Water Tanks - fiberglass

[mx599]

Hey guys, I just wanted to let you know I have bought official Cozy IV and E-racer plans and not a total schmuck, its just not right time for me to undertake plane build.

I really value plane builders opinions when it come to fiberglass applications. I was hoping to get advice from anyone willing to give it. I hope it's okay I ask here.

I want to try to make custom water tanks for my camper van conversion. I plan to fiberglass around a block of Styrofoam and then melt the foam after with acetone. I do not have experience with fiberglass but I think a project like this will be helpful for a plane build someday. I have the old Rutan video and want to use some of the peel ply tape technique for the inner baffles to bond to the outer shell etc etc.

If the whole thing gets messed up it's not that big a deal except waste of money and accepting failure...or water mess in van.

approx dimensions are  48 x 30 x 12 inch rectangle with about 3 baffles. Thickness goal? 1/8 - 3/16"?  1/4" might be overkill, right? advice on material? I guess there is FDA approved resin and I was thinking to use chop strand then 10 ounce fiberglass after?

Lastly, which supply house do you guys like? I talked to someone at fibreglast.com but they did not seem terribly knowledgeable or didn't feel like helping me.

I will gladly answer any follow-up questions to help you guys help me

thank you so very much!!

[Kent Ashton]

Maybe you can find a polyethlene water or fuel tank for boats or RVs; perhaps gang them together to get the volume you need.  This one below is pretty close to your dimensions.    Or Google "DIY boat water tank"  Lots of interesting things there.

https://www.ntotank.com/52gallon-norwesco-white-utility-tank-x6230877

 

[mx599]

I really need the custom molding aspect if possible as space is so limited in setup.

thanks for the boat lead, I will look into these.

[Voidhawk9]

I did some pre-airplane fabricating as well, in my case a custom glass mount for a baggage pod for my motorcycle.

 

I'd be inclined to build a simple mold that is tough enough for multiple uses, then lay-up and pull 2 parts from it, add internal baffles as needed, then bond the two halves together.

Really depends on exactly what you want though. The lost-foam method can be messy, but should work.

[Jon Matcho]

8 hours ago, Voidhawk9 said:

I'd be inclined to build a simple mold that is tough enough for multiple uses, then lay-up and pull 2 parts from it, add internal baffles as needed, then bond the two halves together.

I was thinking the same thing.  OR, Brian, just proceed with your approach but only using half container (forget the acetone technique).  Done right you can pop the half off and then prep and do the other one.  Look into simple fiberglass mold making.  You'll then know how to make wheel pants, baggage pods, and cowlings.

[mx599]

I appreciate it guys.

So if I did do 2 halves shouldn't I do more of the tank body and then a permanent "lid" on top? in other words, would you not want the seam below the waterline as much as possible? I guess if someone does it right it should not leak at the seam even if seam is all the way at bottom?

when doing the seams, this would be good time to try peel ply technique, correct? I thought peel ply was fabric in "duct tape" type size roll? When I look for peel ply at vendor sites all I see are large sheets for vacuum bagging? am I missing something?

also, due to the curved van wall and wheel well and me trying to maximize gallons, there will be a lot of asymmetry to the rectangle foam block that I cut with the hot wire cutter. My cutter should be coming in the mail in a few days. I know they can be easy to make, but it was just easier to mailorder it for now. I wanted to cut a few more spots for sink area etc...that is one reason I was thinking dissolving foam might work better than making mold. Plus I am so new to this that making mold wasn't on my radar. With all the asymmetry, there might be 4 different mold halves as in single use only for each. Knowing this, would that make you guys more apt to try melting foam? or does that idea simply not work?

Lastly, I was going to use the FDA approved resin, chop mat, followed by 10 oz fabric. Do you guys think that is decent approach? Can you give me an online vendor or two I could buy from that has quality supplies and caters to the plane builders as well?

thanks!

[Kent Ashton]

Just an idea:  This is something like how EZ/Cozy strake-tanks are made.  I would make a 5-side container out of fuel resistant urethane or other foam with an open top using BID inside and outside--2 or more layers.  For a wheel-well shape, the urethane can be scored and bent as EZ strake leading edges are bent.  The container could be squeegeed inside with epoxy or ProSeal a standard tank sealant, and checked for leakage.  I'd make a top with a rather large access hole and cover;  flox that to the leak-free container with ample wet flox (flocked cotton + epoxy).  You could then reach inside to finish the joint between top to bottom or fix any leaks.  Those materials are available at Aircraft Spruce or Wicks Aircraft.   Peel ply is un-dyed polyester fabric.  It comes in sheets and tapes or you can buy a white non-stretchy weave polyester at a fabric store.

I think if you did some research on boat websites, you would get some good ideas.  If you drew a picture it might help to see what you want to build.

[mx599]

2 minutes ago, Kent Ashton said:

Just an idea:  This is something like how EZ/Cozy strake-tanks are made.  I would make a 5-side container out of fuel resistant urethane or other foam with an open top using BID inside and outside--2 or more layers.  For a wheel-well shape, the urethane can be scored and bent as EZ strake leading edges are bent.  The container could be squeegeed inside with epoxy or ProSeal a standard tank sealant, and checked for leakage.  I'd make a top with a rather large access hole and cover;  flox that to the leak-free container with ample wet flox (flocked cotton + epoxy).  You could then reach inside to finish the joint between top to bottom or fix any leaks.  Those materials are available at Aircraft Spruce or Wicks Aircraft.   Peel ply is un-dyed polyester fabric.  It comes in sheets and tapes or you can buy a white non-stretchy weave polyester at a fabric store.

I think if you did some research on boat websites, you would get some good ideas.  If you drew a picture it might help to see what you want to build.

Okay, that helps. thanks. Well, whatever I do I will take pictures and post failure or not. Hopefully you guys will get notification to thread for updates. I did order some supplies (tools) and I have the foam. The wire cutter is coming. I just need to order resin and fabrics now.

I was definitely going to have port holes in each baffle section on top. I found some nice big 8" ones with screw cap that I think would work well.

I was considering looking at the fuel tank plans for ERacer/Cozy/open source LongEZ but I did not want my head to explode yet. I was thinking I might be over-omplicating the water tank build.

I think I am going to try something here in a week or two!