[NHCOLL-L:3167] Re: gluing plants down

[Anita F. Cholewa]

As someone pointed out, rarely can we get 100% of the specimen glued - 
generally it's just enough to keep parts from falling off - in fact we 
have found with some tropical items that complete gluing causes warping 
(even though the specimen is completely dried).  In response to Steve, 
it has been my experience that the glue "breaks" before the specimen 
does, perhaps because we are using water soluble glue (where're the 
chemists).  I have found apparantly intact (no doubt microscopic pieces 
break) specimens with remnants of glue attached coming loose from the 
sheets.  On the other hand, those older specimens that are held on 
solely with cloth straps, can be seen fluttering (and sometimes 
breaking) in the meerest breeze of being moved.  The absolute best way 
of preserving the specimens would be to never allow access to them. :-\

Anita
__________
Anita F. Cholewa, Ph.D.
Curator of temperate plants
Bell Museum of Natural History
University of Minnesota
1445 Gortner Ave
ST PAUL MN 55108


Steven Heydon wrote:

> As an amateur woodworker, one of the things you learn is the fact that 
> when you are gluing dissimilar substances together or even the same 
> kind of wood with the grain going in perpendicular directions is that 
> it is very important to allow the wood in the joint to move freely but 
> very slightly. This prevents the inevitable breaking of the glue joint 
> due to different amounts of expansion in different materials or across 
> as opposed to along the grain. A similar problem would seem to affect 
> herbarium specimens glued all down their length. If the specimens are 
> firmly affixed to the paper, any flexing of the paper is not going to 
> break the paper or the glue, but will break the weakest link--the 
> plant specimen. It seems the straps perform an excellent job of 
> keeping the specimen attached to the sheet and at the same time 
> allowing for some movement of the specimen to prevent breakage.
>
>
>
> Steven L.  Heydon, Ph.D.
>
> R. M. Bohart Museum of Entomology
>
> Department of Entomology
>
> University of California
>
> One Shields Avenue
>
> Davis CA 95616   USA
>
>
> Phone 530 752–0493
>
> FAX 530 752–9464
>
> e–mail slheydon at ucdavis.edu <mailto:slheydon at ucdavis.edu>
>
>
>

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