Hey everyone, I'm new to the site, I'm building a set of Carl Goldberg floats for an eagle 2 ,I was wondering what I can coat the floats with to seal them,would polyurethene work? Or should I use some kind of two part epoxy? Any info would be greatly appreciated thanks

WaterBased polyurethane is marvelous. Doesn't stink, cheap, fuel-proof, and easy to apply.

thank you , thats what ill use

heres a pic of it if it works

You may wish to provide some hardpoints for spreaders. Go for a rigid mounting arrangement...diagonals help.
My own preference is to use the wbpu clear both to attach 3/4 oz. glass cloth and finish.
Keep sharp edges @ chines.

Yep I'm going to add supports ,to the landing gear ,I'm not that far yet ,thanks for the tip though, ill add more pics as I make more progress

I have been using MonoKote on my floats. Tougher than you might think. Makes for a nice finnish. Easy to fix. Landing on water only in my case.

Wow, those are some awesome looking planes, the monokote looks great

I have quite a few amphibs and my heavily modded Eagle II was on floats when sold. All have the wood sealed with clear poly before applying paint or covering. With covering there are a few pointers to ending up with a good looking and durable end product.

First is that if you have ANY way for moisture to get in it must have a way to dry or the wood will suffer. With clear poly you should have no entry points if it is fully coated.

Once that is done painting is relatively easy if the materials are compatible. You can do whatever colors you want, but you must realize this is one of the heaviest methods and all are not fuel proof. In fact, due to the environmental concerns, many of the products we are now stuck with up here in Canada are far from fuel tolerant. Pretty much the only ones available are engine paints and the color options are not that varied.

If you go with heat applied covering you can end with a nice looking job, as Fastguy has shown. However, you need to work a lot more as a previously sealed structure will have no escape path for the outgassing that occurs when the adhesive is heated. It takes practice and a steady hand and this is one of the reasons I use Ultracote exclusively now as it has two primary heat ranges. The lower is used for bonding and contouring, but can leave the covering go limp and loosen later. The outgassing is a lot less in that range and easier to handle. It is the higher heat that does the permanent shrink and that is also where much more gas volume is created. If you work slowly from one end and follow along with a wet rag you can have the covering lay down with no bubbles.

Overlap edges or any bond lines that can become directly exposed to water need to be sealed especially well and for that you can brush on a supplementary heat activated adhesive. Any hobby shop with covering should sell it, or know and have access to ordering some. The key is to lightly apply it as any more will create lumps when the covering is applied over it.

Here are some examples. The Eagle II is included with the unfinished floats to show the rigging involved to hold them steady. As Lindart mentioned you need to add that or the floats will move all over the place.

The two amphibs in the foreground in the last pic, (Northstar and Seamaster) are both covered with Ultracote. The Seamaster is now 26 years old!

I wanted to include a few details on the Eagle II mods I added. Most were special purpose to accommodate the float install. The aerobatic tail was just an afterthought to see how it would fly compared to my previous pair of Eagles.

The tips were extended and reversed to give more wing area. A second servo was added to the wing center to give flaperons. This makes an incredible difference and the plane would fly and land at a walking pace. The main gear was replaced with alloy and moved forward to make it a taildragger, an easier conversion to floats and one capable of quick change back to wheels.

This was my motor test bed and several engine plates were fabbed to allow any number of different engines to be quickly installed. Most swaps needed less than 10 minutes.

On a final note, the Goldberg floats should have included all the hardware for the addition to the Eagle, such as spreaders and braces. Along with those there would have been a supplemental vertical surface to add to the bottom tail. DO NOT exclude this with any float installation. The reason is more aerodynamic surface exists on the floats ahead of the CofG and that can and will affect longtitudinal stability. That extra tail surface helps compensate. If left off you may find the plane wants to fight you in turns or be completely unflyable.

p.s. The Superfloats are to be installed on the Skybolt you catch the edge of in the first pic.

Originally Posted by Cougar429

If you go with heat applied covering you can end with a nice looking job, as Fastguy has shown. However, you need to work a lot more as a previously sealed structure will have no escape path for the outgassing that occurs when the adhesive is heated. It takes practice and a steady hand and this is one of the reasons I use Ultracote exclusively now as it has two primary heat ranges. The lower is used for bonding and contouring, but can leave the covering go limp and loosen later. The outgassing is a lot less in that range and easier to handle. It is the higher heat that does the permanent shrink and that is also where much more gas volume is created. If you work slowly from one end and follow along with a wet rag you can have the covering lay down with no bubbles.

Overlap edges or any bond lines that can become directly exposed to water need to be sealed especially well and for that you can brush on a supplementary heat activated adhesive. Any hobby shop with covering should sell it, or know and have access to ordering some. The key is to lightly apply it as any more will create lumps when the covering is applied over it.

I always put drain plugs in my floats. A way to get the water out and air can escape when aplying the covering. None of my floats have leaked yet. One pair is 6 seasons old. I only land on water and don't run them up on the shore.

Thanks to both of you for all the information, I'm going to go the polyurethene route,I'm just about ready to coat them, ill post new pics

heres some progress, the plane is covered and the motor is mounted , i wood filled some spots on the floats and im ready to coat the floats,the motor is a .75 super tiger

has anyone got a set of templates/scan for these floats i could have?

need to build a set of floats for my 72" electric Cub

thanks

David

I have the plans but they don't have the templates on them everything was precut

could i trouble you to give some basic dimensions for the Goldberg floats?

please! its just so i can double check what i am about to do regarding the floats for my 72" world models cub. which is based on the various links listed on here.

all i need is..

length of floats
width of float at widest point
depth/height of float at the step
length from front of float to step
bottom of fuselage to top of floats
centres of floats (how far apart are they centre to centre)

tape rule measurements to the nearest millionth of an inch will be fine

thanks
David