Marine Tex

Rflshootr

Member
I've been thinking about trying marine tex for bedding. Looking at the package, it says "handles like putty". Exactly how thick is this stuff? I'm mainly looking at the white marine tex because I have a project coming up with a white MBR stock.
 
I've been thinking about trying marine tex for bedding. Looking at the package, it says "handles like putty". Exactly how thick is this stuff? I'm mainly looking at the white marine tex because I have a project coming up with a white MBR stock.

Rflshootr,

Marine Tex is my go to bedding compound. It's all I've ever used, and I have been very happy with it. However, "handles like putty" is a bit of a stretch. The last thing you want to do is pick-up a gob of it and try and shape it into a ball or something, like one would do with a wood putty. You'll need a gallon of methyl-ethyl bad sh!t to get it off of your hands! Freshly mixed Marine Tex, to me, has about the same consistency as cold honey. If you let it set after mixing for 10 or so minutes, it will thicken up and tend to stay where you put it better than the freshly made stuff.

I use plumbers flux brushes to "paint" it in to place when doing a bedding job.

Hope this helps,
Justin
 
I've been thinking about trying marine tex for bedding. Looking at the package, it says "handles like putty". Exactly how thick is this stuff? I'm mainly looking at the white marine tex because I have a project coming up with a white MBR stock.

I like Marine Tex. I prefer it's consistency over Devcon. It's a tad thinner IME. Both are very good for bedding, though. I use about as much of one as I do the other...both with good results.
 
Rflshootr,

Marine Tex is my go to bedding compound. It's all I've ever used, and I have been very happy with it. However, "handles like putty" is a bit of a stretch. The last thing you want to do is pick-up a gob of it and try and shape it into a ball or something, like one would do with a wood putty. You'll need a gallon of methyl-ethyl bad sh!t to get it off of your hands! Freshly mixed Marine Tex, to me, has about the same consistency as cold honey. If you let it set after mixing for 10 or so minutes, it will thicken up and tend to stay where you put it better than the freshly made stuff.

I use plumbers flux brushes to "paint" it in to place when doing a bedding job.

Hope this helps,
Justin

Shows it comes in white or grey. Do you add color to it or use as is?
 
Shows it comes in white or grey. Do you add color to it or use as is?

Jerry,

I primarily use the Marine Tex gray, which comes out a very dark gray...closer to black, in my eyes. I don't try and color it.

Once, I didn't have any gray, so I used the white Marine Tex I got from a local boat shop. As white bedding compound would look pretty tacky, I dyed it using some black dye that Brownell's sells to color their Acra Glass compounds. Using less than scientific means (I looked at it, and poked at it with a dental pick), I could see no ill effects from using the dye. I can tell you that you don't need much dye. Start by sticking a toothpick in the dye, and sticking that in the Marine Tex. It will color-up nicely.

Some great advice, IIRC, came from Mike Bryant, who said mix it by weight, instead of volume, the ratio being 6.3 to 1 epoxy to hardener. ALOT easier than trying to mix by volume.

Justin
 
I use one of the digital Ultraship scales that I use for weighing packages. It's the Ultraship 50 that will go to 50 pounds. But, you push a button on the side of the scale and it will change units. I set it to weigh in grams. Put a plastic cup on the scale and zero it. Add the resin to the cup and see what it weighs. Say 63 grams for ease of figuring, divide that by 6.3 and add a little bit by little bit of hardner to the scale until I get up to a total weight of 63 + 10= 73 grams total. Mixing by weight gets you consistency from batch to batch that mixing by volume doesn't. Below is a link to the replacement model for the scale I use.

Ultaship 55
 
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So what do you use to weigh it? Something along the lines of a small postal scale?

Decades ago, while stationed in S. Korea in 1980/81, I picked up a Soehnle battery operated kitchen scale to use for weighing the CO2 cylinders of my Feinwerkbau air pistol. I bought it because it weighed in grams and ounces and it was about 20 bucks at the BX. It's now being used in my kitchen to track how much food is going down my gullet. It looks to be perfect for this purpose. I'm sure you can find something similar or better today.

DSCN0646.JPG
 
So what do you use to weigh it? Something along the lines of a small postal scale?

Rflshootr,

I use a RCBS electronic scale, and my process is exactly as Mike Bryant outlined above.

Once every couple of years, I go on a pudding binge and save all the little plastic containers. Wash em' out, and they are about perfect for mixing Marine Tex and such in.

Justin
 
Can anyone please tell me how does Marine-Tex compare to Devcon when it comes to machining and general wear an tear on a bedded rifle?

Ive only used Devcon but find it can break off on vulnerable edges quite easily.
 
Marine-Tex is good stuff. I use it or Devcon, depending on the application. One word of caution though: Do yourself a favor and find and look at the spec sheet for both the gray and the white products. The strength of the white is way lower than the gray. The white may work okay....I don't know because I've never used it.

-Dave
 
From the Marine Tex site...................White is lower on compressive strength but higher on shear. Both appear to be plenty strong if we torque the action screws to normal rifle action specs.

COMPRESSIVE STRENGTH*:
Gray - 13,000 PSI (910 Kg/Cm2)
White - 8,700 PSI (610 Kg/Cm2)
ADHESION SHEAR STRENGTH*:
Gray - 1,800 PSI (126 Kg/Cm2)
White - 2,300 PSI (160 Kg/Cm2)
CHEMICAL RESISTANCE:
Most common acids, alkalies and hydrocarbons.
TENSILE STRENGTH*:
Both White and Gray - 4,000 PSI (280 Kg/Cm2)
*All strengths are dependent upon make-up of substrate and surface preparation.

Anyone know how to figure the pressure applied to a 1.350 round action with both screws torqued to 45 in/lbs?
 
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.25" steel bolt @ 44 inch lbs unlubricated = ~900 lbs clamping force. Lubricated ~1060-1125 lbs clamping force.

Fixed it. Should have stated inch lbs. End result was correct as I used inch lbs in the original calc.
 
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Rflshootr,

I use a RCBS electronic scale, and my process is exactly as Mike Bryant outlined above.

Once every couple of years, I go on a pudding binge and save all the little plastic containers. Wash em' out, and they are about perfect for mixing Marine Tex and such in.

Justin

I use Marine Tex too. I've used acraglass devcon and JB weld and stayed with Marine Tex. I have considered trying Brownells steel bed but every time I get to the bottom of a big can of Marine Tex I have a job there that I don't want to experiment with so I order another big ole can of Marine Tex.
It is not putty.
 
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.25" steel bolt @ 44 ft lbs unlubricated = ~900 lbs clamping force. Lubricated ~1060-1125 lbs clamping force.


So that is ft lbs per bolt? Is that coarse or fine thread? Does the curved shape, bolt spacing and length of contact come into play?
 
Marine-Tex is good stuff. I use it or Devcon, depending on the application. One word of caution though: Do yourself a favor and find and look at the spec sheet for both the gray and the white products. The strength of the white is way lower than the gray. The white may work okay....I don't know because I've never used it.

-Dave

Dave,

Didn't know that about the white. Thanks for the heads-up.

Justin
 
.25" steel bolt @ 44 ft lbs unlubricated = ~900 lbs clamping force. Lubricated ~1060-1125 lbs clamping force.

Better take a look at your units........those numbers are in ft. Lbs, and guard screws are usually torqued to 45 - 60 in. lbs.

........that would have to be one heck of a strong 1/4" bolt, lol.
 
So that is ft lbs per bolt? Is that coarse or fine thread? Does the curved shape, bolt spacing and length of contact come into play?

Clamping force per bolt. If I recall correctly when calculating clamping force with a torque value course or fine doesn't matter nor would the curved action come into play much.
 
Better take a look at your units........those numbers are in ft. Lbs, and guard screws are usually torqued to 45 - 60 in. lbs.

........that would have to be one heck of a strong 1/4" bolt, lol.

Fixed it. Should have stated inch lbs. End result was correct as I used inch lbs in the original calc.
 
I found a clamp force calculator online. 60in/lbs on a 1/4" bolt gives 1200 lbs of clamping force. Times 2 bolts would equal 2400 lbs of clamping force. I'm not even sure it would multiply by the number of bolts as much as just spreading out the force equally. Therefore if the white Marine Tex can withstand 8700 psi of compression, which is 3.6x the rating and having a higher shear strength, then I would think that would be more then sufficient. Correct?
Just for numbers, 45 in/lbs=900 lbs/force. times 2 bolts=1800 lbs. 9.6x the rating of 8700.
Now I'm curious as to how much compression a fiberglass stock would handle without pillars. I'm thinking no where near as much without distortion.
 
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