Home Forums Hunting & Shooting Ask The Gunwriters JB weld vs Devcon titanium epoxy

When used for the same application which one is better? I'm talkin about for bedding an action to bonding two pieces of metal togeather

You seems to be talking about two different applications or uses. Epoxy putties consist of an epoxy adhesive base with metal filler. It's the epoxy that bonds; the filler is just that - filler. If I want to bond two surfaces, I'd use a good epoxy cement, not a putty, especially if there is no gap to fill.

Neither would be my first choice for bedding a rifle. JB Weld works, but it is a two part consumer product, relatively cheap for a reason. I used Devcon titanium to bed a rifle - once. It is hellishly expensive, and I found its working time to be short, shorter than other similar products I had used. For the cost it didn't seem to provide any particular advantage, although volume for volume, titanium is lighter. It still seems fairly heavy to me.

For routine adhesive jobs I use West Systems T-88. If I ever bed another rifle I'll probably use Marine-Tex grey or Brownell's steel bed. If I want to customize the consistency and add strength, I still like traditional Acraglas. Acraglas also has the advantage of hardening well even in very thin coats, something not all epoxies do well.

Paul

I've used the Brownells kits and JB Weld. Both were fine for that application. I can't speak to the bonding capabilities though.

Never hurts to check a manufacturers literature to see what the design parameters are for a product. From Devcon:

High-tech, titanium-reinforced epoxy putty engineered for making critical repairs to machinery and precision parts. Restore bearing housings and scored shafts; rebuild wear rings, hydraulic rams, and valves; repair equipment and parts
that require a machined finish. So if that is your use, I'd say Devcon has your product.

For bonding metals, the design of the joint and interface is truthfully the most important aspect, then you can look at what would be a good product for that use. If however you have a metal part that is cracked, rarely is using an epoxy product to bond the part going to work and you need to look at welding the part.

I've used JB in rifle applications for many years; had a hard time breaking the bases off a 375 that were bedded with it over 15 years ago.

I frequently use JB when repairing aluminum cased, two stroke engines which have spit rings and/or skirts and rammed the broken parts through the bottom of the crankcase. It works well for many applications.

The titanium stuff is too expensive to justify in a bedding application. I have had good luck bedding with Devcon 11010. I also like Marine Tex. I have also used Acra glas with aluminum powder. I don't feel that Acra glas really ever gets hard like these other two do. I have to heat cure it.

JB Weld works great for bedding a rifle.

Marine Tex....only way to fly.

I agree, except about Acraglas not getting really hard, assuming you are talking about the original Acraglas. I have found thin test strips get hard enough to snap when you bend them much, and that seems harder than some other types of epoxy. As I mentioned in my earlier post, I like Acraglas for final skim coats, thinking that takes care of shrinkage of the main bedding mass.

One thing about original Acraglas, you have to get the 1:4 mix exactly right. It isn't forgiving if you're much off that ratio, and it may not harden correctly.

Everyone has to define "works" for himself. Unless you have technical knowledge of epoxies and a means to measure shrinkage and hardness precisely (I don't), it's pretty subjective. There is also the question of longevity and resistance to solvents.

Paul

Why better than 11010?

I read an article one time about the Chandlers and their tactical rifles. They bedded them with Devcon and then a final skim coat of marine tex! I don't remember why but they found this was the best of the best. I have never tried to do it that way.

This is the reason to use something like Devcon (I use the aluminum version): it shrinkage is absolutely minimal -- making the skim coat unnecessary.

For a pro who counts time, not having to do a second coat justifies the extra expense (which for the Devcon aluminum is pretty reasonable to begin with).

That is an interesting take, and a matter of preference and priorities. It's along the lines of what "works" for different folks.

I first began using Devcon, both F-1 and F-2 aluminum, on the advice and writings of Bob Pease, who was primarily in benchrest circles. He absolutely recommended F-1 for a base, and the thinner F-2 for a skim coat. Also insisted on three days of curing time for each step. The most accurate rifle I ever owned was bedded by Bob.

No doubt time is money, and has to be paid for. That's why a customer and gunsmith have to be crystal clear on standards and expectations. There is no "one size fits all", or agreement on what is "the best".

Paul

Anyone know what the Devcon aluminum heat transfer rate is? Is it an insulator, or does it conduct heat?

Thermal Conductivity 1.73[cal/(secxcmx°C)]x10(-3)

Aluminum Putty (F) Data Sheet