stealth panel

Re: stealth panel

Does anybody know if my frame is anodised? I have a spare piece of each and the KC 130 seems to fall between the 2 in texture and appearance.

Re: stealth panel

Ralph Day wrote: »

I think that's called "distressed" in the antiques (or fake antiques) trade.

When fibreglassing/bonding your mounts be sure to use West System epoxy and it's associated additives, they can't be beat! (not a product endoresement, It's just never failed me).

ralp;hhttp://forum.solar-electric.com/images/icons/icon10.gif
Talking

One thing I don't like about west system epoxy is the 5 to 1 mixing ratio. It leaves too much room for error. Nothing is worse than having a soft epoxy that has to be removed and redone. Another thing is the prolific Amine blush which must be removed before successive layers or paint is added.

I always preferred System 3 epoxies, the clear coat and the sb-112 with the uv stabilizers. Both dry without any amine blush and don't need to be sanded before successive layers are added. The 2 parts resin to one part hardener makes it easier to fall with in the 3 Percent mixing margin for error that ALL epoxies demand for proper curing and structural strength.

Since epoxies are expensive, and are more succeptable to heat and uv degradation than polyester resin, the latter is what I'm going to use for this application.

One other thing to consider is that fiberglass mat is not compatable with epoxy. The adhesive holds the mat together is dissolved by the styrene in polyester resin, allowing the mat to be stretched or compressed. Epoxy will not dissolve this adhesive and will not penetrate the fibers of the mat.

Those qualities ( stretching and compressing) are not easy to obtain with fiberglass cloth, which must be pulled tight and squeegeed flat for maximum strength. Another factor in my application is heat. I don't have any shade. My van won't fit in the garage. With polyester resin I can add just a little catalyst, and not have to worry about the sun's uv degrading the hardener in the epoxy while it attempts to cure, which it will not do properly in direct sunlight, even with a slow hardener.

If I felt I needed the extra bonding and tensile strength of epoxy over polyester resin, I would pay the extra, and devise some shade to work in, but having built many Boats and thousands of surfboards I know the polyester is more than adequate for my application

polyester resin 101

Yep, I'm well aware of the difference between sanding and laminating resin, having learned the hard way over 2 decades ago in my early teens.

In the spirit of passing on knowledge about polyester resin to those that might not know, surfectant(wax) can be added to any laminating resin to make it into sanding/ finishing resin. A lot of people just use the sanding resin to wet out cloth and mat, and this will work, but there is a trade off. Sanding resin is more brittle and does not adhere as strongly as laminating resin. Sanding resin must also be sanded with at maximum of 120 grit paper before any additional layers will properly bond, much like epoxies that form an amine blush when they cure. Epoxies must be rinsed after this blush is physically removed, unless it is a blush free epoxy.

The proper method of layering fiberglass cloth with polyester resin is to wet out the cloth with laminating resin and let dry till tacky. Most likely before another layer can be added if needed, areas(high spots or loose strands) will need to be knocked down so as not to cause bubbles under the next layer. Generally the accepted method is the use of sacrificial 36 grit sandpaper. The paper will get gummed up quickly and become useless. The only way around this is to paint a layer of sanding resin over it, wait till that cures , then sand that. This will compromise the bond of the sucessive layer of fiberglass to some degree.

When enough layers of cloth, saturated with laminating resin are down, then sanding resin can be brushed on over the layers of laminating resin and cloth, allowing the laminating resin to cure fully to it's maximum strength. The resin can now be sanded down through all the layers of cloth now if desired(not) without gumming up the sandpaper.

Covering your laminating resin with a layer of sanding/finishing/gloss resin yields at least a 30 % increase in strength, as opposed to using sanding resin to wet out the cloth. You can paint on the sanding resin just after the laminating resin has 'tacked off' generally after 20 minutes, depending on the amount of catalyst used.

Gloss resin is formulated with extra UV inhibitors and is designed to be polished to a mirror finish. It is also thinner and self levelling. Makes the final product less microscopically porous.

From a non production, maximum strength viewpoint, you want the resin to cure as slow as possible, without the resin draining from the cloth or mat due to gravity and excessive time. Over catalyzing the resin causes it to heat up, and expand excessivly, then contract as it cures seriously impairing its strength and bond to the underlaying material. I've witnessed more than one surfer trying to fix a ding, panic as their repair started to turn brown, smoke, and maybee even catch fire.

One among many advantages of Polyester resin over Epoxy resin is that it will always eventually cure. Even uncatalyzed resin, in contact with cured resin will eventually cure 100%. After 24 hours or so, if epoxy is still gummy or tacky, means it was improperly mixed, and will never attain it's maximum flexural and tensile strengths. It will always be soft.

Epoxy resins when properly mixed are stronger, lighter, less porous and bond much stronger to many more substrates than polyester resin.
Vinyl ester resin falls between the 2 in terms of price and strength, but is mixed and applied in a similar manner as Polyester.

But this has nothing to do with Solar, unless of course you are fabricating fiberglass solar panel mounts for your fiberglass roofed RV. Maybee this info can help someone down the road avoid an aggravating mishap when attempting to use fiberglass.

Thanks again for all the info about painting my panel frames.