Synthetic Tissue

How we create stuff
jackdaw
Posts: 156
Joined: 16 Feb 2018, 20:30
Location: Wet and Windy North Wales

Synthetic Tissue

Post by jackdaw »

Synthetic tissue(tissue substitute) like Solarfilm Airspan requires a coat of thinned dope to seal it and add rigidity/stiffness to the covering and underlying structure. Has any one used/know if using water based polyurethane floor/wood varnish is OK? I indulge my modelling in a bedroom in the house. So, not wanting to cause more marital disharmony I thought a less pungent liquid might prove equally effective. Anyone????
Colonel Blink
Posts: 140
Joined: 21 Mar 2018, 12:43
Location: Ilkley, UK

Re: Synthetic Tissue

Post by Colonel Blink »

I've used the old Ronseal Diamond stuff on tissue over mylar before.... like you, it was to avoid domestic disharmony caused by the odorous nature of our favourite modelling substance.

It works, but (for me) has two drawbacks - firstly, it chemically changes as it dries, and once dry cannot be 'reactivated' or softened by applying water or more varnish in same way as dope can with thinners. This may not be an issue if you are affixing your Airspan (other synthetic tissue coverings are available) with Balsaloc and sealing all overlaps first and just need the varnish for airtightness and rigidity, but when I was applying tissue onto the mylar effectively using the varnish as an adhesive, one had to work quickly and ensure that the overlaps etc were sealed down 100% on the first pass. Any edges sticking up or peeling back dried stiffly to attention - permanently.

The other drawback is that there is significant loosening off in damp air, though it does tighten up again once the humidity drops. On some evenings my old Ajax would look like a wet paper bag, and not a thing to be proud of!

After a couple of models, I decided to try with dope one day when Milady was out - I had the skylights in the modelling belfry wide open hoping to clear the smell. Milady came home late afternoon and actually said she didn't mind the smell............... <sounds of a prostrate Blink>. Since then I have used 'real' dope every time.

This is all my personal view, others may find it great to use - but I would prefer dope.
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Sundancer
Posts: 122
Joined: 07 Jun 2018, 09:28
Location: Limousin, France

Re: Synthetic Tissue

Post by Sundancer »

I have a number of models that I used WBPU (floor varnish) on during a period when I couldn't get dope here in rural France, albeit they are tissue over mylar rather then synthetic tissue. I would endorse everything that he Colonel says above, the finished article is OK but I avoid flying the models in damp evening conditions as the slackening off is a pain and doesn't do anything for the structural rigidity or good looks! His other comments about the inability to dope down overlaps etc are also spot on. So, if it is impossible to use dope then WBPU (or, if you are feeling rich, Eezeedope, which as far as I can tell is the same stuff repackaged in little cans and tripled in price!!) can produce an acceptable job, but dope is easier, better and would be my choice if at all possible. BTW I expect that it will air proof the tissue but don't expect any significant shrinkage/tightening. The model shown is the first one I covered using WBPU and is still going strong after 9 years.
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jackdaw
Posts: 156
Joined: 16 Feb 2018, 20:30
Location: Wet and Windy North Wales

Re: Synthetic Tissue

Post by jackdaw »

Thanks both.
The issue with damp conditions, IMO, excludes the use of WBPU for both applications due to my geographical location. I'm less than a mile from the coast of North Wales and besides the salty atmosphere it sure does rain here! I think I'll reserve the WBPU for tissue covering solid surfaces and foam on larger models.
Looks to me a purchase of some fresh dope is called for. Its an 84 mile round trip to my nearest model shop (Steve Webbs).
Shrinking or non shrinking for these applications???
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Shaun
Posts: 766
Joined: 15 Feb 2018, 21:49
Location: West Yorkshire

Re: Synthetic Tissue

Post by Shaun »

I had a model shop post dope to me late last year. Would save you a 170 mile round trip.
Don't bother with sanding sealer , just add talc to regular dope. Col Blink and I were just discussing on Tuesday at the model club how when sanding dope and talc the smell of the dust reminded us of when the kids were babies and nappy changing....😀

I only buy shrinking dope as I don't build small lightweight models from 1/16" sq balsa. If I did, non-shrinking would be required to stop things warping and being crushed.😮

Usually I use one coat of full strength and then thin down to 75 - 50% depending on what finish or further shrinking I need applying as many coats as required.. I tend to apply with a sponge pad not a brush. Obviously thinning it down tempers its ability to shrink.

I came to the same conclusion that easy dope is water based floor varnish and regularly use it if I'm simply finishing the sheet wood surfaces.

I also use floor varnish on my larger scale models. For colour (over solartex) I use Matt Valspar emulsion (not thinned), applied by a foam pad. Saves lots of masking up as no overspray and then sealed with foam pad applied clear satin or Matt floor varnish. Around the nose area or where fuel (especially neat petrol can get) I add an additional coat of polyurethane spray varnish as the floor varnish doesn't tolerate neat petrol well.

Fully agree with Col ( the tissue master 😉) and his observations on how floor varnish works with tissue etc.

Hope that helps

Shaun.
Last edited by Shaun on 05 Apr 2019, 09:21, edited 1 time in total.
GarydNB
Posts: 249
Joined: 15 Feb 2018, 23:12

Re: Synthetic Tissue

Post by GarydNB »

Shaun wrote: 04 Apr 2019, 18:44
Fully agree with Col ( the tissue master 😉)
Pffftt!

Gary
Colonel Blink
Posts: 140
Joined: 21 Mar 2018, 12:43
Location: Ilkley, UK

Re: Synthetic Tissue

Post by Colonel Blink »

I agree with Gary! Far from being a tissue master, my general mindset when covering with tissue (over doculam) is that I am constantly flirting on the edge of a major disaster. It always amazes me when the finished article looks 'OK-ish from 6ft'.....

Plus, would a Master cover the whole of a wing panel using thinners brushed through the wet tissue.... only to find that he hadn't doped the doculam on the wing first? That was me last night - it didn't adhere very well! :lol: :lol: :lol:

I too have bought dope mail order - in fact from eBay. It just depends how much you want to save the trip....

https://www.ebay.co.uk/itm/Perkins-5527 ... 521a5788fe
https://www.ebay.co.uk/itm/Perkins-5527 ... 364ab4ca3c
https://www.ebay.co.uk/itm/Perkins-5527 ... 590ea6f8a6
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Shaun
Posts: 766
Joined: 15 Feb 2018, 21:49
Location: West Yorkshire

Re: Synthetic Tissue

Post by Shaun »

[/quote]

Pffftt!

Gary
[/quote]

Gary I couldn't include you due to the fact you do strange things with a Pritt stick and hairspray when performing tissue alchemy. Same for Tobe ; it's not natural to be able to cover a model that quick. Some alternative form of Swedish magic or possibly his workshop sits on lay lines And then there's Carl who must have acquired his tissuing skills from the fabled Cornish pixies. :lol: :lol: :lol:

Shaun..

Ps. Col you are too modest. Your latest Ponte model is superb.. Can't wait to see it in the air .
Last edited by Shaun on 05 Apr 2019, 10:03, edited 1 time in total.
Tobe
Posts: 398
Joined: 16 Feb 2018, 06:19
Location: Varberg or Stockholm, Sweden

Re: Synthetic Tissue

Post by Tobe »

...if you make your own sealer by just add talc to regular dope it's fine but please be sure the talc is not scented with any kind of perfume or similar because you will never get that scent out from your model! after completion the doping process. To be honest I don't use sealer at all as 3 cotes of regular dope does the job especially if the first cote contain at least 50 % thinner ( I basically drown the model with this first cote and lat it dry out over night) which will raise slightly the balsa easily smoothed out with a quick sanding off.
jackdaw
Posts: 156
Joined: 16 Feb 2018, 20:30
Location: Wet and Windy North Wales

Re: Synthetic Tissue

Post by jackdaw »

Colonel,
May I recommend an alternative purveyor of the pungent lacquer, cellulose dope.
http://www.slecuk.com/balsa-wood/Phoenix_Paints.html
Cheaper and postage for 4 cans was just £2.90 + VAT
I've also located a local supplier of high quality cellulose thinners, £22.74 inc VAT for a 5ltr can. Half that price if you take the lower quality 'gun wash' grade. It's almost cheap enough to bathe in to remove the castor oil after a model diesel running session.

All,
I have gloss 38 micron(0.0015") LF which is for use on foam that has been painted. I was thinking that matt 27 micron(0.001") LF would be more appropriate for use under tissue. Although it is not made clear if this is hot glue coated.
https://www.ebay.co.uk/itm/Standard-OPP ... 1438.l2649
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