bedding not "hard"

R

rsmithsr

Well-known member
so i switched to marine tex, but had a bit of brownell's steel bed left.
mixed up a batch and bedded a 40x single shot in a mcmillian stock and let it sit for
20 hours at about 78*.
popped it out this am and the surface is like firm plastic..not rock hard as usual.
it's out in the garage at 100 plus.
the excess is the same very firm but not hard.
the only "contaminate" is the usual release agent 2 coat's of johnsons paste wax/buffed.

comments suggestions ???
never before
 
When I've had this happen I've sometimes shot the rifle and been happy (Sometimes bedding need not be hard, some bedding compounds aren't even designed to get hard)

Sometimes I've routed it back out.

In any case this is specifically why I now use only Acraglas by WEIGHT and set my own thixotropicity using fumed silica. I popped three out this weekend all hard enough to cut fingers.

I like them to be ringing hard, same 'feel' as the gelcoat skin.

I pour epoxy onto my scale, multiply by .263, add the two together and have had results I'm consistently happy with.

Araldite
Bisonite
Marine Tex
Acraglas Gel
Devcon
Pro-Bed


All in my past.


Now it's hefty containers of powdered metals, Mg, SS, CU, AL etc, a 'YUGE bag of Aerosil and a bucket of Smith stains and I pretty much make any formulation I want from scratch

And they get HARD, every time :)
 
rsmithsr said:
so i switched to marine tex, but had a bit of brownell's steel bed left.
mixed up a batch and bedded a 40x single shot in a mcmillian stock...
Click to expand...

I'm a bit confused...are you saying you mixed Marine Tex and Steel Bed together? -Al
 
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Sounds like a do-over to me...

When I've had that happen I assume I got the mix wrong. Epoxy curing is a chemical reaction, not a "drying out" so putting it in your hot garage probably won't help (probably won't hurt either, I just wouldn't expect any improvement).

Good luck!

GsT
 
old material will sometimes turn out that way. it might be quite awhile before it fully cures. there are mixes that get hard to a pliable state in about 4-8 hours but full cure will not be reached for at least 48 hours sometimes longer. Adding heat is not always the best choice- some do not react like you likely expect at elveated temperatures. In some case elevated temps will actally cause a reversal or severly slow the chemical reactions down. thickness also plays a role.
 
I'd knock it out and redo it. Bedding needs to be hard enough so that the barreled action returns/remains in the same physical location from shot to shot. A semi-pliable material will never accomplish that.

I tried several semi-pliable bedding materials at one point. All were a bigger bust than Christina Hendricks. :eek:

Good shootin'. -Al
 
WELL IT GOT HARD!
my guess is the catalyst was going bad and slowed down the expected process.
time heals all...well mostly
 
most have shelf life tho is is not always listed.

most stuff is temp sensitive

pretty low humidity and used in a 78 degree facility
 
Strongest epoxy joints often come from heating of the epoxy as it hardens.

Attaching tie downs to hold cables on aircraft racks we generally tried to use
screws to mechanically hold the tie down to the rack.
U-2 racks go through very large temperature swings in regular use.
From 100F on the ground to -65C at altitude.

When Mt. Pinatubo went off the temperatures at operating altitude when down
by another ~-20 C from previous levels.

We had to adjust some ram air cooling scoops to avoid 'electron freeze out' in
power supply semiconductors.

For the most part we could take care of it by turning the equipment on at lower
altitude and keeping it on as the plane climbed to cruise altitude.

Throw a little more fuel onboard to make up for the equipment needing to stay on
as you climbed up to cruise.
 
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brickeyee said:
Strongest epoxy joints often come from heating of the epoxy as it hardens.

Attaching tie downs to hold cables on aircraft racks we generally tried to use
screws to mechanically hold the tie down to the rack.
U-2 racks go through very large temperature swings in regular use.
From 100F on the ground to -65C at altitude.

When Mt. Pinatubo went off the temperatures at operating altitude when down
by another ~20 C from previous levels.

We had to adjust some ram air cooling scoops to avoid 'electron freeze out' in
power supply semiconductors.

For the most part we could take care of it by turning the equipment on at lower
altitude and keeping it on as the plane climbed to cruise altitude.

Throw a little more fuel onboard to make up for the equipment needing to stay on
as you climbed up to cruise.
Click to expand...
Interesting post, thank you for that
 
GeneT said:
When I've had that happen I assume I got the mix wrong. Epoxy curing is a chemical reaction, not a "drying out" so putting it in your hot garage probably won't help (probably won't hurt either, I just wouldn't expect any improvement).

Good luck!

GsT
Click to expand...

The curing reaction is accelerated by higher temperatures, like the vast majority of chemical reactions.
The few exceptions that get cold as they cure are often rather strange concoctions.
 
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