| Author |
Message |
Paul Ghelli (57shadowdog)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 11, 2005 - 10:52 pm: | |
What started out as a little leak on the new bus. has now turned in to the back twenty feet stripped. all the way floor to floor. was told that it had been strpipped before. ha.. now that the 1962 tin ceiling. and the old fiber glass.got all the mold out.hope that all the little leaks are sealed. this week it gets sray foamed. hope that any little leaks left will be blocked with the foam. any one have any luck.. good or bad with sray foam !! thanks paul |
John that newguy
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 12, 2005 - 12:05 am: | |
Paul-
In my opinion, spray foam won't necessarily stop water from
seeping into it.
You'd be better off using a polyurethane sealer or butyl rubber
sealer to stop leaks prior to foaming. |
Paul Ghelli (57shadowdog)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 12, 2005 - 7:31 am: | |
JTNG
would that be a spray or brush sealer. is one better then the other. I do have some two part sikaflex left. From sealing the roof line. I could use that on the inside?
paul |
Stan
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 12, 2005 - 7:46 am: | |
Hot spray foam is a closed cell foam so water cannot penetrate it. The worst leak problem in a bus is water geting in around a rivet or screw into a hollow steel member. It will then travel along the steel until it finds a hole to escape to the inside. |
Sojourner (Jjimage)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 12, 2005 - 9:02 am: | |
You fix the water leakage first to avoid future problem. Any hydraulic action or freezing under skin to harden foam will separate. So first look for inlet source on outside and reseal it there.
One of a great way to detect leak is to close all known opening (windows, heater’s fresh air vents), then adapt old direct-drive furnace squirrel cage blower to one of window opening to induce pressure inside. Run thin film of water over any joints until air flow or bubble appeared.
After all leaks are sealed then apply hot-spray-foam by professional.
The following information is available in case you need it.
Here a list to do after leaks repair;
1) All surface must be free of loosen paint, tar and tape that applied to factory primer or bare metal to get the greatest bonding. Another word a clean bonding surface to get the maximum structural effects such as to support walking on roof. I don’t recommend it but an illustration the effect.
2) All UN-wanted foam surface need to be cover tape or tape with paper to cover large areas. Covers floor with tarp & taped. Suggest having one window open at rear (bedroom) for ventilation while applying Hot-Foam.
2) About 15 min later, it has become hard texture on foam skin but still hot & soft to expand on the inside of masses.
3) After polyurethane is applied, while it still in “hot” state of condition, it still expanding until about 2 hours or more (until it completely cooled).
4) That why it need a professional who know about how much to apply before it get too thick or waste after it completely cooled.
5) Don’t remove excess foam build-up until 24 hrs or longer. Use straight 4 to 4.5” high-speed wire wheel to 10,000 rpm grinder to remove.
How it applied;
1) Poly-Urethane is pre heated to 140 F.
2) Go thru double heated hose at 130 F.
3) Mixing two parts at the gun at pre-set ratio (Adjustable 1.4 to 4.1).
4) All chemicals are under hydraulic pressure from air pump/hyd unit at source.
Equipment supplier;
http://www.sprayfoam.com/module-ContentExpress-display-ceid-14-zone-36.html
Caution about do-it-your-self-err, it only for small application project but a bus shell is for professional to save $$$$$$.
FWIW
Today is Lord's day!
Sojourn for Christ, Jerry |
John that newguy
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 12, 2005 - 9:15 am: | |
Paul-
I don't know the first thing about sikaflex, but I thought that
was an adhesive, not a sealant?
The poly stuff can be wiped on with a toss-away paint brush.
There's another compound that's used on RV roofs that
looks like marshmallow fluff.. that too, can be wiped on. The
GE brand butyl stuff comes on tubes (like the adhesives and
chalking) and used for roofs and gutters... you can trowel it
into tight spaces...
All of it may or may not stop the leak, since the leak's best
stopped from the outside, before it seeps in. It'd have to be
a helluva tight seal inside, to stop the leak "after the fact". The
corrosive effect with pooled water sitting between the sheets
of metal, will still be a problem.
The spray foams aren't generally used as sealant. Even if you
could see what the foam is covering or not covering when you
spray it on, you have no assurance that it's even sticking to the
spot you're directing it to. Water trapped between the foam
and surface will eventually seep down, around and through.
I'd try to locate the leak and repair it on the outside. And doing
that while you can see both sides, is the easiest way.
Lotsa' luck. |
Russ Barnes (Neoruss)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 12, 2005 - 12:01 pm: | |
Stan, just a note: "Hot spray foam" is a polyurethane foam applied by heated equipment as Jerry well described, but its not waterproof. I worked in the marine industry for many years and we have sprayed tankers full of the stuff with all the proper, daily calibrated equipment and it does absorb water. It's a small amount, but it does happen. I was VP of engineering for about 15 years and having Coast Guard certified dozens of small boats I had to be sure to include the proper amount of foam. The certification had to compensate for the fact that "Hot foam" would loose some (relativly small) floatation abilities as it absorbed water. We had to do qc tests daily of small foam cubes from the equipment then soaked in water and weighed before and after to be sure they had the correct ration of A & B and didn't absorb over I think 2% weight. Our buses sweat, we humans add water vapor and water is absorbing into the foam. So if you have a leak, fix it first so the water that will someday get in the foam doesn't wick onto the frame and cause rust. |