1st Time User Guide 2013 - EnG

Bendywood a product of Candidus Prugger Sas Via Johann Kravogl 10 39042 Bressanone (BZ) ITALY

Tel +39 0472 834530 Fax +39 0472 834134 www.bendywood.com [email protected]

BENDYWOOD 1st TIME USER GUIDE

Please read these guidelines before working and bending Bendywood.

INTRODUCTION:

The patented production technique involves steaming and subsequently compressing and stabilizing still green and absolute

defect-free solid wood blanks with a cross section of 120x120mm and 100x120mm.

The maximum finished lengths that can be produced are:

- 1650mm in maple, ash, oak, cherry and walnut;

- 2200mm in beech.

Longer lengths are supplied jointed, either by means of a straight joint or by means of a diagonal cut (e.g. the handrails).

So, produced are BLANKS:

The blanks with a cross section of 120x120mm are sold under the item code BKG and the

ones with a cross section of 100x120mm under the item code BK: both are rough sizes that

shrink for about 10mm after drying. These blanks are supplied unprocessed. As a result of

that the surface of these blanks may show some colour differences and have small ripples.

The usable section after having planed all 4 sides of the blanks is about 100x100mm and

80x100mm respectively.

All items of our Bendywood product range are cut out of such blanks.

In this regard we invite you to visit our website www.bendywood.com or to take a look at

our Bendywood brochure with price list available on request!

DO NOT USE BENDYWOOD OUTDOORS!

BENDYWOOD IS NOT WATERPROOF!

WORKING

Bendywood can be machined using the same tools and machines as used for processing normal wood. However, since it has

been compressed, it is more compact and as a result of that it is advised to observe the following guidelines:

- Saw and sand the Bendywood like normal wood.

- Do not plane and mill against the grain direction: test on the surface planing machine in which direction the wood can be

properly worked.

- The rotation speed of the milling cutter should be about 20% higher as when processing normal hardwood.

HSS tooling is the best.

- Profiles, such as edge bands for instance, are best milled on the edge of a blank and subsequently cut off at the circular saw.

- With regard to the wood moisture following rules apply:

1. Bendywood should be as dry as possible during planing and milling and can be subsequently bent

2. The moisture content should only be raised to about 12% if very tight radii need to be achieved or if it concerns

handrails. See further below for instructions!

3. After the bending Bendywood should be dried again to a moisture content of about 8% before it can be processed.

- Also avoid cutting Bendywood into fixed lengths and then stocking them when its moisture content exceeds 8%. Because

as long as its moisture content decreases, it will shrink in length.

- Given the fact that moist Bendywood has no steady length, it is important to assure oneself that the Bendywood is fully

dry (7-8%) before gluing or fixing it in a definite way.

- Bendywood doesnt get damaged during the final drying process, as it already has been artificially dried before. It is

suggested to keep the bent sections onto the jig and either putting the lot in a well heated room for several days or onto a

60C heated plate until the sections have dried.

Raw blanks



BENDING

At a moisture content of about 12% Bendywood can be bent up to a radius of 1:10 (e.g. a 10mm thick section can be bent up to a radius of 100mm).

1. THIN SECTIONS up to 10mm thickness

Thin sections can be bent

freehand without any difficulty.

2. THICK SECTIONS

For thick sections more force has to be applied:

these sections can be bent using tension belts,

ropes, C-clamps or after pre-bending them on a

ring rolling bending machine.

Always bend them onto a jig and subsequently

dry them in this clamped position to 8%!!!

3. HANDRAILS

Our round handrails with a length up to 6,6m are packed in cardboard tubes and are shipped with a

moisture content of about 12%: this is the ideal moisture content level to bend. The handrails are only to

be taken out of their packing when you start bending. These handrails can be bent as follows:

a)

a) JUST BY HAND (to do so require 2 people), provisionally fixing the handrail onto the banister, onto the

lower part of the banister (steps) or onto a jig. Please also see the video on www.bendywood.com.

In case you should not be able to bend the handrail directly onto the banister, as it is not sufficiently

stable, you should build a jig as shown in the video with a radius of about 10% tighter as the requested

final radius, because the bent handrail will always open up a bit after taking it of the jig. In case the

requested final radius should be larger than 2m, one could bend even tighter. Only take the handrail

out of its provisionally fixed position after a few days, or - even better - only when its moisture content

level lies beneath 8% and permanently fix it onto the banister, as follows: using a fix fixing point halfway its length and oval

holes for all further fixing points, as the handrail will still shrink a bit in length afterwards. Only when bolting down the

handrail on a metal rail each 25cm, this problem doesnt occur!

b) BY USING A RING ROLLING BENDING MACHINE

We suggest to use such a machine in order to achieve uniform radii.

Please also see the video to this on www.bendywood.com.

When using a ring rolling bending machine, the following guidelines should be observed:

- Only use rollers with a smooth surface (nylon or metal) that exactly match the profile to be

bent: a 42mm thick handrail cannot be bent with 48mm rollers, for instance. Only the central driving

roller optionally may be gummed.

- Pre-bend progressively. Do not bend to the requested radius at once. Tighten the radius in 3 steps

during the bending process and do not let the handrail go back and forth through the rollers for more

than 3 times alltogether. Too much passages could squeeze the wood and the joints would get

damaged as a result of that.

- IMPORTANT: Only use the ring rolling bending machine for PRE-BENDING. Bending to the

requested final radius should be carried out by hand (if the requested final radius is 2m, you should

only bend up to a radius of max. 4m with the bending machine, for instance).



MOISTENING

The wood moisture of a Bendywood-handrail should be about 11 to 12% prior to bending!

Should this not be the case, the handrail should be put between 2 layers of moist cardboard. Also a few spacers should be

positioned between the handrail and the wet cardboards to avoid direct contact with the cardboards. Finally, the lot should be

covered with a plastic foil and left this way for about 2 days and nights.

SANDWICH METHOD

This technique (Sandwich method) allows the handrail to absorb moisture from the air without getting wet.

ATTENTION: Bendywood MUST NOT BE IMMERSED IN WATER OR COME IN DIRECT CONTACT WITH WET MATERIAL. A

possible infiltration of water will let the wood swell and - if the sections are jointed - can cause the joints to come apart.

FIXING

1. THIN SECTIONS

Thin sections can be permanently fixed immediately after the bending.

2. THICK SECTIONS

After the bending, Bendywood-profiles should at first be provisionally fixed onto the banister or jig for at least 5

days, in such a way that they can shrink along their length. During this period, it is also very important to reduce the

moisture content of the Bendywood to about 7-8%, as this will stabilize its form: the lower the wood moisture, the

more stable the Bendywood will become. Only after this the Bendywood can be permanently fixed.

Start with a fix fixing point halfway its length during the final assembly and use oval holes for all further fixing points, so that

the handrail can further shrink in length: it can be anticipated that a 6,6m long handrail for instance, will further shrink up to

1cm in length within the first year after final assembly. Mitre joints at the endings of the handrails should be avoided: the risk

that they will open up in the long term is high!

On the other hand, in case you should have the possibility to fix the handrail onto a continuous metal rail, this problem

doesnt occur if you permanently bolt down the handrail from below at small intervals of about 25cm.

ATTAINABLE BENDING RADII

- Bendywood can be bent up to a bending radius of 1:10 (with reference to the thickness of the wood): a 10mm thick

section with a moisture content of about 12% can be bent up to a radius of 100mm.

- This doesnt apply to sections that have been jointed in length:

a) Handrails: thanks to the special joints against long angle cuttings, developed by us, handrails with a moisture

content of about 12% can be bent up to a bending radius of 1:20 (with reference to the thickness of the wood): in this

way, a 42mm thick handrail can be bent up to a maximum radius of 840mm (84cm).

b) Normal-jointed sections: these can only be bent up to a radius of about 1:40 (with reference to the thickness of the

wood). This means that a 29mm thick jointed board (REC) for instance can only be bent up to a radius of about

1,16m.

Plastic foil

Wet cardboard

Spacers

Bendywood



GLUING AND STAINING

- Bendywood can be glued and stained like normal hardwood. Avoid if possible to use water-based glues, stains or

varnishes. We advise to use synthetical glues, stains and varnishes. Nevertheless, in case water-based glues, stains or

varnishes are used, please take care of drying them well as quickly as possible afterwards: in most cases this is

possible!

- Pay close attention when adhesive glueing in length is requested, as it is the case, for instance, with handrails or with

lippings against round table tops:

1. Never use butt joints!

2. Glue by means of a diagonal cut!

The length of the diagonal cut should be 3 to 4 times the size of the sections to be glued

IN SUMMARY PROCEED AS FOLLOWS:

A. THIN SECTIONS Bendywood

1. Work them.

2. Bend them by hand or as the case may be pre-bend them

with a ring rolling bending machine.

3. Dry them well onto the jig and subsequently fix them.

4. Stain/varnish them.

B. ROUND HANDRAILS Bendywood that are

packed in cardboard tubes

1. Bend them:

a) By hand, or

b) Pre-bend them with a ring rolling bending machine

up to max. 50% of the required radius and bend the

rest by hand, if a uniform radius has to be achieved.

2. PROVISIONALLY fix them onto the banister or onto a jig

until the wood has dried to 7-8%, in order to stabilize

their form.

3. Work them (mill them, drill holes, etc).


5. Fix them permanently.

C. THICK SECTIONS Bendywood that are

not packed in cardboard tubes

or

ROUND HANDRAILS Bendywood that are

packed in cardboard tubes and held in

stock for over 6 months

1. Work the thick sections that are supplied in raw

condition at a moisture content of 8%.

2. Raise the moisture content up to about 12% by

means of the Sandwich method.

3. Bend them:

a) By hand, or

b) Pre-bend them with a ring rolling bending

machine up to max. 50% of the required

radius and bend the rest by hand, if a

uniform radius has to be achieved.

4. PROVISIONALLY fix them onto the banister or

onto a jig until the wood has dried to 7-8%, in

order to stabilize their form.

5. Work them (mill them, drill holes, etc).


7. Fix them permanently.

Documents

1st Time User Guide 2013 - EnG