Unibond One

[BKHam]

i do quite a bit of veneering and if i use commercial veneer or thinly cut homemade veneer (maybe trying to stretch materials or my bandsaw wasn't tuned), i've been getting wrinkling in my veneer.

i beleive the other aspect is the amount of glue i'm using. i think that hydraulic pressure builds up and the excess has nowhere to go so it pools, exacerbating the amount of glue issue in places. then combine that with thin materials, it becomes soaked and i get wrinkles.

i guess this turned into an advice post - if you are using thin veneers, be judicious with the glue, especially in the middle of the panel. around the edges, add an extra bead. on the but in the middle, just enough to cover.

if you use a roller, try rolling out the excess from the roller before adding new glue.

 

[creasman]

What glue are you using? Have you tried using hot hide glue with a veneer hammer? I'm no expert, but I find this works well for thin veneers. If you do have a spot where it hasn't fully adhered, then you can use a hot iron and damp cloth to reactivate the glue.

By thin veneer I mean the ones I slice myself, which are thicker than the ones you buy (3/64"ish). For anything over 1/16" I switch to using regular wood glue (e.g., Titebond) and a vacuum press.

 

[BKHam]

What glue are you using? Have you tried using hot hide glue with a veneer hammer? I'm no expert, but I find this works well for thin veneers. If you do have a spot where it hasn't fully adhered, then you can use a hot iron and damp cloth to reactivate the glue.

By thin veneer I mean the ones I slice myself, which are thicker than the ones you buy (3/64"ish). For anything over 1/16" I switch to using regular wood glue (e.g., Titebond) and a vacuum press.

i use unibond one, a long open time, low bleed, rigid line glue for veneer to substrate gluing.

I appreciate the solution but i likely won't go the hide glue route. i like using my vac bag.

i realize you get more options with thicker veneer but for my current project, i using commercial so titebond would be an option. the water content would be prohibitive.

 

[bobby g]

Bradley,
What are you using for cauls?

 

[BKHam]

Bradley,
What are you using for cauls?

i have a 1/2 inch MDF sheet as a platen. then a sheet of rigid foam. then the veneer and substrate. then on top, rigid foam and a caul made of whatever i have lying around plywood wise.

 

[Cuthriell]

Better Bond Xpress from veneer supplies works well and does not bleed through too much. It comes in several tints. Most of the veneers I use are 0.020" and this glue is fine for them and thicker pieces. I always spread with a roller and clamp up between MDF panels.

 

[BKHam]

the first pic is the first side of the first panel i did. i used a fresh roller and it was soaking up the glue. so i had to work to lay down a thin coat.

the second pic is pressed under the exact same conditions except the roller was charged with glue, it rolled on easy and a little thick.

i have extra veneer but now the question is how to get it off of there so i can reuse the ply wood.

 

[Woodmolds]

You should apply glue to only the substrate.
The glue should be like a medium coat of paint, meaning you should be able to see the substrate through the glue.
Too much glue can cause problems. I've learned this the hard, by doing it!

Tony

 

[Woodmolds]

the first pic is the first side of the first panel i did. i used a fresh roller and it was soaking up the glue. so i had to work to lay down a thin coat.

the second pic is pressed under the exact same conditions except the roller was charged with glue, it rolled on easy and a little thick.

i have extra veneer but now the question is how to get it off of there so i can reuse the ply wood.

If you have a belt sander you could sand it off. At the risk of some waviness!
I usually find it less labor to just start over, if you have the materials.
I too have only used the Better Bond glue.

Tony

 

[BKHam]

thanks to everyone who added suggestions. update....not sure what was going on.

my thought process:

Hypothesis. as mentioned i thought it was the amount of glue
my conclusion. i did subsequent panels with less glue (i thought it looked meager) and it ended up that i didn't get good adherence - i think this was not the issue

next hypothesis - back to normal glue amount. despite having good results in the past, i was using the rigid insulation (between the cauls and the work) and thought potentially it was not allowing good compression
my conclusion - i pressed one panel with cauls only, no foam insulation, and still got some waviness in the middle of the panel, more on the bottom (platen side) than the top (bag side).

next hypothesis - i thought maybe my platen was bowing and thus now allowing pressure there.
my conclusion - removed the platen and did a panel with just cauls that were perfectly sized for this project, top and bottom. still got crap adherence

overall - I watched the bag pretty closely and don't think that is the issue. i had good pressure for long enough for this to get better results than I'm seeing.

Maybes - could the glue be bad? the edges got decent adherence so maybe where there was extra air access early in the curing process it powered thru the process. then in the middle of the panel it was lagging and never adhered.

could there be a weird incompatibility between wood (QS WO) and glue? . maybe the thin commercial veneer being quartersaw was causing expansion in the thickness of the veneer and it was pulling away. I'm grasping as straws.

solution - quit being annoyed by veneer and do more solid wood work !