Foam board ME 109, first foam build, anyone else want to join in?

[Bucksboy]

Right, I'm slowly getting there.  I'm using the HobbyCraft paper backed board, I've been unsuccessful at removing the paper.  I've used an iron and every square inch of paper puts up a fight.  I've tried various temperatures and even ended up nearly melting the foam inside.  So, life is too short to peel paper off foam.  

My local B & Q was out of the Vitrex underlay so all building was put on hold over Christmas and birthdays.  The next nearest B & Q was shown as holding stock so I visited them, I couldn't locate the stuff in the store.  When I found someone to ask, they found it high up totally out of reach to customers.  It was about £26/27 for 9 sheets.

So I've tried again with more success.  I had made two wings from the paper backed board, one was flat on the bottom and one was symmetrical,  not good.  I've built another wing today using paper backed board on the bottom and the black foam for the top skin. I rescued the foam spars and reused them. Both wings appear the same now.  The one from two layers of paper backed weights in at 115gm and the black foam/white paper backed foam one is 95gm.  As I intend to cover them both with brown paper and PVA, I don't think anyone will notice.  I've added two ply braces between the wings and guessed the dihedral angle.

 

 

 

 

 

I'll look again at the fuselage, this has been cut from the paper backed board but I'll be using the black foam board to skin it.  I might remake it or just make do with my first attempt.  I've still got to cut lightening holes in it but don't have pictures yet.

 

 

[martin collins 1]

Looking good, the paper should come off easily with the heat iron, i have done several wing top skins like that, the trick is to heat a mall area at a time, peel that bit back then move on. You kave got round it anyway, the bottom skin retains it anyway. Yes, fuz skin from the Vitrex, the pack i bought was £22 for 19 sheets from memory but that was about October last year, just looked on the B&Q website, now £28 for 19, if you only got 9 sheets you've been short changed! 

[i12fly]

To remove Hobbycraft foamboard paper I set my covering iron to 120 deg C. Heat a corner for about 6s with the iron flat then start to peel. Move the iron slowly across the board peeling back as you go. If it starts to tear you're going too fast, so start at another corner and finish off where it started to tear. Comes off easy.

Tends to bow upwards where paper is removed, removing both sides straightens it to some extent.

[Bucksboy]

Gents, my mistake, there were 19 boards for £27/28.  I’ll use the Hobbycraft paper backed where I feel I need extra strength or rigidity, the plain stuff for the rest.  No need to peel any paper off at all.  

[Mark Turner 12]

The easy way to get the paper off Hobbycraft foam board is to soak it in a warm bath, I normmally cut my parts out and float them in the bath for 20 mins in warm water, quite often the paper floats off, and then turn over to do the other side.

[Mark Turner 12]

 

Screwfix also have the foam and can usually get it next day if not in stock, easier than B&Q although I think they are the same company, but also often cheaper! (£20.99 in this case)  https://www.screwfix.com/p/vitrex-premium-underlay-board-9-76m-/757VJ?kpid=757VJ&ds_kid=92700065751868351&ds_rl=1249407&gclid=Cj0KCQiA_P6dBhD1ARIsAAGI7HC59SXDxQW_04SOSX9jH4pw4wzkG9X25-zd8EpmmoeXr3Ebl8HyUgIaAg2oEALw_wcB&gclsrc=aw.ds

Edited January 12, 2023 by Mark Turner 12

[martin collins 1]

Good shout re Screwfix, will check that out Mark. 

[i12fly]

18 hours ago, i12fly said:

To remove Hobbycraft foamboard paper I set my covering iron to 120 deg C. Heat a corner for about 6s with the iron flat then start to peel. Move the iron slowly across the board peeling back as you go. If it starts to tear you're going too fast, so start at another corner and finish off where it started to tear. Comes off easy.

Tends to bow upwards where paper is removed, removing both sides straightens it to some extent.

Ah, not necessarily correct.....! Today I tried removing paper from a Hobbycraft sheet and it was very reluctant to come off, it pulled a thin layer of foam with it. I think it was an A3 size sheet, which is a different make to the A1 size. I've used the covering iron method on parts of 4 different sheets of white Hobbycraft A1 size and it comes off easily.

I'll try some of the A3 size when I have a bath -should be in February sometime........  🛀  😳  🤣

[martin collins 1]

Ahhh, you might have nailed it, not tried the A3 sheets, making the fuz sides for my Skystreak at the moment and removed the inner side paper with the heat iron again, comes off easily with the heat iron.

[ballme1]

Martin, could you advise how you attached the canopy, as I assume that this is removable to get to the receiver ?

 

cheers,

Martin

[martin collins 1]

I attached the canopy using lengths of cocktail stick glued on the inner sides at the rear of the canopy and small round magnets at the front so i can access the receiver which is under it.

 

[ballme1]

Thanks Martin

[ballme1]

Martin, as I have never covered with Brown paper and PVA, I have run into problems, See attached photo.

I seem to be getting lots of creases and can't pull them out whilst still wet.

Is there a certain technique to prevent this ?

[martin collins 1]

The way i did it was to brush thinned PVA on to the model put the brown paper part on a plastic sheet, brush the PVA on the transfer it to the model, starting at the top lay it on working your way down with a rag squeeze all the air out a bit at a time as you go, if you let the PVA soak into the paper too much it becomes unworkable. Once done brush another coat of PVA over the top, i had a couple of small wrinkles but nothing like that, looks like it got too wet before it went on possibly? Others on here use it quite a bit, anyone else want to offer advice on achieving a nice finish?  Not sure if this video will help you as he only covers the wing but you may pick something up from it.

 

[Eric Robson]

I put the brown paper on a plastic sheet and give it a quick coat of thinned PVA  then place it on the model immediately position at one end and lightly pull taught not enough to tear it , then as Martin does work down over squeezing out the air. On wings I work from the centre of the chord and smooth down to the L.E and T.E. underside first then the top side overlapping the L.E to about 12mm back under. If the tips are rounded gently pull the covering ironing it as you go and with care most of the wrinkles will come out.

[Eric Robson]

20 hours ago, ballme1 said:

Martin, as I have never covered with Brown paper and PVA, I have run into problems, See attached photo.

I seem to be getting lots of creases and can't pull them out whilst still wet.

Is there a certain technique to prevent this ?

Hi ballme 1, when I cover a fuselage I cover the underside first, not going up the sides. then cover the sides overlapping on the under side and not going over the top, finally cover the top trying to get a straight line at the overlap with the side so that it looks like a panel line. This way you are not trying to cover compound curves. To me it looks like you have tried to cover the rear fuselage with one piece. 

[ADRIAN BURGE]

Is the size of the original pdf`s 20 x 30 ins each, that is what Acrobat Reader states.

so that means one per foamboard. Six boards in total.   If that is the case how was the cost of the airframe under £10 as stated in BMFA news? 

        

[martin collins 1]

Not sure what size they printed out at as i downloaded them onto a stick and had them all copied onto one plan then cut the shapes out and fitted them onto the boards to make best use of the space. I used 3 HobbyCraft boards, got the wing parts out of 2 of the boards and the fuselage guts, tail and fin out of the other. Fuselage covering was less than a sheet of Vitrex. The foam boards were 4 for £10 when i bought them (4 for £12 now) and the Vitrex was 19 sheets for about £22 when i bought them, i believe the price is about 28 now.

Edited January 24, 2023 by martin collins 1

[ADRIAN BURGE]

The length of a spar is 18.5 ins. Does that sound about right?

I notice that there is a lot of wasted space on the drawings, so I will see if with a bit of juggling around it will all fit on the three boards.

I am drawing it up in CAD , hopefully to laser cut.

 

[martin collins 1]

Just measured the front spar off the plan i used and it is 17 1/4" but you can scale it to what ever span you want, i will be doing another one later this year half as big again as the one i built.

[martin collins 1]

I also made the fin and the tailplane one thickness of the 5mm foamboard, i think the plan says 2 thickness, this is just adding weight at the rear and using more material, the fin is fine at one thickness, i ended up using a Costa stirring sticks across the elevators as those drooped on the outer ends, the front of the elevator probably wants facing with Costa stirrer (free!) or some balsa to stiffen it. Mine came out tail heavy anyway so the weight saved at the back all helps.

 

Edited January 24, 2023 by martin collins 1

[ballme1]

Hi Martin, Brown paper covering now sorted.

 

Regarding the paint finish, have you put any coating over the emulsion, or just left as is ?

 

If not, what happens if the plane gets wet/damp from landing on wet grass ??

 

Martin

[martin collins 1]

Mine has just gone on, not used anything over it yet, probably others on here can recommend a varnish or something similar to coat it with to protect it.

[Graham Davies 3]

10 hours ago, ballme1 said:

Hi Martin, Brown paper covering now sorted.

 

Regarding the paint finish, have you put any coating over the emulsion, or just left as is ?

 

If not, what happens if the plane gets wet/damp from landing on wet grass ??

 

Martin

I have a number of models with emulsion painted either onto brown paper over foam, or onto either the bare foam or the cladding paper. all of them show no signs of losing paint.

 

Clearly, they will go soggy if it's really wet, but they seem to dry out...

[martin collins 1]

Glad you got the brown paper covering sorted Martin, looking forward to seeing your painted model to see which scheme you went with, hope you have enjoyed the build.