[TheForge] Upside down Press - oh what a tangled web weweave

Fri Aug 26 17:52:44 EDT 2005

Bruce all of those you noted below have been and are being used -- but none 
are easy to use and all have various problems compared to good old mineral 
oil hydraulic fluid.  I don't know of any being used on a regular bases in 
low cost systems.

Just a few of the reasons why.  All of the water based / water glycols have 
major pump problems especially with the low cost pump systems that us 
blacksmiths want to use.  Not may blacksmiths are ready to put $ 2000 to $ 
4000 pumps in their systems.  Seals, hose etc all have to be correct for the 
given fluid  which means different valves and cylinder or change out of 
seals in valves and cylinders.  Oil in water systems require a full time lab 
to keep them "right" and running.  All of these have been used in industrial 
systems and can be made to work but it takes a lot of knowledge and 
attention to detail.
As to the three types of synthetic fire-resistant fluids manufactured, 
phosphate esters, chlorinated (halogenated) hydrocarbons, and synthetic base 
(a mixture of these two).  None are an easy change out in low cost hydraulic 
systems.  Like the water systems they all require special equipment and 
seals.  Some have a very costly history -- in terms of environmental impact, 
can you say PCB's.  The PCB's systems are no longer on the market but the 
memory is long and expensive clean up is on going -- which one will be the 
next nightmare?

I happen to be in the camp of using mineral oil hydraulic systems with 
correct designs to keep them from contacting hot metal rather than to let 
the fluid come in contact with the hot metal.  The pump, valve and cylinder 
life of such systems quickly pays for doing the design right over shorter 
life of pumps, valves and cylinders in systems with non mineral oil 
hydraulic fluids.  Just my experience.

Dave Smucker
----- Original Message ----- 
From: "Bruce Freeman" <FREEMAB at pt.fdah.com>
To: <theforge at mailman.qth.net>
Sent: Friday, August 26, 2005 4:19 PM
Subject: Re: [TheForge] Upside down Press - oh what a tangled web weweave

I can see how flammability of hydraulic fluid could be a concern, but why 
not go with a non-flammable hydraulic fluid in that case.  See below:
Bruce
NJ

from: www.uniqema.com/lubricants/lit/lub4/page5.html

4-5. Types of Hydraulic Fluids
a. Petroleum. Petroleum-based oils are the most commonly used stock for 
hydraulic applications
where there is no danger of fire, no possibility of leakage that may cause 
contamination of other products,
no wide temperature fluctuations, and no environmental impact.
b. Fire resistant. In applications where fire hazards or environmental 
pollution are a concern, waterbased
or aqueous fluids offer distinct advantages. The fluids consist of 
water-glycols and water-in-oil
fluids with emulsifiers, stabilizers, and additives. Due to their lower 
lubricity, piston pumps used with
these fluids should be limited to 20,670 kPa (3000 lb/sq in.) Furthermore, 
vane pumps should not be used
with water-based fluid unless they are specifically designed to use such 
fluids.
(1) Water-glycol. Water-glycol fluids contain from 35 to 60 percent water to 
provide the fire
resistance, plus a glycol antifreeze such as ethylene, diethylene, or 
propylene which is nontoxic and
biodegradable, and a thickener such as polyglycol to provide the required 
viscosity. These fluids also
provide all the important additives such as antiwear, foam, rust, and 
corrosion inhibitors. Operating
temperatures for water-glycol fluids should be maintained below 49 EC (120 
EF) to prevent evaporation
and deterioration of the fluid. To prevent separation of fluid phases or 
adverse effects on the fluid
additives, the minimum temperature should not drop below 0 C (32 F). 0 0
(a) Viscosity, pH, and water hardness monitoring are very important in 
water-glycol systems. If water
is lost to evaporation, the fluid viscosity, friction, and operating 
temperature of the fluid will increase. The
end result is sluggish operation of the hydraulic system and increased power 
consumption. If fluid
viscosity is permitted to drop due to excessive water, internal leakage at 
actuators will increase and cause
sluggish operation. A thin fluid is also more prone to turbulent flow which 
will increase the potential for
erosion of system components.
(b) Under normal use, the fluid pH can be expected to drop due to water 
evaporation, heat, and loss of
corrosion inhibitors. The fluid pH should be slightly alkaline (i.e., above 
pH8) to prevent rust. However,
because of their volatility and toxicity, handling of the amine additives 
that stabilize the pH is not
recommended. Therefore, these essential additives are not usually 
replenished. Fluids with pH levels that
drop below 8 should be removed and properly discarded.
(c) Make-up water added to the system must be distilled or soft deionized. 
The calcium and
magnesium present in potable water will react with lubricant additives 
causing them to floc or come out of
solution and compromise the fluid's performance. When this condition occurs 
the fluid is permanently
damaged and should be replaced. To prolong the fluid and component life, 
water added to the system
should have a maximum hardness of 5 parts per million (ppm).
(2) Water-oil emulsions
(a) Oil-in-water. These fluids consist of very small oil droplets dispersed 
in a continuous water phase.
These fluids have low viscosities, excellent fire-resistance, and good 
cooling capability due to the large
proportion of water. Additives must be used to improve their inherently poor 
lubricity and to protect
against rust.
(b) Water-in-oil. The water content of water-in-oil fluids may be 
approximately 40 percent. These
fluids consist of very small water droplets dispersed in a continuous oil 
phase. The oil phase provides good
to excellent lubricity while the water content provides the desired level of 
fire-resistance and enhances the
fluid cooling capability. Emulsifiers are added to improve stability. 
Additives are included to minimize
rust and to improve lubricity as necessary. These fluids are compatible with 
most seals and metals
common to hydraulic fluid applications. The operating temperature of 
water-in-oil fluids must be kept low
to prevent evaporation and oxidation. The proportion of oil and water must 
be monitored to ensure that the
proper viscosity is maintained especially when adding water or concentrated 
solutions to the fluid to make
up for evaporation. To prevent phase separation, the fluid should be 
protected from repeated cycles of
freezing and thawing.
(c) Synthetic fire-resistant fluids. Three types of synthetic fire-resistant 
fluids are manufactured:
phosphate esters, chlorinated (halogenated) hydrocarbons, and synthetic base 
(a mixture of these two).
These fluids do not contain water or volatile materials, and they provide 
satisfactory operation at high
temperatures without loss of essential elements (in contrast to water-based 
fluids). The fluids are also
suitable for high-pressure applications. Synthetic fluids have a low 
viscosity index, anywhere from 80 to -
400, so their use should be restricted to relatively constant operating 
temperatures. When required to
operate at low temperatures, these fluids may require auxiliary heating. 
Synthetic fluids also have high
specific gravities so pump inlet conditions must be carefully selected to 
prevent cavitation. Phosphate
esters have flash points above 204 EC (400 EF) and auto-ignition 
temperatures above 483 EC (900 EF),
making these fluids less likely to ignite and sustain burning. Halogenated 
hydrocarbon fluids are inert,
odorless, nonflammable, noncorrosive, and have low toxicity. Seal 
compatibility is very important when
using synthetic fluids. Most commonly used seals such as Nitrile (Buna) and 
Neoprene are not compatible
with these fluids.

>>> davesmucker at hotmail.com 8/26/2005 2:31:41 PM >>>
I think "Chuck's Design" is the safest one out there.  Especially getting
all of the hydraulic below the hot metal where it can be shielded.  I don't
know of a blacksmith killed or badly burn with a press accident but it may
very well happen.  I know of several very bad industrial accidents of this
type.  Hot metal and a spray of hydraulic oil do not go well together.

By the way -- SACK of Germany has made some very large industrial forging
press of this design.  Union Electric Steel and Forging in Pittsburgh has
one.  SACK is now part of the SMS Demag AG group.

Dave

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