Tank Slosh Questions

My 1993 RV-3 has white slosh in the tanks and during pre-flight this morning I saw a small piece of lose slosh in a tank. Closer inspection found it pealing from a baffle. So the slosh has to be removed. I would consider building new tanks but this is not a pre-punched RV and I'm not sure what problems i would run into fitting new tanks. Questions: Is MEK still the best stuff to remove it? Do I then have to reseal the entire tank with Proseal? Do I have to remove the old Proseal? Can this be done without damaging the finish requiring repainting? Is the best access to the interior with 4" holes along the back or should I drill out rivets and remove the entire back and if it is pro sealed, how would I get the back off? I'm also considering sending the tanks off to Weeps No More depending on cost and time. Thanks in advance for any advice.
Bill

I got a quote last year for RV-4 tanks to be de-sloshed by Weeps-no-more. I think it was about $700/tank plus shipping.

The tanks I was working on had never been in service, but built long ago. it stuff was stuck on good. But 15 minutes with MEK caused it to bubble. Still didn't want to come off. The owner didn't want to spend the money for Weeps, and I didn't have time to clean them. The project is on hold...AGAIN.

Tank Slosh

Hi Bill,
You have really 2 options to be sure your problem is solved.
1. the shorter/more expensive way is to remove tanks and send out to be rebuilt by a pro. Not sure of cost, but not cheap.
2. Remove rivets from back baffle, apply MEK and or Kleen Strip to old proseal and remove. (Time consuming & tedious),ask me how I know. But only the cost of materials and consumables. My left fuel cell on the RV1 requires drilling out the bottom skin (wet wing) after removing wing and inverting on saw horses. But, I now have a properly Clean & prosealed fuel cell.
A caveat: if you are not comfortable with riveting, this IS NOT a project you want to tackle without a person experienced in riveting to show you "the ropes". Hope this helps.
Blue Skies,


Before / After

wilddog said:

My 1993 RV-3 has white slosh in the tanks and during pre-flight this morning I saw a small piece of lose slosh in a tank. Closer inspection found it pealing from a baffle. So the slosh has to be removed. I would consider building new tanks but this is not a pre-punched RV and I'm not sure what problems i would run into fitting new tanks. Questions: Is MEK still the best stuff to remove it? Yes! Do I then have to reseal the entire tank with Proseal? No! Do I have to remove the old Proseal? No! Can this be done without damaging the finish requiring repainting? Yes! Is the best access to the interior with 4" holes along the back Yes! or should I drill out rivets and remove the entire back No! and if it is pro sealed, how would I get the back off? I'm also considering sending the tanks off to Weeps No More depending on cost and time. Thanks in advance for any advice.
Bill

Click to expand...

Remove the tanks. Cut 4" holes in the baffle at each bay except for the inboard. Clean out the slosh with MEK and scotch-brite. The MEK will soften the pro seal but not harm it's sealing properties. Re-coat seams and rivets with a little extra pro-seal. If the original pick-ups are the "squeezed and slotted" tubing, replace them with the screen pick-ups. Seal the cover plates with pro-seal. Reinstall tanks.
Messy, but pretty simple.

xSlosh Questions

Bill, post number 73 on the thread below recaps my experience this past summer.
http://www.vansairforce.com/community/showthread.php?t=102918&page=2

Tanks

Thanks for the replies. I removed the tanks and opened one up at the inboard end access plate. Slosh in that bay was good but I decided to try removing it before going farther so I could get an idea of what I was in for. MEK on a rag softens it up and a Scotch pad takes it off without a lot of trouble other than working through a 4" hole. The slosh on the skins was stuck much better than that on the ribs and leads me to think the builder prepped the skins but not the ribs. It is about impossible to remove the slosh around the rivets and over the pro seal. Weeps no More is booked up until Dec. and I don't want to be grounded that long or I would send them off the them. So the plan is to do as Mel says cutting 4" holes and removing as much slosh as possible. I'm going to tape plastic over the outside of the tank to protect the finish because I'm sloppy. I tested the plastic with MEK and it's ok. After removing as much slosh as I can I will coat the existing pro seal with a brushed on coat of thinned or warmed pro seal. What can pro seal be thinned with? Will this lock in place the slosh that cannot be removed around the rivets? Is one quart enough? The back plate access covers will be sealed with more pro seal and closed pop rivets. For you who have done this, how does this procedure sound?

Call Flamemaster (what Vans supplied), PRC DeSoto (Proseal brand name), or 3M for a recommendation about an overcoat for Class B polysulfide sealant.

With a little care, rear bulkhead ports, sealant, and closed end rivets work just fine.

With the earlier thread regarding the engine out as a result of slosh, I think i'd have a hard time doing anything but grounding my airplane if it had any indication of slosh coming loose in the tanks.

Thankfully mine was not built with slosh. If it was, this winter's project would be removing it.

I didn't think they had a smoking gun in the above case? I will have to go back and read but it seemed like it was not for sure anything to do with Slosh except that the plane was built in 1991 and likely has slosh?

I thought the owner did confirm early on that the tanks had slosh, but you're right that there may not be a 100% confirmation yet that the slosh was the ultimate cause of the event.

wilddog said:

My 1993 RV-3 has white slosh in the tanks and during pre-flight this morning I saw a small piece of lose slosh in a tank. Closer inspection found it pealing from a baffle. So the slosh has to be removed. I would consider building new tanks but this is not a pre-punched RV and I'm not sure what problems i would run into fitting new tanks. Questions: Is MEK still the best stuff to remove it? Do I then have to reseal the entire tank with Proseal? Do I have to remove the old Proseal? Can this be done without damaging the finish requiring repainting? Is the best access to the interior with 4" holes along the back or should I drill out rivets and remove the entire back and if it is pro sealed, how would I get the back off? I'm also considering sending the tanks off to Weeps No More depending on cost and time. Thanks in advance for any advice.
Bill

Click to expand...

Mel said:

Remove the tanks. Cut 4" holes in the baffle at each bay except for the inboard. Clean out the slosh with MEK and scotch-brite. The MEK will soften the pro seal but not harm it's sealing properties. Re-coat seams and rivets with a little extra pro-seal. If the original pick-ups are the "squeezed and slotted" tubing, replace them with the screen pick-ups. Seal the cover plates with pro-seal. Reinstall tanks.
Messy, but pretty simple.

Click to expand...

Did this 10 years ago and have had no problems since. In retrospect I had alodined all the skins ribs baffles ect prior to pro seal in 1991 during initial build. There wasn’t a hint of loose slosh anywhere. I removed it anyway but it wasn’t needed at that time.