Another option is Dow Corning 3-6077 RTV Ablative. I just got some
more today, it's about $170 off of ebay for 5 kg; the stuff I just got
from ebay expired in 2011 but it still works fine. We use it to
protect launch stools for small lift solid launches. So it's just the
ablative painted over mild steel. It can take 250,000 lbf of solid
thrust at a few inches away so it should handle anything in our realm
just fine. I would pick up a 1/4" or 3/8" plate of mild steel and
paint a layer on it. There is usually quite a bit of the ablative left
on the steel after launches so it should work for a while before it
needs to get reapplied. I haven't tried it personally for long
duration protection for a stand, I'm planning on trying it out
sometime here.
Might be a bit overkill depending on what you are doing, the water
saturated plywood sounds like a decent option as well. There is a
primer for the 3-6077 that helps a lot with adhesion, it is a hideous
orange color and I'm not entirely sure where you can get it from. I
have a fair amount of it, but I cant ship it anywhere as it is hazmat.
There are also a few other options on the market that I cant remember
the name of off the top of my head that work, and you can get from
fire protection suppliers. The 3-6077 has some export restrictions and
can be a bit of a pain paperwork wise getting it new.
On Mon, Sep 12, 2016 at 2:56 PM, Ben Brockert <wikkit@xxxxxxxxx> wrote:
Garolite that I mentioned is phenolic resin with fiberglass. I figured
it'd be easier than creating a part using phenolic resin, like a
wooden phenolic heat shield.
On Mon, Sep 12, 2016 at 6:41 PM, Brian Feeney <alaiadesign@xxxxxxxxx> wrote:
What about using red oak. I believe the older Soyuz used it laminated
together with phenolic resin for a heat shield. It would be more expensive
than water saturated plywood. Interesting to see how many cycles you could
get out of the char layer(s)
Cheers
Brian Feeney
On Sep 12, 2016 6:25 PM, "Ben Brockert" <wikkit@xxxxxxxxx> wrote:
Solidified concrete glass is typically black or dark green.
On Mon, Sep 12, 2016 at 2:03 PM, Robert Watzlavick
<rocket@xxxxxxxxxxxxxx> wrote:
What is the black surface over the bricks? It looks like a 1/2 inch
coating
of sorts.
-Bob
On Sep 12, 2016, at 12:39, Carl Tedesco <ctedesco@xxxxxxxxxxxxxx> wrote:
Here's an exhaust deflector I made...
https://www.youtube.com/watch?v=irJEIJ3OVZY
It used a special concrete additive made for fireplaces. Like the pavers
and
bricks, it too has a finite life under these conditions. The end of the
deflector is angled upward by 5 degrees to get the exhaust off the
ground
which is good for video/photography when testing on a dirt surface.
--- Carl
On Mon, Sep 12, 2016 at 10:05 AM, Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Mon, 12 Sep 2016, Robert Watzlavick wrote:
...Or maybe an aluminum one with tubing welded on the back with water
running through it.
The main question would be how hot the surface would get. An impinging
rocket exhaust is the mother of all convective heat transfer systems,
so
even with water right behind the surface, there'll be a serious
temperature
gradient from front to back. You have to keep that low enough that the
surface layer doesn't melt, despite a thin and surely turbulent
boundary
layer. Could be quite a challenge.
Henry
