Home |
Search |
Today's Posts |
#11
|
|||
|
|||
On Thu, 10 Mar 2005 13:40:37 -0500, "Scott"
wrote: Would it really not add strength, I would think the opposite. Yes it would be tough to sand ============================ Anything tough to sand is unsuitable as a fairing material. Sanding, resanding and more sanding is what fairing is all about. |
#12
|
|||
|
|||
I help make one of the products Glen referred to. I just can't not comment
any longer .... My very limited understanding is that if you want tensile strength ( i.e. as in gluing) you don't use a hollow filler. Round hollow particles are exactly NOT what is needed. If you want to get more volume for your dollar you use a low density filler which costs less per unit volume than the resin system. So the cost per volume of filler is reduced ... So lower density is better, provided you are paying for mass not volume. If you want to sand it, it needs to be soft. Essentially you are going to break the sphere when you sand. So it has to be hollow If you want it very smooth, it needs to be fine. But we are not talking automotive gloss levels here, so the particle size really does not matter if there will be other coatings on top of the filler. The strength of even the weakest grade will be more than enough to withstand the shear forces in likely mixing processes for rec.boats.building, we are not talking rapid mixing at very high loadings in ribbon blenders .... And the pressure we apply to the finished product ( deck, hull etc) is not likely to break the spheres before it damages the substrate ...we are not talking stiletto heels here ... As I often say to people, we are really selling packaged air - in adding hollow sphere filler to a resin system you are trying to "fill" it with many small bubbles to reduce it's density and cost in use. As to using DE - it's hard and porous, so adding it to a resin system ( assuming the resin fills the voids) will not reduce the cost per unit volume, and will make it if anything harder to sand. Hope this helps David "Glenn Ashmore" wrote in message news:tX%Xd.60176$SF.48249@lakeread08... What for? Diatomaceous earth would make it heavy and harder to sand without adding any real strength. -- Glenn Ashmore I'm building a 45' cutter in strip/composite. Watch my progress (or lack there of) at: http://www.rutuonline.com Shameless Commercial Division: http://www.spade-anchor-us.com "Scott" wrote in message ... How about diatomaceous earth as a filler. It is the skeletons made of silica of microscopic creatures from long ago. Has anyone tried this as a filler? I would think it would be good and cheap. "John Cassara" wrote in message ... I need to fair large deck surfaces in prep for paint. The repair thus far has been all polyester, can I use microballons to create a polyester fairing compound? John |
#13
|
|||
|
|||
"John Cassara" wrote in message ... I need to fair large deck surfaces in prep for paint. The repair thus far has been all polyester, can I use microballons to create a polyester fairing compound? John I regularly add wood flour to polyester resin to fill screw holes and create small non-structural fillets. Not sure how well it would work on a larger surface though. -- Andrew Butchart |
#14
|
|||
|
|||
Wow thanks for all the input.
It seems to me the answer is Yes Microballoons can be used with polyester. I do agree with many of the points raised, but I could hope that a crew member worthy of stilettos would one day board my hull! Thanks again John "Andrew Butchart" wrote in message ... "John Cassara" wrote in message ... I need to fair large deck surfaces in prep for paint. The repair thus far has been all polyester, can I use microballons to create a polyester fairing compound? John I regularly add wood flour to polyester resin to fill screw holes and create small non-structural fillets. Not sure how well it would work on a larger surface though. -- Andrew Butchart |
#15
|
|||
|
|||
Perhaps not *phenolic* microbaloons. Again, from the Fiberglass Supply
site... "Microballons are primarily used with epoxy resins due to susceptibility to styrene attack with polyester resins, which can cause spheres to collapse." MW |