veneer help needed

[Henry Cavanaugh]

I am making a medium size box with 4 veneered panels sitting in a stile and rail frame with a 1/4" rout. The insides wont be seen very often. The subtrate will be MDF. Is veneering the back side of the MDF panels needed? I understand about finishing both sides of real wood but wasnt sure if MDF had the same issues.

[Matt Day]

3/4" or 1/2" MDF?

[Nathan Conner]

Hey, Henry. The few times I've veneered anything, I did both sides. Not so much due to the mdf core itself, which shouldn't be as suspect, but due to the veneer & glue reacting differently to humidity and moisture.

Even engineered wood, if it's a balanced situation (like veneer on both sides), will be much less likely to warp, buckle or twist. If it does, at least you won't be able to blame your construction techniques.


And, honestly, it's just a couple of minutes more work and a few $$ more in the whole scheme of the box, it always feels worth it to put that final touch on it - at least you'll know, if no one else does.

[Mike K Wenzloff]

In general, yes you need to veneer both sides. Doesn't need to be a nice show quality veneer, but it is good practice to do both sides.

In part it depends on your glue. A PVA type glue will shrink, usually causing the panel to cup to the side of a single layer of veneer.

I have gotten away with veneering only one side by using epoxy with, MDF, Baltic Birch ply--and real wood. But it doesn't take much longer to do both sides.

Take care, Mike

[Henry Cavanaugh]

Matt 1/4" MDF made thinner to accept veneer and put in a 1/4" rout floating.

[Henry Cavanaugh]

I will do the back side. The only veneering that I have done I used white glue let it sit untill almost dry and then ironed on veneer. This was on a curved apron. I was planning the same method unless I hear better idea. Dont tell the wife about the iron idea.

[David DeCristoforo]

"I will do the back side..."

ALWAYS! It's a "rule". Balance is critical regardless of the substrate. Don't let anyone tell you otherwise.

"...unless I hear better idea..."

Here is a "better idea".....

http://www.veneersupplies.com/product_info.php?cPath=40&products_id=738

"Don't tell the wife about the iron idea."

Buy your own iron. Domestic tranquility must be maintained at all cost. They're cheap and it's really hard to sneak out of the house with an iron under your shirt.....

[Mike K Wenzloff]

...ALWAYS! It's a "rule". Balance is critical regardless of the substrate. Don't let anyone tell you otherwise...
Have you ever made a Federal, Regency or other period piece where there is show veneer is on a single side only, inlay stringing, cross-grained edging? And that on cross-banded cores (and sometimes solid wood)?

I understand it is not common practice today. I also understand it doesn't take much to slap a thin piece of veneer on the back side (hence I mentioned it).

But it ain't a rule that has to be absolutely adhered to if you understand how to go about it--including what glue is being used and the method of pressing used.

To be sure watar-based glues will curl the substrate, probably before the glue is fully cured. Epoxy won't in combination with well set up cauls and platens. Same with vacuum bagging. Both need to be applying pressure longer than one would in other applications.

Take care, Mike

[David DeCristoforo]

"Have you ever made a Federal, Regency or other period piece where there is show veneer is on a single side only, inlay stringing, cross-grained edging? And that on cross-banded cores (and sometimes solid wood)?"

And have you ever noticed how many of those panels are cracked and/or warped? Sorry...in my world it's a rule......

[Al Killian]

I cover both sides and use contact cemnet. I have not had any problems with it so far.

[Bill Arnold]

"Don't tell the wife about the iron idea."

Buy your own iron. Domestic tranquility must be maintained at all cost. They're cheap and it's really hard to sneak out of the house with an iron under your shirt.....
Better yet, buy LOYL a new iron and use her old one! Worked for me! ;)

[Mike K Wenzloff]

Well, as long as you mention in your world <g>.

Yes, I've noticed. Bet they wish they had used termite barf (mdf) or had good Baltic Birch ply.

Most lower cost items I have seen the greatest issues of veneer pulling away have been items like sewing machines in areas that get a lot of sun, or tables that were repeatedly damped by filling vases. And hide glue was used. Well cared for, better made pieces generally do not fail like the lower cost pieces can.

I have also seen many "properly" done, veneered both sides pieces fail from roughly the same periods, too. Hide glue had its limitations. Alternatingly cold and damp followed by hot attic storage, garages and the like are not kind no matter how well the piece was veneered. The nice thing about the hide glue, though, was it could be repaired. Split veneers relaid.

I'm not trying to persuade you differently, David. In fact, the conversation is slightly ironic--it is considered best practice to veneer both sides. It just isn't a universal absolute truth (except to those who believe it is...)

Take care, Mike

[David DeCristoforo]

Bill:
"Better yet, buy LOYL a new iron and use her old one!"

Ooooo....bad! Better hope your wife is not a feminist! Either that or hope she doesn't read this. You could end up sleeping alone for a week making statements like that...

Al:
"I cover both sides and use contact cement..."

Contact cement is considered a very poor choice for laying down raw wood veneers regardless of the substrate. The problem is that CC does not form a "hard" bond, allowing the veneer to move. If you have used CC with raw wood veneer and have not experienced cracking, bubbling, de-laminating, etc, you should consider yourself very fortunate indeed. That's the beauty of the "Better Bond" glue I linked to. It can be used like contact cement but forms a hard glue line. What's even cooler is the fact that after coating both surfaces, you let the glue dry so there is no bond until heat is applied. It kind of gives you the best of contact, hide glue and press veneering. I have used this glue extensively for veneering all manner of odd shapes and am amazed that it is not much more popular than it is....