Re: [PSUBS-MAILIST] Carbon Fiber

[TeslaTony@aol.com]

In a message dated 8/13/00 8:57:07 PM Pacific Daylight Time, 
vulcania@interpac.net writes:

> A few more thoughts regarding composits versus steel for use in submarines:
>  
>  If you want to certify your boat, the pressure hull will have to be made of
>  steel to meet the regs, won't it?

Yeah, but what are the advantages to getting it certified? I'm not planning 
on using it for commercial purposes, although if I need to sell it I could 
have a few problems.....

>  People say "fiberglass is lighter", but is that what we really want?  Subs
>  displace a lot of water, and generate a lot of buoyancy.  They need to be
>  heavy to overcome this.  Steel is perfectly suited in this regard.  
Wouldn't
>  a composite hull need to be extraordinarily thick to be heavy enough to
>  counteract displacement buoyancy?  And then, wouldn't a steel hull of
>  identical outside dimensions and displacement, but with thinner walls, have
>  a greater and more useful inner volume available for occupants, components,
>  and such?

Actually I think that lighter _is_ better since I want to have one or more 
drop weights, and it's nice to be able to lose as much weight as possible if 
you have to surface fast.

>  Some say composits are easier to work with, but I don't know if that's 
true.
>  If carbon fiber needs a pressurized autoclave to cure properly; and in any
>  case we've got to make extensive masters and molds; and then go through the
>  labor of casting up and sanding down, I'm not all that sure it would be
>  easier.

Renting a pressurized autoclave is probably cheaper than getting a shop to 
make an elliptically shaped steel hull that can handle the proper depths, and 
using a foam core system might help with shaping the material (which might be 
a problem if it has to be heated, but that's why I asked you guys, isn't it?).

>  And then again, Chris brings up the valid issue of cost per square yard of
>  material.  Shop around, and steel is pretty reasonably priced.

Unfortunately there are three steel suppliers in my local area, one only does 
"1018" (very soft steel, no good for a sub), the other two are junkyards that 
I refuse to do business with unless I absolutely have to.
Now I could always order my stuff directly from the manufacturer, but how 
much would 1000+ lbs. cost to ship? I think the autoclave and the composites 
are starting to look cheap....

>  The basic tooling and manufacturing methods used when working steel are
>  pretty modest, really.  It's great stuff, and fun to work with.  And for
>  those few pieces you can't form yourself, there are shops that will do it
>  for you.

After doing some blacksmithing I got pretty hooked on steel, although my 
equipment consists of one coal-fired antique wagonback forge, a 55# cast iron 
anvil, misc. hammers, chisels, punches and stands, better for making swords 
than subs (or plowshares).
 As for someone else being able to make one of the hulls I want...I dunno, 
it's elliptical, 10+ feet long, 4- or 5- feet wide and a little flattened, 
not exactly sure how flat it will be though, and I have never seen any 
equipment yet that can do something like that yet, nor have I seen anything 
like it either.

>  If anyone is inclined toward composits because of an aversion to working
>  with steel due to a lack of training or equipment,   I suggest get into
>  metal fabrication.  It's not as intimidating as it looks; and once people
>  start working in steel, my experience is they usually come to like it quite
>  a bit.
>  
>  VBR,
>  
>  Pat
>  

Hey, maybe one of you guys can prove me wrong about Carbon Fiber or other 
Composites being cheaper and easier for me to use in the long run, you would 
make me one very happy man (especially since I don't know where to get 
composites in the first place).

Anthony