Glue Clues - Picking the right glue for the job

by Thomas N. Spehar

Home
Buy Music
Special Offers
Ordering

Music Samples
Books
Choosing an Organ
Organ Buyers Guide
Organs for Sale
Harmonette Busker Organ
John Smith Busker Organ
Organ Maintenance
Organ Tuning
Links
Music for Other Organs
Glue Clues - Picking the right glue for the job
Picking a good Glue comes down to selecting the attributes required by you, the Builder. These considerations may be: ease of workability, strength, longevity, appearance, speed, tradition, nontoxicity, other mechanical means of joining.

Following Manufacturers' instructions is a good idea, but they are usually very brief and contain almost no details for success. That is why I wrote this article. I hope it may help you decide which glue to use, or troubleshoot bonding problems, and give you some good advice for a successful project.

I have availed no source information because this is all based on my own experience. These glues are all of a type you might consider using on your instrument, and it is up to you to select the right one for your needs. For any type of bonding it is critical to prepare your surfaces appropriately, which almost always means your surfaces must be clean and dry, and may entail sanding also.

With each glue type I have included positives and negatives, and then added comments. I hope you find them useful!

Glossary

Cure - The creation of chemical bonds as certain glues harden
Fillet - A bead of glue running along bond line, bridging between pieces. Often makes joint stronger
Flash Off - Technical term for the evaporation of solvents
Gelling - A gradual transition from runny to thick exhibited by some glues
Open Time - Period during which adhesive can be spread, moved, etc. before starting to harden
Set Time - Length of time before glue becomes too difficult to adjust
Squish-out - Glue pushed out of bond surfaces by applying pressure to workpieces, similar to 'fillet'. A clue that you have achieved edge-to edge glue adhesion

Wood Glue (PVA)
Dries Somewhat Hard, Long Open Time, Sold In a Bottle

Non-toxic
Water Cleanup
Inexpensive
Excellent consistency for most types of bonding
Can be mixed with sawdust for filling gaps

Will not stick to nonporous surfaces
Slow-drying
Smudges/excess may be almost invisible on wood until you varnish the piece, and then they will show up and look bad.

Plain wood glue is what John Smith recommends for most of the Busker Organ build. Adding water to wood glue, or wiping bond surfaces with a damp rag before glue application, can increase penetration and ultimate strength of joint.

Two-Part Epoxy
Cures Hard, Variable Open Time, Sold In Double-Chambered Plunger Tube or Two-Tube Set

The strongest bond when used correctly
Can also be mixed with sawdust or media to fill gaps
Good tack for setting pieces together without clamping
Can be purchased with different cure times to match application

Will cause skin reactions! Toxic. Do not clean off skin with acetone or alcohol!!
Must be measured and mixed thoroughly with each use
Bad smells
Difficult to clean up

This is somewhat glueing overkill on a JS Busker. For permanent bonds, cleaning is key. "Open up" your surfaces a bit with 80-200 grit sandpaper if they aren't porous, and clean with rubbing alcohol or soap and water before bonding. Do not wipe this glue off your skin with solvent! That will cause more dermal absorption and possibly skin sensitivity in the future. Many epoxies can be neutralized with white vinegar (acetic acid) while wiping off skin with a paper towel. For the strongest and best looking bonds, practice your fillet!

All-Purpose Glue (or Multi-Purpose Cement)
Dries Somewhat Soft, Short Open Time, Sold In a Tube

Good for many different materials- marketed as such
Can be repositioned after glue has set but is not fully dry
Additional applications of glue (containing acetone usually) before full cure will reactivate dried glue, connecting (and strengthening) bond lines
Can be cleaned up almost completely by simply rolling off rubbery excess glue

Hard to spread, does not flow
Somewhat expensive
Quickly loses tack, yet achieves full bond strength slowly

This looks like what has been used for decades in light manufacturing to stick everything from leather to fake glass together. The key is to not let a dry "skin" form on the glue before sticking your pieces together. You might want to try applying glue to one entire surface, then set the pieces gently together and wait a minute for glue to flash off and gel a bit before applying clamping pressure. This will prevent excess squish-out.

Superglue (cyanoacrylate)
Cures Hard, Short Open Time, Sold In a Small Bottle

Can give an almost instant and very strong adhesion on nonporous surfaces
Almost invisible when cured
Many types available

Most stuff generically sold is almost water-thin which absorbs into porous materials and will not join them without multiple coats
Next to impossible to clean up- special debonder product required for removal

This is the glue where you give a quick wipe with solvent, and stick! Works best with small pieces with a tight fit. It will not easily fill gaps, and using excess glue will make it cure slowly and oftentimes the excess will have a whitish appearance and poor bond strength.

Hot Glue
Dries Soft, Short Open Time, Sold In Stick Form and Requires a Glue Gun

Porous and nonporous bonding
Fills gaps
Hardens very fast
No bad smells

Temperature differences between materials can prevent adhesion
Can burn you, can make workpiece too hot to the touch for repositioning
Cannot be cleaned up easily, but can be removed with isopropyl alcohol

It is next to impossible to make hot glue look good. It is always blobby and cannot be sanded or painted very well, but it is in some ways very convenient. If you desire the smoothest hot glue lines, consider warming up your workpieces to help the glue flow.

Hide/Fish Glue
Dries Very Hard, Variable Open Time, Sold As Glue Flakes or Premixed in a Bottle

Traditional Musical Instrument glue
Nontoxic, water cleanup
Can be warmed up to make soft again for repairs
Archival-grade, professional results

Must be prepared properly before use- mix flakes with water and heat
Requires experience and dedicated tools, not amateur-friendly
Difficult to buy

This is what the pros use in guitar, violin, and apparently also organ building. Awesome if you know how to use it, yet everyone has their own individual techniques and procedures. It may be worth buying some and learning. There are premade hide glues for sale, but their performance is diminished.

Last Thoughts on Surface Preparation

For almost any type of bonding it is critical to prepare your surfaces appropriately, but this is greatly dependent on the glue used. For prepping serious jobs, acetone and alcohol are both easy to get and do a good job. Some industrial workplaces actually use a blend of solvents for high-performance prep. Cleanliness will absolutely make or break your bond when the glue can't soak into the workpieces. Acetone dissolves chemicals quickly and evaporates quickly, so if you don't wipe fast with a clean cloth, you may have dissolved the oil or grime only to move it somewhere else on the workpiece. Rub Alcohol is more forgiving but won't clean as thoroughly. I usually use the 70% isopropyl from the drug store with a paper towel. Or use soap and water! Good Luck!

Back to the Articles Index

   

This web site is copyright (C) Melvyn Wright and individual contributors