Best Bedding Material

[tobnpr]

I don't care for the texture of Marine Tex (too runny for me), and it's very sensitive to mix ratio compared to other epoxies.
That said, the gray is plenty hard, with minimal shrinkage so it works well.

Devcon 10110 is what I use.

I wouldn't overthink it. I've used JB Weld, and West System mixed with high-strength fillers also.
Biggest concerns are shrinkage- make sure whatever you use doesn't... and hardness.

 

[jimbires]

another vote for devcon 10110

 

[Andrew Cowling]

Hi. I have been using DEVCON stainless steel and aluminium putty for the past 20 odd years. Never had an issue. I use ROCOL teflon spray as a release agent.

 

[ejg]

Another option, we bed a couple hundred stocks per year and blend our own bedding compound starting with a aero grade epoxy resin and adding fillers. Some fillers increase strength, some increase thermal conductivity and others increase compression strength. One advantage for us is I have worked with the same materials since 30 years and know long term performance also have our heat treatment set for the resin.
edi

 

[Dragoon300]

I have used Devcon Titanium putty for many years, it is a high performance product that is expensive, but I feel it is worth it. Read the product tech sheet and compare. Get Devcon release agent too, they are made to work with each other.

Devcon® Titanium Putty - ITW Performance Polymers

Devcon Devcon Titanium Putty from ITW | Engineered polymer solutions | View full technical specifications here for Devcon Titanium Putty

itwperformancepolymers.com

 

[DoneNOut]

Another option, we bed a couple hundred stocks per year and blend our own bedding compound starting with a aero grade epoxy resin and adding fillers. Some fillers increase strength, some increase thermal conductivity and others increase compression strength. One advantage for us is I have worked with the same materials since 30 years and know long term performance also have our heat treatment set for the resin.
edi

How does this help the rest of us trying to learn when you say you have some secret formula, but not divulge the secret?

Which reminds me of a funnier time, when I was told if captured, I should say "I have secrets! Don't shoot"! Rather than, Don't shoot. I blam!"

 

[jimbires]

@Coyote Shadow Tracker , have you given any thought to your pillars . are you going to make metal to metal contact , or have bedding between the pillar and action ? I bed so they are metal to metal . not the whole pillar making contact , just the center where the round action contacts the flat pillar . . I've read that a thin layer of bedding between is supposedly better , harmonics wise . the ones I've had that used a thin layer of bedding between the action and pillar , the bedding on top of the pillar failed .

 

[ejg]

BFD, Firstly, who said I should help someone? I was merely pointing in a direction that is an alternative. We worked up our own formula be it right or wrong, anyone can do the same. Based on whatever theory one has. Composite fill materials are well known and there is a huge variety like metallic powders, mineral powders such as talk, glass etc or ceramic powders in a huge variety even plastic powders. Of course one can also use short fibres which can be glass, carbon, aramid or more exotic. These materials all have their unique properties and the final bedding compound can be tailored to perform in a certain way, just like Devcon or others blend their additives to achieve certain types of compounds. Of course the base resin / hardener properties play a big role as well.
Another advantage of the home blend is that one can adjust the viscosity to match the job or have one viscosity to start another to finish with.
edi

 

[DoneNOut]

BFD, Firstly, who said I should help someone?

STOP. We are a breed apart.

 

[Coyote Shadow Tracker]

Another option, we bed a couple hundred stocks per year and blend our own bedding compound starting with a aero grade epoxy resin and adding fillers. Some fillers increase strength, some increase thermal conductivity and others increase compression strength. One advantage for us is I have worked with the same materials since 30 years and know long term performance also have our heat treatment set for the resin.
edi

What is the recipe???

 

[Coyote Shadow Tracker]

@Coyote Shadow Tracker , have you given any thought to your pillars . are you going to make metal to metal contact , or have bedding between the pillar and action ? I bed so they are metal to metal . not the whole pillar making contact , just the center where the round action contacts the flat pillar . . I've read that a thin layer of bedding between is supposedly better , harmonics wise . the ones I've had that used a thin layer of bedding between the action and pillar , the bedding on top of the pillar failed .

Metal to metal with the pillars. That's the whole reason for pillars. I just wanted some more information. I always do. Been working on firearms for 50 years, but there is always someone that has a better way than i would do it. No matter how much I think I know i try to always ask other's for more info. I found that being on LRH there is a wealth of information and "Someone that knows more than me" and I can benefit!

 

[ejg]

What is the recipe???

It varies, for a hunting rifle we try to have the compound very tough. Load the resin hardener mix with say 1/3 carbon fibre 0.2mm, 1/3 aluminium powder, 1/3 Talc. This mix is easy to machine as well.
Dry powders well before use. Aero grade laminating resin with at least 40 min pot life. If one knows that the rifles are being used in extreme warm areas or being shot hot we use a hardener that get's post cure heat treatment at higher temperatures. We use this type on most competition rifles. BTW, post cure before releasing the action from the stock. All goes into an oven.
edi

 

[ntsqd]

The comparison that I posted a while back with some minor edits:

You made me curious, so I looked up their properties. Devcon offers their Metallic Putties in these flavors: Steel (ST), Aluminum, Stainless Steel (SST), Bronze (BR), and Titanium (Ti). Click on the "TDS" button to the right to get a pdf of the properties of each.

Devcon Steel (ST) Putty (10110)
Devcon Aluminum (AL) Putty (10610)
Devcon Stainless Steel (SST) Putty (10270)
Devcon Bronze (BR) Putty (10260)
Devcon Titanium (Ti) Putty (10760)

Cf-Thermal Expansion as of this writing (19/05/22):
ST: 48in^2*F°EE-6
AL: 29in^2*F°EE-6
SST: 34in^2*F°EE-6
BR: 33in^2*F°EE-6
Ti: 22in^2*F°EE-6

Compressive Strength:
ST: 8260psi
AL: 8420psi
SST: 8400psi
BR: 8540psi
Ti: 15,200psi

Shrinkage:
ST: .0006in/in
AL: .0008in/in
SST: .0010in/in
BR: .0010in/in
Ti: .0010in/in

Ti is attractive for it's Cf-TE and Comp Strength, but the shrinkage kills it. Their shrinkage also eliminates the SST & BR putties.

AL putty is slightly higher in compressive strength and gives up .0002in/in in shrinkage to the ST putty. So in the total action length of the Howa Mini it will have shrunk about .001in more than the ST putty. AL has ~40% lower Cf-TE than ST and for me makes it the obvious choice.

Note that the page for each putty is linked.
It has been a source of curiosity ever since I looked up all of that info that the AL Putty (10610) has a lower thermal expansion than does the often touted as the best Devcon choice, Steel Putty (10110) and it has a higher compressive strength than the Steel Putty. The Ti Putty (10760) blows everything else out of the water in compressive strength, but it's shrinkage is one of the three worst. For the cost difference I'm not buying the Ti, the AL works well enough.

Later in that thread I posted this:

While I was at it, I looked up Marine Tex. So far I've only found its compressive strength listed.
Gray: 13,000psi
White: 8,700psi
I've asked for the other info & will post it when/if I get it.

I never did receive any further info on Marine-Tex. No idea what it's shrinkage rate is, but the only materials that I know of that have no shrinkage in changing phase from liquid to solid are a couple Bismouth alloys. And I'll bet even those too shrink, just not enough to make a practical difference.

 

[DoneNOut]

The comparison that I posted a while back with some minor edits:


Note that the page for each putty is linked.
It has been a source of curiosity ever since I looked up all of that info that the AL Putty (10610) has a lower thermal expansion than does the often touted as the best Devcon choice, Steel Putty (10110) and it has a higher compressive strength than the Steel Putty. The Ti Putty (10760) blows everything else out of the water in compressive strength, but it's shrinkage is one of the three worst. For the cost difference I'm not buying the Ti, the AL works well enough.

Later in that thread I posted this:

I never did receive any further info on Marine-Tex. No idea what it's shrinkage rate is, but the only materials that I know of that have no shrinkage in changing phase from liquid to solid are a couple Bismouth alloys. And I'll bet even those too shrink, just not enough to make a practical difference.

So that 10610 is the ticket, eh?