Why use glue at all?

[Tim Mackey]

Various different EPP models that I have done suggest different methods. Some say you should spray 3M type glue ...UHU por spray glue or whatever onto the EPP surfaces first, and let it go tacky, before then applying the strapping tape  - sometimes known as CW tape, fibreglass reinforced, or even "Zaggi" tape.

Now what I want to know is why?

My EPP Slipstream flying wing instructions suggested gluing first, - I didn't - and the tape has gone loose in places . However, a well known UK EPP slope combat kit manufacturer - Alan Head - specifically recommends to NOT apply any glues before covering his models....and I never have done, and they all seem absolutely fine, despite a very hard life.

I hate using spray glues - just like whenever I get near a tin of paint, one thing is guaranteed - I end up with more on me and my clothes than on the model!

So come on you chemists and adhesive gurus.... to glue or not to glue?

[001]

Tim, I assume that it is because the adhesive on fibreglass tape deteriorates rapidly when exposed to sunlight. I had some spare pieces of tape in my shed near a window and after a few months the adhesive didn't (adhere). It had turned to powder. Obviously strapping tape applied over the top would help to protect it.

 

 

[Tim Mackey]

No thats a whole different issue....the strapping tape always gets covered in colured parcel tape or solarfilm etc for exactly that reason ( UV light degradation ) - what I am on about is whether to glue the EPP before the strapping tape is applied.

[001]

 

To clarify, by strapping tape I meant coloured or parcel tape.

 

Not everyone covers the whole surface of the model, in colour. I doubt that UV is completely blocked by the cheap tapes that we use, just slows the process of degradation down.

 

 

[Tim Mackey]

Strapping tape usually refers to the FG reinforced cross weave tape.

Anyhooo, despite the terminology confusion, it still doesnt address my original question - why do some EPP model instrcutions say apply spray glue first, and others dont .

[Andy Freeman]

Does the recommendation for glue or not tend to be related to the intended use of the model??? From my limited experience the combat type seem not to ask for glue whereas the more sport/race type do..

Mr Slopetrash might have a more definitive answer..

[iawnski]

i have used the spray adhesive once and only once, and found it to be awful to apply and when u apply the tape you usually have one chance of putting it on, and if you do have a bump with u model and need to fix it, you have a hell of a job trying to take the tape off without big chunks of epp coming with it.  i have numerous epp modlels and i DONT use glue and have never had a problem,as  most of you guys who have seen my models no ,i sometimes use coloured gaffa tape on top of the strapping tape to add a bit of colour but mainly to stop the uv from affecting the straping tape and works great .

[Tim Mackey]

Posted by Andy Freeman on 26/11/2009 15:30:08:

Does the recommendation for glue or not tend to be related to the intended use of the model??? From my limited experience the combat type seem not to ask for glue whereas the more sport/race type do..

Mr Slopetrash might have a more definitive answer..

 

 

 Interesting... but one still wonders why that would be - if anything, one might expect the opposite - the combat stuff being more likely to have its clothing ripped off!

As you say...Mr E may be along to educate us all further

Still agree with Iawnski though...its a devil of a job to use it without making a mess of the model, myself, or usually both

 

[Andy Freeman]

Posted by Timbo - Administrator on 26/11/2009 17:13:13:

Posted by Andy Freeman on 26/11/2009 15:30:08:

Does the recommendation for glue or not tend to be related to the intended use of the model??? From my limited experience the combat type seem not to ask for glue whereas the more sport/race type do..

Mr Slopetrash might have a more definitive answer..

 

 

 Interesting... but one still wonders why that would be - if anything, one might expect the opposite - the combat stuff being more likely to have its clothing ripped off!

As you say...Mr E may be along to educate us all further

Still agree with Iawnski though...its a devil of a job to use it without making a mess of the model, myself, or usually both

 

 Possible explanation might be that the combateers might be expected to be recovered many times in their lifespans where as the racers might not...

 

Seems plausible to me anyway

[Tim Mackey]

Thats a very good point Andy...and I suspect we are gettiing to the root of it.

Heres my thoughts so far.

1) Spraying with suitable glue first makes the CW tape stick much better to the EPP, nothing more, nothing less.

2) It is nigh on impossible to remove after, so restrapping would be very difficult.

3) Alan Head amongst others does mention about re-covering tatty / battered models, and thats probably why he says do NOT use glue.

 

I wonder oif there different surface finishes of EPP supplied with models..... hang on, I have a brand new untouched WT here, and also another model from another supplier, who recommends the glue first...I shall examine the two foams side by side and report back

[Former Member]

[This posting has been removed]

[Tim Mackey]

Well there is certainly a difference..the black stuff of the WT is smoother, and "warmer", whereas the white version of the other model appears more dimpled, and has more "plasticky" feel to it, whereas the WT fus is more like a suede finish - in fact they look and feel so different that It makes me wonder how they can both be called EPP!

Now I dont know if this is due to the colour -  yet I seem to recall that my existing two WTs are white foam and do recall Alan saying he only had black the last time I ordered one (this one ).

I applied a 2" square of CW tape to both surfaces, and used a fishing spring scale to measure how much force was needed to pull the tape off at 90 degree angle.

The WT let go at around 1.25lbs of pull, but the white stuff just peeled off before tghe spring even registered... a lot different. 

Me thinks we are getting there.... some EPP- and there are obviously different types as witnessed by these two examples - is coarse and dimpled...and it would seem this si the stuff which needs the glue on first. Plus the point Andy made also makes sense.

I only wish I coulld tell who uses which type and on what models before I buy them

 

If you click the pictures you may be able to see the texture difference.

It does appear that if I am going to have any chance of the CW tape staying on this white model...then its gonna need the spray glue

Edited By Timbo - Administrator on 26/11/2009 18:06:08

[Tim Mackey]

Posted by Phil Wood on 26/11/2009 17:37:59:

The strapping tape acts like spars or rigging wires because it's on the upper and lower surfaces of the wing.....if the wing trys to flex either way it would mean the tape stretching, which it just won't do.

 All the tape on my combat models comes loose but it only needs a quick rub down to put it back..........the important bit is that, just like rigging,....it needs to be secure at the wing tip and root..

 I've found that the best glue to use is the icing off a sticky bun...........but I think that may be too much of a sacrifice for you Tim.

I don't know why you're worrying about this............there'll be nothing left of your fighting machines when I get down there next. 

Polyphilla.

 

 Yes I know WHY the tape is used.... its still the issue of glue or no glue though!

Icing off a sticky bun ? NEVER Sir

Interestingly , NONE of the tape is loose anywhere on my original 4 year old WT and its had a damn sight harder life than your virgin machines...no glue was used in the making of this film, errr ...model

[kiwi g]

My experiance with the 3m super 77 spray glue  is that its there only to give the surface a base for the tape to initally adhere too. ( EG laying tape on a wing is easier with glue than without.)

If ? its not used it can be more difficult to do the strapping process but like you say tim I dont think its needed in any structural degree.

Some tapes in kits (the coloured tapes in CS sailplanes is a good example) have a limited adhesion to other surfaces yet stick fine to each other.

[Tim Mackey]

Interesting that you feel that taping a wing that has been sprayed is easier than one which hasnt! I find the opposite - almost impossible to peel off the tape if you get it slightly wrong, and the glue is also an excellent magnet for all bits of dust and debris that may be floating around the shop.

[kiwi g]

Ever tried taping a wing when the tape wont stick .

I only spray the glue in the area to be worked ,leave for 5or10 then tape and if you have a messy worksite tim, perhaps its time you had a vac out.

The question being why use glue at all, not what was easier to do and that was my answer.

[Tim Mackey]

The question actually was why do some manufacturers recommend using glue first, and others do not. As for my worksite, I think most people would be hard pushed to find a cleaner and tidier worker / workplace than mine.

Edited By Timbo - Administrator on 27/11/2009 00:13:35

[Andy Freeman]

oops

 

Edited By Andy Freeman on 26/11/2009 22:57:31

[kiwi g]

Well thats my answer and its a shame its not good enough . so you like not using glue ,fine.. I have found when taping some slopeys if the product is old or poor tack , even the room temperature can have an effect on tapes, that spray glueing is a the best for me .  give me a good reason  for not using glue,  then tell me how to apply a tape if the manufacturer has supplied one with low tack. Good on you for having a clean work place Im sorry if a simple comment offended you tim

A friend of mine who use to own CS sailplanes  (David Griffan) supplied the glue for exactly the reason I have said. inital tack of the tape and that was all . it adds nothing in the way of structural strength. 

[Tim Mackey]

Thanks for your answer - and where did I say it offended me?

[kiwi g]

Sorry tim I read it wrong .

If all manufacturers supplied good quality tape, I like you wouldnt bother with the glue but alas some of the tapes are useless.

My jw 40 has great tape and probably wouldnt need spray adhesive but finding a product to glue the wing panels together was another story.  For anyones information we have a product here called silicon adhesive for joining wing panels its made by ados and is called Quattro but you will need to leave a few days to set. But thats another topic.

 

[Brian Parker]

I usually just apply the tape without using glue, I find it stays on OK on both white and black foam and can be removed if required.
But on a Scalegliders foam wing (black ‘pocketed’ foam) the tape just wouldn’t stick and fell off at every attempt. I tried Spraymount, Bostic Fast-Tac spray, etc. etc. etc. all to no avail.
 In the end I used B&Q polyurethane varnish and tissue with nylon re-enforcing for the hinges and achieved 100% successful adhesion. As the finished result appeared durable I did not even bother to tape over the tissue. (But I did try a test piece of tape over both the varnish/tissue and over a section of plain poly varnish covered foam, both adhered OK and could be removed without taking a section foam with it, the varnish acting as a boundary layer).
 Not tried to get tissue/varnish off the wing yet though.