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Depron in the UK

#1
FT, advice for Depron users.

As a beginner...

I have just spent a happy hour cutting out the FT Flyer from Depron, which is really cheap here. Good results after abandoning the fold joints. Without the paper facing component and with the extra problem of it being slightly thicker, 6mm, things were in danger of getting nasty. Any FT suggestions would be very helpful to us 'over here' in the UK.

Paper laminated foam board IS available in the UK at 5mm thick, but it seems much more expensive than Depron.

One soon hears that Depron is highly thought of. Living in the UK it is relatively cheap so I went straight ahead and bought 10 big sheets. I was able at the last moment to change my order to the ‘better’ Aero grade Depron which has been specially developed by the company for modellers.

It would seem that some model shops in the USA eg. Grayson's, are now buying it in bulk to try to save modellers from the prohibitive costs of shipping. So these thoughts my be helpful to someone in the USA too.

Flite Test plans are for 5mm paper faced board, and this board, the techniques for using it, and its plans throw up a few issues.

Flite Test plans are for 5mm board and Depron is 6mm therefore all tab holes are too narrow and need to be expanded on one side or the other: probably always inboard when it is relative to a fuselage.
Without paper-facing, FT’s A and B folds are not really viable. I have currently adopted the technique of cutting the individual pieces to size (without hinge bits), and then simulating the fold with a strip of temporary masking tape, which like the original paper strip greatly helps with alignment and joint pressure.
If we decide to make the external dimensions of a Depron box section the same as the FT plans, then the inside dimension will end up being 2mm less. This can be vital information if another box or bulkhead has to fit inside it: and the dimensions of such components may need altering.
Depron (Aero Depron) is not the same on both sides. The 'dull' side has a fibrous coating which exhibits some of the characteristics of paper, but will crack if pushed too far. From some simple domestic testing it seems that the dull side resists cracking more than the shiny side. Therefore, when bending Depron the scoring needs to be made on the shiny side.
Presumably with Aero Depron the dull side IS the outside/ show-side. This throws up an extra problem because the dull side is so much easier to draw/write on than the shiny side. Not wild about layout lines visible on the final model. A wrap-around fuselage such as the Viggen’s will probably be a bit difficult to layout.
Score cutting and folding doesn’t work ‘as advertised’ with Depron. I tried it on some samples and they broke. Instead one needs to: score the shiny side, ‘hinge’ on the dull side; cut a little deeper to say 4mm; and very slightly relief cut/chamfer the compression side eg. 10˚ for a 45˚ fold.

'Noobie' Problems.

CUTTING: My early experiments with cutting foam quickly showed me that it was going to be absolutely essential to be able guarantee perpendicular cuts. Most foam construction is based on butt-joints and, surely, these depend for strength on accurate vertical cuts. There seem to be some commercially available solutions to this. I would love to be one of those people who can do it easily by eye, but I am not. Some knives/razor-blades (USA?) are maybe more helpful to the user than others. However, if some manufacturers have seen fit to address the problem it is nothing to be ashamed of to need the help.

Personally, I might try and think up jigs for score cuts and control surface relief angles or else I will be guaranteed to bungle it. On the other hand, I do seem to be getting better at managing it by eye, yay !

GLUING: Hot glue can badly melt Depron. After some early failures the problem seems to have been resolved by a Low Temperature gun and sticks. But then there is the worry of managing very long joints fast enough. We'll see.

I am currently addicted to Flite Test programmes so I have now heard JB refer to some of these issues: paper joints for example. The remark was 'secreted' away on one of the scratch build videos.

A little gripe: it would be much easier to tape TILED plans together if there were some ANY marked dimensions. At the moment the only one, usually, is wingspan and the scale ruler. Even random straight lines at measured lengths crossing the plans would make it a lot easier to put TILES together acurately or so it seems to me.

Really love the shows... I couldn't understand at first why I found them so calming, but now I have listened to some of the early podcasts I have a better idea.

Richard
 
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Skyliner

Junior Member
#2
Hey Richard, I answered a comment of yours on Youtube. You linked me to this thread. Is a regular glueing gun really not working on Depron? Have you tried it with regular Depron, too? I´m planning on building the Old Fogey with 4mm Depron, I have it laying aroung. I´ll report how it went in the future.

Greetings. Skyliner
 
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#3
Gluing Depron

Really VERY sorry, I have only just seen this.

My experience so far is that the Flite Test 'normal' glue gun will tend to melt Depron, especially in large volumes. I currently use a 'low temparature' glue gun which works fine EXCEPT... some of the huge long glue lines that they use on FT might NOT be possible AND the glue, being closer to setting, will have higher viscosity and therefore require higher pressures to close a joint.

I use a Stanley Dual Temperature on low temp and with low temp sticks which works well.
The FT style Arrow glue gun is hanging up unused because it is too hot.
 

ztoon

Gone with the Mistral
#4
Hi,
Got the same pb in France.
No DTFB, but 3mm and 6mm depron are available and cheap.
I also had some difficulties with hot glue myself. Now I tape both sides of my depron panel : for strengh AND to resist glue temp.Look at Ed's Experimental Airlines youtube channel, lot of good infos there.
I use both 6mm and 3mm depron for building.
My last FT plane was a 75% Viggen which fuselage is only 3mm depron, tape (both sides) and hot glue, wings being 6mm depron = 300gr without battery, not so bad I guess, because even with a low powered EDF it flies. Canards and vert stab are 2mm coroplast.

IMG_20141019_211556.jpg

On my depron FT Bloody Wonder, just the horizontal stab is 6mm. Everything is 3mm (swappable pod is also, but build for a small motor only) apart the vertical stab and motor mount which are coroplast.
I'm still looking for a "regulated temp hot glue gun". At the moment I switch on/off myself with the power plug...
I use high temp glue sticks, low temp wont works well for me.