I'm building a 701 that will be sitting outside.

I plan to make a full cover, not sure how that will turn out.

Any thoughts on trying to waterproof the plane? I was thinking about putting silicone in some of the gaps or possibly where top metal seams meet. 

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I built a set of Zenith floats, which use the same construction techniques to produce a waterproof structure.  In order to do so, all of the seams are sealed with 3M 5200 marine sealant.  Probably more importantly for your application is the need for a different rivet.  The usual A4 and A5 rivets used in the Zenith kits have a non-waterproof center channel.  The rivets have a hollow center where the mandrel passes through.  Have a look at one and you will see…. The mandrel drives right out - they are not water tight.  There is a different (sealed) blind rivet used in the floats.  I do not know if they have the same strength, if not it would take adjustments to rivet pitch to get the same result.  But such a rivet would be needed to be water tight.  

I can tell you that construing with waterproof rivets and seam sealant adds significantly to the weight of the structure, as well as the difficulty of construction.  Building a shade hangar would be much easier…..

Ah thanks for the insight!

I ran one of the rivets in a piece of scrap under the faucet and it did not leak at all, I'm thinking with paint and a ceramic coating they will be ok, compared to floats that have to contend with pressurized water? 

Do you notice any leaks from non-sealed rivets in your water adventures? 

Things get wet sometimes in a float plane - but that’s not surprising.  Paint will help some.  I believe a standard A4 or A5 rivet sitting in pooled water will seep,  but to know for sure you would need to make a test piece with your intended coating.

Before sealing your 701’s seams with 3M 5200 (or similar), I would suggest making a test joint.  One that includes a bend with rivet lines on either side of the bend.  Then doing your match drilling and prep,  followed by applying the sealant and riveting.  You will find that the sealant affects the hole alignment, which adds some difficulty to the project.  The experience will be worth much more than any advice you can get on the forum.  Then you can make a good judgement about whether the extra work and weight are worth it.

West marine stocks 5200, or there is always Amazon…..  

Let us know what you decide to do.


I think the 701 was designed to live outside and many of them do - just don't forget to drill all the drain holes that are shown in the plans so when water gets in, it drains out. A removable cover for the rudder/fuselage interface would help too, especially if you plan to fly in the winter. 


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