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Metal repairs using epoxy metal and other resin based products

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Fergus OMore:
Actually, John, you could choose  between flour, slate dust and sawdust. Sorry to p** on the parade but I was a bit nearer than most. OK, one had to mill in 'Aerosil' to make things snotty but 'fun, innit?'

Earlier, fillers were probably nothing more than chalk or Paris Plaster with boiled linseed oil and a bit of cobalt nathenate.

We( I was all of 11 or no more than 12) made up a mixture of Paris Plaster, animal glue and torn newpaper shreddings into relief maps during the War. My headmaster was the Captain Mainwaring of the local Dad's Army! Still got me little Scout axe for diggiing out Ferrite bombs( Iron fillings, Aluminium turnings and magnesium). Fun putting them out!

But I digress. So what about all this fabric stuff? Most of that was celluoid dissoved in acetone on Irish Linen or ours was.
Filler was red lead dope and then aluminium dope. Makes a helluva blaze mixture.

Cheers

N

MetalMagus:

--- Quote from: golfpin on April 07, 2015, 04:31:38 AM ---Sorry forgot, my main point further to my blurb above. Part of the Vari eeze build was the use of a powder that was referred to as "micro balloon " this was a white powder that was mixed with the epoxy and then used as a filler and glue. Precursor to castor sugar, bi-carb powder we see used with super glue these days. Perhaps it was castor sugar or the like!!
Golfpin

--- End quote ---

Microballoons is still available. Used as a light weight filler on RC model aircraft and such.

I think it is made up of microscopic glass beads

http://www.easycomposites.co.uk/products/resin-gel-silicone/fillers-and-additives/glass-bubbles-microballoons-microspheres.aspx

Sean

vtsteam:
There are microspheres and microballoons, the red variety made of Bakelite resin I believe. They don't add strength. They lighten the weight of resin mix by making it a mechanical foam. They also make it easer to sand or work when cured, and are usd to fair a surface, though don't necessarily provide a fine finish when used alone.

They and other fillers also reduce the expense of the resin. Commonly used with epoxy are colloidal silica (heavy and much more difficult to sand, but abrasion resistant as a result), microfibers (generally mlled cotton fibers), and in the 70's when I had my boatshop, milled asbestos fibers, which did add strength supposedly. Also graphite powder, which was primarily used not as a lubricant for a molded bearing (though I did wonder about the possibilities) but as a UV inhibitor. Epoxies are usually quite susceptible to UV degradation.

FRP is fiber reinforced plastic, and that is made up differently than fillers generally, and usually involves saturating a mat, cloth, or unidiectional tow of organic textiles (linen, cotton, etc.) or synthetics (glass, carbon, polypropylene, Dynel, Kevlar, etc.) with a resin (polyester, vinylester, epoxy, etc.) in a matrix.

Fillers and fabrics can both be used in combination, but they have different functions, for the most part. There are some reinforcing fiber fillers, like chopped strand glass, but a FRP product made of those tends to be heavier and have lower mechanical qualities than a laminated cloth or tow version. An FRP boat hull laid up with a chopper gun is weak, heavy, and brittle compared to a proper cloth laminated version.

Decks of small craft have been covered in cotton duck and paint (a resin) for ages, and paper was laminated with varnish into fine canoes well over a century ago -- See Nathaniel Bishop's Voyage in the Paper canoe. I'm sure references to similar processes can be traced back a couple millennia.

John Hill:
A nice bit of cartonnage..


...somewhat like paper mache being layers of papryrus, linen etc mixed with plaster.  Last for a thousand years, or several thousand.

vtsteam:
That's quite beautiful!

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