The first rubber stamps I made were a sort of a spur-of-the-moment project for an outreach event I was involved in this past spring (for the CSCC).  They were something to interest the younger set so that we could engage their parents on the subject of watershed protection in SE Portland, and I did not do any research into how to produce a durable and reliable rubber stamp.
    The first set was quite popular at the event (and at others in the summer) but they had two problems: a) they were not durable enough for continuous use outside the studio, and b) some of the the larger stamps were difficult to get a solid print out of, even when a grown-up pressed hard, both on the ink pad and the paper.
    The solution to the first problem of course was to use better quality rubber.  The first set was made (somewhat inadvertently) from two separate products, Speedball's Speedy-Cut rubber, and Dick Blick's Soft-Kut, both inexpensive and seemingly serviceable rubber products.  They worked quite well, being easy to cut (I'm used to linoleum), and printing well with either brayer-applied ink or with an ink pad.  The durability problems showed up at the end of several hours of continuous and frenetic use by several dozen school-aged children, and after transporting the stamps home stacked one on another.

right:  Damage from rough handling is visible at the edge above the ear and at edge of foreleg.  Possibly this was exacerbated by the use of quick-drying alcohol-based ink. The river otter is a favorite at events.
    The new rubber is another Speedball product called Easy-Carve, which is nearly as soft as the other two but not at all prone to crumbling (the Soft-Kut is particularly prone to this).  Easy-Carve is pink and pliable, and seems more durable not only to me but has proven itself in the letterboxing community where it's known as "the pink stuff".  It can be had for a very reasonable price at Stampeaz.com, which also has impeccable service. 

left: A sliver of Easy-Carve.  Cuts like butter, seems to last like Vibram.
    The second problem was caused by a slight warping of the boards that the larger stamps were mounted to, producing a dead zone which would not print properly.  The new stamps have a sturdy hardwood backing and a layer of foam in between the wood and rubber in order to distribute pressure over the printing surface.  The hardwood is less prone to warping and splinters than the random pieces of pine and plywood I used first, and also looks great after sanding.  These details of construction were learned from the website of American letterboxer Kirby Palm, who is an eccentric of a different sort than I am, but is a creative and lucid one.  He also gives good and detailed advice on things he knows about.

right: Placing a newly cut stamp on foam cut a little bigger than the stamp.   This particular one was copied directly from the damaged one above, with a few improvements in detail and style.  Old style otter stamp used a piece of plywood originally cut by my grandfather Charlie Norton for mounting a photograph, probably forty years ago.  The drawing table was his as too.

left:  Completed new style stamp with foam and hardwood block.  This one has been proofed by my two-year old Samara, hence the smudges.

left:  Water ponded upstream of undersized pipe culvert at SE Glenwood St., just north of Westmoreland Park. This culvert is slated for removal within a year or three.

    After the duck pond is replaced with a stream channel and wetlands and the undersized culverts are replaced with larger box culverts or bridges, both the overall appearance and the hydrology of the creek will change.  The undersized culverts slow the current on the upstream side and cause siltation of the streambed as well as ponding and warming of the water.  Within the pipes the current is accelerated, causing scouring of the streambed near either end and making it difficult or impossible for juvenile salmon to pass upstream.  The replacement of these culverts and the removal of the duck pond at Westmoreland Park should go a long way towards restoring Crystal Springs Creek as salmon spawning and rearing habitat, but not all the changes are entirely predictable.  In any case I think a good set of before and after photos is warranted.    

right:  Crystal Springs Creek where it enters the duck pond at Westmoreland Park. Note the collapsing concrete liner and Great Blue Heron. Most of the pond is no deeper than a heron can wade, which contributes to it's temperature problem in the summer (too hot for salmon).

left:  Overfed Domestic Swan Geese (Anser cygnoides) and hybrids at the duck pond. Note the total lack of vegetation along the shore here due to feeding and trampling by ducks and geese. Also note the decrepit concrete liner falling into the water. It really smelled terrible here.  Please do not feed the waterfowl!

right:  Damage to picnic area west of duck pond. The grass is cropped to about half an inch and the ground is covered with droppings (difficult to convey in a photo, but try leaning close to your monitor and sniffing the image).  I probably will not do a lino-cut of any goose droppings.

Luckily for you, the damage is much more apparent in person (you’ll bring some home on your shoes) than in photos.  What I did find, at the south end of the park, is a fair diversity of plant species growing near the stream, and I will show you some of this instead. 

right: South of the duck pond things look a lot better in the vegetation department.  Here we see western redcedar (Thuja plicata)and weeping willow (Salix babylonica) which are both good riparian shade trees.  The willow is not a native variety, but my guess is it does more good than bad for the creekside habitat.  The understory here is mainly rushes (possibly Juncus effusus, the common rush) and a jewelweed (Impatiens capensis or possibly Impatiens noli-tangere, based on details of the leaf tips and pigmentation on some blossoms).  The former was probably planted by the Parks Dept., but the latter spreads readily by seed along stream banks.  Impatiens noli-tangere is a native here in the west (and in Eurasia) but it's cousin the orange jewelweed (I. capensis) is introduced here from east of the Rockies.  This specimen could be either variety or a hybrid, the descriptions are so similar and these plants had some characteristics of each.

left:  Blossoms of the jewelweed.  Note that, like an orchid, the nectary is way in the back and the anthers (pollen-bearing structures) are poised overhead in the front, waiting for the next bee.

    The seed pods are the fun part.  As they mature they develop spring tension in the flexible case, and spread their seeds by bursting when disturbed.  The riper they are, the less provocation they require.  Botanists call this attribute explosive dehiscence, and there are other plants along the creek that share it with the jewelweed. 

right: Seed pods of Impatiens capensis
(and a ladybug larva).  The fatter they are the better they pop!

left:  Impatiens noli-tangere pod after explosive dehiscence.  Imagine a banana peel made of sections that really wanted to curl up on their own until it peeled itself and spit out the banana.  Five seeds in this pod.

right:  Reed canary grass (Phalaris arundinacea) growing in the stream channel.  There is some debate as to whether this species is native to some parts of North America or not, but in wet places of the Pacific northwest it is definitely an aggressive invasive.  It spreads by seed and by rhizome (underground stem) and will form dense monoculture stands that preclude other species from gaining a foothold.  It is difficult to eradicate once it has formed a large stand.  This little clump probably grew from a fragment that broke off a larger bunch upstream and snagged on a submerged branch here. 

left:  Douglas spirea (Spiraea douglasii).  Native, has lovely pink blooms earlier in the season, here gone to seed. 

right:  Quercus garryana, the Garry Oak or Oregon White Oak.  You don't think of oaks as doing well so close to water but there are several mature specimens of this species on the banks of the duck pond that look quite healthy. 

Well, I haven't shown all of the interesting plants I saw on my walk, but I hope I have shown a little of the variety along a short stretch of Crystal Springs Creek.  One or two of the subjects will surely be depicted in a future illustration or rubber stamp of mine.