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coilline
11-20-2010, 01:47 PM
When fabricating duct work for medium and high pressure systems, how are you sealing the pittsburgs?

How are you applying the sealants (brush,caulking guns, spray guns)?

This has become an issue in my workplace, especially with Joints of pipe.
We are currently injecting sealant into the pitts. while it is being formed but our installers are telling us it is insufficient during testing. My employer now is thinking of using a spray gun to apply water-base sealant both inside and outside the duct.

Just curious on how other shops are dealing with this issue. Thanks

fabrk8r
11-23-2010, 09:30 AM
We use a 3" chip brush and gallon buckets of Pro-Seal and apply it manually the the seam inside after the fittings have been knocked together. For duct we use a caulking gun. For square to rounds and other spot welded fittings the process is the same...assemble, seal, wait for cure then line if necessary.


It's labor intensive, but it seals very well.

TheDarkCanuck
09-26-2011, 12:15 PM
Since I'm an apprentice I do a lot of it. Pro Seal also, up to 14 W.G I think.

Also Duro Dyne makes the chemical High V.O.C stuff. Its pretty brutal applying it, very flammable but dries with in minutes and offers a great seal when moving air+chemicals or gases. It does NOT come off skin and you shouldn't be in a closed room with it. And is also reddish brown. Applied with a spray, probably could be sprayed but would clog gun after use.

http://www.durodynecanada.ca/canada/products/sealers_adhesives/spec_s2.pdf

TimC
09-26-2011, 01:53 PM
For what it's worth we had a building envelope engineer tell us once that the only way to get an airtight seal with liquid mastic is to tool it on as smoothly as possible.
It's kind of brute but it's pretty hard to beat a bucket and a paintbrush if the operator is paying attention to what he/she is doing.
When pressure testing ductwork I make sure the layers go on in approx 3/16" thick waves and reapply as necessary once that layer has had a chance to cure. Too thick at once and the inside stays liquid and bubbles out under pressure.

Good luck!

tinbender2
10-06-2011, 01:01 PM
Sounds like a lot of work. If this is an interior application I typically use what we call "pookie". It is a water based sealant that we brush on and it seals great. It doesn't have a strong odor and cleans up very good. Made by BOSS. One coat usually does it.

aramage
11-05-2011, 03:39 PM
We use a product called Airseal 22 from Polymer Adhesives Sealant Systems Inc. It is very good, and water-based so it can be cleaned up easily.

b.c.tinbasher
12-07-2011, 12:48 AM
That Duro-Dyne S-2 is probably the best all round duct sealant.
indoor, outdoor, hot, cold, chemically laden air, food grease, hi velocity,
it handles them all with aplomb. Spreads easily with a brush, flows well.
The fumes will get you high, then you have a stiff headache afterward.
The fumes will ignite and the flames spread quickly, I have experience with this, trust me.
And sure it comes off skin! Just use gasoline, like we used to.
Even better, the gas was leaded, in those days.
Probably NOT a good idea to use gas though, now we know better, right?
The biggest problem with S-2 is the price, we are probably being gouged, but the last time I bought a gallon pail from the local wholesaler, it cost $92.00
We have been using a water based product I think it is Carlisle 321 gray in colour, good for high velocity, supposedly good for outdoors, but we only use S-2 for outdoors, It has never failed us, so why experiment with a water based product that might?

cactassdupree
12-07-2011, 07:56 AM
That Duro-Dyne S-2 is probably the best all round duct sealant.
indoor, outdoor, hot, cold, chemically laden air, food grease, hi velocity,
it handles them all with aplomb. Spreads easily with a brush, flows well.
The fumes will get you high, then you have a stiff headache afterward.
The fumes will ignite and the flames spread quickly, I have experience with this, trust me.
And sure it comes off skin! Just use gasoline, like we used to.
Even better, the gas was leaded, in those days.
Probably NOT a good idea to use gas though, now we know better, right?
The biggest problem with S-2 is the price, we are probably being gouged, but the last time I bought a gallon pail from the local wholesaler, it cost $92.00
We have been using a water based product I think it is Carlisle 321 gray in colour, good for high velocity, supposedly good for outdoors, but we only use S-2 for outdoors, It has never failed us, so why experiment with a water based product that might?

I wanted to adress your price grougeing problem. For years the shop i workd for use a locally owned company to purchase "Stay Clean" soldering flux from "Harris" i believe. they would pay between $60-$70 per gallon. A friend of mine (another tin-knocker) went to a different place to purchase some welding Equipment. He got a great deal, almost half off. The company we were dealing with were local family owned that's why the boss like to use them. Well some big outfit bought them out. So I went shopping for my StayClean and I found that if I bought 2 Gals. the were $34 each and if I want a case (4gals.) they would take off $2 more on each gal. We did alot of soldering and useat least 4 gals. a year. So The boss was getting it at half price. I worked for another guy and he would shop out his copper prices. He would call one supplier and get a price. back then it was like $1.67 a LB. then he would call another and ask them what it was going for. He would tell them (XYZ) has it for $1.67. they would always drop a couple of cents. He had 4-5 guys he would buy from and when he would finish he always came in 10 -20 cents cheaper than the first offer. We would buy cases at a time. I was told that before i was hired they would have cases stacked to the ceiling (1080lbs per case). Beside our own flashing we would stamp out stock and send it back to all the suppy houses. Sometime the supply houses would just send us the copper and he would cahrge them about .07 per fot for brakeing it up and they would supply the copper. Then the peeps down south of us started to use our method and hired cheaper people so we slowly lost most of the business. But it was an enjoyment to work there, one of the best shops and Bosses I ever worked for. ;) dupree

MoranSheetMetal
01-04-2012, 06:30 PM
Has any one used the ductmate proseal duct seal with the spray gun? I use ductmates everseal duct seal right now, but have been looking into the spray system. Some of the guns and spray systems just seem way to expensive for what they are. I havent seen the set up ductmate has. Any ideas?