I'm thinking about building some bridges/viaducts, and ordered a few Plastruct beams and open web trusses. The OWTS-4 web trusses in particular have pretty bad ridges (mold parting lines, I assume) on the top and bottom flat beams. Is that to be expected, or did I just get parts from a bad run? It would require quite a bit of shaving and sanding to get rid of those; they can be up to 0.3-0.4 mm (12-16 mil) thick, 10% of the total profile height. The pics below show a side view, and a top view of an as-bought (beam at top) and a shaved/sanded part (beam at bottom). Ignore the bow and distortions, I took the pics holding a loupe in front of my cell phone camera; the parts are straight. The HFS-4 and HFS-6 H columns look ok, and the OWTS-6 trusses also seem better than the OWTS-4. I don't think Evergreen makes a corresponding product, or do they? Plastruct OWTS-4 side view by S t e f a n posted Nov 26, 2020 at 4:24 PM Plastruct OWTS-4 top view by S t e f a n posted Nov 26, 2020 at 4:24 PM And a better picture of the ridge running along the length of the beam: Plastruct OTS-4 Top View by S t e f a n posted Nov 26, 2020 at 4:59 PM
Update: I also ordered an Evergreen H-beam profile, and the proportions are nicer (thinner flanges) than the corresponding Plastruct part: 3/16" H beams, Evergreen 286 vs Plastruct HFS-6. The price seems actually comparable per foot; the Evergreen profile comes in a shorter length.
