gluing pcb to wood

My guesses.

Silicone + filler. Reason: Removable on both surfaces and not grossly lost into a porous wood. Or

2 part epoxy with filler. Reason: Faster cure than silicone. Better bond on conformal compared to wood glue.

Experiment with the filler amount to get the bond strength.

See auto body supplies for filler types.

Double-stick foam tape.

I use it to stick little surface-mount adapters onto copperclad FR4. Nothing much else, except solder, will stick to copperclad.

John

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You don't have mounting holes on the PCB? I always design boards with

4 corner mounting holes if possible. Screws and spacers will mount it on wood securely.

Usually it does weaken the bond versus a bare PCB. The only way to approach this is to contact an engineer at the manufacturer of the conformal coating. I can almost bet they'll tell you that it won't work.

I don't know about your wood glue but the stuff I generally use results in lots of splinters and large chunks breaking out of the wood if I pry things apart. Essentially the pieces of wood are junk afterwards.

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Regards, Joerg

http://www.analogconsultants.com/

You don't have mounting holes on the PCB? I always design boards with

4 corner mounting holes if possible. Screws and spacers will mount it on wood securely.

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No, I can't use screws for aesthetical and mechanical reasons.

Double-stick foam tape.

I use it to stick little surface-mount adapters onto copperclad FR4. Nothing much else, except solder, will stick to copperclad.

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I doubt this will work at all(the pcb can shift in any way even a few mills 
as it will cause alignment errors). Anyways, the pcb's are coated and so the 
copper has nothing to do with it.

Use the double sided tape - not the foam tape. You will get nil movement. Its often used in small machining processes for that reason.

My guesses.

Silicone + filler. Reason: Removable on both surfaces and not grossly lost into a porous wood. Or

2 part epoxy with filler. Reason: Faster cure than silicone. Better bond on conformal compared to wood glue.

Experiment with the filler amount to get the bond strength.

See auto body supplies for filler types.

--

I imagine I'll have to use some type of epoxy. From the silicone I have used 
I doubt there will be enough hold(I'm thinking of the silicone caulk... I'm 
sure there are many variants). The epoxy may be too rigid making it 
difficult to separate the pcb if needed.

I guess I'm ultimately going to have to do some experimentation... not a big 
deal but was hoping to avoid the mess...

Usually it does weaken the bond versus a bare PCB. The only way to approach this is to contact an engineer at the manufacturer of the conformal coating. I can almost bet they'll tell you that it won't work.

----

Well, the whole point of conformal coatings is to resist such things but I'm sure there is some way to bond to it. Might have to rough it up a bit. I guess I'll have to experiment and hope for the best.

I don't know about your wood glue but the stuff I generally use results in lots of splinters and large chunks breaking out of the wood if I pry things apart. Essentially the pieces of wood are junk afterwards.

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It depends on the application, the type of woods(harder woods with smaller pores will have less an issue), etc...

What's unaesthetic about screws? Or unmechanical for that matter?

John

IF the surface is flat and clean, 3M VHB tape (The Black stuff, not the grey) will stick to just about anything. I believe it?s the same tape used on the Auto Ventvisors. (which I have and they last forever)

Some conformal coating is pretty durable, some not so much. I'd remove it in the spots for the tape.

Cheers

Silicone can take forever to cure if it's trapped. Not good if you want instant test results. Slow cure means it's doesn't reach max bond strength. Maybe go to 2 component silicone. Special order.

One time I used some left over GE Silicone 2 black RTV and after 3 days it still wasn't cured enough. Could have been old. I used it to hold a toroid in place. Messy.

Alternatively, don't forget good'ol contact cement to test. There's waterbase available.

What about the old hot melt glue ??

Rheilly.

Use "GOOP". You can get it at Home Depot. Both plumbers and household versions should do what you want.

>

You do realize that proper wood glue is stronger than the wood it is gluing, right? If you want removable, then a removable contact cement is probably the answer. If you don't care about destroying the device removing it, then epoxy.

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I'm never going to grow up.

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A few mils (0.001 inches) will cause alignment error? How much is your piece of wood going to expand with humidity changes?

What is being aligned? and why wood? How 'bout a nice peice of phenolic?

George H.

Anyways, the pcb's are coated and so the

If the joint is a perfect, well mated, wood-to-wood (long-grain to long-grain) joint, wood glue is stronger than the surrounding wood. It's not so great at bonding to other than wood, though. Wood glues. like Tite Bond will also soften with heat and water will do it in.

This sounds like an "art" project. Art is almost 100% associated with bad electronics. Art is 95% associated with bad welding.

John

I suspect one gains more glue knowledge with electronics experience. I seem to have accumulated a mass of adhesives over the years.