by mezmo » Tue Jan 03, 2012 1:09 am
Since I sorta stirred the pot a little with the HWFF coatings postings
I thought I'd add a comment or two.
My reason for looking more into these other exterior coatings is that I was
wondering on the strength of the TBII&III and canvas as an outer skin - i.e.
as a structural feature, since one of our premises here is that 'the strength
is in the skins' and the sum of the components working together is also
'the strength'.
I realize and understand that this old canvas/glue/paint technology
application has been used successfully for a very long time, but the main
application of it - to my understanding - was on top/over another structural
surface -e.g. boards a/o plywood/Masonite etc., so that it was more of a
protective skin/coating as opposed to a "structural" component.
I was concerned with the puncturability, durability and longevity of the
exterior and its function as a structural element. The other aspect I was
concerned about was the effect that heat had on the TBII&III - it's apparently
thermally affected some at relatively low temperatures that could come
about through 'normal' sun exposure. [I'm in SC and the summer sun here
is brutal - I'm sure other southern and western states must be the same.]
Fiberglass and epoxy become rigid when applied together over the foam.
Since I have no direct experience with it yet, my understanding [from the
various posts] of the TBII&III over fabric is that it is not that rigid [or as
rigid as fiberglass and epoxy]. And as a result of surface heating, it
softens, or can soften or perhaps separate from the foam core. So I was
looking for some other exterior coating that'd provide more rigidity,
strength,durability and longevity etc., and not separate from the foam.
Since the HWFF products [I'm sure there must be other manufacturers
too] are made for use on/with foam it seemed reasonable to check them
out more to see if they could be beneficial for our Foamie purposes. It
appears that they very well could be. I'll be awaiting the results from
mel's/atahoekid's test strips using the various HWFF samples he had. It
also seems that Steve/linuxmanxxx has also come across another
company/source for possible application on our Foamies - the Polygem
epoxies - namely the flexible ones. I would plan to use a 'fabric'
reinforcement with the coating used unless it says specifically that it
is unnecessary.
And again, another consideration is the COST. Thrifty is good, but part of
that to me, has to also consider any possibility of extra benefits that the
extra cost of these alternate [from TBII&III] exterior coatings provide.
They may be worth it. But overall, I think there's room for all methods
here - as long as they meet the individual builders needs/criteria.
Now: About concerns of the lightweight Foamies blowing over, or their
bodies being blown off their frames by high winds. For some unknown
reason, that hasn't been a big concern to me, but I understand the
concerns others have raised. As Gary/St. Patron said, Corwin's post on
it [can't recall which thread at the moment] pretty much would allay for
me any concerns about being blown over. Louella/eaglesdare's concerns
about the body being separated from the frame should be taken care of
by our 'sock effect". If you overlap the fabric and glue/paint/epoxy that
covers the sides onto the underneath of the floor several inches - I'd
guess 6-8in would be reasonable, and especially if you reinforce that 'joint'
with extra fabric or fiberglass cloth/tape and glue/paint/epoxy - whatever
you're using - that should take care of it. [Don't forget to also do that
internally as well.] I'm a fan of reasonable redundancy, so if it will give
additional peace of mind, why not laminate in on the top level of the
exterior fabric some of those flat woven straps that come with the hooks
and ratchet set ups that are used to secure cargo/loads you carry.
They're reasonably priced and available. The ends could be mechanically
attached, as well, to the underneath of the frame. This way they'd be
permanently installed and they wouldn't subject the Foamie body to any
chaffing or compression stresses that any inadvertent over-tightening
would produce.
I guess what it boils down to for me is that it appears [I have to say that
as I haven't finished a design yet or started in on a build yet.] Foamies,
as originally conceived, and/or with whatever additional elements added,
seem to be the most economical and simplesrt way to build a TD/TTT.
But, doing so still entails investments of time, materials and mental
processes. I just want to get the best result possible for my efforts
and money when the time comes. Too much maintenance or short
'product' life won't satisfy my aims when building one. Therefore the
further look into the HWFF exterior coatings, especially for the use on
the "larger" TTT type of Foamie.
Cheers,
Norm/mezmo
Last edited by
mezmo on Tue Jan 03, 2012 1:18 am, edited 2 times in total.
If you have a house - you have a hobby.
I think rounded edges help a Lot ... Square edges induce drag producing vortices ... That may be the problem with those Big TTs that blow over... Just a Box in the Wind !!! 
