Darryl Keil Last Activity 2025-09-09 11:09 AM
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Jimmy G

Posts: 4

Joined: 2009-03-28
Location: United Kingdom

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Subject : Help!
Posted : 2009-03-28 4:18 PM
Post #35335
Hello all. Newbie here. I have a small kitchen company in the UK and I am increasingly being asked by my customers for curved doors, panels etc. I have made one or two curved pieces in the past which have been successful but very time consuming and not very profitable. I mainly use kerfed veneered boards and thin mdf's for laminating into various component parts. I decided to invested in a vacuum press system to try to simplify and speed up the process and hopefully make some money. This turned up on Friday so today I had a chance to tinker with it. I had already prepared the former for a radiused end cupboard door I was working on and had the rails and stiles all ready slotted and tennoned. I decided to leave the panel so I could try out the air press when it arrived. I have used a vacuum press in the past so I did have a rough idea what I was doing. So to get to the point. I needed to make a 6mmish thick curved panel using 3 pieces of 2mm mdf. The pieces are 600mm long x 450mm wide, and the former radius is 280mm. This would be an easy bend to achieve using other methods. The problem I'm having is that the vacuum bag is being sucked under the lamination's before they start to bend, so when they do bend the bag is trapped underneath. I have tried pulling on the bag to stop this but it's impossible. I have a drawing to illustrate this and will attach it if all goes well. Any advice would be appreciated. Jim
Attached file : Publication1.jpg (48KB - 86 downloads)



 
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Don Stephan

Posts: 825

Joined: 2003-07-18
Location: Cincinnati, Ohio

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Subject : RE: Help!
Posted : 2009-03-28 6:40 PM
Post #35336 - In reply to #35335
Jimmy:
Most of us chaps going to be across the pond and rather archaic in terms of world measurement systems (metrics). If I'm staring at this combination ruler correctly, your 2mm thick MDF is about 1/8" thick, your 600 mm x 450 mm MDF pieces are about 24" x 18", and the 280 mm radius of your form we would call an 11" radius.

Are you bending along the 600 mm or 450 mm dimension, how much larger is your form than the panel pieces (length and width), do you have a grooved bottom platen under your form, and if so how much longer and wider is the platen than your form? Finally, how easily can the MDF pieces be bent to the shape of the form with hand pressure, individually and the stack of 3?


 
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Jimmy G

Posts: 4

Joined: 2009-03-28
Location: United Kingdom

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Subject : RE: Help!
Posted : 2009-03-29 4:28 AM
Post #35338 - In reply to #35336
Hi. Thanks for the replies & Sorry about the metrics, it just seems so much easier when you get used to it. I am bending the panel across the 18" dimension. Individually the pieces are quit easy to bend but they are quit rigid when bundled. I used 10 pieces to form the rails and stiles so I thought the 6mm panel would be easy. The end part of this video (if the link works) gives an idea of what I mean.

http://www.airpress.uk.com/videos/airpress.wmv

I had planned on using the former to clamp up the door so I made it bigger than the finished door and then some, so it is considerably bigger than the panel. (sorry to be vague. It's at work, I'm not) probably about 250mm overall (10" ish) I didn't use a grooved bottom platen but I did consider it as a possible cause. I also only used half of the bag length and placed a 4’ft x 4ft board inside which I now realize was probably a mistake. Thanks again. Jim



 
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Darryl Keil

Posts: 1455

Joined: 2003-05-22
Location: Maine

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Subject : RE: Help!
Posted : 2009-03-29 3:33 PM
Post #35339 - In reply to #35338
Jim,

Depending on the tightness of the radius and the stiffness of the laminations the bag can get drawn up between them and the form. In these conditions I just climb up and stand on the laminations while the vacuum is drawing down. This usually gets the lamination bent enough to the form that the bag doesn't get caught.

Darryl Keil


 
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Jimmy G

Posts: 4

Joined: 2009-03-28
Location: United Kingdom

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Subject : RE: Help!
Posted : 2009-03-29 3:56 PM
Post #35340 - In reply to #35339
Thanks Daryll. I'll be trying that tommorrow.


 
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Danek

Posts: 5

Joined: 2009-03-23
Location: Bend, Oregon

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Subject : RE: Help!
Posted : 2009-04-02 7:22 PM
Post #35343 - In reply to #35339
I've been pressing curved parts for 12 or so years and I can't believe it's never occured to me to climb up there to hold stuff down!
This method has revolutionized vacuum pressing for me over the past two days. Earlier in the week I was struggling to hold the parts to the form so the bag wouldn't get pinched. No longer!
The pieces I'm laminating are 40 inches long so I climb up, put my knees in the middle and hold down the ends. I turn on the pump first and have plenty of time to situate things. It's easy!!
Thanks for the GREAT tip!

David


 
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craig tufankjian

Posts: 308

Joined: 2004-02-01
Location: syracuse ny 13208

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Subject : RE: Help!
Posted : 2009-03-28 8:45 PM
Post #35337 - In reply to #35335
Jimmy,

push the panel down on the form first then hit the switch on the vacuum press. your gonna have to work like a chinese acrobat but it will solve the problem. the bag is sucking faster than the panel is bending.

second, why is your form so much bigger than the panel? you may want to elevate the form so the bag pulls down the panel edges tight to the form.

Craig


 
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Brad

Posts: 87

Joined: 2008-04-22

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Subject : RE: Help!
Posted : 2009-03-30 5:08 PM
Post #35341 - In reply to #35335
I think Don might be on to a part of your problem. I made some very similar arched panels not long ago laminated using 3 layers of 1/8" Baltic Birch. The rad in my case was around 20" if I recall correctly, and the panels were 18" x 30". Once I had a proper form it worked very well. My form was open at the base and the panels were pretty much flat until the vacuum pump was turned on. What size of vacuum pump do you have?

Have you looked at the bladder Darryl sells? One thing I have found is the arched forms stretch the bags quite a lot. A bladder will help reduce this and sure will save you a lot of time building forms. Next order I place, I will be getting one for sure.

Brad


 
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Jimmy G

Posts: 4

Joined: 2009-03-28
Location: United Kingdom

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Subject : RE: Help!
Posted : 2009-04-02 1:51 PM
Post #35342 - In reply to #35341
Just wanted to say thanks again for the advice. Bending the laminates by hand then switching on the pump was the obvious solution, I think I was expecting a bit too much from the vacuum bag. And raising the former does help press the ends of the laminates tight to the mould. I've built 3 formers just for one small base cupboard so I would be very interested to see how Darryl's bladder works (you know what I mean) Are there any links to demonstration videos or images of them in use anywhere? Cheers. Jim
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