[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: GSBN:RE: pre-compression



Hi Derek,
I have spoken with the manufacturer about this issue. They assure me
that their strapping, because it is made specifically for packing large
packs of timber, is not affected by being drawn over a sharp corner. In
Australia we have Kiln dried hardwood which is dressed. The corner of
the timber is so sharp a corner that it is possible to cut yourself on
it. The strapping is designed for this application. We us it wit radiata
pine, which does not have such a sharp corner, and bruises with the
application of pressure. If you would like to see some of the strapping
I can get the details for you. I believe there is a distributor for the
company in the US.

Regards
Brian Hodge

-----Original Message-----
From: GSBN [<a  target="_blank" href="mailto:GSBN@...";>mailto:GSBN@...] On Behalf Of Derek Roff
Sent: Friday, 1 September 2006 8:52 AM
To: GSBN
Subject: GSBN:RE: pre-compression


I appreciate your clarification, Brian.  I would recommend that no
strapping or cable make a 90 degree bend around a sharp corner of a
timber, or anything else.  Corners should be eased under the strapping
before tensioning, so that the strap or cable follows a more gentle
radius.  The needed radius varies with the material, but I would think a
minimum radius might be 25mm (1").

I believe that polyester _will_ have the same concern, as will steel.
Details of the specific material and configuration matter, but every
material is subject to issues of point loading and deformation.  Perhaps
for polyester, it is less of a problem than for polyethylene, although
I'd like to see the testing to support that assertion.  In general,
stretchy things do better on this kind of cycling that harder, stiffer
things, like polyester.

Derelict

Derek Roff

--On Friday, September 1, 2006 7:23 AM +1000 Brian Hodge - Anvill
brian@... wrote:

> Hi Derek,
> The crease that the strapping company is referring to is not only the
> crease at the buckle, but at any point along the length of the
> strapping such as where it runs over timber. If the retensioning is
> done on both sides it is likely that the crease will remain in the
> same position across the timber, however, given that we deal only with

> owner builders, I am concerned as to their capacity to reliably
> achieve this. Consequently, the shift to polyester which does not have

> this concern.
>
> -----Original Message-----
> From: GSBN [<a  target="_blank" href="mailto:GSBN@...";>mailto:GSBN@...] On Behalf Of Derek
> Roff
> Sent: Thursday, 24 August 2006 11:28 PM
> To: GSBN
> Subject: GSBN:Re: pre-compression
>
>
>> The manufacturers of the plastic strapping advised
>> me that it cannot be tensioned more than once, as the crease created
>> by the initial tensioning will be a point of failure.
>
> Strapping systems vary.  On the ones that I have used, after
> re-tensioning, the crease from the initial tensioning is no longer
> within the tensioned section of the strap.  It is hanging loose,
> unloaded, and flapping in the breeze.  Therefore, it won't be a point
> of failure.  I can imagine that it might be, if I were progressively
> loosening the straps, rather than tightening them.
>
> Derelict
>
> Derek Roff
> Language Learning Center
> Ortega Hall 129, MSC03-2100
> University of New Mexico
> Albuquerque, NM 87131-0001
> 505/277-7368, fax 505/277-3885
> Internet: derek@...
>
> ----
> For instructions on joining, leaving, or otherwise using the GSBN
> list, send email to GSBN@...HELP in the
> SUBJECT line.
>
> ----
>
>
>
>

>



Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek@...