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Correct Glues To Use


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#19 mper

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Posted 31 December 2003 - 07:35 AM

I note a brief reference in the above thread to "natural gums". I understand that these are particularly valuable for revalving, because water-solubility gives damage-free release. The most readily available is probably gum-arabic but gum-benzoin and gum-tragacanth are also of interest.

#20 Richard Morse

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Posted 31 December 2003 - 12:44 PM

How is the "plasticizer content" determined and what is the scale to determine if it's high or low (percentage? grams? etc.)?

The simplest way is to spread a thin amount of the glue on some paper and bend the paper after the glue has cured. How much you can bend the paper/glue before the glue cracks and crazes is an indication of how much plasticizer it has in it. Some samples will crack with only minimal bending. Some can be bent (even creased!) in half before any cracking occurs.

For bonds requiring flexure (such as bellows hinges) a more flexible glue (more plasticizer if using a PVA) glue would be desirable over a more rigid glue.

What is meant by a "weak PVA"

A PVA made to be easily reversible. Many bookbinders supplies sell "weak" PVA's.

And finally, what's a "white" PVA?

White PVA is the "original" formulation, I think was developed by the Borden company primarily as a general purpose paper and card glue around 1950. It is naturally white in color, is fairly thin (making it easy to spread), has a medium grab (making it easy to position things), and an medium set/cure time. Subsequently "yellow" PVA's were introduced that were/are formulated more toward woodworkers to be thicker, grab better and set/cure quicker, and have a higher resistance to heat (for better sandability).

#21 Richard Morse

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Posted 31 December 2003 - 01:59 PM

For most of us we use so little glue that hide glue and fancy shellacs are both impractical and uneconomic. If you are using these media for other purposes as well then the case would be different

I don't think of shellac as "fancy". It is an incredibly simple product that is cheap and widely available - or at least the pre-mixed kind is. The flake type can be obtained at woodworker supply places, but the pre-mixed seems to be available in most hardware, lumber, and building supply and hobby stores.

The only difference between flake and pre-mixed is that the flake can be stored virtually forever (protected from excessive heat and moisture) and be mixed up to full potency with the addition of its solvent: alcohol. Pretty much any alcohol will do. I've used vodka to good effect. Pre-mixed shellac is made from flake shellac and has denatured alcohol added as the solvent. In the prepared state, shellac has a "working" life of only a few months if properly sealed against air when not in use.

Shellac sold as a pre-mixed (prepared) product has an unopened shelf-life of about 3 years. Beyond that it is usually discarded as it will not ever harden properly (check the date on the cans before you buy!). Once opened, the pre-mixed has a working life of only a few months just like flake shellac that is mixed with alcohol.

Using shellac isn't particularly difficult nor impractical and at about $6 for a half pint is pretty cost reasonable. For folks considering that amount to be a hassle, a starch glue (like wheat paste) may be the ticket. I've not used such for instruments as I've heard that grain-based glues can become moldy. Commercially-available wallpaper paste is a wheat paste but has additives in it to inhibit mold and bacterial growth.

Back to shellac.... If anyone would like to go the pre-mixed variety route, do check the drop-dead date imprinted on the bottom of the can. For use as a valve glue, stir before using and pour a couple of teaspoons onto a dish and let it sit for several hours till reduced by about 1/3 to 1/2. Use. Throw it away when you're done or keep in a VERY small jar. Add more shellac from the can to thin it when it gets too thick.

Everyone is accepting shellac, it seems. I'm all for going that route if I can manage to come up with the right formula.

If you get the pre-mixed shellac, there are no additives for you to add. There are, however, several "cuts" of shellac (how much flake is dissolved in the alcohol). Pretty much any cut will work as you're going to reduce it anyway. The most widely available cut is the "3-pound" version which is fine.

Does this have any advantage over the hide glue I would mix up myself?

That depends on what you're using it for. As we're talking about valves here, I consider shellac better than hide for this purpose as shellac can be made thicker more easily, doesn't need to be heated, can be made up in smaller quantities, and dries/cures MUCH faster. Shellac also is much more brittle and so can be removed easier than hide glue can be.

Edited by Richard Morse, 31 December 2003 - 02:44 PM.


#22 d.elliott

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Posted 01 January 2004 - 04:35 AM

Rich,

Shellac in the UK, small amounts, 500ml: 12, plus P&P.

The shelf life is not very long, particularly as the usage rate is so low. Unless using the stuff for other purposes, I think that the amateur repairer, or 'once in a liftime fix it up' musician will need other answers.

I probably restore six instruments a year and service around another six or eight, and my work load would use how much shellac? Hence the need to identify and use acceptable and yet conveniently available adhesives

Dave

#23 Greg Jowaisas

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Posted 01 January 2004 - 05:31 AM

Rich,

Best glue for redoing chamois seals ?

Thanks, Greg

#24 Richard Morse

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Posted 01 January 2004 - 11:02 AM

Shellac in the UK, small amounts, 500ml:  12, plus P&P.

The shelf life is not very long, particularly as the usage rate is so low. Unless using the stuff for other purposes, I think that the amateur repairer, or 'once in a liftime fix it up' musician will need other answers.

Wow - I had no idea shellac was so expensive in the UK. A little does go a long way, and even with us overhauling several scores of concertinas/year we don't go through an entire pint before it expires.

The next best glue for valves may be hide, but even that glue is rarely found in most households. White PVA may be the most prevalent glue though removal will be much more difficult that with shellac or hide.

At one point we were putting together "Concertina Repair Kits" for sale that had an assortment of valves and pads, a few right and left springs, some bushings and bellows corner patches, and a good quality jeweler's screwdriver. We discontinued making these as they didn't seem to be a popular seller. Maybe we should reconsider and bolster the assortment with a teaspoon of shellac flake and a corresponding amount of alcohol in a small vial that was pre-proportioned to make the right mixture of prepared shellac. That way it would keep "good" until use (and for several months thereafter).

We had originally embarked on this as we had seen so many "home repairs" which had seriously damaged and/or caused us undue time in repairing these "fixes" for their concertinas. Maybe the time has come to make these kits available again. They would probably make a nice accessory sales to your well-regarded and popular Concertina Maintenance Manual....

Would anyone out there be interested in such a repairs kit?

#25 goran rahm

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Posted 01 January 2004 - 01:11 PM

Rich:The next best glue for valves may be hide, but even that glue is rarely found in most households. White PVA may be the most prevalent glue though removal will be much more difficult that with shellac or hide.

Goran:Have neither you or anyone else tried what I have said a few times the 'starch glue' type used for wall paper?? I actually see no disadvantage but I don't want to directly recommend it since it is not 'established'. Check it up and tell me what you think of it! Costs *nothing* and if kept airtight lasts long *enough* and is absolutely perfect for removal. There are most certainly 'bookbinder' products also that could be ideal. BTW...I used some different "glue sticks" too (Pelikan and Henkel) and it is enourmously handy but I don't actually know what the substance is...if it is starch based too.... or synthetic.

Goran Rahm

#26 Erik Murray

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Posted 01 January 2004 - 01:18 PM

Thanks, Rich, for the follow up on shellac. I would be interested in the repair kit you mentioned, not necessarily for the shellac though. With what I've learned here I'm fairly confident I can find, prepare and use some shellac. Adding it to the kit is a good idea though and I suppose one never has too many screwdrivers.
EM

#27 Richard Morse

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Posted 01 January 2004 - 03:04 PM

Adding it to the kit is a good idea though and I suppose one never has too many screwdrivers.

Ah, you are a fortunate and thoughtful soul!

Actually, we thought that the most important item in the kit WAS the screwdriver (it was certainly the most expensive part!) because we had seen so many people use worn, rounded tip screwdrivers, butter knives, fingernail files, etc. for endbolt removal which damaged the bolt slot and marred the adjacent wood. The ones we sold with the kit were only about 2" long with a hardened hollow-ground blade and swivel pommel.

#28 Richard Morse

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Posted 01 January 2004 - 03:15 PM

Have neither you or anyone else tried what I have said a few times the 'starch glue' type used for wall paper??

I've not used home-made starch glues for instruments as I've heard that grain-based glues can become moldy. Commercially-sold wallpaper paste is a wheat paste but has additives in it to inhibit mold and bacterial growth.

If the major concern here is paying too much for a minimum quanity to have the rest go to waste.... wallpaper paste comes in even larger quanitities than shellac does. Then again maybe more people have leftover wallpaper paste in their cupboard than have a usable can of shellac or tube of hide glue?

#29 Dave Prebble

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Posted 01 January 2004 - 07:29 PM

Hi All,
Firstly to Frank. Having gone back and re-read the postings, I really should have known straight away that you would never even consider fixing valves using a glue of the type I described and I should like to offer my apologies for not realising immediately that there must be some misunderstanding – My apologies to you Frank.

Now then Dave. We have had similar discussions in the past and remained good friends so I will chance my arm and have another try for at least a partial conversion towards reversible glues.

< Dave - re- bushing key holes, the job is supposed to last another eighty years…>
In my experience, bushes compact and wear with use, rather than fail due to weak glue. Indeed the use of weak glue may have been intentional to allow for easy renewal. They are certainly to me a ‘standard service’ item. In an instrument that gets very regular use I would say your ‘80 year lifespan’ is out by a factor of 10 or more.
The Pad, I would agree is a throwaway item that would not normally be repaired and, I suggest, if you use non-reversible PVA glue, your lever arm nuts or ‘spuds’ become throwaway items too.
Again, if one considers bellows to be expendable items (in the long term) and are always prepared to ‘patch over’ rather than replace damaged parts, then non-reversible glues are OK.
I would always avoid their use, however on original vintage bellows

< Dave - Wood glue failure on veneers, framing, and all manner of wood working activity, we want these to be permanent so PVA is OK there too.>
The hide glue structural joints in old concertinas have lasted (excepting ill-use or accident) in good condition for a full century before PVAs were even invented…. How permanent do you want?
The traditional glues are not only reversible but they are, to my mind at least, proved to be permanent.
They were certainly intended to be permanent when first made though I somehow doubt that Messrs. Wheatstone, Crabb, Jeffries et al. realistically expected their instruments to still be intact, played and so highly prized, after the passage of anything up to 170 years, and I might add, looking 'odds on' to still be in good playing condition a century or more from today!
Over such long periods of time, accidents and periods of abuse or neglect are bound to occur. I would suggest that, had high strength non-reversible glues been universally available and used by our forebears, far fewer instruments would be in such good condition today. Many more accidental fractures would have occurred in the wood itself rather than along glue lines and damaged parts could not have been so easily removed to facilitate repair or replacement. Similarly, what we do today should not be considered to be ‘one off, fixed for all time’ solutions as it is clearly just as impossible for today’s repairer/restorer/maker to predict whether or not his work or his repairs might need to be reversed or re-done perhaps many years into the future.

Using non-reversible glues seems a bit like welding up all the nuts and bolts on a vintage car engine on the grounds that it has just been rebuilt and should ‘last for years’ and that welding would permanently prevent them ever rattling loose. There are plenty of better alternatives than welding.....all of them reversible!

My views on the principle of reversibility have, I freely admit, been heavily reinforced by years spent undoing the harm done to antique furniture by well intentioned, but totally ‘cobbled up’ repairs very often involving intractable modern glues and hidden nails!
I hope the above missive will go some way to explain my feelings about reversibility and I am only thankful that very few folks have attempted to nail broken concertinas back together! :)

The only advantages you offer for the use of PVA glues for 'permanent' fixes seem to be that they are cheap easily available and easy to use, along with the fact that a certain maker uses them; though it certainly seems to me that not everyone agrees with all his working 'practices'.

Your main objections seem to be on the grounds that traditional alternatives are hard to obtain and difficult to use but your use of the word ‘fancy’ in relation to shellac and hide glues, does suggests to me the presence of that 'aura of mystique' I spoke of previously.

As regards cost:
Shellac Flake or Shellac buttons 250g - 5.00 sufficient for 1 1/2 pints of 3lb cut polish or 3/4pint of 6lb
Methylated Spirits 500ml - 1.40…(1.60/pint) (local hardware store)……(De-natured Alcohol in US?)
The above works out at:
8.25/pint of thick 6 lb cut polish or
4.93/pint for 3lb cut suitable for polishing

Pearl Glue (dry pellet form) - 3.80 /250g
Rabbit Glue ( Ditto) - 6.40 /250g

All the above materials will last for years and years in airtight containers and can be mixed easily in amounts as small as you wish. The costs per litre are pretty much equivalent to basic PVA glues bought in similar quantities.
One further point might be that you can’t re-polish the concertina’s woodwork with PVA :D
The above glues and shellac are all ‘Liberon’ products which, although good quality, are far from the cheapest available brand so shop around. I quote their prices because they supply nearly all the Big D-I-Y and craft Superstores and are thus easily available.
I pay 3.75 / pint for ready mixed 3lb button in gallon cans.
For smaller quantities, try ‘Rustin’s ready made button polish which is widely available at approx 3.50 per 250ml and 6 per 500ml.
Franklin's Liquid Hide Glue 3.75 / 8 Fl.oz.

As far as left-overs are concerned, I reckon that anyone handy enough to undertake repairs to their concertina would soon find uses for the excess. … learn how to polish perhaps??

In all, I would say that UK availability and cost should pose no problems.

(Dave, perhaps the polish you bought was a premium grade or pre-coloured polish. This might easily account for the unusually high price as certain spirit colour pigments are expensive.)

As for ease of use, the postings above describe the processes and the only really difficult part is to remember to prepare the shellac or soak the pearl glue 24 hours or so in advance. Beyond that they are pretty easy to use and, in doing so, you may just be earning the thanks of an, as yet unborn, restorer or repairer.

Go on give it a try ....
You know it makes sense!! ;)

Regards

Dave

#30 Dave Prebble

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Posted 01 January 2004 - 08:57 PM

Hi Greg,
Sorry, you seem to have been left a bit by the wayside in this thread.
You don't say why you intend to replace the chamois partition and pan seals though I take it from your posting that you are having some leakage problems, either from one chamber to the next or past the sides of the pan??
The answer to the glue question is simple enough though the tasks that you have in mind can be a lot more complicated than at first expected. Before getting to that stage, I should prefer to know a little more about the symptoms arising from the leakage?
If you have a look inside the instrument,
- What is the general condition of the pads and valves and are they all seating properly?
- Are there any signs of localised blackening on the partition seals?
- Look in or near the corners of the inside of the wooden bellows end frames. Are all the pan support blocks there and are they still firmly stuck in place? Are there any telltale glue residues that might point to other blocks having once existed?
- If you place the pan, partition side down, on a true flat surface, is there any sign of rocking that might indicate the presence of warping?
- If you look inside the bellows end frame, is the chamois pan seal glued down to the inner face of the frame, (as opposed to the face that mates with the action box when bolted up) or is it loose?

I ask these questions because in a high proportion of cases leakage can be resolved without all the hassle of ‘major surgery’

Regards
Dave

#31 d.elliott

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Posted 02 January 2004 - 06:33 AM

Dave P,

as we live next door to each other (in internet terms), perhaps we should settle this over a pint of not too de-natured alcholic beverage of shellac colour!

Most of the good old hardware and DIY small outlets have been replaced by the large Block and Quail (B&Q) like emporia that do not seem to address the needs of people like us, yes my shellac was pre coloured, my last lot of button polish was a lot more than you paid!

Most of the woodwork repairs I deal with result from damp and age causing glue failure, ye olde PVA would have prevented this.

Bushings are a throw away item, I have removed bushings fitted with PVA without dificulty, yes they do compact but only after an awful long time.

I think that the glue choice issue hinges around several aspects:

Is one doing harm?
The amount used
Does one have a seperate workshop where there is space for glue kettles etc?
Availability of the media
How often is the job to be repeated.

Most people enquiring here are people who are doing a job for the first time, many of whom may never do the job more than a couple of times (if that) again.

I stay with the concepts of: avoiding harm and of maintainability, rather than reversability, but respect your views.

Now on the subject of non-de-natured and bio-degraded alcohol.....

Dave E

#32 Greg Jowaisas

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Posted 02 January 2004 - 07:10 AM

Thanks for your reply, Dave Prebble!

Yes, I was beginning to feel like the student in class who is waving his hand desperately to be called upon.

Let me first say that I want to thank all the makers, repairers and experienced players that are sharing their hard won knowledge and expertise in this thread and throughout these forums. Your efforts will help leave the next generation with more concertinas in better repair.

Regarding my concertina: The instrument had a layer of leather glued to most of the old chamois in an ill advised attempt to compensate for other problems. Given the poor state of the damaged and glue soaked chamois and since all the end bolt sets needed attention, I've carefully removed the old seals.

The good news is the bellows are in good shape. The reed pan blocks are in place and, now that the end bolt sets are attended to and the extra leather removed, seem ready to line things up. The reed pans and sound board (button pan) are relatively unwarped. With resealing and repadding and revalving (And a professional tuning, preserving original temper) I'm expecting this instrument to recapture some of its former glory.

I would like leave this instrument easier to maintain for the next custodian.

Any advise on the best glue to use for the chamois seals is appreciated.

Thanks again to Dave and everyone else.

Greg

#33 Dave Prebble

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Posted 02 January 2004 - 08:58 AM

Hi Greg,
Thanks for the Info.
Yep! Certainly seems that you are straight in at the deep end with that one!
Your news of the worn out/stripped end bolts comes as no surprise whatsoever to me. Far too often when leakage problems present, folks tighten down the end bolts as far as they dare and then just can’t resist that last fatal extra turn. This does nothing to address the original problem but merely creates a new one. Light finger pressure on a well fitting small screwdriver is all that is required. These are delicate thin fixings and not truck cylinder head bolts! You have inherited the results and, I think you will agree, a lot of extra work.

I shall take that you have already cleaned up the old glue. Do take a couple of minutes to check all the partitions for any signs of damage. Now is the best time to repair any faults there.

For the partition seals I would tend to use liquid hide glue applied to the wood partitions and not directly onto the leather. Use sparingly or it will soak into the leather and cause hard spots. Get a feel for the job by gluing up some scraps to wood before you start.
On the seals that extend over the ends of the partitions and contact the bellows seal, leave these about a ” over length. I find these easiest to trim to a chamfer once they have firmly dried in place.
If you have large fingers like me, you may find that working round the pan doing alternate seals results in less accidental disturbance of just completed work.
Each time I place a seal, I invert the whole pan and press down lightly on a flat surface (the glass top sheet of my light table usually). This helps to ensure even thickness and consistent results.

I shall take it that the bellows end frame is still sound. I have seen pans jammed in to the extent that the joints give and the whole end frame starts to expand! As before, make good any repairs needed before starting to reline. Use some off cuts to try and determine what thickness of leather will be required to form a smooth but not over tight seal.

Though many concertinas have the Chamois sealing leather glued throughout, I am in favour of gluing just the onto the ends of the bellows, ie the faces that mate to the action box when bolted up. For this joint, again liquid hide glue is fine. Prick through your bolt holes and, placing a sheet of ‘greaseproof’ ..ie non-stick!. kitchen paper in between, make use of the concertina end as a clamp by fitting them to the bellows with the end bolts. (leave reed pan out at this stage)
Once this has thoroughly dried, You now can shape the unglued section of the seal and make a trial fit of the pan. The idea behind leaving this section unglued is that paper strips can be gummed to the wood behind the seal to shim out for a perfect fit. When the seal has been adjusted you may find that it tends to pull out a bit with the pan, If so, a little hide glue along just the bottom edge should prevent this without making it too hard to make future adjustments.

One further point to bear in mind is that the bellows blocks that limit how far the pan will push into the bellows end frame may well have to be adjusted to account for variations in the partition seal material thickness. Either gumming little triangular card scraps onto the block or taking a thin shaving off the block with a craft knife blade will afford a means of accurate adjustment. Be patient and work slowly and methodically.

So that all sounds easy enough on paper. You will find it to be quite a fiddly and frustrating job at times but be patient and don’t rush and you will get there. One tip in gluing up is to keep handy a few fine dressmakers pins or ‘notice board’ pins. These make great temporary ’third’ hands

I hope the above is helpful to you

Regards

Dave

#34 Dave Prebble

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Posted 02 January 2004 - 09:19 AM

Hi Dave,

Yes we shall have to meet up soon for a good ‘shellacking’.

I intend to get 1/2” ‘cut’ on Richard’s ‘Vodka Flake cocktail’, but I’ll be a good chap and stand you a pint of PVA…… sup that and you really will find out about non-reversibility :D

Best Regards and a Happy New Year

Dave

#35 Greg Jowaisas

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Posted 02 January 2004 - 10:42 AM

Although the jokes are getting "tacky" and folks are having trouble "adhering" to the original topic I want to thank both Daves for their very good and particular advice; Thanks to Rich for "bugging" us to try shellac; and Goran for his postings on pasting. Much learned. Much appreciated.

Greg

#36 d.elliott

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Posted 02 January 2004 - 11:19 AM

Dave P

pint of PVA eh! a certain cure for the runs (of triplets), not that we are at all 'stuck up' in South Yorkshire.

Glad your advice to Greg includes the comment about the re-setting of the pan support blocks, I won't say which adhesive I would use for want of starting another debate.

My comment on the chamois gasket problem would include the need to select a thickness of chamois that allows for some compression when compared with the projecion of the bellows leather above the end of the bellows frame, and the need to make sure that the reed pan is held tightly, again as the chamois will compress in years to come.

Other than that, wish you well Greg, Dave's point about leaving a chamber wall gasket 'overhang' to allow for trimming and chamfering is a good one.

Dave E




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