I want to cut access ports into the top of 2 s/s water tanks. I did
this a while ago on my alum diesel tanks and it was easy to put covers
back on the cutouts - the alum is 1/4" thick and takes a 1/4" fine
thread easily with bolts every 2 inches and a 1/8" neoprene rubber
gasket. The s/s is thinner and won't hold a bolt. I'm thinking of
using s/s pop rivets to hold a 1/4" alum collar with 1/4" fine
threaded holes in the collar around the cutouts in the s/s tanks - and
using 1/4" alum plate covers again. Or I could use s/s plates held in
with alum pop rivets and drill them out when I want to gain access
again in another 5 or 10 years. The tanks are 25 years old and have
not had access before - but we're very careful what we put in them -
so this is not a frequent event.

Any other good options?

304 and 316 weld beautifully with a MIG welder but that may not be an
option with the tanks in place.

NT wrote:
I want to cut access ports into the top of 2 s/s water tanks. I did
this a while ago on my alum diesel tanks and it was easy to put covers
back on the cutouts - the alum is 1/4" thick and takes a 1/4" fine
thread easily with bolts every 2 inches and a 1/8" neoprene rubber
gasket. The s/s is thinner and won't hold a bolt. I'm thinking of
using s/s pop rivets to hold a 1/4" alum collar with 1/4" fine
threaded holes in the collar around the cutouts in the s/s tanks - and
using 1/4" alum plate covers again. Or I could use s/s plates held in
with alum pop rivets and drill them out when I want to gain access
again in another 5 or 10 years. The tanks are 25 years old and have
not had access before - but we're very careful what we put in them -
so this is not a frequent event.

Any other good options?



--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

I had a similar problem to solve on my tanks, which I made from 316 TI. I
went to a firm that manufactures food processing equipment and they showed
me an access hatch that they buy in Italy for about $150 US. They use the
hatch for tomato processing. The tank hatches are about 14" x 18". They are
2 part with the lids and hold downs all polished. The base is 2.5" tall,
bent from 5/16" plate and brush finished. They are supplied with gasket and
all hardware. They are designed for welding.
Steve

"NT" wrote in message
...
I want to cut access ports into the top of 2 s/s water tanks. I did
this a while ago on my alum diesel tanks and it was easy to put covers
back on the cutouts - the alum is 1/4" thick and takes a 1/4" fine
thread easily with bolts every 2 inches and a 1/8" neoprene rubber
gasket. The s/s is thinner and won't hold a bolt. I'm thinking of
using s/s pop rivets to hold a 1/4" alum collar with 1/4" fine
threaded holes in the collar around the cutouts in the s/s tanks - and
using 1/4" alum plate covers again. Or I could use s/s plates held in
with alum pop rivets and drill them out when I want to gain access
again in another 5 or 10 years. The tanks are 25 years old and have
not had access before - but we're very careful what we put in them -
so this is not a frequent event.

Any other good options?

You could do the same thing as the aluminum tanks but instead of threading
the bolt down you could thread the bolt up from inside the tank and locktite
them as to give you studs from the outside of the tank. I understand the
tank is thin but the threading would only have to hold the bolt in place
from underneath while you put a nut on. Pop rivets would most likely leak.
Can you buy a plastic flange and cover from maybe Ronco-Plastics? Don't put
aluminum in there if you don't have to.
Phil

"NT" wrote in message
...
I want to cut access ports into the top of 2 s/s water tanks. I did
this a while ago on my alum diesel tanks and it was easy to put covers
back on the cutouts - the alum is 1/4" thick and takes a 1/4" fine
thread easily with bolts every 2 inches and a 1/8" neoprene rubber
gasket. The s/s is thinner and won't hold a bolt. I'm thinking of
using s/s pop rivets to hold a 1/4" alum collar with 1/4" fine
threaded holes in the collar around the cutouts in the s/s tanks - and
using 1/4" alum plate covers again. Or I could use s/s plates held in
with alum pop rivets and drill them out when I want to gain access
again in another 5 or 10 years. The tanks are 25 years old and have
not had access before - but we're very careful what we put in them -
so this is not a frequent event.

Any other good options?

If you expect to use this access hole more than once, why not install a deck
plate? You cut a 4" hole, install the deck plate collar using flat head
screws with nuts on the inside (you have a 4" hole to reach through to put
the nuts on). The deck plate then screws into the collar and seals with an
O ring.

Only hard part is getting a 4" hole in stainless......


Rod

This is a very typical aviation application. Call http://www.skybolt.com/
and they can get you the part you need. Basically it is a machine thread
nutplate that you would rivit/pop rivit from the outside. You can use
countersunk pop rivits so that you have a flush finish for the gasket to
seal to.
Good luck
Bruce
"Rod McInnis" wrote in message
...


If you expect to use this access hole more than once, why not install a
deck
plate? You cut a 4" hole, install the deck plate collar using flat head
screws with nuts on the inside (you have a 4" hole to reach through to put
the nuts on). The deck plate then screws into the collar and seals with
an
O ring.

Only hard part is getting a 4" hole in stainless......


Rod

Check out http://www.seabuilt.com/noflash.html. They make great access
plates. Even if you don't want to buy you will get some good ideas.

Douglas

WOW!!! $120 for a 6" aluminum plate, 8 bolts and a ring that I could
turn out in 10 minutes with $8 worth of material. I need to stop
selling anchors and spend more time in the shop!

Douglas Nikkila wrote:
Check out http://www.seabuilt.com/noflash.html. They make great access
plates. Even if you don't want to buy you will get some good ideas.

Douglas

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

WOW doesn't do it. I saw one this afternoon at a marine jewellery
store - highway robbery of stupid people.



On Mon, 22 Mar 2004 21:55:39 -0500, Glenn Ashmore
wrote:

WOW!!! $120 for a 6" aluminum plate, 8 bolts and a ring that I could
turn out in 10 minutes with $8 worth of material. I need to stop
selling anchors and spend more time in the shop!

Douglas Nikkila wrote:
Check out http://www.seabuilt.com/noflash.html. They make great access
plates. Even if you don't want to buy you will get some good ideas.

Douglas

"Glenn Ashmore"writes:
WOW!!! $120 for a 6" aluminum plate, 8 bolts and a ring that I could
turn out in 10 minutes with $8 worth of material. I need to stop
selling anchors and spend more time in the shop!

You obviously have never been involved in private label women's cosmetics.

Lew