How to fold long pieces without bending

[Peter Weir]

Morning
I am working on a lorry and have a long piece (many) that needs to be folded square. I have scored the lines to be folded, but find when i try to bend them to fold a box, the paper warps and bends. Is there a better way to fold the pieces.
i have tried a long ruler which works to a point but any tools or gizmos to assist?



thanks

[Don Boose]

Don't cut the part completely out before scoring and folding. Leave plenty of paper on both sides of the fold line. The more paper there is on either side of the fold line, the easier it is to get a clean fold. After you have folded the part, then cut away the excess.

Don

[airdave]

In this case, Peter is talking about the long frame rails of my Lorry kit.

These are box tube rails, straight end to end.
Dimensions are about 4mm by 8mm

They are assembled with four flat sides, plus a fifth shorter side that is the overlapping glue tab.

Print the parts on at least 65lb cardstock...I may have used 110lb for this.
You need some strength and rigidity for best results.

1. Start by scoring the length of the parts, the four fold lines (using a straight edge).
Care must be taken to score well and straight.

2. Carefully cut out the frame rail parts again using a straight edge.
I can't stress the importance of maintaining straight lines when cutting and folding.

3. Fold (carefully) along all the fold lines, making sure to crease well.
In fact, I crease the parts so well that the surface/ink cracked. I touched up the edges and corners after the rails were assembled
A straight edge won't help much here because the parts are so narrow...I used my fingers on a flat surface and carefully folded the parts as straight as possible.

Lay the part flat on two flattened sides...fold over the other two sides as one flat side, and press to the glue tab.
You now have a squashed box rail, two sides down, two sides up...
and you can run your finger along the folds to make sure it all folds straight.
Then...unfold the rail and refold flat, with the alternate two sides up, two sides down.
You are diamond shaping the box rail in two ways...this makes sure the opposite sides of the rail are the same dimensions. And you are keeping the edges in a straight line.

4. Now the hard part...gluing.
You need to apply glue to the entire glue strip/tab, all at once...so work quick.
Do the diamond folding trick again as you connect the glued section.

5. paper tubes...be they boxes or round tubes...will always try to twist on their own.
I think its the wet glue on one side and as the paper dries, it twists, shrinks and expands...
So, thats why I immediately tied the two rails together using some paper strips.
And let them dry this way for a couple of days.

The pictures show the steps, although it doesn't really show my way of "diamond folding".
If you don't understand, I'll try to make a video.

Another important tip: jigs and weights help hold things in the correct position while glue dries.
After you wet the card with glue, it wants to do all kinds of weird things, so take the time to rig up jigs, templates, or holding methods before you glue and assemble things. (pic 5)
Allow parts and assemblies enough time to dry and cure, before attaching more parts...I let parts sit for days.
This frame took me 1-2 weeks to assemble.

[Peter Weir]

This is correct Dave your Lorry is my next project . I found your tutorial and build on the site and have started to do as your direction. I might try the 110 lbs paper as i have used it in the past and does help keep thinks straight and easier to fold.

I have plastic clamps that will work to hold the parts till dried


thanks

[airdave]

I wrapped in paper strips (as you can see in the photo) so it didnt damage or crush the card tubes.
They are hollow, so pretty flimsy.
Clamps might be too strong, but whatever works for you.

[Peter Weir]

agreed going to print on 110 lb paper also and see if that helps



thanks

[Mike Stamper]

As Dave says, a straight line is needed. I found that the ruler I used to score the line moves. To get round this I clamp the ruler and card to my work top at one end and hold the other to my work top with my fingers. I make the score line using a few gentle score lines with a blunt blade.

I lay the scored bit on the edge of my bench and fold the part along the edge.

When it comes to gluing, I glue about an inch at a time I find that gluing about an inch at a time works. Glue the first inch then leave it to dry. Then continue an inch at a time

Cheers
Mike

[airdave]

Originally Posted by Mike Stamper

When it comes to gluing, I glue about an inch at a time I find that gluing about an inch at a time works. Glue the first inch then leave it to dry. Then continue an inch at a time

Cheers
Mike

Mike, with these particular rails, that is how I did my very first set of frame rails...
I worked my way along, gluing the tab down at shorter increments.

But I ended up with a very buckled and twisted frame rail!

Maybe because this box frame rail is quite narrow in its dimensions (only 4mm wide), and long (over 300mm), its prone to twisting and warping during assembly?

I found that getting it creased and folded as squarely as possible,
and then gluing the entire length of the glue tab area,
resulted in the best frame rail.

[SJPONeill]

I've had this problem as well but I often cheat and add an internal structure that I can fold around...

[yukonjohn]

I have a variety of square and rectangular brass tubing in my tools pile. Using Dave's method and also using the brass tubing inside to burnish the still-damp joint seems to help keep things straight.


Regards,
John