Kitfox 4 fuel tank kreem peeling

[Justin 5]

I have a kitfox 4 and upon inspection I realized both fuel tanks the kreem is peeling away showing bare fiberglass my question is what options do I have replace them with new or are there other oprions out there thanks 

 

[Av8r3400 1178]

That's a tough one.  You'll need to get the old cream out before you can retreat with something else. MEK or acetone may soften it up to remove it, but you'll probably need to pull the tanks from the wing. 

You can cut open the tops of the tanks and do a "wingtanks.com" type of inserted tank.  This may also be tough because wingtanks.com is Airdale and who knows if Brett is still in business or not. 

I have a set of 13g tanks that are out of the mangy fox I will give you for shipping cost if you want to work with them and replace yours.  They are the "old" resin with an unknown coating inside them.

[1avidflyer 1983]

I believe others have cleaned out the coating with acetone.  Have to take the wings off and shake them and rotate them as much as possible.  I can't point you to a post where some one described doing this, but I remember reading about someone doing it.  I did something similar with an Avid with aluminum tanks that started leaking.  Took the wings off and used KBS coating to seal the tanks.  I did it by myself .  Put one end of the wing in a wing rotisserie and spin it and shake it from the opposite end.   Jim Chuk

[EDMO 1078]

Jim,   How do you keep those round parts from coming out of the tip end of the wing?  Are those early spars with the internal I-beam?   I am still hearing that Caswell is the best sloshing epoxy, and Kreem is about the worst.   EDMO

Edited 28 Mar 2016 by EDMO

[1avidflyer 1983]

Ed,  the pipes go into the spars about 12" or so.  I keep an eye on the wing stands and if they start moving apart, I push them back together.  And yes, those are the early spars with the internal I-beam.  I had to make new arms for my wing stands with smaller pipes on them.  I used some 1" thin walled conduit, and slid some plastic tubes over the conduit so they won't scratch up the inside of the spars.

[EDMO 1078]

Thanks Jim.    EDMO

[zadwit 105]

I have one installed fibreglas tank (1999 SKystar Kitfox Classic IV and the other tank is removed and the wing covered...... think both tanks have that Kreem sloshing compound.....

Are new poly tanks available to just replace these with rather than mess around trying to clean and reslosh them???

[Av8r3400 1178]

No.  Polyurethane tanks are not available as a replacement.  There were some that went inside the old fiberglass (wingtanks.com) but I think that venture died with its parent, Airdale. The tanks are structural to the wing and polyurethane doesn't offer the needed strength.

The new tanks from Kitfox are of a more ethanol resistant fiberglass.  I put these in my rebuild and have been very pleased with them. 

I had the creamed tanks in my old plane and never had any issue, but watched them closely. 

[dholly 718]

I assume Brett's poly tanks are unavailable, even though www.wingtanks.com is still up. Kinda like his Airdale website, probably left them up with ads to generate a few click-bait pennies. Some folks here retrofitted poly tanks from Stace Schrader at Rocky Mountain Wings (Ridge Runner kits) for their under camber Avid wings, not sure if those would fit the newer laminar profile KF4-7 wing but I suspect so. There is a notable difference for install however, being that the original KF wingtanks did not employ the Avid style installation with fiberglass wrap totally around the spars and tanks. Cutting the tops off and dropping a poly tank inside is not really an option with the original KF slip-in wingtanks, IMHO. If you opt to replace the KF wingtanks with the RR poly tanks, at the very least you will need to add a new short rib between the tanks (assuming you want two 5-gal tanks in a wing). I would also add a ply bottom between the butt-2 ribs and 2-3 ribs, Hysol'd to the underside of the lower capstrips (or maybe better yet to blocks Hysol'd to the rib webs) before setting, gluing and foaming the tanks in place. Should support the weight of a filled tank and provide much needed structural strength.

[edit] I would add that the install photos on wingtanks.com also show support tubes between ribs, not convinced they are critical.

Edited 21 Nov 2017 by dholly