Glues: An introduction.

[Rue]

"Wood" (pun intended ) it be handy to have brief "glue facts" all in one place?

After almost 20 years of reading opinions about glue use with regards to violin making, it seems that confusion and misinformation hasn't really abated.

***This is very rough info. I'll edit/reorganize as I have time.***

Feel free to post info, experiences and opinions!  For more detailed information on any of the following please consult Wikipedia.

1. Wood glue: catch-all term used for a myriad of glues used to hold wood together.

Pros: Glues wood.

Cons: Catch-all term. Can be confusing as to chemical make-up. 

2. Hide glue: Made from animal collagen found in animal hides. Comes in different strengths; examples:  251 g (8.9 oz) is normally used for instrument building, 192 g (6.8 oz) is most commonly used for woodworking and the lower strength 135 g (4.8 oz) can also be used for general woodworking.

Pros: Non-toxic if ingested (similar to gelatin). Does not creep. Can be "unglued" relatively easily. Cystals, if kept dry, have an indefinite shelf life.

Cons: Crystals need to be mixed with water and heated - requires constant supervision. May smell bad. There are also different formulations available and not all are equal. Example: Liquid hide glue contains urea.

3. White glue or polyvinyl acetate (PVA)[hobby/craft glue]: Originally made from milk proteins AKA casein. Example: Elmer's Glue All. Also safe (if clean) and was used in classrooms.

If yellow: called Carpenter's glue.

Pros: Easy to use. Non-acidic. Used in bookbinding and as a wallpaper adhesive.

Cons: Subject to degradation by various microorganisms. Will creep. Does not stick well to itself (when regluing).

4. Fish glue: A hide glue made from fish collagen, keratin or elastin. Different types of glue are formulated from different fish species/fish parts. Mostly used in various art endeavours.

Pros: Safe.

Cons: Weaker than regular hide glue.

5. Rice glue: A plant glue made from rice.

Pros: Safe. Transparent when dry. Non-acidic. Reversible.

Cons: A weak glue. 

5.  Muscilage: Made from plants. Edible.  Historically used on envelopes, the back of stamps and for classroom use. Largely discontinued in favour of newer formulations.

Pros: Safe and edible.

Cons: Weak adhesive prone to drying out. Best for temporary use.

6. Cyanoacrylate (CA): A synthetic, or "plastic" product. Different formulations exist, such as thin and watery, a thicker gel or foam.

Pros: Very strong. Easy to use.

Cons: Not reversible. Can glue living skin. 

7.  Epoxy: A  group of basic components, or cured end products, of epoxy resins. Epoxy resins (AKA polyepoxides) are a class of reactive prepolymers and polymers which contain epoxide groups.

Pros: Very strong, comparatively chemically inert when cured, won't melt or dissolve in heat and humidity.

Cons: Toxic when uncured, two-element, requires preparation, irreversible. 

8. Polyurethane glue: Similar to cyanoacrylate. Multipurpose. Waterproof. Will bond different materials together such as metal to wood.

Pros: While uncommon in violin making, may be used when installing certain geared pegs.

Cons: May bond poorly. Short shelf life (~1 year). Toxic: contains carcinogens.

[Violadamore]

1 hour ago, Rue said:

"Wood" (pun intended ) it be handy to have brief "glue facts" all in one place?

You realize that you've chosen a sticky subject here, right?   

[MikeC]

4 minutes ago, Violadamore said:

You realize that you've chosen a sticky subject here, right?   

Sounds like one of my lame jokes   

[MikeC]

I think you forgot casein glue.  Pros and cons?  

[Rue]

Casein glue: see 3. White glue. 

[bkwood]

This is getting tacky.

[Violadamore]

A recipe for casein, and some info on Elmer's products: 

http://www.chymist.com/Glue from Milk.pdf

https://en.wikipedia.org/wiki/Elmer's_Products

https://www.elmers.com/

https://americacomesalive.com/elmers-glue-the-surprising-story/

 

[Violadamore]

2 hours ago, Rue said:

"Wood" (pun intended ) it be handy to have brief "glue facts" all in one place?

After almost 20 years of reading opinions about glue use with regards to violin making, it seems that confusion and misinformation hasn't really abated.

***This is very rough info. I'll edit/reorganize as I have time.***

Feel free to post info, experiences and opinions!  For more detailed information on any of the following please consult Wikipedia.

1. Wood glue: catch-all term used for a myriad of glues used to hold wood together.

Pros: Glues wood.

Cons: Catch-all term. Can be confusing as to chemical make-up. 

2. Hide glue: Made from animal collagen found in animal hides. Comes in different strengths; examples:  251 g (8.9 oz) is normally used for instrument building, 192 g (6.8 oz) is most commonly used for woodworking and the lower strength 135 g (4.8 oz) can also be used for general woodworking.

Pros: Non-toxic if ingested (similar to gelatin). Does not creep. Can be "unglued" relatively easily. Cystals, if kept dry, have an indefinite shelf life.

Cons: Crystals need to be mixed with water and heated - requires constant supervision. May smell bad. There are also different formulations available and not all are equal. Example: Liquid hide glue contains urea.

3. White glue or polyvinyl acetate (PVA)[hobby/craft glue]: Originally made from milk proteins AKA casein. Example: Elmer's Glue All. Also safe (if clean) and was used in classrooms.

If yellow: called Carpenter's glue.

Pros: Easy to use. Non-acidic. Used in bookbinding and as a wallpaper adhesive.

Cons: Subject to degradation by various microorganisms. Will creep. Does not stick well to itself (when regluing).

4. Fish glue: A hide glue made from fish collagen, keratin or elastin. Different types of glue are formulated from different fish species/fish parts. Mostly used in various art endeavours.

Pros: Safe.

Cons: Weaker than regular hide glue.

5. Rice glue: A plant glue made from rice.

Pros: Safe. Transparent when dry. Non-acidic. Reversible.

Cons: A weak glue. 

5.  Muscilage: Made from plants. Edible.  Historically used on envelopes, the back of stamps and for classroom use. Largely discontinued in favour of newer formulations.

Pros: Safe and edible.

Cons: Weak adhesive prone to drying out. Best for temporary use.

6. Cyanoacrylate (CA): A synthetic, or "plastic" product. Different formulations exist, such as thin and watery, a thicker gel or foam.

Pros: Very strong. Easy to use.

Cons: Not reversible. Can glue living skin. 

7.  Epoxy:  https://en.wikipedia.org/wiki/Epoxy  A complicated subject that I'll hand off to Wikipedia. 

Pros: Very strong, comparatively chemically inert when cured, won't melt or dissolve in heat and humidity..

Cons: Toxic when uncured, two-element, requires preparation, irreversible. 

[Brad Dorsey]

3 hours ago, Rue said:

…Hide glue: Made from animal collagen found in animal hides…Pros: Non-toxic if ingested…

Maybe not non-toxic.  I once joked to a retired-doctor-turned professional-violin-maker that I was going to cook my supper in my glue pot to make a meal that would stick to my ribs.  He became alarmed and told me that I could possibly contract bovine spongiform encephalopathy (aka “mad cow disease”j.  Because hide glue is not intended for human consumption, he explained, it is not subject to food safety regulations, and the disease-carrying vector for this disease is not destroyed by high heat.

[MikeC]

1 hour ago, Rue said:

Casein glue: see 3. White glue. 

My bad,  I saw polyvinyl and skipped the reset.   Didn't expect casein to be 'stuck' in there with PVA

[Rue]

11 minutes ago, MikeC said:

My bad,  I saw polyvinyl and skipped the reset.   Didn't expect casein to be 'stuck' in there with PVA

I can always move it as I edit.

All suggestions welcome! 

[Rue]

@Brad Dorsey

Thanks!

I don’t want the list to get too complicated...or for sure no one will look at it!

So adding this sort of useful info in the comments will be wonderful! 

Er...I do hope there aren't folks actually eating hide glue.... I was more thinking about accidental consumption...

[Rue]

1 hour ago, Violadamore said:

7.  Epoxy: ...

Added! 

Do we need to add a "valid use in violin making" sentence?

[chiaroscuro_violins]

/

[David Beard]

1 hour ago, Rue said:

@Brad Dorsey

Thanks!

I don’t want the list to get too complicated...or for sure no one will look at it!

So adding this sort of useful info in the comments will be wonderful! 

Er...I do hope there aren't folks actually eating hide glue.... I was more thinking about accidental consumption...

If you don't to make an extensive list, regardless of relevance to violin making, then what is the purpose.

The short list is simple. Hide glue, with occasioanl guest visitors. Done.

 

If you want an extensive detailed list, than there are many types of just collogen protein glues.  And, there are/were many glues from other proteins.   All sorts of things from honey, to disolved mastic resin, to garlic juice, fig milk, and tar have been used as adhesives in the historical arts.

And then the modern chemical industry has added many new items.

Make very good friends with hide glue and hot water.    That's it.

[Carl Johnson]

3 hours ago, Violadamore said:

7.  Epoxy:  https://en.wikipedia.org/wiki/Epoxy  A complicated subject that I'll hand off to Wikipedia. 

Pros: Very strong, comparatively chemically inert when cured, won't melt or dissolve in heat and humidity..

Cons: Toxic when uncured, two-element, requires preparation, irreversible. 

One of the nice ways to remove some types of epoxy when it’s cured in lumps in the wrong place, is to apply heat. West system8s advice for their 105

Quote

Removing Cured Epoxy Coating

Use a heat gun to soften the epoxy (200°F). Heat a small area and use a paint or cabinet scraper to remove the bulk of the coating. Sand the surface to remove the remaining material. Provide ventilation when heating epoxy.

There’s a wide variety of epoxies out there of course; some are much different in properties.

Resorcinol type glues (marine plywood, aircraft)are often better with heat/humidity, but much finickier - minimum temp for cure (often 70F), well fitting joint required, and some leave an ugly purple glue line. But they are rock solid,

[Violadamore]

3 hours ago, Rue said:

Added! 

Do we need to add a "valid use in violin making" sentence?

IMHO, it's mainly for fixtures and such, though it has some uses in bow frog repair, and would be a "go-to" if anyone is working with carbon fiber materials.  IIRC, it's been discussed here as a wood filler base, and as a tropicalizing adhesive.  Its big negative is the irreversibility.  

[Violadamore]

41 minutes ago, Carl Johnson said:

One of the nice ways to remove some types of epoxy when it’s cured in lumps in the wrong place, is to apply heat. West system8s advice for their 105

Removing Cured Epoxy Coating

Use a heat gun to soften the epoxy (200°F). Heat a small area and use a paint or cabinet scraper to remove the bulk of the coating. Sand the surface to remove the remaining material. Provide ventilation when heating epoxy.

,

 

[Facepalm.]  Not on a violin.  Period. 

[John Alexander]

Rue,  thanks for sharing this information.  Now I understand what “Gluey” the violin is mostly made of!  lol 

[Michael Richwine]

11 hours ago, Violadamore said:

 

[Facepalm.]  Not on a violin.  Period. 

I used to work for a shop with a rental fleet of hundreds of instruments to maintain. Epoxy saved more than one kamikaze'd cello from the dumpster. I agree it has no place on anything that one plans to resell, but if it's gonna get another couple of seasons' revenue out of an elementary school cello that's ultimately headed for destruction, and it's quick, cheap and effective, and there's  no other way, then it's gap filling qualities and speed can be indispensible.

[Rue]

13 hours ago, John Alexander said:

Rue,  thanks for sharing this information.  Now I understand what “Gluey” the violin is mostly made of!  lol 

[Rue]

16 hours ago, chiaroscuro_violins said:

Polyurethane glue should be on the list.  It's uncommon in violin making, except when installing certain geared pegs; then it's a necessity.  

Okey dokey!

[Violadamore]

3 hours ago, Michael Richwine said:

I used to work for a shop with a rental fleet of hundreds of instruments to maintain. Epoxy saved more than one kamikaze'd cello from the dumpster. I agree it has no place on anything that one plans to resell, but if it's gonna get another couple of seasons' revenue out of an elementary school cello that's ultimately headed for destruction, and it's quick, cheap and effective, and there's  no other way, then it's gap filling qualities and speed can be indispensible.

Sorry, Michael, but I guess that I wasn't clear enough.  My response was only directed at the @Carl Johnsonpost recommending "heat gun and scrape" epoxy removal.  That would destroy any finish or wooden surface it was directed at, along with any existing glue joints in the area affected.  It's an approach intended for vehicles and such, not fine woodwork. 

IMHO, the judicious use of "variety glues" in maintaining a rental fleet, school fiddles, etc., shouldn't be subject to aesthetic criticism. 

[Carl Johnson]

On 1/24/2022 at 12:02 PM, Violadamore said:

Sorry, Michael, but I guess that I wasn't clear enough.  My response was only directed at the @Carl Johnsonpost recommending "heat gun and scrape" epoxy removal.  That would destroy any finish or wooden surface it was directed at, along with any existing glue joints in the area affected.  It's an approach intended for vehicles and such, not fine woodwork. 

IMHO, the judicious use of "variety glues" in maintaining a rental fleet, school fiddles, etc., shouldn't be subject to aesthetic criticism. 

I wasnt recommending that for a violin  I was using that technique to illustrate that epoxy is not impervious to heat. 200F from a heat gun is lower temp than many a bending iron in use.

West gflex has been used for bow repairs; sow mixes fail at a lower temp than 200F. Cyanoacrylate glues often do better with temps.

[JacksonMaberry]

On 1/23/2022 at 11:38 AM, Rue said:

Hide glue: Made from animal collagen

Yes, but to clear it up - by the time we get it and use it, it's no longer collagen, which is insoluble in water unless a base is added. The collagen is converted to gelatin at the glue plant.