Glue bleed with veneer sandwich, cascamite.

[nick1982]

Hi,

Thanks to everyone who has replied to other threads, your advice has been really helpful. I thought I would ask a new question on a new thread this time, as it is about glue. Hopefully I can be of help to others in the future.

I've been making a sandwich of three sheets of veneer. Poplar burr/ Burr walnut/ Poplar burr.

I've used Cascamite. I've noticed it is bleeding through.

Is there anyway to stop this? I'd quite like to keep the fresh look of the poplar and the cascamite darkens in when it bleeds through.

I've also noticed that in order to get the rigidity of the pick guards, I need more sheets, five really.

So I had another idea I'd like to ask about. If I could find a supplier that could cut the sheets double thickness, this would solve all my glueing issues right? I doubt I would get much bleed through if they were twice the thickness, it possibly wouldn't get through the grain?

What do you think? Is there anyway I can prevent glue being pressed through a burr veneer with cascamite or is there another glue that will prevent this? they will be stained I should add but i'm worried the glue will make them look patchy.
Or is the sourcing a double thickness veneer the way forward? I think the second is perhaps the way, but I have 42 sheet of veneers at the moment i'd like to use.

Thanks,

Nick

 

[AJB Temple]

am I understanding you correctly? You are making pickguards for guitars, yes? And the reason that you are using veneers in this way is you must be chamfering the edge so that the laminations show?

I used to do this back in the day when I was doing luthiery, and I used hide glue. You can get synthetic or liquid hide glue now. You will not get bleed through. Pick guards are small enough to plate clamp and then chamfer when dry. I use greaseproof paper to stop sticking to my homemade plate clamps.

 

[custard]

There's a couple of things going on here.

Firstly burrs virtually always have voids where the glue comes through. There's all sorts of remedies for that, from straight forward hide glue to taping the face side of the burr to a pane of glass and pre filling the voids with UF tinted with earth pigments.

Secondly some woods are notorious for UF bleed (Sycamore has a particularly bad reputation, it also suffers from green and blue staining, but other woods are also susceptible). Cascamite is a fine product, but for UF veneering you're better using specialist UF adhesives like Bordens which have additives like thickeners and fast dryers which control bleed through. The problem with those specialist adhesives is they only come in fairly large (1 litre plus) containers and they have extremely short self lives.

 

[nick1982]

Thank you both, great advice, I didn't know this.

AJB - Yes the pick guards are for Stratocasters, So quite large, about A4. Yes I'm wanting to chamfer the edge so that there is a dark band through it. I'm planning to stain them and have them lacquered. I really want them to look high quality, so at this stage there is a lot of experimentation. If I can just get this sandwich bit sorted I'll be ok. So you suggest liquid hide glue? Do you know any brands?

Custard - I think you have replied to another post of mine, thank you! Could you tell me what UF means? The pressing with glass sounds interesting, I'm currently pressing them in a homemade veneer press, it's doing a good job so far.

I basically want to stick the three sheets together. have a black band in the middle. Have them rigid and flat, and no bleed so when I stain them they look great. They will also spray lacquered as well, so will need to be flat and stable for this so they don't crack.

Thanks again.

 

[nick1982]

This is the veneer press.

 

[custard]

Could you tell me what UF means? The pressing with glass sounds interesting, I'm currently pressing them in a homemade veneer press, it's doing a good job so far.

Urea Formaldehyde. Cascamite is a UF glue, but the commercial versions are liquid with powder hardeners.

You don't press with glass, you tape a burr to glass show face down, hold it up to the light, and fill the voids. You can also use white melamine coated chipboard, but then a wipe of paste wax is a sensible precaution.

 

[nick1982]

Custard I read you post again.

Another problem I have is the burr veneers dry wobbly and are not flat. I was trying to avoid going through the time consuming process of drying them flat. So presumably I would need to do that before filling them?

It must be possible to get veneers cut at any thickness? Would doubling them sort this issue? My gut says yes.

 

[nick1982]

Sorry, custard, I read that again. If I was to fill with UF, the veneer being flat and taped to glass, would this not just have the same issue? Would the UF not just bleed through, or is this is the stuff that doesn't do that?

- I think I have answered my own question.

So the process is to get none bleed glue, flatten to glass, fill voids, allow to set. Then press to other sheets with UF glue, and touch "wood" that should be it?

Thanks,

Nick

 

[custard]

The thicker a burr veneer the worse the "cockling" and the harder it is to flatten it. Veneers do come in different thicknesses, that's true, but it's not something you can just order up in whatever specification you want. I don't think thicker burr is necessarily the answer.

Yes, you almost always have to flatten burrs. Yours look way better than most by the way! I normally advise people who have never veneered before, start with the drabbest most boring piece of veneer you can find, dramatic grain generally comes with an application penalty.

I'm puzzled why you're sandwiching three burrs together? Surely you just need a burr on the show face, or am I missing something?

 

[custard]

Sorry, custard, I read that again. If I was to fill with UF, the veneer being flat and taped to glass, would this not just have the same issue? Would the UF not just bleed through, or is this is the stuff that doesn't do that?

- I think I have answered my own question.

So the process is to get none bleed glue, flatten to glass, fill voids, allow to set. Then press to other sheets with UF glue, and touch "wood" that should be it?

Thanks,

Nick

Not quite, you can fill burr voids with 5 minute epoxy or cascamite, you tint it first with earth pigments that match the darkest shade you see in the burr. You first flatten the burr, then you tape the edges to a sheet of glass, hold it up to identify the voids, if you want you can tape the burr to a window and ring the voids with a coloured pencil, you then tape it to a flat non stick surface (glass, melamine, etc) you then fill the voids, you then lay the veneer to the substrate and press.

 

[nick1982]

Hi,

It was basically just down to cost and sourcing. I'm new to this... I couldn't find any none burr veneers in the colour I wanted. In the end they worked out about £2 a sheet, and other none burr sheets from other suppliers were more. I since learned about burr "cockling" - nice word by the way. The walnut is pretty flat to be honest. Yes it was down to cost, in the end I though, £2 a sheet, ok. It does seem a shame to waste such pretty sheets on that won't be seen. Do you know anywhere I could source better/more suitable veneers for base/middle in the future?

I'm sandwiching three so I can have a strip of walnut through the middle.

 

[nick1982]

Sorry, custard, I read that again. If I was to fill with UF, the veneer being flat and taped to glass, would this not just have the same issue? Would the UF not just bleed through, or is this is the stuff that doesn't do that?

- I think I have answered my own question.

So the process is to get none bleed glue, flatten to glass, fill voids, allow to set. Then press to other sheets with UF glue, and touch "wood" that should be it?

Thanks,

Nick

Not quite, you can fill burr voids with 5 minute epoxy or cascamite, you tint it first with earth pigments that match the darkest shade you see in the burr. You first flatten the burr, then you tape the edges to a sheet of glass, hold it up to identify the voids, if you want you can tape the burr to a window and ring the voids with a coloured pencil, you then tape it to a flat non stick surface (glass, melamine, etc) you then fill the voids, you then lay the veneer to the substrate and press.

OK, great, I may give that a go. I think flattening is going to have to be done unfortunately.

 

[custard]

It might be worth checking on a luthier forum, I'm a cabinet maker not a luthier and even though the basic principles of veneering will be common I'm sure there'll be specific techniques more relevant to luthier work.

Good luck!

 

[profchris]

It might be worth checking on a luthier forum, I'm a cabinet maker not a luthier and even though the basic principles of veneering will be common I'm sure there'll be specific techniques more relevant to luthier work.

Good luck!

Try the Official Luthier's Forum - quite a few there have built laminated sides. They press them in a mould, and might use heat as well.

My only attempt at laminating as an experiment failed because I couldn't get the veneers to lie flat.

Silly thought, but have you considered 1.5mm plywood as your substrate? A4 sheets are available cheaply via eBay, and once you put finish on the edge you see a dark line, though not so dark as your walnut.

 

[nick1982]

Hi, Thanks for all your replies.

Profchris - Thanks, I did consider using a 1.5mm substrate, but I want to do this properly, I really want a nice band through it, and I'll feel bad if I've cheaped out a bit. I did originally consider just veneering to some precut ply templates.

I have a new way now. I plan to make my own ply, using 5 layers, and getting some tighter grained veneers. It's turning into a bigger project. I'm having curling problems, so this should solve that.

And cascamite is not good for staining I have found.

I just need to find and inexpensive glue I can use for the play, and then I'll probably buy some hide glue for the veneer. But I'll need to flatten the poplar and fill before attaching to my homemade ply.

It is turning into quite the project! hopefully will look good. Still got to figure out how to stain them to make the burls pop out too.

Thanks again

 

[custard]

Dump the burrs and veneer with PVA, some people thin it 10% with water, personally I've never bothered (I just roller it on) and after hundreds, no thousands, of square feet of veneer I've never had a problem. My default glues are PVA for vac bagged work, UF for laminations, and hide glue for burrs. I'll happily mix and match if there's a reason to do so but for a beginner PVA is just far simpler than the others.

 

[AJB Temple]

Liquid hide glue, such as titebond, is readily available on-line. Be aware that once you have opened it, the shelf life is relatively short. It's clear and transparent to stain. In winter you might need to stand the bottle in a pan of hot water to get good flow.

I have a glue kettle so I use hide flakes (on the rare occasion I do this kind of work these days). Hot hide is stronger than liquid hide from a bottle. Its pretty cheap and you can make it in a small slow cooker (also cheap). Pearl glue is much the same. Costs about £6.50 a kilo roughly. Available on-line.

 

[nick1982]

Hi thanks again for your replies,

AJB - That may be something I look into, tight bond is about £8/9. Thanks.

Custard - I have taken your advice, I'm making some ply out of more stable veneers now. I've gone for Walnut and ash now... What are your thoughts on this? I plan to crossgrain them. It'll be a total of 4 layers. this will be my ply base. I'm hoping this will prevent curling and provide a solid base once dry. Will PVA be up to the task do you think? Or are there other glues that will be better. It doesn't matter about bleed on these ones as they won't be seen. They will be lacquered at the end so I need to make something that is pretty stable.

Thanks

Nick

 

[nick1982]

Hi thanks again for your replies,

AJB - That may be something I look into, tight bond is about £8/9. Thanks.

Custard - I have taken your advice, I'm making some ply out of more stable veneers now. I've gone for Walnut and ash now... What are your thoughts on this? I plan to crossgrain them. It'll be a total of 4 layers. this will be my ply base. I'm hoping this will prevent curling and provide a solid base once dry. Will PVA be up to the task do you think? Or are there other glues that will be better. It doesn't matter about bleed on these ones as they won't be seen. They will be lacquered at the end so I need to make something that is pretty stable.

Thanks

Nick