| Veneer Question [message #38219] |
Sun, 08 September 2002 08:07  |
LuxmanLover
Messages: 164
Registered: May 2009
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Master |
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I need some advice on applying veneer over MDF. A local supplier has shevles of assorted unbacked veneers that he is selling very reasonably. Any suggestions on the best method of application? Contact cement, white glue?
Thx Kelly
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| Re: Veneer Question [message #38221 is a reply to message #38219] |
Sun, 08 September 2002 09:07  |
BillEpstein
Messages: 886
Registered: May 2009
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Illuminati (2nd Degree) |
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I can tell you for sure what NOT to use: 3M #77 spray. I veneered the 4Pi's with it and when they were exposed to some dampness, became washboards!
It had been recommended to me by a veneer supplier.
It's suppposed to be possible to use contact with unbacked as long as it is flat, straight grained and no checks or cracks. But the rubber contact is said to lose it's bond even in direct sunlight.
Right this minute I have a batch of hide glue warming up in a drip coffee pot and in about one hour I'll know if a method learned 40 (yikes) years ago has left me or not.
Hot hide glue goes back to the ancient Egyptians and was used for pretty much everything until PVA was developed after War II.
If you need to make NO seams, spread yellow carpenters glue on the substrate, let it dry and then iron the veneer with a DRY iron set on highest heat. When the veneer hits the glue it will want to curl so have a sprayer ready to spray the face side. But don't get it too wet. The veneer will shrink away from the edges if you do.
And if you veneer panels, as opposed to completed carcases, you must veneer both sides. Veneer one side of a piece of 3/4 MDF and see the bow next day!
If you don't want to invest in the tools and time for hot hide glue, go to the Tape-ease sight for NBS backed veneer. Not cheap, but everyone seems to get good results. Good tutorial there too. Sorry, I lost the bookmark.
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| Re: Hide Glue Veneer Question [message #38228 is a reply to message #38221] |
Sun, 08 September 2002 16:08 |
Till E.
Messages: 7
Registered: May 2009
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Esquire |
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What I've accomplished so far has turned out well.
Put about 1/2" of glue flakes in $12 drip pot carafe with enough cold water to cover them. Less water would have been better, I had to add more flakes. Let stand 2 hours. Turn on the coffee maker for 1 hour. Perfect 150 degrees.
All the while I am cutting sheets for tops and bottoms no more than 1/2" oversize. You need some trim, but too much or curling is a big problem. Always cut with veneer saw or knife to the waste side where a slip away from grain won't be trouble.
Test the glue by getting some on your index finger then squeezing out moisture with your thumb. As it cools, your fingers should glue together. Make the consistency gooey but not thick.
Now you need a pot of warm water, the veneer saw and veneer hammer soaking in it. Be near the hot water supply as you need to get more with each sheet. Cool water will not dissolve the glue. Always have the saw and hammer warm and wet.
You also need a clothes iron set to low-,medium; it should be uncomfortably warm but not burn you. Make sure the sole plate is smooth and won't scratch or tear the veneer. And the ground had better be good because you're going to have it sit in a pan with about 1/4" of water! I didn't do that instead kept a rag in warm water and wiped off the glue after each use.
Now lightly spray the veneer both sides with clear water. Just right if it takes a moment to seem completely wet. If you soak the wood, bad news. This wetting will pre-soak and also reveal which way the wood will curl.
Concave side goes down so edges won't curl up. Good thinking, huh?
O.K. Now brush a generous amount of glue on the substrate. For MDF, be more generous. In fact, next time around I will coat the MDF, let it dry (sizing) and then re-coat. It's that thirsty.
Put the FACE side of the veneer in the glue (!) and brush a healthy amount on the glue-line side. Push on the brush a bit so the face gets covered with glue.
The glue on the face saves drying problems and more importantly lubricates the face for the hammering. The glue will easily scrape off when dry.
Now take the warm, wet hammer and while holding the veneer in place (it's slippery) push down in the middle of the workpiece. Push the hammer down the middle both ways and then work diagonally to the edges, squeezing out the glue. It's real messy. Don't work over the Aubusson rug, schmuck! But it feels good.
"Kinky", says Hedley.
As the glue cools it will grab. Keep hammering until it's all stuck down. Edges that don't stick need more glue and then hammer. Bubbles are for the iron.
If you have bubbles after it cools, re-heat the area with the iron for a few seconds and then use the iron as a hammer until the bubble is gone. Same if you need to repair one of the Smithsonian's Chippendales: just heat the veneer and lift it. After 400 years. Cool, huh?
Turn the workpiece over face down on another piece of plywood or MDF. Using the edges of the workpiece as a straighedge, cut off the excess veneer with the warm and wet veneer saw. Wet veneer cuts real nice. If the overhang is an 1/8 or less, leave it alone until the glue dries.
You "shoot" the edges with a sanding block. Get an 80 grit sanding belt, 3X21 is a good size. Cut a piece of 2x4 to just fit inside the belt. Now cut a pair of wedges that when pushed together inside the belt forces the belt tight.
Wait 24 hours to shoot and scrape. Shoot the edges flush with the sanding block. Even a sharp plane, and I have $200 ones, can cause tear-out.
Can you use a scraper? You can sand off the glue from the face but it's a pain. A scraper is saw metal, spring steel sheets about 2"X4" that you put a burred edge on. That's a subject by itself. You can buy Sandvik scrapers with an edge on that will get you thru a pair of speakers. You push it ahead of you on the wood holding the top edge forward and the edge in contact with the wood back a little so the burr scrapes, actually planes the wood. Wrong angle you get dust. Good angle you get less than paper thin shavings.
Scraping compresses the wood so afterward you sand a few passes with 220 garnet paper. Then apply finish,
The End.
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