As I recall Phenolics decompose around 300 deg C. Regardless of their excellent mechanical properties at elevated temperatures, when burnt, they give off a characteristic "Bakelite odour". The barest trace (I believe parts per billion)is easily detectable by smell or taste and that...
Look at marfotd's original spec:"To keep the inner stainless steel wall free of the burned food residu, we use ptfe(eriflon) scrapers (l=162mm,b=50mm,d=20) The scrapers
are pressed against the wall with a spring construction."
The key word here is burned. PTFE is great stuff but in...
Hi nbucska I agree with your sentiment but it woodn't do because you wood end up with a lot more fibre than you wood bargain! Try hitting wood with high pressure steam at 180 deg. C.
As an engineering excercise my choice would be to use a fully cross-linked high molecular (novalac) phenolic...
sciguyjim
I think you got on to something with your "long lasting non permanent bubbles" glycerine comment. It made me think how would gelatine or room temp setting agar agar go. Being such a thin film one of them might emulate a rapid set polymer.
Has anyone tried either?
Dave, this is way out of my area but could you punch the holes with a special forming punch - you might "extrude" a longer hole for more threads.
Thanks CoryPad I was not reccommending socket head cap screws only stating that we use them. We have space & streamlining issues that overide bearing area. The device is made of 316L stainless steel and fastened to aluminium with M10 316L socket head capscrews.
It is my experience that during a...
Stainless steel if continually worked hard becomes stiff & brittle. We have tried ss springs but they did'nt last as long & were unpredictable. We went back to conventional spring steel.
For what its worth I remember seeing a laboratory mixer which employed an external geared revolving magnet as the driver. A self centering magnetically attactive material was placed in a glass jar with the solution to be mixed and it worked a treat. Sounds like you will need strong magnets! Hope...
We have an application which requires a device to be "permanently" fastened to an aluminium base with M10 coarse thread ss scocket head cap screws. If the screws get loose the device fails. In operation it is always underwater and subject to constant vibration and occaisional severe...
There are two strengthening mechanisms present.
IRstuff is right ......"A rule of thumb is that stiffness increases as the cube of the thickness, so 6 folds works out 24^3 increase in stiffness, which explains why the difficulty in folding does not go linearly."......
But DVD is also...
To hero123
If you have direct experience and can provide practical information about a high rpm seal that will work in the 100mm x 120mm x 50mm space we have available we would appreciate.
The shaft rotates, the carrier does not
To seal or not to seal
We are involved in an R&D project. Part of the project requires that a seal isolates fluid from the inner chamber to the outside.
Fluid = water + fine abrasive particles
Shaft dia = 100mm
Carrier = 120mm
Len = 50mm
rpm = 1000 ~ 6000
Fluid pressure = 100 psi
We were...
I need to correct a typo ........."Fast rotating shafts are the Achilles heel of this group of materials . We sometimes come across marine".......
Should read ......" Grease and fast rotating shafts are the Achilles heel of this group of materials . We sometimes come across...
Hi Lovison
Amen to your observation: ........"It seems grease lubricated bearings require a little more clearance then we normally apply to water flush designs."...........
I am unfamiliar with ......."micarta CG (plastic graphite impregnated) sleeve bearing"........ but...
PTFE significantly lowers starting friction. In some cases so does PE (polyethylene, the poor man's PTFE).
As I see it your options are
1) Grease or oil that is significantly loaded with either PTFE or PE and keep using it forever.
2) Fix a scrubber, made of either PTFE or PE (PTFE is better...
Hi sciguyjim
Try polyvinyl acetate (PVA). It is dissolved by water (becomes milky white suspension)and easily dissolved by a number of organic solvents eg acetone as a clear liquid that dries to a clear plastic. Many fibreglass & resin sales outlets sell it as a brush/spray on liquid-to-film...
Hi Wraith
Polyurethane elastomers are one of the better cut resistant elastomers and polyurethanes generally have excellent wear properties. you will need a low durometer with good stretch properties.
olympic_hopeful makes an interesting observation. Re-enforced phenolics and some other thermosets resist the combined affects of heat and load better than nylon or poly acetal because they don't creep under hot load. If your job only gets warm, creep won't be an issue.
