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Joewoodworker veneer press

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Project by ShopCat posted 1433 days ago 1842 views 11 times favorited 5 comments Add to Favorites Watch

Prior to starting a course in Marquetry and Veneering at RedRocks CC in Colorado, I took the time to build a JoeWoodworker designed veneer press. I found it worth the trouble, because once you start veneering, you never stop. I found that I can pull in the range of 20-21” so I’m getting roughly 10psi. Sometimes I go as low as 7psi on cold days. Pull seems to be strongly correlated to temperature, more so than barometric pressure. A warm pump is a happy pump. Even though I built the auto-cycling version, I find I have to run in continuous mode to get good pressure. That’s probably related to my shop being at 6000’, outside of Denver. Your mileage may vary.

If all of that sounds techy, not to worry. The JWW web site (joewoodworker.com) has very detailed instructions on all of this, and I obviously found it idiot proof.

-- ShopCat





5 comments so far

View mrg's profile

mrg

514 posts in 1502 days


#1 posted 1432 days ago

I had looked at the plans a few months ago and have been toying with building one of these. From what I have read I thought you could use a pancake compressor. How hard is it to get the parts, did you order the parts from joe woodworker or from another source.

Thanks Mike

-- mrg

View ShopCat's profile

ShopCat

48 posts in 2081 days


#2 posted 1432 days ago

Everything is stock/standard JWW EVS plan and parts (except PVC, etc.). Pump is one of his rebuilt Thomas’. Once you are done and have played with it for a while, the possibilities of varying the design become obvious.

That said, my time horizon was short. I wanted it in time for the class, so I introduced no variation. I am glad I went with a portable version instead of his Venturi plan. I think the venturi plan is probably a good plan, potentially more powerful (depending on your compressor) than the EVS plan, but my pump moves frequently, and is usually a long way from my compressor.

Something to seriously consider is the effect of altitude. You lose about 1” (or 0.5 psi) of mercury pull for every 1000 feet of elevation gain. I like to maintain between 8-9 psi (or 16-18” of pull) with a ideal of 10 psi (or 20” of pull), which means at 6000’ for a pump (rebuilt Thomas) that has a theoretical maximum of 25” of mercury pull (roughly 12.5 psi), I start close to the max I can ever expect the press to perform – under optimal conditions and performance – and can’t expect much better than my desired minimum level of pressure. This means the idea of auto-cycling to reduce run time, the whole idea behind his EVS plan, is nothing more than an abstract concept. I read all of that before I started, but I can’t honestly say I understood it. And, yes, I am very sure my system is not leaking.

What his EVS plan did for me, was to give me the extra PVC tanks that allow me to have pre-built vacuum pressure. I put my piece in the bag, I close it, I open the valve, and I’m at 5-7 psi instantly. Nice. Very nice. But, Vacuum Systems has a very nice, small, continuous run pump (as does JWW), which would have given me the same or better result, without the effort needed to construct the auto-cycling stuff. I just would have to wait longer to get the bag vacuum.

Also, I am using Titebond Coldpress for Veneer for my glue, and usually MDF or 1/8 plywood for substrate. I find that I need about an hour, no more than that, to press even reasonably sized (2’x3’) pieces. I haven’t tried curved surfaces yet. All you need to do is get the veneer to adhere to the substrate. You do not let your pieces sit in the bag under pressure for hours or days because the glue won’t cure, and with a wet glue like the Titebond, funky things like mold and swelling can (reportedly) happen. I follow his guideline of scribing a pencil line on the substrate before gluing, and only applying enough glue to get to the point where the pencil mark is just visible. More glue does not make for a stronger bond. Generally, I have found the JWW website info highly accurate.

I started out using two 1” melamine coated cauls, but now I use one on the bottom, and the JWW breather mesh on the top. I also bought one of his 30 mil poly bags when he had a sale around Christmas.

-- ShopCat

View SPalm's profile

SPalm

4618 posts in 2384 days


#3 posted 1432 days ago

Nice. Looks like a good Joe build.
I was just playing with mine last night. Fun stuff.

I never thought about your pressure being ‘that’ much different up there. I guess. Makes sense. But it sill sounds like you can pull enough vacuum to do the job.

Steve

-- -- I'm no rocket surgeon

View ShopCat's profile

ShopCat

48 posts in 2081 days


#4 posted 1432 days ago

Yeah, shows up in unexpected places. Mostly, altitude is just something we lecture the tourists on, and use to victimize visiting sports teams, but every now and then it’s real. Colorado has one of the highest enrollments in scuba diving classes in the country (the students then go dive somewhere with more than 10 feet of depth like Mexico). Does funky things to the regulators and BCDs.

But, I have found the warmth of the pump environment is a biggy for improving performance. Somewhere there is a known equation for all of that, but generally, if I want good results I need to run the pump in an environment at 70degrees F, or better. Direct correlation (up to a limit) between warm pump and productive pump. I have a small green house that can get up to +100degrees in the summer, and I have pulled nearly 22” in that environment, but it’s low on space to roll out the bag, plus the cat sleeps in the green house and gets pissy when I run the pump in there. Comes in and attacks the furniture. Amazing how far the American sense of entitlements has penetrated.

Playing with these things is an entertaining diversion.

-- ShopCat

View a1Jim's profile

a1Jim

109374 posts in 2079 days


#5 posted 1432 days ago

I built one and never used it’

-- http://artisticwoodstudio.com Custom furniture

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