Foam Board in the UK

[Nigel Heather]

What is there to use for foam board models in the UK?

 

Ideally, I would buy Flite Test foam board but not so easy to find in the UK and very expensive when you do.  Quite jealous of our American friends who can buy a pack of 50 sheets for £100.

 

I am aware of the Hobbycraft 5mm foam board sheets, but consensus is that it weighs more than Flite Test foam, also the paper layers are more difficult to remove.  Speculation is that the glue used to adhere the paper is the cause for both those challenges.  Means the models tend to build heavier but in particular come out tail heavy.

 

I am also vaguely aware of the Vitrex underlay from B&Q, but don’t much more than it exists.

 

Anyone use anything else - in particular, anyone know where to get Flite Test foam board in the UK at a sensible price?

[John T]

I can't help you with the Flite Test foam, but with regard to removing paper from the Hobbycraft foam I've found that it peels off quite easily if you run a covering iron over it.

[Eric Robson]

Elite models on line have maker foam 40"×30" 15 sheets for £124.99 

Or £8.99 per sheet  it is folded and would be useful for a large model.

 

[leccyflyer]

Lots of subtly different foam boards knocking around in the UK and good to experiment with.  I had some of the HObbycraft 5mm foamboard which was on offer at 4 sheets for a tenner, a saving of six quid. Haven't tried it yet. I do still have a few sheets of the proper white Depron from years ago, in 6mm and 3mm thicknesses. That is the real modeller's depron which has a slightly satin sheen on one side and a distinct grain. Good stuff.

 

Mostly these days I'm using a grey 6mm "depron" that I ordered online, which seems to work reasonably well. Comes from www.astra247.com - Depron Insulation Board for Under Laminate, 1250mmx800mmx6mm, £4.64 per sheet, shipping is £6.50 for 10 sheets, so that works out at £5.29 a sheet.

 

 Astra https://www.astra247.com

[SIMON CRAGG]

I have been getting mine from Amazon.

 

Large sheets both 5 and 10mm.

 

£4 and £5 a sheet post free.

 

Strong and light.

[Futura57]

I haven't been much of a foam board user until recently. A while back I made a speculative purchase of Depron from The Balsa Cabin which, I was lead to believe, was amongst their last stock. I was anticipating using it for prototyping and in the main this is what I have done. Of course, I wish I had purchased more because it now seems difficult to obtain in the UK, and I am running out.

 

I recently bought three packs of Diall expanded polystyrene board from B&Q in 3, 6 and 9mm thicknesses. I honestly can't tell the difference between this Diall board and Depron. Diall Polystyrene Insulation board (L)0.8m (W)0.6m (T)6mm, Pack of 8 | DIY at B&Q 

 

I also took a punt on some XPS board from Underfloor Heating Direct in 6 and 10mm thicknesses. XPS Insulation Board | Underfloor Heating Direct (underfloorheating-direct.com) This comes in slightly larger sheets and is lilac in colour. The surface finish is a little rougher than Diall/Depron but the board is a little stiffer, harder and more resistant to dents and squashing with fingers and thumbs. It sands really well too. Up until now I have only used it for prototyping my new Strange Quark design for EDF (pictured below). A hot glue gun works if you don't linger over the same spot for more than a second, and gives quick results. I'm not sure what glue I would try if I were to build a flying model from XPS. The surface finish can have areas that look like woodworm infestation, so take this into consideration. I suspect that brown paper covering would be the way to go with XPS, not that I have tried the technique.

 

As for the Hobby Craft foam board, I can't get on with the stuff. The boards warp easily, and must be kept absolutely flat and dry before use. Even with a new/sharp blade I find it rarely cuts clean without little tears. The foam inside the paper layers is softer than Depron. I don't much like it at all so I mix up expoxy on it 🤣

 

 

Strange Quark prototype mostly from 6 and 10mm XPS board. Front top fuselage from 3mm white Diall board to get the curvature I need.

 

 

 

 

 

 

 

 

Edited November 8, 2023 by Futura57

[Robin Colbourne]

The Sussex Model Centre have the Flitetest 5/16" foamboard in stock:  Flitetest Foamboard

If you're going to be peeling the paper off, would Depron sheet work?

[Simon Chaddock]

Probably the cheapest foam board is the 5mm XPS laminate underlay from B&Q. 3mm is also available.

It is light but relatively brittle so needs some thought if it is to be used structurally but it can be done.😉

 

A 50 mm EDF made from 5mm underlay apart from the EDF ducting and the nose cone which are printed. Relatively big and light for an EDF it has no reinforcing even in the wings.

[Futura57]

13 minutes ago, Simon Chaddock said:

Probably the cheapest foam board is the 5mm XPS laminate underlay from B&Q. 3mm is also available.

It is light but relatively brittle so needs some thought if it is to be used structurally but it can be done.😉

 

A 50 mm EDF made from 5mm underlay apart from the EDF ducting and the nose cone which are printed. Relatively big and light for an EDF it has no reinforcing even in the wings.

What is the covering/finishing Simon?

[PDB]

Which foam to use depends on which model you’re building and there’s a learning curve with each type.

 

My slope soaring wing flys great, made from 2 Hobbycraft foamboard sheets.

 

 

Edited November 8, 2023 by PDB

[Simon Chaddock]

Futura57

There is no covering. After filling and sanding where appropriate just two light coats of Scola water based acrylic paint followed by a mist spray of acrylic clear varnish to give an appropriate sheen of the full size. The varnish also hardens the paint surface a bit. A true high gloss requires many mist coats spread out over several  hours as the spay propellent attacks the foam!

 

Some of the Scola paints are gloss, not the high gloss of a film. but certainly adequate for a 'scale' finish. Took a bit of repeated sanding and filling to get the basic foam surface sufficiently smooth. 

The fuselage and nacelles are made from 3mm grey Depron. The wings and tail from 3mm white. It does have a substantial balsa spar out to nacelles but tapering to zero at the tips.

Like the Q400 'stolen' from Seattle-Tacoma airport by a airline mechanic for a 'jolly' that ended in a suicide crash mine too will loop!    

Edited November 8, 2023 by Simon Chaddock

[Nigel Heather]

7 hours ago, Robin Colbourne said:

The Sussex Model Centre have the Flitetest 5/16" foamboard in stock:  Flitetest Foamboard

If you're going to be peeling the paper off, would Depron sheet work?

Looking at the build videos, you only peel the paper off one side or just in parts.  Typically where you are forming curves you peel off the paper on the inside to make the foam board bend round the curve.

[Nigel Heather]

With the suggestions of using Depron do you add paper for strength?

[Lipo Man]

45 minutes ago, Nigel Heather said:

With the suggestions of using Depron do you add paper for strength?

I’ve tried this for the first time in the last week. Brown paper applied with PVA glue to 6mm B&Q insulation foam. I lost orientation and crashed hard - and was amazed that most of the airframe was intact. I think it does add a lot of strength. Worth a try!

[Simon Chaddock]

I suppose it depends on the sort plane you are building whether adding paper is structurally strength/weight effective.

Virtually all my Depron planes use build up structures than only needing additional strength in the form of wing spars. The rest of an all Depron sheet wing has sufficient torsional rigidity.

One other aspect of unreinforced Depron is the way it crumples to give excellent energy absorption characteristics.

My most recent example is the result of an almost vertical 'nose plant' of my 36" span Douglas Skyray.

After the loose bits had been cleared away it looked like this.

 

The significant bit is not the destruction to the nose but the complete lack of damage to the rest of the structure. No stress cracking anywhere also all the electrics still worked. I have crashed all balsa planes and it can be very disappointing how far the structure gets disturbed. 

If you couple this with the ability of Depron sheet to be glued edge to edge yet give a joint as strong as the original foam sheet the repair becomes a task of cutting the damage back to a sound surface.

Build up the structure to good reference point.

Then build a complete replacement section and simply stick it on!

Some lightweight filler and to quote Morecombe & Wise "You can't see the join".

I have done this sort of repair quite a few times on my Depron planes but of course it is still better not to crash in the first place!

  

        

[Albert Ace]

Guys

Not into foam for building. Still balsa/ply. But can see the cost advantage of say, using foam for ribs. Anybody else done/doing this. And what type of foam would work best.

Regards

Albert

[Simon Chaddock]

Albert

You can certainly use foam for ribs but a rib is loaded in part a structural beam so the flexibility of foam has to be taken into account. The rib may have to be significantly thicker than the material used for the wing skin. If the design requires rib capping strips these over a relatively thick foam rib can provide an effective balsa/foam/balsa composite structure. The big advantage of foam apart from weight & cost is that it is easy to cut out.

 

An example is my Depron Ballerina showing its 3mm Depron ribs before the rear top skin was added.

 

Just as an aside I have found a 3D printed rib can be an effective compromise of stiffness, weight and cost particularly for a plank wing where creating multiple exact copies is just a matter of pressing the printer button. Of course it does require access to the appropriate software and a 3D printer.😉

 

 

 

Edited November 9, 2023 by Simon Chaddock

[Albert Ace]

Thanks Simon. I was thinking of 6mm Depron replacing 3/32 inch ribs. 62 inch scale twin. Fully sheeted wing. ??

[Andy-H]

Simon,

As a matter of interest, have you fitted undercarriage to your foam Ballerina ? If so, did you add any additional strengthening or just adopted the original ply plate approach ?

Thanks,

Andy

[Nigel Heather]

It's been an interesting read.  Question though - if I was really determined to use genuine 3/16" (5mm) Flite Test Maker Board because it is lighter and the paper peels off easily is there anywhere in the UK where I can buy it?

 

See plenty of places selling 5/16" (8mm) but not the 3/16".  And strange thing is that if I go to the official Flite Test Store they only sell 3/16" which is making me doubt whether the 5/16" is even genuine Maker Board.

 

I've looked at stuff on Amazon, there are some good packs there but again, is it the same as Hobbycraft stuff - I assume so.

 

Cheers,

 

Nigel

 

 

[Eric Robson]

As I mentioned earlier Elite models sell Maker foam. Not at the price you can buy it for in America,  the last I bought was 3/16" without the paper but not 5mm with. The sheets are now  40" x 30" I have not yet ordered at this size so I can't comment on it   

[Simon Chaddock]

Andy-H

My foam board Ballerina had retractable undercarriage hence the extra leading edge fairings in P51 style. The tail wheel was also retractable.

The retracts are held in place between two leading edge ribs both reinforced with acetate sheet. With the retract secured at their extreme ends this spread the loads as widely as possible to the Derpon structure . The provided fixing were not used as they would have required a substantial ply member probably from one retract to the other to spread the load in what was a delicate structure. The whole object was to create a super light Ballerina to demonstrate the properties of Depron.

A retract test.

Note the 'instant' retract tail wheel.

To protect the retract mountings I used a soft UC wire. This was a mistake as anything but a landing on a smooth hard surface and they bent causing the wheels to foul the wheel wells likely resulting in a 1 up 1 down situation.

On my rough grass field the best option was a hand launch with the UC down to use the wheel wells as finger grips then retract the UC and fly. Landing on the wheels only if the grass was cut and a gentle wind was blowing in the right direction. Rather pointless retracts but the Depron Ballerina did fly well and ridiculously slowly compared to a balsa & ply version.

https://www.youtube.com/watch?v=TkiZDSYXUCU&t=27s 

Note the landing run of about 8 feet!   

 

ps The 8.5 mm is 'water resistant' genuine Flight Test Maker Board and has a product number FLT3105. Like the 3/16 board it is also made by Adams Readi-board.   I would guess that only the water resistant type is imported into the UK.  

Edited November 10, 2023 by Simon Chaddock

[Nigel Heather]

2 hours ago, Eric Robson said:

As I mentioned earlier Elite models sell Maker foam. Not at the price you can buy it for in America,  the last I bought was 3/16" without the paper but not 5mm with. The sheets are now  40" x 30" I have not yet ordered at this size so I can't comment on it   

 

Out of stock of 3/16" and based on the low advertised price suspect they have been out of stock for some time but they do have the 5/16".  This is basically the same story everywhere I have looked in the UK - no problem with the 5/16" but either no listing for 3/16" or if it is listed they are out of stock.

 

The proper 3/16" Flite Test Maker Foam does have paper on both sides.

[Eric Robson]

Sorry Nigel, I did not notice the thickness, I  still have 3 sheets of the 3/16, I will have to use it carefully.

[Andy-H]

Thanks Simon,
Andy