Multi bend lamination project.

[DragonImprovements]

Hi all,

Firstly id like to state that I'm not a carpenter. I hold qualification in various trades but sadly not carpentry. My background which could loosely resemble carpentry is a kitchen fitter, but i do see that as some sort of insult to fully qualified carpenters.

Anyways, to my project.

I am looking to create a ply laminated shape. Now i have done some research of the lamination process which seems pretty straight forward. The part I'm struggling with is the former.

This is extremely hard for me to explain but i'll try my best.

Ill post a very basic shape as a view straight on.

i plan on using sheets of 3mm play the dimension of the ply as in width (or depth when looking at it from a project point of view) would need to be roughly 500mm

now i understand the process of cutting sheets and stick them together. My problem, like i mention is the former.

Do i need a former at least 600mm wide/deep which would have the shape cut out so to then clamp the laminated ply between? Or could some sort of peg formation me be planned out then the sheets pushed through the pegs?

Projects i have seen on youtube are of very small width so the formers they use are easily created.

any help will be greatly received

Thanks in advance

 

[DragonImprovements]

Hope you can make out what I'm trying to achieve. Granted my sketching skills are sh!te.

 

[DragonImprovements]

Apologies but it needs to be rotated 90 degrees to the right. Vertical piece is the beginning

 

[Steve Maskery]

Hi DI

I really don't want to burst your bubble for your first project, but you are asking a lot, if I understand you correctly. If that width is 500mm, the overall length must be, what, a couple of metres? That is a big laminate, a very big curve and quite a tight turn. I don't think the acute bend at the straight end is even physically possible, although you could make the rest as a laminate and then joint it.

If you did want to go ahead with this I think a vacuum press would be the way to go, but there is a significant capital outlay. The mould would have to be made as well. Have you approached a company that specialises in this sort of work? It might be the better option. Bagpress do this sort of stuff and would be well-place to advise you.

Steve

 

[DragonImprovements]

Thanks for the reply Steve. The image is just a guide the turns would just be as close to maximum as they could go, not necessarily really tight turns. Yes, i would imagine the length of the runs would be close to 2/2.5m. Does the length play a part in the lamination process?

Its something I'm looking to create for myself so if possible id like to achieve it myself. Granted if after careful consideration it isn't possible, well, i'll leave it be a pipe dream so to say

 

[Steve Maskery]

It's just that something that size is going to require a decent-sized bag and the pump to evacuate it. It's an ambitious project for a first attempt, that's all. Why not have a chat with Bagress and see what they say?
S

 

[DragonImprovements]

Bag and pump to evacuate it? What do you mean by that mate?

 

[Steve Maskery]

OK.
The way that vacuum laminating works is to use the weight of the air above us to press down the layers of the laminate onto the mould.
So first you make the mould, allowing for any anticipated spring-back when the workpiece is relesed, then you apply glue to you various plies and stack the the plies onto the mould.

The whole lot is put into a large bag and all the air is pumped out. The plies then get pressed onto the mould and when the glue cures you end up with your lamination.

Yours is big and complex.

If you've ever used a vacuum clothes storage bag for keeping your knitwear or spare duvets so that they take up less space, you will have a good idea of the process.

 

[custard]

It's not an impossible lamination, but it is very, very demanding.

A common problem with lamination is "springback", where the lamination slightly straightens once it's removed from the former, what's less well known is that once the curve exceeds about 100 degrees the reverse happens and the lamination actually tightens once it's removed from the former. So with two curves that are each about 180 degrees you would probably have a struggle getting it to actually release from the former!

Another issue is that for the very best quality laminations you really want both a male and female former, but that's going to well nigh impossible with this curve (unless you went for a multi part former), so you'd probably end up point cramping to a male former. And that's going to introduce a number of hurdles. I normally prefer to make the former from a master template in one pass using a ring fence on a spindle moulder, but for this lamination I'd construct a master curve and use that as a template to rout out a copy in 18mm or 25mm MDF, I'd then glue and screw that copy to a slightly oversize MDF blank and use it as a fresh template to run a bearing cutter and cut another perfect copy. The process is repeated until the former has been built up to the required thickness, it's do-able but it's a long job to make accurately and for something this big it's certainly a two man job. Also cramping into that tight curve on the top right would be a devil of a job, it may possibly require special saddle cramps made out of threaded rod. The 90 degree joint in the bottom left should be a separate component jointed on with dominos. All in all there's at least 40-60 hours labour in making the former and probably the thick end of £200 in materials.

All things are possible, but this a major undertaking.