Introduction: How To: Caulk a Bloody Brain Cap

Picture of How To: Caulk a Bloody Brain Cap

Make and wear your own bloody brain cap using a couple of tubes of latex caulking and a fitted ball cap!

I wrote this project originally for Craft:
The project has also appeared in Make:

Fitted cap, without adjuster
Craft knife or seam ripper
Acrylic paint, red and black
Bowl, approximately same size as cap
Tall jar
Plastic bag
2 tubes of latex or acrylic caulking (not silicone)*, ivory or bone color
Caulking gun


Step 1: Remove the cap's brim by carefully ripping the seams with a craft knife or seam ripper.

Step 2: Place the cap on newspaper. Paint the cap with dark red paint (a mixture of red paint and a little bit of black paint). Let dry.

Step 3: On newspaper, create a work stand for your cap by placing a bowl upside down over a tall jar. Place a plastic bag over the bowl, and the cap over the plastic bag.

Step 4: With a craft knife, cut the tip of the caulking tube to have an opening approximately 1/2" in diameter. Load the tube into a caulking gun.

Step 5: Caulk convolutions on one half of the cap to create one hemisphere of the brain. Repeat on the second half of the cap.

Step 6: Let the caulking dry for approximately one to two hours until the surface loses tack. Wearing gloves, lightly press on the convolutions to slightly flatten the surface.

Step 7: Let the caulking cure for 24 hours.

Step 8: Once the caulking has cured, mix water with red paint and a little bit of black paint, to a thin, runny consistency. Use a brush to dab paint mixture onto the caulking, focusing on crevices. Apply a second coat if needed. Let dry.


mazzinga made it! (author)2015-07-27

This was one of my favourite Halloween costumes.

Sarrux (author)2015-03-30

Um, is it possible to replace the baseball cap with some rounded foam core it create a model? And how would one go about making the inside of the brain with the caulking?

aje127 (author)2013-10-12

I am so doing this for a halloween party!!

Bard (author)2013-10-11

I wonder if you can use a clear caulking and have LEDs embedded in the cap.

pipea (author)2013-10-11

Fabulous idea mate!

tomokomiya (author)2013-01-09


imp (author)2011-11-14

it's brilliant idea! :)

roftranspo (author)2011-11-07


mikeasaurus (author)2011-11-06

Haha, that's great!

l8nite (author)2011-11-06

I've used caulk for a couple projects with mixed results, one night wounds are ok but they tend to crack when drying and in other cases the project is super heavy for its size or the caulk didn't stick to the surface, it's still a go to material for tests though. Cool idea !

Penolopy Bulnick (author)2011-11-06

I love this cap! I couldn't tell it was caulking the first time I looked at it! To finish it off, is that just a bandage strip with red paint?

About This Instructable




Bio: Hi! I'm Jeromina Juan. Former blogger. Former freelance crafts contributor for Canadian Living in print and Craftzine online. Former full-time civil engineering Utility Design ... More »
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