In addition, the costume designer needed to be able to wash the blood completely out of the costumes between performances, the set designer wanted to prevent staining the set, and (since there was a possibility of splashing the audience) we needed to be able to assure audience members that their clothes would not be ruined. This pretty much meant no red food coloring could be in the recipe either.
Furthermore, the blood would have to be visible on both light and dark surfaces and work in several different delivery devices, including air cannons, pneumatic squibs, squeeze bulbs, blood bags and a trick knife. (For a truly excellent pneumatic squib, see Crosius' phenomenal Instructible here: https://www.instructables.com/id/Pneumatic-Squib-Tutorial/)
After experimenting with several formulas I came up with this one, which met all of the needs listed above very well, and only costs about $13.00 a gallon. Compared to some commercial blood at $60.00 a gallon or more, this is quite a bargain. If you need buckets of blood for any reason, give this a try.
Step 1: Gather Your Ingredients and Tools
Four 28 oz. bottles of orange or red ultra-concentrated dish detergent (the red frequently contains bleach - do not use any detergent with bleach)
One small bottle of ultra-concentrated Dawn dish detergent (blue)
1.5 cups of creamy sugar-free peanut butter (regular will also work)
One 16 oz. bottle of washable red poster paint
Blue washable poster paint
Black washable poster paint
Sugar-free chocolate syrup
Large pot or mixing bowl
Gallon-sized jug or pitcher
Strainer or cheesecloth
Step 2: Make the Detergent Base
Pour all four bottles of orange detergent into a large bowl or pot. Add 8 oz. of blue Dawn. Mix well. The blue detergent helps to tone down the orange color. When done mixing, you should have a big bowl of caramel colored goo.
Step 3: Nuke the Peanut Butter
Step 4: Add the Peanut Butter to the Detergent Base
Step 5: Make It Red
Step 6: Make It Bloody
If the blood is too red, add a little more blue, or a little more Dawn, if you prefer. If it needs to be darker, add more black. If it lacks a certain undefinable "richness", add more chocolate syrup.
When adjusting the color, go in small increments to avoid overcorrecting, mixing well at each increment. If you do overcorrect, try adding some of the remaining red paint left over from the previous step. If you have seriously overcorrected, you may be able to salvage the mixture by adding another bottle or two of orange detergent and more red paint. Otherwise, you'll have to scrap the whole thing and start over.
Step 7: Feeling the Strain
Step 8: Let It Bleed
As I mentioned in the intro, this formula has been successfully used in a large variety of effect devices, including air cannons, pneumatic squibs, squeeze bulbs w/ tubing, blood bags and a trick blood-squirting knife. I had some initial reservations about foaming, especially in the air cannons, but testing showed that my reservations were unfounded.
For all these applications, we used the formula without diluting it. If you need a higher flow, the blood can be cut with water, but be careful not to use too much. Excessive dilution will cause the blood to tend to bubble and foam when ejected through the delivery device, and will probably require additional paint to maintain the correct color.
Step 9: Precautions
1) Dish detergent is very unpleasant to have in your eye. Take care to avoid getting this blood in anyone's eyes. If the blood does get in someone's eye, flush immediately with water.
2) Likewise, do not use this blood in anyone's mouth. That would just be nasty. For our recent production we needed several mouth packs, which we filled with corn syrup blood. The actors were grateful.
3) This formula, unlike the corn syrup stage blood, is very slippery. Walk with caution when blood is on a smooth floor. Do not use this blood on the floor in any area where an audience member may walk. A non-skid floor treatment is highly recommended, especially on raised platforms and angled floor surfaces. If sugar content is not a major concern, corn syrup may be substituted for up to half of the detergent, which helps to reduce the slipping hazard without a major impact on the washability.
4) Although this stage blood has been designed specifically for washability and stain-resistance, clean all costumes as soon as possible after exposure to the blood. If costumes cannot go immediately into the wash, rinse immediately under running water and leave to soak in a bucket of water to prevent the blood drying on the costumes. Dried blood is much more difficult to remove, and may stain permanently on certain fabrics.
5) This formula contains peanut butter, so inform all cast members and crew, and verify that no one who may come into contact with it has peanut allergies. If audience exposure is likely, a warning to the audience is also in order.
6) If left to sit too long, the blood will coagulate and potentially clog delivery devices. Clean all delivery devices after use.