanical lock. Wrap what you don't use in plastic wrap and it will have a shelf life of a year or so. I've never used it in a heavy recoil application, however.
 
highseas said:
Thanks, what are you useing for tints/color? standard epoxy pigments?
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I go to the local store where I buy some paint and they squirt some tint (any color) into small bottles. It's concentrated and only takes a smidgen to tint. I've used it for years.
 
MColeman said:
I go to the local store where I buy some paint and they squirt some tint (any color) into small bottles. It's concentrated and only takes a smidgen to tint. I've used it for years.
Click to expand...

Thank you, Ill try it on a test sample.

Ethan
 
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