CAN POR-15 BE USED WITH FIBERGLASS?
Absolutely. POR-15 is fully compatible with fiberglass and can be used to repair cracks in gelcoat. It will adhere better than polyester resin and has greater strength. Use also with fiberglass cloth to make super-strong surfaces in rusted-out areas. But be aware that POR-15 doesn't contain styrene and thus cannot melt fiberglass cloth like polyester resin does. .por-15 link
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Well, Sonofagun!
I knew. Just read the can on Saturday. 
IaM-Ray posted:CAN POR-15 BE USED WITH FIBERGLASS?
Absolutely. POR-15 is fully compatible with fiberglass and can be used to repair cracks in gelcoat. It will adhere better than polyester resin and has greater strength. Use also with fiberglass cloth to make super-strong surfaces in rusted-out areas. But be aware that POR-15 doesn't contain styrene and thus cannot melt fiberglass cloth like polyester resin does. .por-15 link
Ray...could you please elaborate on how polyester resin melts fiberglass cloth ? Thanks.
David I have no clue just tead it in the POR site thought you guys might be interested in this... I am clueless on FG
Yeah pretty sure the glass mat and cloth doesn't melt. Fiberglass resin WILL dissolve a styrofoam coffee cup so maybe there's the source of the confusion.
IaM-Ray posted:David I have no clue just tead it in the POR site thought you guys might be interested in this... I am clueless on FG
No sweat, Ray. I've used POR extensively and maybe you misread something or their website has bad info or a typo etc. I've built several fiberglass fuel tanks for airplanes and they will last for about 10 years and then begin to soak / soften etc. One cure is to clean it very well and slosh with a POR15 product.
I'm currently building another FG fuel tank and will slosh it with POR15 sealant from the get go. BTY...I've gone aircooled again. Google Verner Motor 5 SI for a look. Going into a vintage single place homebuilt airplane I'm restoring similar to an Aeronca C2 Razorback.
If you do fiberglass over foam, I think you need to use epoxy. If it's plain glass cloth and/or mat polyester or epoxy works.
David;
Do you have a suggestion or link for the building of a FG gas tank? Or is that better left to experts?
thank you
Art posted:David;
Do you have a suggestion or link for the building of a FG gas tank? Or is that better left to experts?
thank you
I've been building them since pre internet so have no need for a link, Art. I'm sure you'll find some good info by searching the net or Youtube. It's a simple process so no need to be an expert. Learn the technique, take health precautions while doing so and build to your needs.
My particular tank is a very unusual shape to maximize volume in a predetermined space. The top chamber is a flat bottomed half barrel with larger 1/2 curve at rear and smaller at front. The lower attached chamber is triangular in shape, off center to the above and has a sump in the bottom. If you brought dimensions to a welder, they'd likely run away or quote about $1000 with no guarantees. You could rivet up an aluminum tank and Proseal it but that is messy as hell, hard to fit and a one way street in terms of dimensions. Fiberglass you can adjust, grind, re-fit, undo, do over etc.
It is time consuming, it stinks, it does present a potential health hazard, it's not fun to do, but sometimes if you need something unique....well ..ya gotta bend over and do it.
Several techniques can be used and one is to make a Dow SM styrofoam mould that you can make to the right shape and glass over, then pour in gasoline to dissolve the styro, try to clean it out and POR 15 the inside when you think it is clean enough. My technique is to make sheets of fiberglass cloth with polyester resin flat on a bench and then use those flat sheets to make up shapes that I need, scuff / bond them together to make the basic tank, then add more to the outside to make the tank strong enough to do the job. Step by step, I scuff up the inside prepping for the POR15 coat.
David, do you build in some ribs to the flat glass sheets to make the flat surfaces stronger?
Also, I'm a fan of the lost foam one-time mold technique. I used it on a custom fiberglass cowl on a good-sized RC airplane I scratch-built.
David;
Thanks for the help. When I get off holiday I will give this a whirl.
DannyP posted:David, do you build in some ribs to the flat glass sheets to make the flat surfaces stronger?
Also, I'm a fan of the lost foam one-time mold technique. I used it on a custom fiberglass cowl on a good-sized RC airplane I scratch-built.
Ribs with limber holes are a good idea if the flat area is large enough to flex. I just go by eyeball on that. One a larger tank, I'd build in a complete wall to prevent sloshing again with limber holes in the bottom edge for fuel flow and sometimes I'll include a rib on that.
The lost foam technique is a good one. I once lost most of the bottom of the fuselage on a SkyPup airplane I built many years ago. It was mainly built from blue Dow SM foam. A poor fuel connection allowed fuel to drip into the fuselage overnight and when I came back the next day the bottom fabric was sagging badly and was filled with melted foam. It was repairable.
Any tank I build is with fiberglass cloth and epoxy, not fiberglass resin. Always coated with POR15.
