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Author Topic: Dope and Tissue hull covering  (Read 9633 times)

WCW

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Dope and Tissue hull covering
« on: April 21, 2007, 05:15:37 PM »

I'm building a Police Launch from a plans in a 1977 issue of Model Boats.  I've built the hull out of 2mm liteply covered with 0.4mm plywood, very strong but heavy.  The plan said to build it from balsa covered with dope tissue but I wanted one a bit more robust.  I'm considering building another one from balsa, what is the tissue to cover it with?  Is it tissue paper?  Some of Glynn Guest's plans in Model Boats have been built in balsa covered with model aircraft tissue, is this the tissue to use? 

My launch has been sealed with HMG dope, when well stirred it was rather thick and didn't go on that well.  Is the best make to use? 

Christopher
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kendalboatsman

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Re: Dope and Tissue hull covering
« Reply #1 on: April 21, 2007, 05:58:53 PM »

Hello Christopher,

The tissue I use is the model aircraft tissue and the dope I used (never really tried any other) was the Humbrol Tissue Dope. Although I am not sure if that is still available. I built a Balsa Tiddler tug this way and it withstood a lot of knocks.

Hope this helps,

Clive :)

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HS93 (RIP)

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Re: Dope and Tissue hull covering
« Reply #2 on: April 21, 2007, 09:22:42 PM »

Good old Pear drops.  thin with cellulose thinners. It should go on ok then  Peter
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WCW

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Re: Dope and Tissue hull covering
« Reply #3 on: April 21, 2007, 10:37:56 PM »

Dear Clive,

Where did you get the model aircraft tissue from, please?  I don't have any model shops nearby so would need to get it mail order.  Does the tissue paper this shop is selling look like the stuff to use?  http://www.rcworld.co.uk/cgi-bin/sh000001.pl?REFPAGE=http%3a%2f%2fwww%2ercworld%2eco%2euk%2facatalog%2findex%2ehtml&WD=tissue&SHOP=%20&PN=Poly_C%2ehtml%23aT_2dM11#aT_2dM11
You are right about Humbrol stopping making their dope, I'll have to try another make. 

HS93 - what is pear drops please? 

Christopher
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kendalboatsman

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Re: Dope and Tissue hull covering
« Reply #4 on: April 21, 2007, 11:03:40 PM »

Hi,

Just to show you how long ago i bought mine, it was from D & D Models in Hereford. I think they retired and closed up in the early eighties. Anyway if I wanted some now my first port of call would be my local model shop (Bob's Models in Solihull) after that I would mail order from Hobbies of Dereham. Usually good service from them. http://www.alwayshobbies.com/products.asp?sid=240 and they also do model boat kits and plans.

I would guess that pear drops is a nickname for that particular dope you used! ;D

Clive :)
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FullLeatherJacket

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Re: Dope and Tissue hull covering
« Reply #5 on: April 21, 2007, 11:16:26 PM »

Hello Christopher
Ripmax still sell traditional tissue to the model trade. It's listed here
http://www.ripmax.com/item.asp?search=tissue&Category=130&submit.x=19&submit.y=9
J Perkins also sell their own-brand sanding sealer and thinners, as well as dope, to the trade, so you ought to be able to buy the proper materials. Don't pay silly model shop prices for thinners, though. Go to your nearest car paint suppliers and get a gallon of standard thinners - it's a fraction of what you'll pay for the same stuff in daft little cans.
I wrote a short article a while ago about finishing models with these materials, at the request of a member of the old Model Boats Forum. I still have it on disc and would happily send it to you in PDF format if you forward your E-mail address on a private message.
I reckon the stuff you had was HMG Glider Dope, which has the consistency of thick molasses on a very cold day!
Glad to see there's still someone out there who likes the smell of cellulose; kids these days don't know they're born, do they?
Suit yourself, but let's hear it one more time for balsa and dope!
FLJ  8)
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WCW

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Re: Dope and Tissue hull covering
« Reply #6 on: April 23, 2007, 10:04:03 PM »

Dear Clive + FLJ,

Thanks for the link to Hobbies of Dereham, I'll get some tissue from there and see how it goes.  I'll see if the dope they sell is the J Perkins stuff, I did have a jar of it a while back.  It was much thinner than the HMG stuff so soaked in better.  I don't think the weather helped for the HMG dope, I used it outside on a very cold day.  Is it better to thin the dope for the first few coats, please?  Do you thin it in an old dope jar or put the thinners straight in the jar of dope?  The brushes I use for doping the bristles fall out of so I have to keep getting new ones, does this happen to you? 

I not so sure about children these days, I'm nine years younger than the boat plans I've used!  This'll be my sixth boat when it's finished, I've got several half-built but somehow they never get finished!  I don't mind the smell of dope, but using it indoors gives me a splitting headache.  Even outdoors is a bit dicey. 

Many thanks,

Christopher
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tobyker

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Re: Dope and Tissue hull covering
« Reply #7 on: April 23, 2007, 10:16:41 PM »

Is aircraft tissue all that special? I only ask because I've used supermarket own brand mansize tissues - which come double, so you have to split them - to cover balsa boats in the past, and I'll probably use it for the balsa superstructure on the current Perkosa project too. I also wonder if I could use tissue with epoxy finishing resin.
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kendalboatsman

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Re: Dope and Tissue hull covering
« Reply #8 on: April 23, 2007, 10:24:22 PM »

Hi FLJ,

I just used an old tin of Humbrol Sanding sealer on my Springer Tug, and that was like molasses on a cold day. Smelled like it as well  ;D

Clive :)
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kendalboatsman

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Re: Dope and Tissue hull covering
« Reply #9 on: April 23, 2007, 10:26:34 PM »

. I also wonder if I could use tissue with epoxy finishing resin.

Hi Tobyker,

You could use tissue with epoxy resin but be careful it doesn't tear. I just used Glassfibre tissue with Polyester Glass resin and that was trying to tear when applying it onto the resin.

Clive :)
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biggles1

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Re: Dope and Tissue hull covering
« Reply #10 on: April 24, 2007, 06:22:25 PM »

Hi  to you all  Just to answer a few questions on tissue and dope! I still cover my free flight model aircraft using tissue it is indeed specially manufactured for the purpose don't use toilet tissue, it has no wet strength.Proper tissue is meant to shrink when doped giving open structure like wings there  strength, in fact we pin down covered light structures on a building board to prevent warping whilst drying.Dope should  always be thinned  with thinners I would suggest 50/50 as it is meant to shrink as well as giving a air tight finish. I would suggest on sheeted surfaces give the bare balsa a couple of coats of dope rubbing down each between each coat,then put on tissue  using thinners brushed through the tissue as an adhesive. when dry apply more coats of dope, you then have a really strong structure. Tissue can be brought from www.freeflightsupplies.co.uk   flitehook.net   and  www.samsmodels.co.uk  Dope cannot of course be sent by post you need your local model shop I brought some on sat. from Geoff Stubbs in Oundle northants. The manufacturer is HMG Paints phone no. 0161 2057631 give them a ring for local stockist. If you see banana oil in your model shop this none shrinking dope. Hope  this has been of some help if you would like to see some nice model aircraft visit peterboroughmfc.org  Dave
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StarLocAdhesives/FiveStar

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Re: Dope and Tissue hull covering
« Reply #11 on: April 09, 2008, 07:19:34 PM »

We supply dope and sanding sealer by mailorder (legaly) , from our ebay shop ,we also supply it to shops but most dont stock dope these days

All our dope is manufactured 100% by ourselves and is deffinately not from HMG !......

There are many types of dope,  ( a description of the types of dope etc on www.starspan.co.uk )

Shrinking dope, generaly used for tissue to shrink it
Non shrining dope , formulated to not shrink ideal for use on wood surface to waterproof
Banana oil , a non shrinking dope that is highly flexible and does not set as hard as non shrinking dope so it can be scratched easily
Butyrate dope , a non flammable (when dry) dope, with a higher gloss than the nitrocellulose based other types
Sanding sealer NOT TALC MIXED WITH DOPE! , it has a lubricant filler to ensure you can sand and/or polish to a smooth finish

For a boat hull i would use non shrinking ope or sanding sealer

http://cgi.ebay.co.uk/Clear-Cellulose-Shrinking-Dope-Nitrate-Balsa-Kit-Model_W0QQitemZ280021339727QQihZ018QQcategoryZ34056QQrdZ1QQssPageNameZWD1VQQ_trksidZp1638.m118.l1247QQcmdZViewItem

we also have a non woven tissue as well (starspan)  this is full strength when wet so you can wet it before application and then rub it down without it breaking like the normal modeling tissues they sell as jap tisue (most normaly just bought as packing tissue), the starspan is made from a mix of cellulose and aramid so is very very high strength if used With epoxy it will not tear ether on application , giving similar strength to a grp hull





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Martin13

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Re: Dope and Tissue hull covering
« Reply #12 on: April 09, 2008, 08:18:46 PM »

Hello Christopher

I wrote a short article a while ago about finishing models with these materials, at the request of a member of the old Model Boats Forum. I still have it on disc and would happily send it to you in PDF format if you forward your E-mail address on a private message.
I reckon the stuff you had was HMG Glider Dope, which has the consistency of thick molasses on a very cold day!
Glad to see there's still someone out there who likes the smell of cellulose; kids these days don't know they're born, do they?
Suit yourself, but let's hear it one more time for balsa and dope!
FLJ  8)

Christopher,

I highly recommend that you take up FLJ's offer - I have a copy of the article and its brilliant... O0 O0 O0

Martin down under
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g7tmu

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Re: Dope and Tissue hull covering
« Reply #13 on: April 16, 2008, 08:51:03 AM »

I have covered my latest JIF65 yacht in JAP tissue, stuck on with normal model shop dope, but thinned a bit with cellulose thinners. I had a stock of JAP tissue from my model flying days, it is a bit smoother than the standard Modelspan type 'model shop' tissue.

The finished surface is very good and has taken paint well. Certainly for a model planked or sheeted in balsa it is essential to sheath in tissue or fibreglass tissue, if you want a long life out of it!

I will add a photo sometime of the finished model.

Victor G7TMU
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