Doing first build, a few basic questions

[Reptar]

Hi Guys,

Just ordered my FT Mini Scout, first build attempt ever, and I have a few quick questions.

1) Is it waterproof? I’ve heard the FT crew refer in various videos to their products now using waterproof foam. Or is it only certain kits?
— If it isn’t waterproof, I just coat it in Minwax Polyurethane prior to popping the foam out, yes? But I could’ve sworn I saw a FT video where they mentioned Minwax not takings hot gun glue?

2) In the FT videos their builds are always white but the kit comes papered over in brown paper. What is that? I assume I’m supposed to take it off?

3) I’d like to paint it. It would seem easier to paint it prior to assembly. Is this order of operations correct?

1) Remove brown paper covering
2) Coat foam board in Minwax to waterproof prior to punching out parts.
3) Let dry
4) Use spray paint to paint foam.
5) Let dry
6) Punch out parts
7) Assemble according to FT build video, applying glue to now waterproofed and painted parts.

Is that right?

 

[nwnugget]

Hi Guys,

Just ordered my FT Mini Scout, first build attempt ever, and I have a few quick questions.

1) Is it waterproof? I’ve heard the FT crew refer in various videos to their products now using waterproof foam. Or is it only certain kits?
— If it isn’t waterproof, I just coat it in Minwax Polyurethane prior to popping the foam out, yes? But I could’ve sworn I saw a FT video where they mentioned Minwax not takings hot gun glue?

2) In the FT videos their builds are always white but the kit comes papered over in brown paper. What is that? I assume I’m supposed to take it off?

3) I’d like to paint it. It would seem easier to paint it prior to assembly. Is this order of operations correct?

1) Remove brown paper covering
2) Coat foam board in Minwax to waterproof prior to punching out parts.
3) Let dry
4) Use spray paint to paint foam.
5) Let dry
6) Punch out parts
7) Assemble according to FT build video, applying glue to now waterproofed and painted parts.

Is that right?

The brown board is not a coating to be removed. That is the new water resistant foam board. Do not remove it unless the build directions specifically say so.

There are a couple of videos on the site about painting the foam planes. I do not think the glue will adhere well to a coated surface.

I paint after building.

Good luck.

 

[Snarls]

Welcome to the forum Reptar!


As nwnugget says, the brown board is the waterproof foam board. The white foam is the original foam board that is not waterproof, but can be found at almost any dollar tree store in the US.

Most people paint their planes after assembly and after the maiden flight (because crashing a freshly built and painted plane is no fun). Alternatively, a forum member 'rasterize' here has created many graphic designs for FT planes which are applied to the foam before assembly. Similar to what David did when making the camo FT Viggen. But those may be a little more involved to get a hold of, print out, and apply.

 

[SteveRobey]

Hi guys, I'm going to jump in here and clear something up before it's too late for a new builder.

The brown foam board is NOT waterproof! It is water resistant though. You'll notice when your speed build kit arrives that the brown sheets have a glossy, almost waxy feeling to them and this is the water resistant coating. I think it is more likely that this is a thin veneer of some sort of plastic rather than a wax impregnation as adding heat to scraps of it didn't reveal any wax melting up out of the paper. It does take hot glue very nicely but be careful any time you are applying hot glue directly to the foam edge on this material. Use minimal glue and be careful not to move too slowly as the tip of the gun will start to melt back the foam and so can the glue. I'm using an 80 watt gun that I picked up locally and it's definitely more than hot enough.

I realized this foam board is not waterproof when I was cleaning my wing during construction. You have to put a double bevel on the fold that makes up the leading edge of the wing on some of the models and I opted to sand mine rather than trying to bevel cut with a razor knife. Josh makes those bevel cuts look really easy in the build videos, but a sanding block with 120 grit will produce a very uniform and clean bevel.. And a lot of dust. So I wanted to clean that dust off before gluing my spars in place. So what did I use? Well, I used a baby wipe because it's waterproof foam board right? Sure isn't. I noticed this the most at the edge of the paper where the bevel is that even the little bit of moisture in the wipe was seeping into the paper because I had sanded off the plastic coating. It dried fast enough and I didn't have any problems other than the moisture softening the paper in the root of the double bevel which would be the outside of the wing. So, just to be safe, I laid a long strip of clear packing tape along that leading edge before I folded the wind up just in case the paper decided to let go.

Needless to say, All open edges of your parts where you can see the foam core and both sheets of brown paper and potential places for water ingress. If you land in wet grass, I would recommend wiping the plane down with a towel and leaving it to dry. If the plane gets completely soaked like if you have crash landed in a lake or a large puddle, all bets are off, I'm not sure how fast this stuff will wick up the water.

Good luck and have fun building your kit. Always best to take your time and follow the build video as you go even if you have watched it several times already, you will likely get reminded of a step or two that you almost forgot.

 

[Igoo57]

Reptar,

As stated, brown is the new white, do not remove unless instructed in the plans or build video.

No it is not water proof, it is water repellent.

Painting the parts before popping them out still leaves the cut edges unpainted. Which is the very part that needs to be sealed to help keep moisture out.

So pop the parts out. On some of the scrap, remove the paper and paint the foam with the paint you intend to use. Just to make sure the solvents in the paint do not eat/dissolve the foam. Build the plane and paint any edges, then the larger surfaces. Since the scout wings slide into the fuselage. They could be painted before inserting, just make sure you pinch the edge as Josh shows in the build video before painting.

Bottom line these are foam & paper planes. They are not, nor ever will be, totally water proof. Part of the attraction is the fact that, baring electrons damage, the planes can be rebuilt for a few dollars in foam board. Compare that to a $200 balsa wood & paper skinned plane that took 150+ hrs to build and 30 seconds to destroy. Give me Foam board or Dea... errr a padded cell!

 

[SteveRobey]

Re: Painting water resistant foam board..

There are a lot of members of my local club that have been building FT models for a long time and most have painted them. Some recommendations that were given to me regarding painting the foam board models are first to take and lightly sand the surface of all of your parts before you remove them from the sheet. You don't want to completely remove the water resistant coating, you just want to buff it a little. This gives your paint a surface to hang onto. Once you have removed the parts and assembled each part you can do a base coat. I don't remember the brand name of this paint right off but I'll reply back when I find it, there is a water based white paint that comes in a spray paint can which you can use as somewhat of a primer. You want to coat as light as possible and not completely soak your model of course.

There's also a really good tutorial by FliteTest's own Chad that talks about your different options if you prefer to paint your models. The key thing to remember is to only use water based paints. The solvents in typical spray paint will eat the foam core and you'll be left with something that can't be flown. Also remember to keep your paint layers as thin as possible to avoid warping. Paint can also make a foam model more brittle rather than allowing a crushed surface to crumple it can just break.

Here's a link to Chad's painting tutorial..

https://www.flitetest.com/articles/painting-foam-board

If you decide painting is more work than you are interested in, a lot of us are also using colored packing tape as a coating. It's lightweight, quick and easy and you're left with a nice shiny finish.

 

[PsyBorg]

All I do for painting the foam is seal all exposed edges where the foam is exposed with white Gorilla wood glue. Then I prime the whole thing with the standard spray bomb "Sandable" primer. After that its paint as you want with what ever you want. Here is an experiment I had done with rolling foam into nice circles by treating the paper with the Gorilla glue before rolling. Made it easier to bend and I will be doing a whole video on that process soon. That took the sandable primer perfectly as well.

Here is the rolled foam video I did just as proof of concept. Then the most recent paint job I did using my methods.

Indoor lighting



Bright sunshine

 

[nhk750]

In the words of Josh Bixler "These things aren't meant to be family heirlooms". I spent time building a few, painting, making all fancy, then bam, crash and its never the same again, or its just easier to rebuild. Balsa models can last forever and can be repaired back to original condition much better. Plus the foam board starts to fatigue after a while. So, I would keep builds basic and just fly the crap out of these things until you feel comfortable enough to move up to balsa building. I know guys spend a lot of time on these foam board planes, but my heart has been broken too many times now by foam board...

 

[kdobson83]

And something you asked about, minwaxing your plane? Only needed if your using the white foam board. But make sure you use oil based minwax or your paper will peal off. I just use paper towels and dip it in the minwax and apply it that way, and use paper towels to wipe off the excess. Light coats. But I minwax AFTER build. Glue doesn't like minwaxed surfaces very well. I personally use hotglue to seal up my edges. Just like reinforcing bevel cuts, I apply to exposed edges, keeps from delaminating and also keeps paints from touching raw foam. Easy and quick reinforcement. Any spray paint will work on an oil based minwax finish with glues edges. I personally use Rust-Oleum, I think Walmart carrys it for like $4 a can. Usually covers in one coat.

But since u have brown foam, just lightly sand with sand paper, a fine grit like 200 will suffice, then paint. I'd recommend sealing ALL edges first tho.

Good luck and have fun.

 

[blueangel6]

I have one to ask. On delta wings. How do you know where to put the main spars at.( regular wings to).

 

[Hai-Lee]

I have one to ask. On delta wings. How do you know where to put the main spars at.( regular wings to).

Spars are normally fitted around the point of maximum stress, (often the point considered as the point of maximum lift). This simple rule is not always the total answer because the stresses in a wing can be many and varied including forces caused through flight control surfaces. Ideally the spars are just part of the structural design and the remainder of the wing is designed to also be somewhat structural and rigid.

With solid skinned wings the wing surfaces can provide a considerable amount of support and load distribution. So with FB wings, (Deltas included), the spar is added to provide a load bearer that can withstand the total sum of all flight forces as well as stabilise the structure from deformation due to flight forces.

FB designs of small size use spars as a method of making accurate wing profiles. So it is obvious that spars provide a number of functions but the 2 main purposes are to support the wing structure and shape/support the wing profile.

Have fun!

 

[SteveRobey]

I have one to ask. On delta wings. How do you know where to put the main spars at.( regular wings to).

The spar placement will be marked with a shallow etch line on the speed-build kits and is also detailed in the accompanying instruction video. Are you talking about a scratch built delta of your own design?