Thread: Veneering - Making a Vacuum Press

Right! No questions or suggestions so far, so we can move on...

First Tests

A spare stick of Blackwood was cut into 3mm strips 60mm wide on the Laguna 14 bandsaw using my scary re-saw blade. I bunched and taped them together and ran both edges across the jointer which seems to work OK. I still wonder if a low angle smoothing plane or even a scraper might result in even better butt joints.

The strips were laid out on the bench face side up and pushed together before taping along each join. A second pair of hands would have been useful here.

Strips laid out for edge glueing.jpg

The resulting mat was the laid onto a convex surface rough side up to open the joints and Titebond 3 applied. Then the surface was covered with cling wrap before allowing it to dry under vacuum.

I found a spare panel of 4mm plywood and used a small foam rubber roller to apply glue to both the substrate and veneer in that order. I’ve since changed to a nylon paint brush because the loaded roller tended to slip rather than roll. This isn’t the time to muck around because I since discovered that some other timbers cup quite quickly when the glue is applied.

Test veneer under vacuum.jpg


After an overnight stay in the vac bag, the panel was trimmed up to this:

Test veneer.jpg Edge view veneer onto 4mm ply.jpg


Lessons learned the hard way

With the sea trials completed, it was time to go live with my Hoop Pine desk top onto 13mm ply. I cut veneers 195mm wide and discovered that despite taking the utmost care, the wider the cut, the harder it was to achieve an even thickness across the width. Using double sided adhesive “spots” I fixed the wonky veneers to a flat plank and ran them through the thicknesser.


The mat was then glued up and laid into a sheet of ply which was 150mm larger than the mat on all sides. Big mistake! The mat moved a bit on the ply when they were being inserted into the bag. After it came out, I had to make a special fence for the table saw which registered onto the edge of the veneer to square things up again. Now I make sure that the mat fits the ply exactly and I use masking tape around the edges to keep everything square. Cling wrap is wrapped around the edges to catch any squeeze out. BTW, the end of the masking tape is turned back on itself because It sticks like anything after vacuum treatment.

Hoop Pine veneer taped for edge glueing.jpg Veneered Hoop Pine panel.jpg


During the early tests of the system, I had to re-apply the vacuum every 30 minutes to keep it at max. It looked like the air was entering through the vacuum pump so I added a half inch ball valve into the line. It’s still only good for a couple of hours but a perfect seal is just not worth chasing.


Having spent a lot over the years working with solid wood, being able to make my own veneers will not only save money but expand design possibilities for future projects. It's great to add a new skill and equipment which broadens capabilities.

mick

Good and helpful post. I would like to do some veneering some time in the future and I’ll refer back to your post.

Leigh


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I forgot to mention

When I first hooked up and turned on the pump:

The bag started to collapse and then suddenly stopped before the pump started making funny noises. What’s going wrong? Maybe the pump’s a dud. That night I worked it out over a glass of red as an aid to clear thought. Quick connect fittings have a non-return valve and are designed for positive pressure, not negative. The guts of the female fittings include a tiny spring-loaded metal disc which seal against a rubber washer under pressure up the line. So, into the bin went the discs and voila! I was no longer working against myself. The bag collapsed and revealed every saw cut clearly.

Better you know now...

mick

Can you let us know which pump you went with Mick. There are so many out there, especially on eBay.

i need to start putting my kit together.

Cheers
shane

G'day Shane, long time no see.

There isn't a brand name on the pump or in anything which came with it.

The label on its side reads:

2 Stage Vacuum Pump
Model VP215N
Free air displacement 1.8 cfm
Ultimate vacuum 15 microns (0.00029 psi) (That's a big claim)
Power 1/4 HP

The pump came with spare oil and a case of gauges, hoses and fittings, none of which I've used. The following photos might be helpful when you go searching online. It must be a year since I bought it so I can't remember much detail.

Vac Pump 1.jpg Vac Pump 2.jpg Vac pump accessories.jpg

I'll be interested to hear how you go.

mick

This looks like it from HVAC. It sounds like the outfit where it was bought.

https://hvacdirect.com.au/130-l-min-refrigeration-vacuum-pump-2-stage/?gclid=EAIaIQobChMIupK5qdiC6QIVmnwrCh2ujQvxEAYYBSABEgK_o_D_BwE

mick