I'm building my latest contraption. Its a large metal plenum for directing
the air from an air blast sprayer down onto three rows of strawberries.
Think of an air duct for heating with three registers, only use a forty
horse power fan and very small openings.

I made the whole plenum out of sheets of 1/8" steel, and 1/8" round tubing
of different sizes. Its all tack welded together now. I'm going to finish
welding for strength this afternoon. I'll stitch weld with a three inch or
so gap between every one inch of weld.

I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

Karl

"Karl Townsend" remove .NOT wrote in
message ink.net...
I'm building my latest contraption. Its a large metal plenum for directing
the air from an air blast sprayer down onto three rows of strawberries.
Think of an air duct for heating with three registers, only use a forty
horse power fan and very small openings.

I made the whole plenum out of sheets of 1/8" steel, and 1/8" round tubing
of different sizes. Its all tack welded together now. I'm going to finish
welding for strength this afternoon. I'll stitch weld with a three inch or
so gap between every one inch of weld.

I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

Karl


There's a product that's like foil duct tape, check a heating/cooling supply
house. Here's a couple of links. This stuff is great!

http://www.hermanscentral.com/site/d...7048F82458EE5A

http://amconservationgroup.com/catalog.aspx?catid=169

In article . net,
"Karl Townsend" remove .NOT wrote:

I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

There is a liquid duct sealant, some sort of flexible-rubbery stuff.
Don't know how paintable it is.

Then there's household caulk, which can be had in known to be paintable
formulations.

--
Cats, coffee, chocolate...vices to live by

"Karl Townsend" remove .NOT wrote in
message ink.net...
I'm building my latest contraption. Its a large metal plenum for directing
the air from an air blast sprayer down onto three rows of strawberries.
Think of an air duct for heating with three registers, only use a forty
horse power fan and very small openings.

I made the whole plenum out of sheets of 1/8" steel, and 1/8" round tubing
of different sizes. Its all tack welded together now. I'm going to finish
welding for strength this afternoon. I'll stitch weld with a three inch or
so gap between every one inch of weld.

I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

Karl


Sounds like a good use for Automotive seam sealer...Paint on or in a
caulk tube.

www.eastwood.com or any auto paint store should have it.

HTH

Jeff

"Karl Townsend" remove .NOT wrote in
message ink.net...
I'm building my latest contraption. Its a large metal plenum for directing
the air from an air blast sprayer down onto three rows of strawberries.
Think of an air duct for heating with three registers, only use a forty
horse power fan and very small openings.

I made the whole plenum out of sheets of 1/8" steel, and 1/8" round tubing
of different sizes. Its all tack welded together now. I'm going to finish
welding for strength this afternoon. I'll stitch weld with a three inch or
so gap between every one inch of weld.

I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

Karl



What more would you want??
http://www.homedepot.com/prel80/HDUS...e=09-8350843-2
and you can buy it at Home Depot too!
We use buckets of a similar product where I work. The stuff goes on with a
1" paint brush, it has the consistency of pudding. It stays flexible and you
can paint over it once it dries. It dries completely overnight.
Greg

....
We use buckets of a similar product where I work. The stuff goes on with a
1" paint brush, it has the consistency of pudding. It stays flexible and
you can paint over it once it dries. It dries completely overnight.

Thanks, this is what I'll use.

Karl

Karl, would continuous welds be sufficient? It does not seem as though
you have a shortage of welding electrodes.

Beside taking forever to do it, the welds will warp the sheet metal.

FWIW, I mig this. The electrodes I have are only good for thicker metal.

Karl

Tom Gardner wrote:

"Karl Townsend" remove .NOT wrote in
message ink.net...
I'm building my latest contraption. Its a large metal plenum for directing
the air from an air blast sprayer down onto three rows of strawberries.
Think of an air duct for heating with three registers, only use a forty
horse power fan and very small openings.

I made the whole plenum out of sheets of 1/8" steel, and 1/8" round tubing
of different sizes. Its all tack welded together now. I'm going to finish
welding for strength this afternoon. I'll stitch weld with a three inch or
so gap between every one inch of weld.

I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

Karl


There's a product that's like foil duct tape, check a heating/cooling supply
house. Here's a couple of links. This stuff is great!

http://www.hermanscentral.com/site/d...7048F82458EE5A

http://amconservationgroup.com/catalog.aspx?catid=169

I have used the heavy foil tape enough that I would not use it in a
vibration area.

I would look to acrylic or silicone caulk for something like this. More
likely acrylic, given the paint requirement, though you could use paint
that is color matched to the silicone, like white.

Cheers
Trevor Jones

On Sun, 26 Mar 2006 13:37:03 GMT, "Karl Townsend"
remove .NOT wrote:

I'm building my latest contraption. Its a large metal plenum for directing
the air from an air blast sprayer down onto three rows of strawberries.
Think of an air duct for heating with three registers, only use a forty
horse power fan and very small openings.

Strawberries? What happened to the apples? ;-) I go through
Oxnard regularly, right past the pro pesticide places (AgRX for one)
that own these blast sprayers. And they're put together to be rugged.

I made the whole plenum out of sheets of 1/8" steel, and 1/8" round tubing
of different sizes. Its all tack welded together now. I'm going to finish
welding for strength this afternoon. I'll stitch weld with a three inch or
so gap between every one inch of weld.

I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

More weld. Seriously - go back and fill in all the blank spots
between the stitch welds, an inch at a time so it doesn't warp on you.
Then get out the angle grinder for the pre-paint clean up.

If this blast sprayer is to be mounted on a tractor and bounced
around regularly by hired farm workers who don't care about being
gentle on the equipment (they just want to get done and go home) you
have to build it bulletproof or it will crack and fall apart. And
they won't say anything about it when the crack appears, only when it
fails totally.

(And they get the afternoon off while you fix it.)

Put X bracing anywhere it might twist, brace all the register
opening arms, triangulate the arms mounting it to the tractor
three-point and the fan unit. Stiffen any large flat metal areas so
they don't "oilcan" on you. Then go drive it around and have someone
watch and videotape while you hit bumps - you may be able to see where
it needs more reinforcement before breaking it.

After that, you can get spot putty and urethane based seam
sealer/filler (to make your welds look good) from an auto parts with
an auto paint department, use stuff that is meant to be painted.
They'll also have the 'tractor paint' for the finish coat.

And you might want to paint the inside so it doesn't rust as fast.

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

"Karl Townsend" remove .NOT wrote in
message ink.net...
I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

When we built large air handlers for a convention center, we simply sent one
of our 'rats' (a young guy) down inside the duct with several boxes of Butyl
caulk and a air powered caulking gun. The stuff takes a couple of days to
set up strong, but it will withstand 8-10 psi across a 1/4" gap, Never EVER
loses its flexibility (out of sunlight), and sticks to ANYTHING.

LLoyd