"Dave" wrote in message
...
On Wed, 30 Jul 2008 06:58:45 -0400, said:

Vinegar is greatly diluted acetic acid. Something around 5% acidity.
Acetic acid
can also be 20%, 50%,100%, or anything in between, all which might
surprise you
with their effects on metals including stainless.

Where does one buy the higher concentrations? I'm looking for something to
apply to the aluminum stanchion bases in order to get loose the stainless
bolts securing the stanchions to the bases. Might the higher
concentrations
of acetic be what I'm looking for?

I would not slosh strong acid of any sort around anything on your boat as
you never know where it will seep down and end up.
I would first heat the bolt with one of those precision small burners you
can attach to a can of gas. The bolt will expand but the aluminium will
expand more and this should break the bond and make extraction easier. You
can get really precise flames with the right sort of burner so it will
concentrate the heat where you want it and not damage the surroundings..

On 30 Jul 2008 08:56:02 -0500, Dave wrote:

On Wed, 30 Jul 2008 06:58:45 -0400, said:

Vinegar is greatly diluted acetic acid. Something around 5% acidity. Acetic acid
can also be 20%, 50%,100%, or anything in between, all which might surprise you
with their effects on metals including stainless.

Where does one buy the higher concentrations? I'm looking for something to
apply to the aluminum stanchion bases in order to get loose the stainless
bolts securing the stanchions to the bases. Might the higher concentrations
of acetic be what I'm looking for?

Photography supply outlets have the pure stuff.

Casady

On Wed, 30 Jul 2008 06:58:45 -0400, wrote:

On Wed, 30 Jul 2008 01:21:16 GMT, (Richard Casady)
wrote:

On Thu, 10 Jul 2008 06:35:50 -0400, wrote:

Just the same, I know quite a few folks who thought all "Silicone" was the same,
and they bought their's at Home Depot to save a few bucks. OOPS! The home
version releases ACID as it cures. Pretty hard on boat hardware.

Acetic acid, that is, vinegar. Not in a class with some other acids
for corrosiveness, but not desirable. Won't normally do much to
stainless.

Casady

Vinegar is greatly diluted acetic acid. Something around 5% acidity. Acetic acid
can also be 20%, 50%,100%, or anything in between, all which might surprise you
with their effects on metals including stainless.

We are discussing silicone caulk. What is the concentration of the
acid?

Casady

On Wed, 30 Jul 2008 10:42:02 -0400, wrote:

On 30 Jul 2008 08:56:02 -0500, Dave wrote:

On Wed, 30 Jul 2008 06:58:45 -0400, said:

Vinegar is greatly diluted acetic acid. Something around 5% acidity. Acetic acid
can also be 20%, 50%,100%, or anything in between, all which might surprise you
with their effects on metals including stainless.

Where does one buy the higher concentrations? I'm looking for something to
apply to the aluminum stanchion bases in order to get loose the stainless
bolts securing the stanchions to the bases. Might the higher concentrations
of acetic be what I'm looking for?

I don't know. Have you tried PB Blaster, and a hammer driven impact
driver?

If you want to try a strong acid, use the stuff they sell for
dissolving barnacles. Just be very careful with it, and don't
accidentally inhale the fumes.

Hydrochloric, sold as muratic for cleaning mortar from bricks, and for
adjusting the acidity of swimming pools.

Casady

wrote:
Hammer DRIVEN Impact driver

Like this:

http://www.harborfreight.com/cpi/cta...emnumber=37530


When you strike this device with a hammer, it applies the impact, as
well as turning force at the same time. Very effective. Japanese
motorcycles used to have steel Phillips head screws holding on the
aluminum engine parts. This tool could get them out, even of the screw
heads were already partially rounded out from previous attempts.

Absolutely correct! Still have mine I bought in the '70s to pull the
screws out of my Kawasaki. Works like a champ.

Keith Hughes

wrote:
On 30 Jul 2008 11:48:01 -0500, Dave wrote:

On Wed, 30 Jul 2008 12:32:47 -0400, said:

Hammer DRIVEN Impact driver

Like this:

http://www.harborfreight.com/cpi/cta...emnumber=37530


When you strike this device with a hammer, it applies the impact, as
well as turning force at the same time.
Might be worth a try. I have one of those and have used it to remove some
tough fittings. Didn't occur to me that banging and twisting on the head end
might be more effective than trying to simply drive the bolt from the
threaded end.

It's not quite a substiture for a pnuematic impact driver, but when a
compressor is not available, it's a good alternative.

Sorry, I missed what the OP's use would be, but for slotted/phillips
screw removal, the hammer version is actually much more effective, since
the downward (or inward if you prefer) force will keep the screw head
from stripping. For hex/allen heads, I'd agree with you about the
pneumatics.

Keith Hughes

wrote:
On Wed, 30 Jul 2008 11:39:39 -0700, wrote:


wrote:

He's trying to free steel bolts from aluminum after 30 or 40 years.

Ahh...

We
are in agreement about the hammer driver vs. the pneumatic gun for
screws, although, when I had air available, I always tried each screw
first with the small air gun first, because it usually worked, and was
so fast. Recalcitrant screws got a follow-up from the hammer driver.
Occasionally a screw was so welded to the aluminum that the screw head
would twist and break off, but that thankfully didn't happen often.

No, but it happened *too* often :-) And 30-40 years ago, I couldn't
afford a compressor!

Keith

On Wed, 30 Jul 2008 14:10:25 -0400, wrote:

On Wed, 30 Jul 2008 16:45:17 GMT, (Richard
Casady) wrote:

On Wed, 30 Jul 2008 06:58:45 -0400, wrote:

On Wed, 30 Jul 2008 01:21:16 GMT, (Richard Casady)
wrote:

On Thu, 10 Jul 2008 06:35:50 -0400, wrote:

Just the same, I know quite a few folks who thought all "Silicone" was the same,
and they bought their's at Home Depot to save a few bucks. OOPS! The home
version releases ACID as it cures. Pretty hard on boat hardware.

Acetic acid, that is, vinegar. Not in a class with some other acids
for corrosiveness, but not desirable. Won't normally do much to
stainless.

Casady

Vinegar is greatly diluted acetic acid. Something around 5% acidity. Acetic acid
can also be 20%, 50%,100%, or anything in between, all which might surprise you
with their effects on metals including stainless.

We are discussing silicone caulk. What is the concentration of the
acid?

Casady

Don't know and don't care. Just pointing out that not all acetic acid
is 5%.

Of course not. The caulk is undoubtedly less than one tenth that.

Casady

On 30 Jul 2008 14:33:05 -0500, Dave wrote:

On Wed, 30 Jul 2008 14:46:05 -0400, said:

He's trying to free steel bolts from aluminum after 30 or 40 years.

Not quite correct. The PO apparently removed the stanchions from their bases
each year when he covered the boat, and I also removed them from their bases
the year after I bought the boat. So it's been about 3 years since they were
loose. I'm surprised at how quickly the bolts became irremovable.

Tapping and patience often works with frozen bolts. Soaking with your
choice of a "rust-buster," then whacking repeatedly, coming back later
and whacking a bit more. Only loosen the nut enough to protect the
end threads from the hammer, and bang on that, not hard enough to
deform the threads so the nut won't come off. But even banging in the
direction of insertion provides corrosion freeing action.
Might work for you, but use due caution not to overdo it.
I've used the method with good success. Even works on recalcitrant
pipe joints, preventing smaller rusted pipe diameters from twisting
off in the joint.

--Vic

Dave brought forth on stone tablets:
On Wed, 30 Jul 2008 16:17:15 -0500, Vic Smith
said:


Soaking with your
choice of a "rust-buster," then whacking repeatedly, coming back later
and whacking a bit more. Only loosen the nut enough to protect the
end threads from the hammer, and bang on that


Been there. Done that, though I'm not so concerned about the end threads as
the replacement bolts are readily available. In fact I hit the nut
protecting the threads hard enough with the hammer to deform the threads
even with the nut on.

A nut buster is sometimes the best and easiest solution, if you can get
it on the nut, and if the nut is a "low value" one. It is frequently my
FIRST choice.

bob