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 Townsend" wrote in message news:3OwVf.7047$ snipped-for-privacy@newsread1.news.pas.earthlink.net...
What more would you want??
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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
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.
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.
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.
"Karl Townsend" wrote in message news:3OwVf.7047$ snipped-for-privacy@newsread1.news.pas.earthlink.net...
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.
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