Re: Annealing ovens

[protek@shreve.net]

Alan,
    The one I built was out of an available piece of aluminum channel maybe
8 inches wide and 12 inches high.  I used another smaller channel to
complete the cycle of air flow.  It would not be difficult to build a
larger oven that would  allow many more to be run at the same time.  I
could run two probably.  I figured that the main thing here is to have each
part of the window, all surfaces at the same temperature.  That is why I
used the fan.  It is a flue (Sp?) fan.  Grainger sells it to put inline
with heater exaust etc.  It can take the heat.  I used a resistive element
connected to a relay.  The relay was part of what is commonly called a
"Bang Bang" system.  It is on and off.  I wrote a BASIC program that with
some sensing knew the temperature and would cycle the relay.  I got fancy
with it.  I anticipated the temperature and compensated for the lag in
heating and cooling.  I do not think this is necessary though.  I just
placed the window in the vertical plane in a bracket that kept it stationary.

Gary

At 10:48 PM 3/1/99 -0800, you wrote:
>Gary,
>
>How difficult do you think it would be to build one that will run, oh.. 6
at a time
>?
>What does the port sit on ?
>
>Anyone else have a design ?
>
>I really do have to make one, I have 16 ports to anneal !!! and that's
just this
>sub.
>When Subview one is complete, I am going to use the experience gained to
build
>Subview 2.  This a little more than just a hobby, I'm working toward
building a
>certified sub.
>I do not intend to die with my dreams still inside me nor die inside my
dream on the
>same token.
>
>Any and all info and help greatly appreciated.
>
>Alan Long
>Subview
>
>Alan Long wrote:
>
>> Hi Gary,
>>
>> I take it that you are using the chart on page 284 ?
>> I believe the use of a safety factor of 5 is from A.B.S.
>> Thanks for pointing this out.
>>
>> protek@shreve.net wrote:
>>
>> >     I just looked up the short term critical loading failure
prediction for
>> > the window you mentioned and it is right at 725 PSI from the chart in
>> > Stachiw's book.  It recommended you use a factor of 8.  I built my
>> > annealing oven with a closed loop of aluminum with a high temp blower
>> > purchased from Grainger.  I packed the whole assembly in a plywood
(UhOh!)
>> > box with a lot of fiberglass insulation backed around it.  I have a
>> > resistive heater in the channel with a location where I can place the
>> > window inside the channel.  The circulating air keeps the temp constant.
>> > Stachiw's book has the numbers for annealing.  You need two cycles.  I
used
>> > a computer to monitor the temps and control the heating.  It took a
full 10
>> > hours to run one window.
>> >
>> > Gary B.
>> >
>> > At 09:05 PM 3/1/99 -0800, you wrote:
>> > >Hello again Jon,
>> > >
>> > >Well maybe it wasn't as load as it seemed, you see, this was my first
>> > destruction
>> > >test and I was exited and not sure what to expect,
>> > >it took me by surprise!  It sure did seem load... anyway...
>> > >
>> > >The "bang" was just the port.
>> > >The test chamber is about 3 ft in length and 18 in. dia.. It belongs
to my
>> > friend
>> > >Doug Previtt of Delta Oceanographics.
>> > >I feel very lucky to have access to his facilities, He is a very nice
guy.
>> >  He
>> > >has been building subs (about 7 or 8) for over 35 years.
>> > >His sub, the Delta has over 4000 dives all over the world with a perfect
>> > safety
>> > >record.  He has dove for many government agencies and institutions, and
>> > on, and
>> > >on, and on...  I think you get the idea.
>> > >
>> > >When I was a kid my hero was Clint Eastwood.
>> > >As an adult... sorry clint, doug has you beat !
>> > >He has done in his life what I am just beginning.
>> > >
>> > >Sorry, back to the subject.
>> > >
>> > >The view port I was testing was a flat, acrylic disc, 1 in. thick, flat
>> > bearing
>> > >surface flange, I.D. of 6 in, O.D. of 8. this of coarse gives me a DO/DI
>> > ratio of
>> > >1.333 which is above the minimum 1.25 acceptable. I needed the port to
>> > maintain
>> > >to 675 psi to get my safety factor of 5 and it blew at 760 psi which
puts the
>> > >depth at 1707 ft.  My operating depth goal is 300 ft. so I'm in the
green !.
>> > >Oh yeah, the port I tested was not even annealed, even better because
the
>> > ports I
>> > >use will be.
>> > >
>> > >Do you know anything about how to make a good port annealing oven ?
>> > >ttyl
>> > >Alan Long
>> > >Subview
>> > >Jonathan Shawl wrote:
>> > >
>> > >> Alan Long wrote:
>> > >>
>> > >> > Jon,
>> > >> >
>> > >> > Of coarse the chamber was water filled !
>> > >> > What did I say that made you feel I was using air ???
>> > >> > >It sounded like a gun shot !!!
>> > >>
>> > >> I didn't think it would be that loud if it was a small water filled
test
>> > rig.
>> > >> I guess I made an assumption, sorry about that.
>> > >> Was the bang just from the cracking or exploding plastic view port?
>> > >> How big was the water filled chamber? volume?
>> > >> How big was the lens?
>> > >
>> > >
>
>