Sorry I'm entering this discussion late, I guess I was _lagging_ behind.
Okay, bad joke, but I don't know any good ones.
Anyway, I've lagged two boilers, including a pot boiler. (I just lagged
the top, above the sidetanks.) It's really pretty simple.
As Vance said, there are any number of materials available for lagging.
My personal favorite is 1/8" cork. It resists heat well, and is fairly
sturdy. The secret for lagging the boiler lies in the boiler bands.
I tried rolling my own sheet out of .015" brass, but if you don't have a
sheet metal roller, you will not get a good, smooth roll. Now, I have
come to realize that you don't have to have thick wrapping material,
just good boiler bands.
I use .020" x 3/32 brass strip, annealed, then bent around a metal pipe
about 3/4 the diameter of the boiler. The band will spring out a bit,
leaving the curvature just about the same diameter that you need for a
tight fit around the boiler. Take the ends of the band, and bend them
out at 90 degree angles, so what you have resembles a closed horseshoe.
Drill a hole through both of these tabs. That is where you will run your
clamping screw to tighten the whole thing onto the boiler. Make as many
of these as you need for your boiler - two, three, twenty (for those
doing a really long articulated.) Now, here's where the fun comes in.
Take some .005 brass or tin sheet, and cut it to the size you need to
wrap your boiler. If you wish to chemically treat the wrapper now, you
may want to do so. This will allow you to leave the bands polished, or
at least not have "mask marks" where the bands are if you wait until
after you lag the boiler. Now, if you want a slightly more "realistic"
appearance to the lagging, you can take a page out of Sonni Honneger's
(sp?) book...Take the sheet out to the driveway or gravel bed or
something like that. Now, walk on it. This gives you a slightly scuffed
look to the wrapper. If you look at a real locomotive, those wrappers
are anything but smooth. Minor creases, dings, and other things are the
order of the day here. The lighter you tread, the lighter the effect.
Trust me, the effect is worth it. It really makes our locos look real,
not just like miniatures.
But, I digress...
Once you have your wrapper, you can either attach the bands to the
wrapper, or let them float. Your call. I find that attaching them makes
for a stronger finished product.
Place the lagging material (Whatever you end up choosing) around the
boiler, then place the wrapper on the outside of that. Don't try to do
each layer at once. Take time to make sure everything lines up properly.
Tighten the screws at the bottom of the bands (which, I should mention)
you want to locate on the underside of the boiler.), and secure
everything in place.
Viola, you have now lagged your boiler.
Now - for some caveats...
Boiler fittings such as domes, fill valves, etc., need to be accounted
for. In most cases, the domes hide some feature of the boiler such as a
goodall valve or safety valve. The domes are usually attached somehow to
the fitting, not the boiler. If this is the case, just leave a hole in
the lagging and wrapper to accommodate. Remember that you have just
raised each piece 1/8" higher though, and may need to deal somehow with
that.
Cosmetic attachments to the boiler...All non-functional domes,
generators, bells, whistles, handrail stantions, checkvalves,
injectors...These need to be taken into consideration, as well. The best
way to attach these is via a screw secured through the wrapper. If the
wrapper is a bit thin (and .005 falls into this category) you may want
to solder a small pad or washer on the underside to give it something to
support itself. (Note, do not try to thread this - use a nut if you have
to) Otherwise you are in extreme danger of ripping off your wrapper. It
is not recommended that you try to carry your loco by any of these
attachments. (Ask me how I know.)
NOTE* You can use a thicker wrapper material if you so desire, but you
have to be able to bend it - not something that's terribly easy to do,
at least not in my experience.
So, if anyone has anything to add, please do. I'm still looking for a
good way to attach running boards to a boiler.
Later,
K
