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Adventures in Vacuum Veneering #4: First Lessons Learned

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Blog entry by SPalm posted 12-28-2009 06:27 PM 10682 reads 2 times favorited 6 comments Add to Favorites Watch
« Part 3: Adding a Frame Press Part 4 of Adventures in Vacuum Veneering series Part 5: Lingerie Chest Build »

1) A soft glue roller really works well.
All I can say is I am impressed. This seemingly cheap roller spreads glue like paint. Just squirt glue out as normal and roll, up/down and left/right. The result is smooth and consistent throughout. Clean up is with soap and water.

2) A veneer saw is great but needs a tune up.

I tried both cutting with a knife and a veneer saw. For now, the saw wins. I guess that’s why they still sell them every place veneer is sold. But mine needed a tune up. This saw is meant to cut on the pull stroke only. The teeth all point towards the handle, and actually this is the most obvious way to use it. The blade is removable and double sided, both sides are the same. Rotate when one side gets dull.

The blade needs to have its ‘set’ modified to work effectively. First remove the blade. Flatten the side that will ride against the straight edge on a water stone. Then flip the blade over. Now the top must be honed at an angle using a curved sweeping action. Using both hands to hold the blade worked the best for me. Keep honing until the saw points become more like little knifes than like a regular saw. It is now the best combination of a knife and a saw. It will cut a V into the veneer with the side next to the straight edge being vertical.

To use it, hold a fat straight edge board tightly down on the veneer, with a scrap board underneath to catch the cut. Pull the saw in long strokes from the top towards you, using a slightly rocking motion. It usually takes more than one stroke. Several veneers can be cut at one time.

3) Paper veneer tape is pretty good stuff.

The standard paper veneer tape with holes works great. (This is the only tape that I know of that has the glue on the top side of the roll; Strange.) Tear off strips; do not cut, as the ragged edge becomes more hidden. The tape goes on the top, or non-glue side of the veneer. Activate the glue by wiping it across a wet sponge. Place several strips tightly across the joint, followed by one long piece running the entire length. Some people use temporary blue masking tape on the back side to pull the sheets together before veneer taping, but I found that an unnecessary step. But maybe this is needed for more unruly veneers.

This tape has a few nice features. It shrinks when it dries so the joint pulls together even tighter. It is thin so it does not leave any outline dents after coming out of the press. And it removes quite easily by wetting and scraping when all the glue has dried.

4) Don’t try to bookmatch quarter sawn stock.

This was a new one to me, and I guess it is the same with standard lumber. Quarter sawn lumber has really impressive rays that run perpendicular to the grain. This is one of the reasons it is sought after (it is also very dimensionally stable). But these rays really play with the light and will shift as you view the boards from different angles. If you bookmatch, the effect will be that one piece will look good from the left, and one piece will look better when viewed from the right. The result is kind of goofy. And anyway, the grain is so vertical that bookmatching really does not bring out the standard mirrored patterns.

5) Don’t get cocky about using a shower curtain liner.

I was gluing up some double stacked 3/4” MDF and veneering the sides to see how some table legs might look. (I plan to complete the other sides too.) This was a bit much for the vinyl and I ended up puncturing my vinyl on two sharp corners. Wooden cauls with rounded corners would have saved me. So would have some stronger vinyl. From now on I will probably use both.

Steve

-- -- I'm no rocket surgeon



6 comments so far

View Blake's profile

Blake

3442 posts in 3342 days


#1 posted 12-28-2009 06:51 PM

aw, shoot. I was rooting for the shower liner. I like this blog because veneering is something I haven’t done yet but I’d like to get set up some day to do it. And your approach is just like mine most of the time… just dive in head first and figure it out as you go. That what makes it fun.

-- Happy woodworking! http://www.openarmsphotography.com

View SteveMI's profile

SteveMI

956 posts in 2762 days


#2 posted 12-28-2009 07:19 PM

I bought a similar (Hirsch) saw, but haven’t used it. Manager at Woodcraft said to do exactly what you have done on the stone.

He also pointed out that on mine the teeth are different on each side, one side has directional angled teeth and the other side has 60 degree notch between each non-directional tooth. His advise was to file the directional angled teeth to match the non-directional 60 degree side.

I haven’t either of the modification yet, was just getting the stuff together and really following your posts.

Couple years ago I was in a prototype shop that was vacuum forming vinyl to larger automotive interior parts. They had a 8 ft by 4 ft hinged frame almost identical to the veneer frame press. It had vacuum pump and used a rubber membrane instead of the clear plastic on the upper frame. I had asked at the time how often the rubber needed to be replaced and they said it was 5 years and still going so far. They used light duty spring clamps on the sides with explanation that once the vacuum caught, that it created its own seal with the rubber.

Steve.

View SPalm's profile

SPalm

5257 posts in 3350 days


#3 posted 12-28-2009 08:17 PM

Hey Blake, I haven’t given totally up on the cheap vinyl yet. I bought another one to make a cheap bag like I had before if I want to do larger or curved panels. Ger21 put in a good link for less expensive 20mil vinyl, but I have not pulled the trigger yet. The Polyurethane plastic sheeting is supposed to be the toughest but $$$.

Ger21:
” Here’s a source for 20 mil for $7 /yard. http://www.tapplastics.com/shop/product.php?pid=248&

Steve, My saw is from Two Cherries. I have some of their chisels and they have been good to me, so I thought ‘what the heck’. I just checked on the web and both sets of teeth are angled back. I wonder why one would want one side without this. Maybe for more aggressive cuts?

Another really important lesson learned is to ground the vacuum pump. I have since run a grounding wire from the chassis to the switch box and tied it into the earth ground. Lets just say it was a little exciting when I went to check the temperature of the pump last night with my other hand on my grounded bandsaw. My body went kind of boogly.

Steve

-- -- I'm no rocket surgeon

View Julian's profile

Julian

880 posts in 2993 days


#4 posted 12-28-2009 09:45 PM

I have used shower curtain in a pinch for a temporary bag, but it is no substitute for vinyl from joewoodworker. My vinyl bags that I built have lasted hole free with heavy use for over 3 years now.

-- Julian, Park Forest, IL

View Drewskie's profile

Drewskie

53 posts in 2723 days


#5 posted 12-28-2009 09:52 PM

I suggest going with the thickest vinyl you can afford i have 6-7 bags made out of the .2 vinyl. I love that you used a shower cutian linner, now thats some ingenuity. My experice is that i get about 10 uses on them before i have to start patching them, usally while ive got somthing in the bag im trying to press. We also fold them up and put them on a shelf which contrubutes to the degradation, we should probly roll them up on a large piece of PVC with some bungies.

-- I cut it three times and its still to short? www.work-in-wood.com

View Karson's profile

Karson

35035 posts in 3868 days


#6 posted 12-28-2009 11:31 PM

Lee Jesberger got me pointed to using scalpels to cut veneer. They are very thin and I sharpen them on a piece of cherry wood that I put the finest polishing rouge on and basically polish the cutting edge. They cut like a dream.

I went searching for scalpels and found autopsy scalpels that are throw away. They are plastic and don’t take much pressure. The autopsy scalpel also don’t have replaceable blades. I’ve broke a couple So I now went to the stainless handles and bought a package of blades. You only cut with the tip of the blade. I bought ones that have a curved edge. I don’t know if they are any better than the ones that have a straight edge and go to a fine tip. Mine have at least some more blade bulk at the tip. I keep forgetting to ask Lee what blades he uses. I’ve only replaced a blade when the old one broke, never because it was dull. I always resharpen after every use.

What ever blade decision you go with you will live with it for the rest of your life. You will never run out of blades. The handles also use a couple of different style blades but the handles won’t work for all blades. You need to get a blade/handle match.

I also a saw and use it when I’ve got some gnarly veneer and the blade wants to wander

I bought a completed bag and am using the same one after 5 years. I did buy a second bag when I found that he charged me too much on the first one so I got a second bag for the difference. It sits unused. I use epoxy glue to patch the small pin holes. I fill the bag with nothing (I guess that means I take out all of the air) and put a little glue over the hole. The vacuum pulls the glue into the hole and seals it.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Southern Delaware soon moving to Virginia karsonwm@gmail.com †

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