How to Rehydrate and Spread Butterflies

November 29, 2025

Rehydrating (or "relaxing") and spreading butterflies transforms dried, folded specimens into stunning display pieces with symmetrically positioned wings. This essential technique allows you to work with papered butterflies, field-collected specimens, or old dried butterflies that need repositioning. With patience and proper technique, you can create museum-quality displays that showcase the full beauty of butterfly wing patterns and colors.

When You Need to Rehydrate Butterflies

Common Scenarios

• Papered specimens: Butterflies stored flat in glassine envelopes
• Field-collected butterflies: Dried for transport and storage
• Old specimens: Previously pinned butterflies needing repositioning
• Purchased dried specimens: Unmounted butterflies from suppliers
• Damaged specimens: Requiring repair and re-spreading

Why Rehydration Is Necessary

• Dried butterflies become stiff and brittle
• Wings will break if you try to spread them dry
• Legs and antennae snap off with minimal pressure
• Rehydration makes specimens pliable and workable
• Allows positioning without damage

Essential Materials

For Rehydration (Relaxing)

• Airtight container (plastic storage box with tight lid)
• Clean sand or paper towels
• Water
• White vinegar or phenol (mold inhibitor)
• Screen or platform to elevate specimens
• Glassine envelopes (if specimens aren't already in them)

For Spreading

• Spreading board (appropriate groove width for butterfly size)
• Insect pins (size 2 for most butterflies)
• Tracing paper or glassine strips
• Fine forceps
• Additional pins for holding paper strips
• Pinning block (for consistent height)

Optional but Helpful

• Magnifying glass or lamp
• Soft brush (for positioning antennae)
• Tweezers with fine tips
• Good lighting

Part 1: Rehydrating (Relaxing) Butterflies

Step 1: Build Your Relaxing Chamber

Container Setup

• Choose an airtight plastic container (shoebox size works well)
• Must have a tight-fitting lid to maintain humidity
• Larger containers can process multiple specimens

Moisture Source

• Sand method (preferred): Add 1-2 inches of clean sand to bottom, saturate with water
• Paper towel method: Layer damp (not dripping) paper towels in bottom
• Sand maintains more consistent humidity over time
• Ensure no standing water pools in container

Add Mold Prevention

• Add 1-2 tablespoons white vinegar to the water/sand
• OR add a few drops of phenol or carbolic acid
• This prevents mold growth during the 24-72 hour process
• Essential step—don't skip it

Create Platform

• Place a screen, mesh, or perforated platform above moisture source
• Specimens should not touch water directly
• Platform allows humidity to reach specimens from below
• Crumpled paper towels can work as simple platform

Step 2: Prepare Specimens for Relaxing

If Butterflies Are Papered

• Leave butterflies in their glassine envelopes
• Envelopes protect delicate wings during relaxing
• Humidity penetrates the paper
• Prevents wings from sticking together

If Butterflies Are Loose

• Place each butterfly in a glassine envelope before relaxing
• Fold wings vertically over the back (natural resting position)
• Write collection data on envelope exterior
• This protects specimens during the process

Step 3: Relax the Specimens

Placement

• Place enveloped butterflies on the platform
• Don't overcrowd—allow air circulation around each
• Larger specimens need more space
• Keep envelopes flat, not folded or bent

Seal and Wait

• Close container tightly to maintain humidity
• Place in warm location (20-25°C / 68-77°F)
• Warmth speeds the relaxing process
• Keep out of direct sunlight

Relaxing Time by Size

• Small butterflies (1-2 inches): 24-36 hours
• Medium butterflies (2-3 inches): 36-48 hours
• Large butterflies (3-4 inches): 48-72 hours
• Very large moths (4+ inches): 72-96 hours
• Very old specimens: May need 3-7 days

Step 4: Test for Readiness

How to Check

• After minimum time, carefully remove one specimen
• Gently try to move a wing base with forceps
• Should flex smoothly without resistance or cracking
• Legs should bend without breaking
• Body should have slight give when gently pressed

If Still Stiff

• Return to chamber for another 12-24 hours
• Check daily to prevent over-relaxing
• Better to relax longer than to rush and break wings

If Too Soft

• Remove from chamber immediately
• Allow to air dry for 1-2 hours
• Should be pliable but not limp
• Over-relaxed specimens are prone to mold

Critical Timing

• Spread immediately after relaxing
• Specimens will re-stiffen within hours if not pinned
• Remove specimens from chamber one at a time
• If you can't spread immediately, return to chamber
• Don't let relaxed specimens sit out—they'll dry unevenly

Part 2: Spreading Butterflies

Step 1: Choose the Right Spreading Board

Groove Width

• Board groove should match butterfly body width
• Body sits in groove, wings rest on angled boards
• Too narrow: body won't fit properly
• Too wide: wings won't be supported

Common Sizes

• Narrow (6-8mm): Small butterflies, skippers
• Medium (10-12mm): Most common butterflies
• Wide (15-20mm): Large butterflies and moths
• Adjustable boards accommodate multiple sizes

Step 2: Pin the Butterfly

Remove from Envelope

• Carefully remove relaxed butterfly from envelope
• Handle only by the body, never touch wings
• Use fine forceps for control
• Work gently—wings are still delicate

Insert the Pin

• Insert pin vertically through center of thorax
• Pin should go exactly between the wing bases
• Push through until pin emerges centered on underside
• Use size 2 pin for most butterflies (size 1 for small, size 3 for large)

Position on Board

• Insert pin into the groove of the spreading board
• Body should sit in the groove with wings resting on angled surfaces
• Butterfly should be positioned 1/3 down from pin head
• Use pinning block to ensure correct height
• Body should be straight, not curved or twisted

Step 3: Spread the Wings

This is the most critical and delicate step.

Starting Position

• Wings will be folded or partially closed
• You'll move them into display position
• Work on one side at a time for symmetry

Technique for Moving Wings

• Never touch wing surfaces with fingers or forceps
• Use an insect pin as a hook
• Gently insert pin tip under the thick vein at the wing base
• Carefully slide the wing forward into position
• Work slowly and patiently

Proper Wing Position (Standard Museum Style)

• Hindwing first: Move hindwing forward until its rear margin is perpendicular to the body
• Forewing second: Move forewing forward until its rear margin forms a 90-degree angle with the body
• Result: Rear edge of forewing should be straight across, perpendicular to body
• Front edge of hindwing should just touch rear edge of forewing

Repeat on Other Side

• Spread the opposite side to match exactly
• Symmetry is critical for professional appearance
• Compare both sides frequently
• Make small adjustments until perfectly matched

Step 4: Secure the Wings

Paper Strip Method

• Cut strips of tracing paper or glassine (about 1/2 inch wide)
• Place strip over the wings to hold them in position
• Pin the paper strip to the board (NOT through the wings!)
• Use multiple pins along the strip for even pressure
• Paper should hold wings flat but not crush them

Coverage

• Cover entire wing surface with paper strips
• Overlap strips if necessary
• Ensure wings cannot move during drying
• Check that wings are flat against board surface

Step 5: Position Antennae and Body

Antennae

• Position antennae forward and parallel to each other
• Should point straight ahead, not crossed or bent
• Use fine pins on either side to hold in place
• Or use a small paper strip over antennae

Abdomen

• Should be straight and centered
• If curved, gently straighten while specimen is pliable
• May need support pin underneath during drying

Legs

• Tuck legs against body
• Should not be visible from above in final display
• Use pins to hold in natural position

Step 6: Drying

Drying Environment

• Warm, dry location (20-25°C / 68-77°F)
• Good air circulation but not direct drafts
• Away from direct sunlight (prevents fading)
• Protected from dust and pests
• Low humidity area

Drying Time

• Small butterflies: 7-10 days
• Medium butterflies: 10-14 days
• Large butterflies: 14-21 days
• Very large moths: 21-28 days

Testing for Dryness

• Gently touch the abdomen—should be completely rigid
• Carefully lift edge of paper—wings should not flex
• If any flexibility remains, continue drying
• Removing too early causes wings to droop

Step 7: Removing from Board

Careful Removal

• Once completely dry, remove pins holding paper strips
• Gently peel paper away from wings
• Work slowly—dried wings can still break
• If paper sticks, don't force it—may need more drying time

Remove Support Pins

• Remove pins from around antennae
• Remove any support pins from under abdomen
• Specimen is now ready for display or storage

Common Problems and Solutions

Problem: Wings Break During Spreading

Cause: Specimen not relaxed enough

Solution: Return to relaxing chamber for 12-24 more hours

Problem: Mold Grows on Specimen

Cause: Insufficient mold inhibitor, over-relaxing, or too humid

Solution: Add more vinegar to chamber, check specimens daily, gently brush off mold and re-dry

Problem: Wings Not Symmetrical

Cause: Uneven spreading or positioning

Solution: Adjust before paper is pinned down, compare both sides frequently

Problem: Wings Droop After Removal

Cause: Insufficient drying time

Solution: Return to spreading board and dry longer; prevention is key

Problem: Antennae Break Off

Cause: Rough handling or specimen too dry

Solution: Can be reattached with tiny amount of archival glue

Problem: Specimen Re-Stiffens Before Spreading

Cause: Waited too long after removing from chamber

Solution: Return to relaxing chamber and start over

Tips for Perfect Results

Best Practices

• Work in batches: Relax multiple specimens, spread one at a time
• Check symmetry constantly: Step back and view from above frequently
• Use good lighting: Essential for seeing wing position clearly
• Be patient: Rushing causes mistakes and damage
• Practice on common species: Before attempting rare or valuable specimens
• Keep workspace organized: Have all tools ready before starting

What Not to Do

• Don't touch wings with fingers—oils damage scales permanently
• Don't force stiff specimens—they will break
• Don't skip mold inhibitor in relaxing chamber
• Don't remove from spreading board too early
• Don't work in humid conditions—slows drying
• Don't leave relaxed specimens sitting out

Professional Alternative

Rehydrating and spreading butterflies is a time-intensive process requiring patience, proper equipment, and considerable skill. The learning curve involves inevitable mistakes, and the process takes weeks from start to finish. Many collectors prefer professionally spread specimens that offer:

• Perfect symmetry and wing positioning
• No risk of damage during relaxing or spreading
• Museum-quality results guaranteed
• Immediate display readiness
• Expert handling of delicate specimens
• Ethical sourcing documentation

Museum-Quality Spread Butterflies

Our collection features professionally spread butterflies prepared by expert entomologists using the techniques described above. Each specimen is perfectly symmetrical, expertly positioned, and ready for immediate display—eliminating the weeks of work and technical challenges of the spreading process.

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