vacuum press veneering

[fergy]

I've searched the forums here using "veneer" as the keyword but come up with nothing.

Are there any people here using vacuum presses for veneering work? I'm about to embark on my first project using this, but I've got a few questions that I'm not finding information on elsewhere, and there are surprisingly few books dedicated to this that I can find. I'm not really looking to learn hide hammering techniques at this point, nor am I up to that mess. I've got a bunch of veneer and my vacuum system will be finished this weekend, so I'm just about ready to go.

If you've done this before, please chime in and I'll start posting my questions so that others can learn along with me.

 

[WoodWrangler]

I have much interest in it .. but haven't taken the dive yet.

There are two decent DVD's on the market (Woodcraft carries them, I know) about vacuum presses and vacuum veneering. I've watched both with much interest and think you might find those.

I'd also visit www.joewoodworker.com, if you haven't already. Lots of information.

As you get into it ... I look forward to future posts. Also, I'm in Charlotte ... maybe I'll just borrow yours! (just kidding, don't panic)

 

[BillPappas]

I have a vacuum setup and have made a few tables using veneer but that is all I have done. I can answer a few questions based on that experience. Table frames are maple and the top is bubinga veneer, the dark trim is ebony.

Pictures of the tables are below...I would be happy to answer your questions if I can so post away.

Regards,

Bill

 

[fergy]

Bill: what's the veneer species in table 6?

I'll start with some simple questions. I've read that I need to veneer both sides of the pieces, yet I see samples all the time where only one surface was done. I understand the point of doing both surfaces, but is a plywood substrate static enough to only need one surface done?

Are you just using melamine-coated MDF as the bottom platten in the press? Are you bothering with true breather mesh on top, or using quilt batting?

What glue are you most fond of? It's been recommended that I use Unibond 800 for this project, due to the humidity issues I'll have. I definately want to use a 2-part catalyzed glue.

Jeremy: I'm actually building a venturi press based on Joe's stuff. It's also where I ordered the stock bag that I have. I've got to build a custom one for a slightly larger surface, so I'm off to Alpha Canvas to get 20mil vinyl. You'd be welcome to borrow the rig at any point. I'm all about sharing the wealth. That being said, I need to go collect some stuff I've loaned out. Thanks for reminding me.

 

[BillPappas]

Bill: what's the veneer species in table 6?

I'll start with some simple questions. I've read that I need to veneer both sides of the pieces, yet I see samples all the time where only one surface was done. I understand the point of doing both surfaces, but is a plywood substrate static enough to only need one surface done?

Are you just using melamine-coated MDF as the bottom platten in the press? Are you bothering with true breather mesh on top, or using quilt batting?

What glue are you most fond of? It's been recommended that I use Unibond 800 for this project, due to the humidity issues I'll have. I definately want to use a 2-part catalyzed glue.

Jeremy: I'm actually building a venturi press based on Joe's stuff. It's also where I ordered the stock bag that I have. I've got to build a custom one for a slightly larger surface, so I'm off to Alpha Canvas to get 20mil vinyl. You'd be welcome to borrow the rig at any point. I'm all about sharing the wealth. That being said, I need to go collect some stuff I've loaned out. Thanks for reminding me.

The veneer is bubinga.

I did veneer on both sides but used a cheap mahogany veneer on the hidden side.

I did make a melamine bottom platten and I used melamine on top - no mesh and it worked fine.

I used a PVA like glue (single part) called Better Bond from joewoodworker...no issues so far. I have read good things about unibond and it comes from the same place I bought my equipment www.vacupress.com and they swear by the Unibond. Daryl Keil is the owner of www.vacupress.com and he is very experienced and I think gives sound advice on his forum as well. He has articles in a few of the books devoted to veneering.


Hope that helps...also I added a couple more pictures from the last time I pressed veneer.

Table top in the press:

Table top just out of press:

 

[fergy]

Do you wind up with any mark-off on the veneer from the grooves in the platten? I was debating a top platten of MDF as well, just like you did, but was worried about mark-off on the show side of the piece.

Have you done any thin substrates, or just the thicker ones for tabletops? I'm doing up a bunch of panels for frame and panel construction, but I'm sort of limited to flat panels, and therefore thin subtrates.

I thought that was bubinga. I've got a bunch of curly bubinga that I'm using for this project. Unless I decide that I like the etimoe better, but I'm leaning toward the bubinga.

I've looked at the vacupress site as well. Seems that their prices run pretty high compared to other places I've looked, if I'm remembering correctly.

 

[BillPappas]

Do you wind up with any mark-off on the veneer from the grooves in the platten? I was debating a top platten of MDF as well, just like you did, but was worried about mark-off on the show side of the piece.

Have you done any thin substrates, or just the thicker ones for tabletops? I'm doing up a bunch of panels for frame and panel construction, but I'm sort of limited to flat panels, and therefore thin subtrates.

I thought that was bubinga. I've got a bunch of curly bubinga that I'm using for this project. Unless I decide that I like the etimoe better, but I'm leaning toward the bubinga.

I've looked at the vacupress site as well. Seems that their prices run pretty high compared to other places I've looked, if I'm remembering correctly.

Only the bottom platten has the grooves which allow the air to move in the bag so that it can be evacuated. The grooves do not leave marks on the veneer at all. The top platten does not need to have grooves. I have not done anything thinner than 3/4 inch MDF as a substrate but I do not see that thinner would really be any different.

I am not real sure on how vacupress prices compare to other vendors for like items, it has been a couple of years since I bought my system. I do recall they had good service when I made the purchase.

BTW - The veneer in the pictures came from the joewoodworker site and the veneer was good quality. The project I am planning now required considerably more veneer than I could find at joewoodworker so I tried www.certainlywood.com and I am very please with the transaction. I think they have good prices (especially if you buy in bulk) and they have excellent customer service. If you have run across a better vendor let me know.

Regards,

Bill

 

[fergy]

The veneers I currently have came off Ebay, from a seller named "Thinwoodandoldtools". I was quite happy with the pieces I got. Rough cost was $1/sq ft.

I'm confused why the top platten doesn't need grooves if it's suggested to use breather mesh. I know MDF is porous enough on its own, but the melamine covering makes it more airtight.

What vacuum pressure are you running for these projects? Have you had any issues with the glue bleeding through? Anything else to be aware of or that I'm not thinking of?

 

[woodnick]

I veneered some drawer fronts using plywood substrat once and only veneered one side and they did warp. So I would do both sides!

 

[fergy]

I veneered some drawer fronts using plywood substrat once and only veneered one side and they did warp. So I would do both sides!

That was my thought as well. However, last time I was at Woodcraft and asked if they ever did any veneering classes, they showed me the work their "resident expert" had done, and he'd only veneered one side of the plywood substrate. It made me wonder if it was stable enough.

 

[fergy]

Another question that I just thought of. I assume that the bottom platten should be the same size as the bag, such that a 2x4 bag would have a 2x4 bottom platten, since the bag is actually oversized to that dimension. But, can I use smaller plattens for smaller projects? Or does it make more sense to use the larger platten for ease of layout?

 

[woodnick]

Keep the platen size as close as possible to the wook size. If not the vacuum will pull the ends together causing the platen to bend.

 

[BillPappas]

The veneers I currently have came off Ebay, from a seller named "Thinwoodandoldtools". I was quite happy with the pieces I got. Rough cost was $1/sq ft.

I'm confused why the top platten doesn't need grooves if it's suggested to use breather mesh. I know MDF is porous enough on its own, but the melamine covering makes it more airtight.

What vacuum pressure are you running for these projects? Have you had any issues with the glue bleeding through? Anything else to be aware of or that I'm not thinking of?

Fergy,

The top platten does not need grooves because its purpose is to apply even pressure on the veneer and substrate. The bottom plattens grooves allow the vacuum pump to pull the air out of the bag which causes the bag to pull together the bottom and top platten with the substrate and veneers sandwiched in the middle. The platten method was used for years before they came up with the mesh. I have not tried the mesh but can see how it would work fine.

It is my understanding from what I have read in the books and have seen in the veneering I have done that some amount of glue squeezeing though the veneer is actually what you are looking for as it shows that you have a good bond. You just do not want it to be excessive...it is more like a you can just see the glue coming through the veneer and it sands away without affecting the finish.

In a following post you asked about platten size to bag size. My bag is much bigger than the bottom platten and you mak be able to see that in the pictures. I roll the bag up and clamp it off so that it is about the size of the bottom platten. If I am veneering something smaller then I just make sure the bag lays even around the object being pressed as the air is drawn out. I selected the large bag size as a "just in case" I wanted to do something really large and I made the platen a size that I could routinely handle without help and would work most projects. Worst case now is I have to make a larger platten for a bigger project. So far the plan has worked out ok for me.

Regards,

Bill

 

[fergy]

Thanks for the elaborate responses, Bill. It helps quite a bit.

 

[fergy]

Bill: Reviving this thread for a minute...

The grooves in your platten appear to be milled on the melamine side.

From what I'm seeing the plattens and cauls should be grooved on the back side. You want the smooth surfaces to press together, and the grooves on the back are to allow air to flow when the bag sucks up tight to the platten and caul.

Or am I confused about something here?

 

[BillPappas]

Bill: Reviving this thread for a minute...

The grooves in your platten appear to be milled on the melamine side.

From what I'm seeing the plattens and cauls should be grooved on the back side. You want the smooth surfaces to press together, and the grooves on the back are to allow air to flow when the bag sucks up tight to the platten and caul.

Or am I confused about something here?

fergy,

I only grooved the platten, that is what the directions that came with my vacuum press said to do and it is what I had read and seen on TV on a couple of the David Marks episodes. The grooves are just there to insure the air will move out of the bag creating the vacuum. I actually placed a caul on both of the outsides of the veneer substrate sandwich so one of the cauls was between the platten and the veneer which protected it from the grooves. So sitting on top of the grooved platten I had a caul > veneer> substrate> veneer> caul. I do not think I explained that real well in previous posts, sorry if it confused you.

Hope that helps.

Regards,

Bill

 

[fergy]

Okay, got it. Thanks. I was assuming the pieces were sitting on the bottom platten.

I'm getting close to starting this project. Just making sure I've got all of my ducks in a row.

 

[fergy]

I finished the platen and cauls today, and took it all for a test drive.

This is a 2x4 bag. The bottom platten is 19x36, or near that.

I was very pleasantly surprised at how fast the bag drew down, and that the system didn't need to cycle on and off. No leaks:eusa_danc

Pardon the poor quality. These were taken with my phone.

 

[WoodWrangler]

Looks good, Fergy. Did you make the pump?

 

[fergy]

Yes, that's a venturi-based one built from the plans, and a few parts, from joewoodworker.com.

There's a better pic of it in another thread, if you search on "vacuum".