Veneering techniques for harsh conditions

[weinstro]

Hi,

I have two applications coming up: speakers for garage and speakers for patio.

The garage experiences seasonal swings in temperature and humidity, from maybe 40 F in Feb to 95 F in Aug. Summers are dry; winters are wet. The patio experiences these same conditions, plus daily temp swings of 30-40 degrees.

What would be a recommended veneering technique that will last?

Thanks,

Rob

[andykriech]

Hi,

I have two applications coming up: speakers for garage and speakers for patio.

The garage experiences seasonal swings in temperature and humidity, from maybe 40 F in Feb to 95 F in Aug. Summers are dry; winters are wet. The patio experiences these same conditions, plus daily temp swings of 30-40 degrees.

What would be a recommended veneering technique that will last?

Thanks,

Rob

Hi Rob,

Don't take this wrong, but your seasonal swing in NorCal are about as benign as they possible get (we lived in the silicon valley for 14 yrs). Try the temp/humidity swings in the South, etc.

Just my opinion based on my empirical evidence, if veneering, I would use contact glue and NBL/2ply or at least paperbacked veneer. This would allow some movement still, as the contact cement doesn't become completely rigid.
You also might want to do some form of sealing the inside in an attempt to equalize the forces on the box. With our dramatic humidity swings, I painted my latest garage speakers and sealed the inside of the box, too. The previous speakers were sealed with poly on the outside, but not the inside and there wasn't any issues noticable after 5 years.

Andy

[cixelsid]

Use wood grain Formica (high pressure laminate) or truck bed liner

[weinstro]

Hi Rob,

Don't take this wrong, but your seasonal swing in NorCal are about as benign as they possible get (we lived in the silicon valley for 14 yrs). Try the temp/humidity swings in the South, etc.

True enough. I grew up in Chicago. Now, if I want to scrape a windshield, I drive up to the mountains.

Thanks for the tips regarding the contact cement. I wasn't sure if that was god enough, or if I needed to think about PVA, heat lock, or something more exotic.

[LouC]

I'd scrap the veneer and use a couple coats of Duratex. I did a coating on a scrap of mdf and left outside in Tucson, in the sun. Took over a year and half to start showing weather. They'll even tint it for you. Probably won't cost much more than veneer + heavy duty polyurethane.

If it's a vented cabinet, I'd seal the inside too (at least for the patio speakers)

[bobbarkto]

I would use the most rigid glue I could get.
Resorcinol or urea resin would be optimum. Epoxy will work but is at least 5x the cost. PVA, if it's a rigid one like Titebond 2 or 3, might be ok.

The last thing I want is my veneer bubbling and cracking. A soft, flexible adhesive will allow the veneer to move independent of the substrate, which means buckling and cracking. I want it to become one with the substrate. It will have enough flexibility to follow any slight movement of the substrate.

Finish inside and out for the outdoor speaks if they are vented. 3 full coats of whatever exterior finish you like. Pick one with UV stabilizers and be prepared to refinish the exterior often if much sun exposure.
Or go with Waterlox Marine. It only needs a light sanding and recoat every year or three. Pretty easy to do. Most other finishes will need to be stripped completely before refinishing.

[evilskillit]

For surviving the weather? How about laminating it with those vinyl squares that they use on the floors of department stores.

[Ludo]

I'd scrap the veneer and use a couple coats of Duratex. I did a coating on a scrap of mdf and left outside in Tucson, in the sun. Took over a year and half to start showing weather. They'll even tint it for you. Probably won't cost much more than veneer + heavy duty polyurethane.

If it's a vented cabinet, I'd seal the inside too (at least for the patio speakers)

Ouch! Lived in Phoenix for 3 years so I can relate to that.

+1 on the Duratex. Easy to apply, easy to clean, tough, with the added benefit that it does a fine job of hiding minor imperfections.

[billfitzmaurice]

The garage experiences seasonal swings in temperature and humidity, from maybe 40 F in Feb to 95 F in Aug.

That's a severe temperature swing in a day, but in New Hampshire not unusual over 48 hours. Over a year? No big deal. In any event, it's not the veneer that counts, it's the finish. DuraTex will hold up well.

[weinstro]

I would use the most rigid glue I could get.
Resorcinol or urea resin would be optimum. Epoxy will work but is at least 5x the cost. PVA, if it's a rigid one like Titebond 2 or 3, might be ok.

The last thing I want is my veneer bubbling and cracking. A soft, flexible adhesive will allow the veneer to move independent of the substrate, which means buckling and cracking. I want it to become one with the substrate. It will have enough flexibility to follow any slight movement of the substrate.

OK, I'm veneering using the iron on method with Titebond III, based on one of the veneering links provided in the Speaker Building Bible sticky. The veneer used is paper-backed maple, sourced from Woodcraft.

After 2 of 5 sides, I've noticed that the corners don't want to stick well. I'm addressing this by using touch up spots of glue and clamping. Any tips on what I should be doing to get this to stick right to begin with?

Second question - how much glue should I be using? I'm raising my eyebrows a bit, as the cabinet is roughly sized the same as a PE .375 cf box, but I'm using about an eigth of a bottle for each pair of surfaces.

Third question - what's the most effective way to keep (touch up) glue from getting on an adjacent veneered surface?

Thanks,

Rob

[fastbike1]

For the first, is the glue rolled out to the corners? Clamped out to the corners?

For the second, yes seems like a lot of glue. I cold press and that requires just enough glue to make the surface look like it was painted.

For the third question, use blue painters tape for the surface that doesn't want to be glued.


PS, I'm w/ Lou. For outside, I'd have painted.

[ckmoore]

+1 on Duratex.

Commercial pro grade cabinet makers do not use it for no reason.

I just wish I could afford it to put on my AutoTuba....

[bobbarkto]

Make sure you have even glue coverage.
A small piece of mdf or smooth wood is handy as a follow on press to help hold the veneer down while the thing cools.
Also, if the corners have been dubbed or rounded over just a little from sanding or trimming then the large flat surface of the iron might not be making good contact there. You can tilt the iron just a little around all the edges to insure you applyadequate pressure and heat at those spots.

Raw MDF will soak up a bit.
What size bottle? A small 1/2 pint or a gallon or? (it's all relative)
How are you applying the glue? How many coats?

Wide blue/low tack painters tape works pretty good for keeping glue off adjacent surfaces. using a roller to apply glue will help eliminate drips and runs. You might still get a little bleed over, the tape will take care of that.

OK, I'm veneering using the iron on method with Titebond III, based on one of the veneering links provided in the Speaker Building Bible sticky. The veneer used is paper-backed maple, sourced from Woodcraft.

After 2 of 5 sides, I've noticed that the corners don't want to stick well. I'm addressing this by using touch up spots of glue and clamping. Any tips on what I should be doing to get this to stick right to begin with?

Second question - how much glue should I be using? I'm raising my eyebrows a bit, as the cabinet is roughly sized the same as a PE .375 cf box, but I'm using about an eigth of a bottle for each pair of surfaces.

Third question - what's the most effective way to keep (touch up) glue from getting on an adjacent veneered surface?

Thanks,

Rob

[weinstro]

+1 on Duratex.

Commercial pro grade cabinet makers do not use it for no reason.

I just wish I could afford it to put on my AutoTuba....

I should clarify -- this particular pair will be inside the garage. For the outside speakers, they'll probably be covered with slate tile or something organic appearing.

Make sure you have even glue coverage.
A small piece of mdf or smooth wood is handy as a follow on press to help hold the veneer down while the thing cools.

I'm using a stiff foam roller, and follow with a veneer roller.

Also, if the corners have been dubbed or rounded over just a little from sanding or trimming then the large flat surface of the iron might not be making good contact there. You can tilt the iron just a little around all the edges to insure you applyadequate pressure and heat at those spots.

Good point. I'm using the household iron, dry, through some parchment paper. I attach two 10 lb weights to my arm to give the iron some down force. I can try working the edge above, but was worried about cracking the veneer.

Raw MDF will soak up a bit.
What size bottle? A small 1/2 pint or a gallon or? (it's all relative)
How are you applying the glue? How many coats?

Yes, it does dry fast. Standard Titebond bottle - about 1/2 liter size. Glue is applied with a foam roller, one coat per side (veneer and substrate). The last one I did with two coats. Better, but the corners still didn't adhere well.

Regards,

Rob

[jonpike]

Make sure you have even glue coverage.
A small piece of mdf or smooth wood is handy as a follow on press to help hold the veneer down while the thing cools.
Also, if the corners have been dubbed or rounded over just a little from sanding or trimming then the large flat surface of the iron might not be making good contact there. You can tilt the iron just a little around all the edges to insure you applyadequate pressure and heat at those spots.

Raw MDF will soak up a bit.
What size bottle? A small 1/2 pint or a gallon or? (it's all relative)
How are you applying the glue? How many coats?

Wide blue/low tack painters tape works pretty good for keeping glue off adjacent surfaces. using a roller to apply glue will help eliminate drips and runs. You might still get a little bleed over, the tape will take care of that.

In my somewhat limited but fairly successfull experience, it's always seemed that not enough glue was the source of my loose area problems. I've taken to doing two layers on the veneer, and at least one if not two on the box.

I got a tip from a Rockler guy, use a broken off piece of hacksaw blade as a glue spreader.. 24 tpi, not a fine one. Acts as a "rake" that leaves just about the right amount. This was for laminating two boards for a thicker baffle, but works good for veneer, too. Smooth it out, if it doesn't level itself. Rollers work good, as well.

For the MDF soaking up your glue... and the edges of MDF can really soak it up, you might try a sealer like Zinnser's Seal Coat. A few coats, straight or cut 1:1 with alcohol. Really takes the edge off your MDF's "thirst". Also, seems to make the MDF sand easier and smoother.

Hope that helps...

[weinstro]

In my somewhat limited but fairly successfull experience, it's always seemed that not enough glue was the source of my loose area problems. I've taken to doing two layers on the veneer, and at least one if not two on the box.

I got a tip from a Rockler guy, use a broken off piece of hacksaw blade as a glue spreader.. 24 tpi, not a fine one. Acts as a "rake" that leaves just about the right amount. This was for laminating two boards for a thicker baffle, but works good for veneer, too. Smooth it out, if it doesn't level itself. Rollers work good, as well.

For the MDF soaking up your glue... and the edges of MDF can really soak it up, you might try a sealer like Zinnser's Seal Coat. A few coats, straight or cut 1:1 with alcohol. Really takes the edge off your MDF's "thirst". Also, seems to make the MDF sand easier and smoother.

Hope that helps...

Well, this project has been about trying and improving upon different techniques.

I appreciate the tips and I'll give this a try.