Building tips for foamies

[thevon]

There are a lot of guys getting into foamies and I thought it would be good to have some tips on building methods. I want to kick it off with this one. When you're cutting tape (fibreglass tape, or coloured packing tape) it can be really annoying how it sticks to the scissors, and that can make it get bunched up or torn. I found that by smearing a little bit of oil eg cooking oil, on the sharp edges of the scissors the taps cuts really cleanly. You don't have to use enough to wet the scissors - just a light smear. You can work a lot faster this way.

[thevon]

I would have to say that the instructions that Kye of Wowings has written for the "Duck" are extremely comprehensive and useful. He has them available for download on his website
www.wowings.com/product/wowings_duck_aus.asp?id=76
so I don't think he has a problem with them being publicly viewed. He's closed down production now too, which is a shame - he provides great service.
The most easily available foamie to buy seems to be the Bee - but its instructions are absolutely hopeless! So my advice is to use the principles described in the Duck instruction to build other kits such as the Bee! And while you're doing it, thank Kye for his excellent work!

[sean]

Hey Thevon, nice work on the first tip (oil on scissors). I tried it today and it makes things much easier.

I've been playing with thinned Shoe Goo on my Bat. I bought the Shoe Goo from Amart All Sports in Mitchelton, and thinned it with Xylene bought from Bunnings in Gordon Park. I thinned it about 1:1, which makes it a good consistency for brushing. I've also found that applying it with a disposable foam brush (bought from Bunnings) makes it much easier to apply without streaks.

I put a couple of coats over the nose below the fibre tape and the nose feels much tougher. I'm hoping this will ensure the fibre tape sticks to the spackled EPP without lifting. I've also applied a couple of coats over the Profilm in the areas that take a pounding during landings (nose, bottom centre and wingtips). Not sure how big a help this will be yet, will write again when I find out.

When using Xylene, you MUST NOT use plastic! Xylene melts plastic. I found this out by putting some in a plastic cup and in a couple of minutes the cup had disolved. Fortunately it doesn't melt the sponge brushes I've been using

[thevon]

Hey good to hear from you Sean, it's Andrew here. Yep I only recently tried Shoo Goo. Mine cost $14 at the shoe repair stand at Margate next to Woolies. As the shoe repairer said ... it is incredibly tough stuff! I've even successfully used it to make a patch on the inside of a cut in my racing bike tyre and it's holding up well, so I'm going to publicize that to the cycling fraternity.

When I recovered my Duck I smeared it over the nose area and into the cutouts of the battery and lead weight, and it really makes them rubbery-strong. But I didn't dilute it, I just smeared it on out of the tube. I'm planning to thin it when I make my Drongo plank. By the way, Xylene is used for thinning concrete lacquer and costs about $70 for 20 litres. I have about 1/3 of a drum here!

I hear people talking about spackling the EPP but I worry that it will separate from the foam too easily and make the covering come loose sooner. Andrew.

[sean]

Hey Andrew, I thought it was you $70 for 20 litres of Xylene, that's amazing, I paid about $15 for maybe 1 litre at Bunnings. That's not as bad as it seems because you only need a tiny amount for thinning Shoe Goo. It's nasty stuff though, I hear it's banned in many countries and having used it I'm not surprised, good ventilation is a must.

Spackling EPP gives excellent results, I spackled the Bat all over and the covering stuck well in most areas and looks really smooth. However as I said it did lift off the nose after a high speed, straight in crash on the road at Shorncliffe (this happened after a mid-air knocked the tail off). I'm pretty confident the Shoe Goo over the spackling, and under the fibre tape will stop this kind of separation from happening again. We'll see I guess...

Hopefully the Bat will be back in the air this weekend...

[thevon]

When I got the 3M90 at PRomark last week I also asked whether they had any very strong clear packaging tape. Because the US guys talk about using "3M storage tape" for hingeing etc and say it's much stronger and stickier than normal tape.

They have a variety of thicker tapes there and I got a roll of 3M "375 clear packaging tape" which the catalogue says is the premium stuff. Tried it out and I'm really impressed - about 3 times (I think) thicker than the normal tape, and it REALLY sticks.

So there.

[callun]

Hey guys, I'm pretty set on the M60, and making it as stiff as possible. I bought a tub of filler and I just bought a tube of shoe goo and am experimenting with it on an old bed.

Newb question - I've heard you guys talking about spackle, and wondered if it differed from filler, and if one is better than the other etc etc?

Andrew - how much goo did your drongo take to cover and how much of it did you cover?

[GotrekGurnisson]

You want the spackle/filler that is super light. Red Devil is a popular one in the US that Bunnings sells over here. Whatever brand you get, the tub should feel empty when you pick it up.

[callun]

I got one of them The Speedfreeks site says to "rinse and repeat" the gooping process. Does it sand? or is it on once it's on, and that's that?

[GotrekGurnisson]

The Red Devil spackle is just like regular wall spackle and sands easily. In fact I found it a little too soft for my tastes. It really needs some sort of protective coat over it once it is sanded smooth (WBPU or similar).

[sean]

Hey Callun, the Red Devil is the brand I use and I have had good results. Apply heaps, let it set overnight ideally and sand it right back (using a light touch) until the high points of the EPP are visible again. I have found that covering doesn't stick too well to it though, but gooping fixes that right up. You can either just goop the LE and tips or goop the whole wing which will be stronger but add more weight. Once gooped any covering or strapping tape you use will stick like nothing else, especially if you iron the strapping tape after application.

You can't really sand goop, it sets like rubber, but on my Reaper I gave the goop a light sand with 150 grit once dry to remove the lumpy bits that inevitably form and it worked quite well. For an idea on weight, gooping the entire wing of my Reaper (which is about the same size as the M60) added about 40g, and I'll need a bit more lead in the nose to balance now too.

A lot of people on RCGroups say to goop the bare EPP, then spackle, then goop again. Sounds like that would make a really tough plane but gooping's not fun so I just goop one coat over the spackle.

[callun]

Yeah, I thought of gooping over bare EPP - I've got a small section of filled and sanded EPP which I've spread a small amount of goop on, and next to it, a small amount of goop on bare epp. It's only been a few hours, but even immediately after application, the filled EPP seems to have taken it much better - smoother finish and even application. I'd imagine thinned goop would sit a lot better on bare EPP.

Is thinned goop CONSIDERABLY more useable - enough to make it more worthwhile doing? Or just a little bit? Or similar?

I have a Bostik filler which was pretty cheap from Bunnings - they didn't have red devil when I was there.

[sean]

Thinned Shoe Goo is definitely much easier to use, you can paint it on like paint to give a nice even coat and save weight, so I think it's worth the extra effort (and smell). I do find though that while the thinned goop drys in about 30mins, it takes a week or more before it doesn't feel a bit sticky to touch, and to stop smelling. I guess that's the Xylene. I've read that some people use lacquer thinner instead of Xylene, might be a bit less toxic.

[callun]

Does it run when thinned? Obviously if you did too much, but to the warm honey consistency? Sorry for all the questions, but i figure, anyone who knows can answer, and it's here from then on for future reference and for other people's benefit.

[sean]

No worries on the questions. Thinned to the warm honey consistency it does run a little so you can't brush it on too thick. I guess thinning less would help there although it might be hard to brush on then.

On Speedfreeks they recommend using a sponge brush and in my experience that's a great idea, it is easier to apply it that way than with a normal brush, and gives a smoother coat.