The challenging field of Body Hits

Posted by Sarge on Wednesday, 25 February 1998, at 7:24 p.m., in response to Re: bullet effects on walls, woodwork, rocks, posted by Ricardo on Wednesday, 25 February 1998, at 4:53 p.m.

I've been experimenting with a garden-style weed sprayer... the kind that uses compressed air, has a long plastic hose, and some kind of a valve arrangement at the base of a metal wand... and I've had a lot of success. Things like, for example, making a blood hit... using gaffer tape and a non-strecthy yet not-too-thick plastic film, make a bag, and fill it with your blood mixture. Run some airline tubing from the metal wand, across the floor, up your actor's pantleg, and into the bag of blood. Tape or hot-glue it in place (if you hot glue, do it BEFORE you attach the bag to the actor, or course).

Then, on cue, squeezt the valve trigger, the air rushes into the bag (you did remember to pump up the tank, didn't you), and it blows up spectacularly.

Or, after you've cut the end off the metal wand, leaving a straight pipe, diip it in red jello, to which you have added stringy bits, aim, and splatter.

Wall hits, you can do the same thing, except dip the wand in a damp mix of talc, sand, coloring, anything that hardens up brittle on drying, aim, and fire.

You can also use a bicycle pump, a pea-shooter and red-dyded frozen peas (after they've thawed), jello or anything else that's sufficiently red and messy.

Have fun...Roy

Posted by Webmaster Dale on Wednesday, 24 June 1998, at 7:19 p.m.

To do body hits with compressed air, you will need the following:

Compressed air source

Tubing

Impulse sealer

Duct tape

Plastic for blood bag

Hot-melt glue gun

Clamps

Razor blade

Sand paper

Scotch tape

For a compressed air source, you can use an insecticide sprayer, or an air
storage tank. The storage tanks are sold for airing up tires. If you use a
storage tank, you will have to air it up, but it will hold more pressure.
You will also have to get a valve of some type. An air nozzle will work, or
if you want to do multiple hits, you will need solenoids. The air tanks run
30 to 40 bucks, and the sprayers are about the same. The advantages of the
sprayers is that they have a built in pump, and you can add blood in it, if
you need more than you can get into a hidden blood bag. you can also use
them to spray down areas that need to be bloody very easily. Do not use one
that has ever had any chemicals put in it. Buy one for this purpose, and
never use it for anything else. You don't want to make any one sick. To use the
sprayer for the hits, you will need to remove the adjustable nozzle at the
end of the wand. By doing this you should be able to use smaller tubing,
than if you get tubing to go over the nozzle.

For the tubing, you can use almost any small tubing you can find. The
easiest to find is poly-ethaline. It is a milky color, and very cheap. It
will take the pressure well, but is not very flexible. Vinyl tubing is more
flexible, and will also take the pressure, but it is harder to find.
Surgical silicone tubing is great if you can find it. It is also a bit
pricey. The size you will need is simply what ever will fit very snug over
the wand of the sprayer. You can use reducers available at auto supply
stores if you need to go down to a smaller size to hide it easier. The
reducers will be next to tubing.

The next part is making the blood bag. For this you will need poly-ethaline
film (saran wrap, or any kitchen plastic wrap), an impulse sealer (a seal-a
meal works), and duct tape or gaffers tape. Decide how big a bag you will
need to hold your blood. Use the impulse sealer to make a bag out of the
poly-ethaline plastic. It will fuse together, and cut the excess off very
easily. Don't worry about putting the blood in at this time. Next, take the
duct tape, and wrap the bag so that it is completely covered, except for a
small area, around 1/4 inch square. The edges will need to be taped so that
the seams will not blow out. The uncovered area should only be on one side.
This is where the bag will burst when you hit the air. Try to keep it close
to what will be the bottom edge of your bag. If it is at the top edge,
after it blows, air will come out before all the blood does, and you will
have wasted most of the blood.

Now you are ready to hook the bag and sprayer together, and fill the bag.
Cut a corner of the bag off. Only cut off enough so that you can get the
tubing into it. Fill the bag with as much blood as you will need. It might
be easier to use a very small funnel, or hobby syringe. Try not to squeeze
the blood back out, and put the tubing about 1/2 inch into the corner.
Remember, you need to do this on a top corner, not the bottom where the
untapped area is. Clamp the bag onto the tubing, (you can wrap it tight
with a bread tie), Then cover the joint and clamp with hot-melt glue. This
will seal the opening, and keep it from just blowing out the tube. If you
want, you can attach the tubing, the fill with blood through the tube. This
may be slow since you will have to add a little blood, the carefully
squeeze the air out, then add more blood until you have the right amount.
If you have adapters, you can put one in, close to the bag, and seal the
tube to the adapter. Then fill it with blood, through the adapter, and
clamp off the tubing. Hemostats will work fine for this, unless you are
using poly-ethaline tubing. If you crimp poly tubing, it might not open
back up when you take the hemostats off. When you are ready to use the bag,
hook it to the sprayer, and clamp the tubing to the wand. If you have used
adapters, then you can put the tubing on the sprayer a head of time, and
just plug the tubing onto the adapter. If you have clamped the tubing with
hemostats, blow a little air into the tube after you take the 'stats off.
this will make sure that the tubing opens back up. Don't use compressed air
for this, you might wear the contents of your blood bag. Just blow into it
with your mouth. that way you wont blow out the bag.

You will need to prep the cloth over the hit. You can use sandpaper, or a
razor. If you use a razor, first be careful that you don't cut yourself.
Cut part of the way through the cloth. Leave just enough to hold it
together. If you cut too deep, and the cloth wont hold together, put scotch
tape on the backside of the cloth. It will hold it together until the bag
burst. Make sure you cut on the back side of the cloth, so that the cuts
can not bee seen. If you use sandpaper, stretch the cloth over a light
bulb, with the outside of the cloth against the bulb. Use about 22 grit
paper, and sand the cloth to weaken it. If you are using a white shirt, you
can also weaken the cloth using bleach. Put a little where you want the
hit, and let it set, rinse it off, and repeat. Do this until the cloth is
as thin as you need it to be for the air to break it. The bleach may need a
little water added to it, and this takes a while. Bleach does not eat
through cloth very fast. It could take a day of letting it sit for 30
minutes, then rinsing, over and over.

When you are ready to use the hit, tape it to your actor so that it lines
up with the weak part of the cloth. Run the tubing under clothing so that
it is not seen, and out to the sprayer. Hook it up, and you are almost
ready to go. You might want to attach the cloth to the bag, to make sure
that the air pressure will blow it out with the bag. You can use liner-less
tape for this, or play around and find something else that will work.
Liner-less tape is basically a roll of the adhesive on tape, without the
plastic on top. It sticks on both sides, and has no plastic in the middle.
You can use carpet tape, or regular double sided tape, but it has a liner.
You will need to cut through the liner to use it. Put it on the cloth, cut
through it, but not through the cloth, then stick it to the uncovered part
of the blood bag.

When you are ready for the shot, make sure the sprayer is pumped up. The
more pressure in it the better. Read the directions that came with it, and
make sure it is pumped up to what they say. Mine needs 50 pumps to be
ready, but yours might be different. When you call action, and it is time
for the hit to go off, squeeze the handily on the wand quick, and
completely. It will do the rest.

If you want more than just blood, add it to the bag before you finish
sealing it. You can use pieces of foam rubber, or what ever else you can
think of. Just remember that it will have to go out through the hole that
will be made in the uncovered part of the bag when you hit the air.

I hope this helps you in your movies, and keeps you safe, and legal. Please
don't attempt to use explosives unless you have a pyro license. If you have
to light it, with a match, fuse, or rocket igniter, it is an explosive. The
police, and government can get real upset if you do this. The family of
your actor might get upset and sue you right after the funeral too.

Rex 'Critter' Winfrey

Highly recommended reading for compressed air bullet hits. Check 'em out:

Explosive Production's Home page http://members.aol.com/bgbdhummer/spfx/explosive.html

and...
http://www.exposure.co.uk/eejit/blood/index.html

The article was also published in the UK video magazine Camcorder User