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help! veneer top not gluing properly!

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i had it clamped with about 10kg's of weight for 3 hours and it STILL did that to me.

is there anything i can do? maybe wet the high spots, and somehow put them down?

or just ripping off the top? :D

i really cant afford a new one

aaaaaah B)

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Actually, that is fairly typical of veneering, even when lots weight is applied. The best thing to do is get a book on veneering and essentially iron it out. Follow the instructions in the book, and it will work.

Guitar Ed

Advice worth what you paid for it. Nothing.

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i had it clamped with about 10kg's of weight for 3 hours and it STILL did that to me.

Well, there's your problem right there. Try making that 3 days and you're less likely to encounter a problem.

When gluing large flat areas with a waterbased glue, common sense dictates that you allow a massive amount of time for setting - the glue in the middle is basically sealed in by wood or more glue on all sides, and like any liquid in a sealed container it will take much longer to dry!

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OK, first things first.

You need to determine if those are glue-starved humps or glue-heavy humps. They look to me like glue-heavy humps.

Take a sewing needle and stick a tiny hole in one of them and press down and see if glue comes out or whether it's got no glue in it at all.

Either way, you're probably screwed as far as getting it down, you'll probably have to remove it and try again. Perfect veneering is -not- easy, and I doubt anybody would get it right first jump out of the gate, so don't feel too bad. But I would also recommend practicing on scrap until you're pretty good at it. :D

There is one way that has worked successfully for me. That way is to have a glue-board of very hard wood, like Eastern Hardrock Maple, Paduak, Oak, Walnut, one of the hard boys...NO Plywood, Basswood, anything soft like that will not work, even at 3/4" it won't work. No soft woods. And it has to be at least 3/8" thick, 1/2" is better. And it has to be as big and wide as the piece/body you're gluing it down to, i.e. no 2 or 3 separate pieces, it has to be 1-piece that will cover the entire area that you are gluing on one shot.

Use a piece of wax paper between your veneer and glue-board, and massive amounts of clamps.

That is the only way I have had repeatable perfect success minus using some complex piece of equipment like a vacuum bag.

VERY hard wood for the glue board.

As big as the piece you are gluing.

Use wax paper in between and plenty of clamps.

Do not use excessive amounts of glue, and spread the glue out evenly using a white plastic spatula or something similar. Lightly spritz the 'other' side of the veneer with water if it's curling too bad for you to handle. Lightly.

I have tried various many other ways besides this, this is the single only way that has worked with complete success for me. All others failed and resulted in lifted veneer or humped veneer or throw-away jobs or 'well, it worked one time but not the next' jobs.

If it's a glue-heavy situation, you're only chance is to take a piece of hard wood as already outlined and clamp it down against the humps, but if time has passed, it might be too late already. What the hell, give it a shot, you got nothing to lose at this point. You might try to doctor some glue in there with a syringe, but if clamping doesn't work, I'd just call the job toast and move on to removing it and trying again.

Using an iron to iron it down is also possible, but only if the job is 24 hours old or less. If it's past 24 hours old, it might go down, but when you go to apply finish, it will most likely bubble back up again. And using an iron has it's own dangers. Using an iron will shrink the veneer. It will make your centerline uneven and can possibly crack the veneer along grain lines unless your familiar with moving an iron across veneer. And you can wind up lifting spots and making new bubbles that didn't exist before. Or burning the veneer. I have ironed on many veneers, and I have stopped using the iron method, this one works much better.

The guitar is generally not the place to experiment or to do an operation for the first time, you should practice on scrap first until you've worked out all the kinks in the operation. Once you approach the 'real' guitar, you should be doing operations that are already basically comfortable to you.

BECAUSE...It's a helluva lot easier to sand off a piece of scrap or just grab another than it is to have to completely re-prep a real guitar again. B)

I hate having to completely re-prep a guitar, scrap is sooo much easier.

PS, using a normal amount of glue, it will dry properly within the specified times the glue bottle calls for. I can usually pull my clamp boards off after 2-3 hours and have everything just fine.

Actually, I -recommend- you do pull your clamp boards off after an hour or two to visually inspect the job so far and be sure that all has gone well. Then re-apply them until the job is dry. If you have a hump or a lift, you can catch it and fix it within an hour or so. If you pull your boards off after a full day (or two or three) and there is a problem hump, the job is usually toast.

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I haven't seen the type of glue mentioned but I'm assuming it is a water based glue. You'll want to use either a veneer specific glue or something like a 3M spray adhesive and a roller to squeeze out any bubbles. Just for good measure I would probably clamp it as well. With the small inlay sized pieces I work with I use an epoxy but even that has a tendancy to curl and swell the wood. I can use that to my advantage for an inlay because it can help close up any gaps I may have but for a large flat piece it will work against you. I generally clamp for the full cure time not the set time but checking it after the nominal set time isn't a bad idea if you're not using a contact cement.

Ironing may help but I've never tried it with a piece that large. Somehow I have my doubts that it will fix it but at this point it's worth a try. If you used a water based glue it should soften the glue just like steaming off a fretboard but I don't know if the glue will still be viable a second time around. Just use lots of steam and have everything ready to reclamp in a big hurry. You might try steaming it off and reflattening but I think it would become a mess. The veneer is going to be saturated with glue and will be hard to work with. Worth a try if nothing else works.

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right, well i did decide to cut out the cavities....... then it kinda got better, and i decided to glue the other half on.... then cut that out......

and well






this aint perfect, but for the first try i think it aint bad

the other side bumped up in places, but these also mysteriosuly disappeared after i cut the cavities out.......

now i've put the body back under some weights, but only just in case.

i'm very happy now actually.... though thanks for the ironing advice!

so am i the luckiest bugger on the planet earth or what? B)

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B) Most definitely congratulations! :D

But you're not quite out of the woods yet. Whenever you have problem humps like that, you have to be pretty careful when applying your finish, they can re-appear again as the first coat or two go on, then it's a much tougher fight. Those areas usually are not quite as glued down as the rest of the area, and any heavy saturation from finish solvents can sometimes lift them right up again, I hope that doesn't happen.

Another tip...make sure you sand the entire thing down nice and flat...dead flat, as when you start sanding your finish coats flat, if there are any veneered areas that are even the -slightest- bit 'high', or 'humped', or 'wavy', you'll sand thru those finish areas very quickly, and if your using a tinted color, it will wind up uneven, so make sure you do a good thorough level-sanding job first. You can tell if it's sanded properly if you look at the sanding residue sitting on the veneer as you sand, any high areas will leave a tell-tale mark that will look different than the rest of the top. Sometimes you can actually 'hear' it, as the sanding block goes over a hollow area, it makes a 'poppy' sound (it sounds hollow). Also you can take your index finger and 'tap' the entire top. If you get an area that sounds hollow, you've got a glue-starved area there. It should all have a pretty much uniform sound when tapped.

If you use a water-based wipe-on stain on the bare veneer, that is another time when re-lifting will be a good possibility. How were you going to finish it?

PS, as far as glues go, they recommend regular old Titebond 1 for the iron-on methods (aliphatic-based glue which reacts to heat) and that is also what I use for all my veneering, iron-on or just regular clamping, it works fine once you get the amount right. The deal is with aliphatic-based glues is that they have a distinct cure time (window) that you need to use the iron within that time parameter if you want the 100% adhesion that heat/aliphatic-based glues give. 2-3 days later is way past the window of opportunity. It might hold, but not nearly as well as if caught within the window. It will be like 'tacking' it in place as opposed to full-adhesion cure. Also, if the veneer piece of the bubble is glue-starved to begin with, ironing it down is really just like tacking it in place again, it doesn't really make the glue creep up into the pores of the veneer, that's why it will never be as strong as the rest of the piece and those areas remain weaker than the rest with the possibility of bubbles re-appearing again under solvent application. This is why it is best to catch any problems quickly, not 2-3 days later, as if you catch them within a few hours, the glue has not passed the 'window' yet, and you still have a chance of full adhesion if ironed on or re-clamped.

PPS, you have to be careful what glue you use as a lot of times (especially with burls) the glue will creep up thru the pores and bleed onto the top of the veneer (the reason for the wax paper) so whatever glue it is has to be 'somewhat' compatable with your finish materials, as they will wind up interacting to some extent when it comes time for finishing. And the fact that Titebond is usually readily available (most of us will already have it)

Make sure you post pics of it done! :D

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i couldnt get titebond in this friggin country! nobody's ever heard of it! and i've tried like 5 stores..... :D....... so had to settle for the glue the recommended me

i'm quite concerned about them bubbling up again Drak, but there's nothing i can do if they do, and i might as well try to finish....

finish wise, no idea yet. might use black dye and orange translucent or blue translucent paint. or varnish mixed up with cellulose thinner. i have no idea yet...... i ahve about 15 70mm x 70mm offcuts of the maple left, so i'll have plenbty to experiment on.

but i'm sooooo hoping the veneer doesnt bubble back up. if it did, i'd cry B)

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Whatever you use, just try to keep it quick and dry it off ASAP...y'know, don't wipe on some water-based dye really wet and leave it there, that's where trouble will start...alcohol-based dyes dry faster as a rule...or if you're spraying on your finish, shoot your first coats dry, not real thick and wet...if you're wiping on some dye on the bare veneer, I've even had a hair dryer going to dry it off as quick as I could once I wiped it on to dry it as soon as I could (within normal limits, nothing extreme...too much heat from a hair-dryer will also loosen glue and pop up spots, and drying it too fast will not let the dye dry evenly...you'll get 'wipe marks'...just keep it moving quickly, lightly, and briskly over the piece).

Remember to sand it dead-flat and avoid another headache down the road. Don't oversand the already-flat parts, it IS veneer, but those humps have to be levelled or it will return to haunt you. It takes more than I think most people think to actually sand thru veneer. Don't get me wrong, you CAN sand thru, but it's thicker than you think when it comes to sanding humps flat. Just proceed with common sense and be watching...use a piece of hardwood for your sanding block, not those rubber-backed jobs, and go with some 320. It'll take you longer with 320, but you'll have more control over it also. By using 320, you're slowing the veneer removal process down so you can be watching...Maybe 220 if you feel the need...just use the hardwood backer block, it'll work for you to level the remaining parts of any old humps. Use your hands and fingers as the final judge, running them over the top to feel for any remaining humpy spots.

Believe me, as much of a PITA as it is to deal with humps now, it's a walk on the beach compared to them showing up once you've applied dye or finish to it, so catch them all now. Do the fingernail tap-test over the whole piece, listening for hollow areas, and if you find any, deal with them now, 'cuz they will come back to kick your ass later on! :D

You're still in 'prep stage' now, this is the time to find and deal with any possible trouble-spots, not later on. And I've had them hit me 'later on', when you've got several coats of finish on it...no fun 'atall...

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right, thanks.

sand flat, then finish FAST with 'thin' coats.

i'm gonna go shopping for dyes and translucent paints tomorrow, to experiment with finishing, what type of dye and what type of paint do i need? and then just a coat of clear laquer, yup?

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It sounds like you're trying to enhance the grain by doing a 'stain black then sand back' routine? If so, I use Behlen's Solar Lux Black to do that, but most any black anilyne dye should do. Try not to let your black sink in too deeply since you'll be sanding it back and it 'is' veneer after all and you will already have sanded it to some extent beforehand during your flattening stage...but it does work, I've done the 'stain black then sand back' with veneer before, it's totally do-able.

If you're doing that, when you wipe on (if you're wiping these on) your 'real' color (blue, orange, whatever) try to do that as fast as possible too, don't continue to wipe and wipe and wipe the stain around over and over, 'cuz it will start to pick up the black dye from the grain and start to darken the overall color. This is more noticable on the lighter colors like yellow and orange, not very noticable with blue. Blue over black is pretty easy to do.

PS, be very careful of the ridge on your front arm bout (the drop top area)...that area is prone to sand-thrus with veneer...go very easy with the sanding around there. :D

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thanks for the useful advice.

this is what i'm leaning towards now:

green / black finish liek this one


with possibly black burst round the edge, inner cavities sprayed black (or green), and the circuit board in between p-ups!

the flames are actually very close to the ones on this PRS, so i could emulate it with reaonable success i think.....

matrix meets flame maple..... ooh yeh :D:

whadda ya think?

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heh, looking forward to that wes.. but hopefully i'm gonna be done before then! :D

looking forward to taking on your green maple top in GOTM in a couple of months time ey :D

that is if mine doesnt decided to rise up on me B)

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^thin top as i'm modding a body, and thats the only way without having to cut off 1/4" off the body.....

anyway i glued some offcuts on some scrap wood, and i've done the first finish, and i'd like some feedback to whether its good, etc (i will do many more experiments with dyes, etc)

(sheet on left is unfinished)




i sanded the veneer with 200 grit, then dampened with some water, then applied my finishing mixture (50/50 mix of clear gloss varnish and cellulose thinner), then sand with 800, then reapply.. 3 coats.

whadda ya think?

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The dampening with water I would avoid when working with veneer, it's fine when doing a solid wood piece, but chancy when doing veneer work, my .o2...

The pieces look like you glued them down nicely, that's the most important part.

PS, that's very nice veneer!

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i know i know water is dangerous, but this is why i gotta try it out now......

i've managed to get it to look nice on the pictures..... however it only looks like that at the 'right' angle, if you know what i mean. is there any way to make it look like tha from all angles?

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  • 1 month later...

ok well i decided to dig this thread out as i've just applied the first coat of the finishing mixture.

very nervous, as i am fearful of what that veneer might do to me (hence the clamp)...



this is like the final job.... so hopefully will enter this axe into this month's GOTM (again) :D - but last time it was without teh maple top!

i have also kept an online diary at another forum, which i might edit (in order to brief down) and post here to boost my chances of success B)

but so far the maple doesnt look too bad, does it?

*fingers and toes crossed*

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