Another foam standie...

[Wobbly Wheels]

Out of town and posting from phone so I'll keep it short:
Rough up the foam if needed to hold the glass in place. The masking tape in the pic was just to hold the corner together while I smoothed the cloth. It was removed long before I mixed the resin.

[bonnie]

Gotcha. Was lost there for a moment. Happens. We've had a break in the weather. Maybe I'll make some progress today.

[PcHistorian]

Well, what holds the cloth in place when you are laying the resin, I guess is my question. I've done some VERY ameture bondo and cloth and layed the resin, slapped the cloth on, jiggered it around and even used a putty knife to push it into a rough position, but you are doing too fine of work it seems for that method. (are you telling me, "It ain't as if it's 'brain surgery.' It only takes semi-skill to get good results and skill to get great results?")

have a great trip

[Wobbly Wheels]

Pch, if you're trying to wet the cloth with bondo, that's your problem. Resin is liquid and wetting out the cloth shouldn't push it around.

[wagondude]

I think he may have been referring to bondo as the brand. They make polyester resin that can be had as either liquid or gel. they also make a fiberglass reinforced filler called Bondoglass. But, I could be wrong. That's just a thought I had.

Bill

[PcHistorian]

ok, so I think I'm coming up to speed here. This resin gets mixed in small buckets, then you POUR it on, with a viscosity similar to oil? honey? Let it soak through to the foam surface, then kind of smooth it out with the "spreader," til it starts to set. Any way to thin it to a paint viscosity. would I want to?

Yeah, I guess I'm guilty of never having used epoxy like you are talking about. The car body bondo with the fiberglass fibers is about as close as I come, and that I put on with a "spreader," using it like a putty knife, so that would goose the cloth around without something to hold the cloth in place.

I should go out and buy some just to experiment with and then ask intelligent questions. It is such a leap in my experience now...

[atahoekid]

you should definitely be using a thin epoxy to wet out the cloth. Most epoxy I'm used to working with is thin to begin with unless you add some thickeners such as microballoons or wood dust or something like that. Depending on what you're doing, I've kind of tacked a section in place and waited until it got somewhat tacky before going around and doing the rest. Helps keep the cloth from sliding around especially in those tricky areas. I've also been told to let the cloth drape overnight before applying epoxy if it's a tricky shape. Hope that helps...

[PcHistorian]

so letting the cloth drape overnight isn't a procrastination in this case. That's kind-of what I was asking, about the tack with drips & drops. I know now why to "cut the shell into manageable smaller piece for the epoxy phase." I suppose experience is irreplaceable in this case.

[bonnie]

Or hard won.

[Wobbly Wheels]

Once you play with it a little, it'll all become clear (no pun intended). The viscosity of mixed resins varies pretty widely - IFF's G2 epoxy glue system is like molasses, whereas West 15/205 and Interlux HT9000 laminating resins are more like pancake syrup so it's easy to wet out. And yeah, you mix it in a little pot (start saving plastic margarine, yogurt, etc containers now) pour it on, then spread it. I use those cheap yellow plastic putty knives in various widths as spreaders - just round off the sharp corners so they don't snag the cloth.

[Wobbly Wheels]

Once you play with resin a little, it'll all become clear (no pun intended). The viscosity of mixed resins varies pretty widely - IFF's G2 epoxy glue system is like molasses, whereas West 15/205 and Interlux HT9000 laminating resins are more like pancake syrup so it's easy to wet out. And yeah, you mix it in a little pot (start saving plastic margarine, yogurt, etc containers now) pour it on, then spread it. I use those cheap yellow plastic putty knives in various widths as spreaders - just round off the sharp corners so they don't snag the cloth. I don't even bother cleaning them: just let the epoxy harden on them and hit 'em with an RO sander to 'clean' them.

[PcHistorian]

so when it dries it is still flexible that you have to sand that off the putty knives? you can't just flex them and have that break off?
Hmmm.... and it dries clear. How level/flat/smooth does the surface have to be? Do you have to use the cloth?

Reason I'm asking now is that... I can't find a replacement source for shingles, like the hurricane ones I have on there. (driving-towing-hurricane interlocking shingles...) and these are starting to frey. SO, I can strip them off, paint and seal the roof and then paint the shingles on there, which won't look as prefect as actually HAVING the shingles on there, but it needs that for the look. On the third hand, I COULD epoxy those shingles right into the roof, and seal the outer shell that way. The epoxy could be paper thick and I'd still have all the benefits at total transparency... I'd have to figure out how to level each surface as I did them, but that is kind-a minor considering if the rest will go down or not...

[Wobbly Wheels]

The putty knives I use will snap long before the cured resin does simply because the resin is so thin on the blade that it's happy to bend. Plus, having been previously sanded, the flat of the blade has exactly the texture you would give it if you wanted the resin to stick.

Apologies if I misread your thought: I don't think you would have much luck putting epoxy (w/ or w/o cloth) over asphalt shingles. I think what you'll find is that the epoxy will bond to the aggregate but once the substrate warms up in the sun, there won't be a bond there. More importantly, UV will trash the resin in short order. I'd suggest maybe some aluminum roll flashing with compound over it (Sno-Roof, etc) like how RVs are built.
That said, I'm still going by your sig pic - I'll look up your thread when I get back to my 'puter ( still posting from phone: aaaargh!, my fingers are WAY too big for this, lol)

[mezmo]

Hi PcH,

Another way to approach your roof -and it may save weight too - is
to strip off the old shingles, cover the roof with the ice/water shield
membrane - see viewtopic.php?f=21&t=45873
[It's supposed to seal all fasteners that penetrate through it] -
and then cover that with interlocking aluminum shingles you could make
out of aluminum flashing. Cut that into the square size you've decided
on [based on the roof dimensions] , trim off each corner point a small
equilateral triangle so that 1/2 the side length of that will give you the
overlap you need [probably @ 1/2inch, if so, make the corners you cut off
1inch] to join the pieces together, and use sheetmetal seaming pliers
[inexpensive] or a small mini brake jig [you can make from scrap wood]
and bend two adjacent edges over onto one side of the square's face one way,
and then bend the remaining/opposite two sides the other way onto the other
side/face so that there are thus two bent over adjacent flanges on each side. This
will allow you to interlock the aluminum shingles by installing them diagonally
[diamond-like as your existing shingles] starting with one set of the bent
over flanges in the down position on the underneath [which results in the
other two adjacent bent over flanges being on the top/outside in the upper
position allowing the next shingle's underneath bent over flanges to interlock
with the previous row's upper-outside bent over flanges on two side by side
shingles - bridging them from above. [By any chance are the current shingles
attached similarly?] Of course, [There's always an "Of, course"!]
you'd need to make half shingles, shaped like triangles [with appropriate edge
flange bends] for a starter and an ending course of shingles, and some ridge
strips to tie in the tops where the different hip planes meet. If your hip is
based on 45degrees this should all be simple. Other angles would need more
figuring but it's not a big deal.

I hope my description isn't too confusing. I thought I'd offer the idea as I'd be
wary of epoxying/glassing over deteriorating existing shingles. It's my understanding
that the epoxy itself is only as strong as to what it is applied to, and that it is brittle in
and of itself, when dry, so if the material it is applied to is in bad shape it will just be
material in bad shape with epoxy on it. The strength of the 'fiberglass' is in it being held
rigid in position by the resin used, not just the resin itself. [This is only from what I've
read about it here and there.]

It'd be neat to do the roof in copper shingles - if cost was no factor - but maybe copper
colored anodized aluminum sheet would be a possibility too. Regular aluminum
flashing would be the most economical and still look fine I think.

'Just thought I'd toss the idea your way.

Cheers,
Norm/mezmo

[mezmo]

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