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Author Topic: Obtaining a good finish on ply and balsa hulls with simple materials.  (Read 8153 times)

FullLeatherJacket

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Topic withdrawn as per originator request.

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Martin13

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #1 on: December 10, 2007, 11:39:14 AM »

Dumb Question No.265

What is the purpose of laying tissue paper down and why is it only done in certain places.....I have never done that before, so I am obviously missing something ??? ???

Martin Doon Under
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RipSlider

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #2 on: December 10, 2007, 12:13:44 PM »

Martin,

The tissue paper can be used to help cover up tiny voids, like the grain of the wood, or micro cavitys in body filler. It's a good method to use if the wood underneath is in bad condition, but if your going to be using 3-5 coats of Hi-lift primer (really bulky primer with Talc added to it ) there is usually little need unless you've made big mistakes.

From our discussions on your builds, in your personal situation, I would recommend glassing the ply wood, instead of using tissue pape as your going to need LOTS of practise with epoxy when it comes to the armidaler. Similar if not the same method as FLJ uses for tissue:

1) use 25gsm finishing glass, drape it over the thing to be covered
2) pour on a tiny amount of resin
3) Spread with a playing card until it'll all taken up and you've got a lovely smooth surface
4) Once dry, break out the Hi-Lift.

For really tight curves, like if you have a strake that is jutting from a hull, as it can be a pain, as the covering is dragged off the "sticky out bit", and you loose detail and it looks like you have bubbles under the tissue paper. Glass is less affected, but it still happens, so you just leave these bits alone if your covering. Or, you Vac-bag the piece your working on, and everything sticks down properly.

There is, however, a much quicker way which gives as good, if not better, finish. Again, like FLJ, this is only for Pre paint work, although it's good for using on your first 2-3 layers of primer. I also takes what ever your doing down to a completely mirror finish, so if something is meant to actually BE wooden on the model, it's not for these sections.

All you do is get a get a few packs of generic stanley knife blades, which go for something like 60p for 5, and, holding the blade between finger and thumb,, perdendicular to the bit you want to flatten, start to drag and scrape the blade forwards and backwards. Start with the grain, and then when your down to close to a mirror finish, you can go accross the grain.

You'll be suprised how rough you can actually be with this method, as you can REALLY attack the piece with no problems at all. To give you an idea of it's effectiveness, i did the entire top deck of a 700mm boat in maybe 15 minutes probably less. This includes working my way through some fairly rough body filler and a cyano spill. The ply is now so smooth that I had to move it into the shade, as it dazzling when it was sitting in the sun reflecting it all over the front room.

Works perfectly on curves etc as well, as is still quicker than blocking off with sand paper, you just have to do a bit at a time. For small area's, just cut down a few stanley blades into 1/2 and 1/3 size sections.

Again, I'll say that you shouldn't do this if you you actually want to KEEP the grain. I forgot, and used this method on an interior section, and how I'll have to paint a grain on by hand.


Steve

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Martin13

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #3 on: December 10, 2007, 12:24:35 PM »

Steve,

What's HI-LIFT ??? ???

Martin doon under
PS I'm getting around to your email :angel:
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Martin13

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #4 on: December 10, 2007, 12:30:17 PM »

Topic with drawn as per originator request.

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FLJ

Any chance I can have a copy of your thread - it was good stuff O0 O0

I wanted toi put it into my "HOW TO" file

Martin doon under
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RipSlider

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #5 on: December 10, 2007, 12:40:43 PM »

Martin,

Hi-Lift is a kind of generic name for spray primer that fills in tiny gaps. Not at all sure what it will be marketed as in Oz, but there are maybe 20 different brands of it over here in the UK.

Essentially, it's just bog standard primer with a little bit of ultra finely powdered talcum powder in it. When you spray it on, the talc acts to fill in tiny holes and gaps, like the grain of wood. it also sands down to a lovely finish.

It's OK to use it as your only primer, but I usually do 3 coats of hi-lift, sanding, or more usually using a blade, to bring it down each time, and then drift 1-2 very thin coats of thinned "normal" primer, which I then sand down to 1200 grit level.


For tips on finishing and sanding, FLJ has written a couple of good posts ( including this one ) and stavros has also produced some really excellent articles and stickied posts.

Steve
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Marks Model Bits

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #6 on: December 10, 2007, 12:43:58 PM »

I think it is also called Hi-build primer as well.

Mark.
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Martin13

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #7 on: December 13, 2007, 08:19:05 PM »


[/quote]

FLJ

Any chance I can have a copy of your thread - it was good stuff O0 O0

I wanted toi put it into my "HOW TO" file

Martin doon under
[/quote]

FLJ,

Thanks for sending a copy of your thread. Was great to be able to read again and absorb the content - another one to keep.
When is the next instruction thread comming?. Recycled modelers like myself enjoy these new techniques not to mention how useful they are to newbies......Keep up the good work..much appreciated..

Martin Doon Under

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FullLeatherJacket

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #8 on: December 13, 2007, 11:15:37 PM »

OK - on the basis that anyone who reads this should take it as A method and not THE method (like I said before), let's have another try, shall we?

Extract from article describing Fairey Swordsman finishing method – Original plan and article published in “Model Boats” May 1999. Reproduced by kind permission of The Editor.


“After final sanding with 180 and 320 Finishing Paper, give the whole model one coat of sanding sealer*, thinned at least 50/50. It should be almost as thin as water i.e. if you can see brush-strokes in it then it's still too thick. Rub down with 320 grit Finishing Paper*. Cover the hull sides, bottom panels and transom with lightweight tissue* as separate panels. Cut the tissue slightly over-sized then lay it onto the model and brush thinned sanding sealer through it. Immediately smooth down the tissue with a folded piece of kitchen roll, mopping up any excess sealer in the process. Allow to dry, then feather off the edges with 320 paper. Apply a further three coats of thinned sealer, allowing to dry between coats. Rub down to a satin finish with 320 Finishing Paper. Don’t cover around the inside corners between the hull sides and the spray rails and rubbing strips, as the sealer has a shrinking action and will result in voids under the tissue; cut the tissue hard up into these corners with a sharp blade instead. The cabin sides and roof are tissue-covered in the same way as the hull. The wood veneer is not covered in tissue but has three coats of thinned sealer.
Mask off the wooden decks and rubbing strip. I personally use and recommend Tamiya masking tapes; they aren’t cheap but give a superb edge and can be bent around quite sharp curves. Also never use newspaper as masking; the ink usually comes off onto the model. I purchased a pad of A1-sized Flip Chart paper some time ago for about a fiver; so far it has served over a dozen models and will probably last me until I retire! Now apply two spray coats of Halfords White Primer (or equivalent car paint); allow to dry for 24 hours, then rub down with 600 grit Wet or Dry* paper, used wet. Rinse off any paint dust; allow to dry naturally; dust off then apply three thin coats of Appliance Gloss White, leaving each coat to dry for about 20 minutes before applying the next coat. Remove the masking as soon as this is touch-dry, but leave it at least 24 hours before proceeding. Re-mask the decks and mask the areas to remain white, then spray the hull below the paint line, the sides of the cabin and the face of frame 25 with Renault Midnight Blue (mine took four thin coats). Finally apply two slightly thinned coats of Ronseal Satin Wood Finish to the deck, cockpit floor and rubbing strip”.

*Further notes:
Finishing paper (which is also sometimes called Production Paper) is a pale grey colour. It’s manufactured from aluminium oxide and can be obtained in the UK from Wickes Do-It-All under their own brand, or from other DIY stores under the 3M or Scotch brand names. Grades vary from 60 grit, which is far too coarse for all but the crudest shaping, to 320. I use a selection of 120, 180, 240 and 320 for finishing wooden models.
Sanding Sealer is a mixture of clear cellulose dope and a filler powder. Humbrol is probably the best-known brand but I also have acquired assorted tins from H Marcel-Guest and J Perkins. If you can’t obtain any then you can make your own by adding talcum powder to clear dope. It should not be used “thick” – I thin down the commercial stuff 50/50 and apply it with a flat, soft brush. Ripmax used to do a fantastic little range of very soft dope brushes called “Flatties” – these are just the right tool for this job, but I don’t know if they’re still available. If not, a wide, flat squirrel-hair brush is nearly as good. Best advice is to visit an artists’ supply shop.
Modelling tissue is available from most model shops and is commonly used to cover the open rib-and-spar structures of small model aircraft.
Wet or Dry Paper is available from practically any shop which sells car paints – Halfords being the most obvious. I use several grades from 600 to 1200 for finishing paintwork; the former for flatting down primer and the finer grades for later coats. Wetting the paper helps it “stick” to the paint and eases removal of the paint surface, while rubbing wetted 1000 or 1200 paper onto a block of ordinary soap will give a very fine abrasive suitable for flatting down final gloss coats prior to lacquering, burnishing or polishing.

When sanding a timber hull smooth prior to painting, ALWAYS wrap the paper around a flat block – never use a fold of paper in the hand (you’ll just dig grooves in the surface where your fingers are). Sand with a circular motion and let the paper do the work; don’t press on too hard. Once the paper clogs, replace it.

Don’t just rely on a good blow to remove dust; use a clean paint-brush on uncoated wood to brush away the dust, then go over the whole thing with the domestic vacuum cleaner, using that little round dusting brush attachment. Wash down the sanded primer and gloss coats with clean water and allow to dry naturally.
Never spray in a cold or damp atmosphere; aim for a minimum 15 degrees C. Any colder and you risk the paint crazing at a later stage; ask me how I know….. 
Always wear a face-mask when spraying (Machine Mart do an excellent one with replaceable filters for about £15).

THE TWO BIGGEST ENEMIES OF A DECENT PAINT-JOB ARE DUST AND IMPATIENCE.

There is no agreed “best practice” here. This is just the way I did it – there are numerous variations on the same theme. Suit yourselves; works for me.

FLJ



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Circlip

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #9 on: December 14, 2007, 03:21:12 AM »

FLJ, some of us remember the "WORDS AND MUSIC" of LBSC, YOU got the gift, great description, will print it quick fore it dissapears into the abyss.
     Cheers Ian.
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djrobbo

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #10 on: December 14, 2007, 09:45:17 AM »

Thanks for putting it back up F L J ....iv'e worked on car bodies etc for years but wood is a totally different animal to get a good finsh on ..the method you describe here is working well.....there aint no grain to hide in metal !!!

          I'm sure i speak for the majority on here ,the input of people like you and stavros and lots of others is much appreciated , i have been making models for of one sort or another for 50 + years and i am still learning , and the first one to admit ,I DONT KNOW EVERYTHING !

        thanks again and keep it up

         regards.............bob..
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dougal99

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #11 on: December 14, 2007, 01:58:46 PM »

Quote from FLJ:

THE TWO BIGGEST ENEMIES OF A DECENT PAINT-JOB ARE DUST AND IMPATIENCE.

Quote


And there was me thinking it was me and a paintbrush  :'(
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barryfoote

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #12 on: January 04, 2008, 08:38:24 AM »

Dougal,

Funny thing as I was thinking exactly the same thing as I read the article.

Excellent FLJ.

Thank you.

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portside II

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #13 on: January 04, 2008, 09:44:50 AM »

Quote from FLJ:

THE TWO BIGGEST ENEMIES OF A DECENT PAINT-JOB ARE DUST AND IMPATIENCE.

yes and the paint brush ,and of course ME!
daz
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tonyH

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #14 on: February 07, 2008, 10:08:48 AM »

Thanks for the guidance FLJ,

I'm just covering a Walrus with tiissue/dope and I've been concerned about the paint compatibility with cellulose. Since I need to keep the weight down and only have a light spray of primer, is there any likelyhood that the Halfords aluminium finish will react or is the solvent, in your experience, the same?

Thanks

Tony
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Stavros

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #15 on: February 07, 2008, 06:12:59 PM »

You should not have any problems wiht Halfords paints


Stavros
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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #16 on: February 08, 2008, 01:24:50 PM »

re thinner for sanding sealer: what should you use for the thinner? (a basic question, I know, but it needs to be asked...at least by some folks)
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Stavros

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #17 on: February 08, 2008, 05:49:14 PM »

I use cellulose thinners



Stavros
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pomybill

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #18 on: March 25, 2008, 12:07:41 AM »

Hi FLJ.
Followed the "Words and Music" in the artical accompanying the Swordsman Build and found it to work wondefully well. The Sorwdsman is now finished and sailing (motroing) well.
Lots of favourable comments. Will send some finished photos soon.
 Any show of the 36" Huntsman plans?

Pomybill.
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FullLeatherJacket

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #19 on: March 25, 2008, 08:50:52 AM »

Hi FLJ.
Followed the "Words and Music" in the article accompanying the Swordsman Build and found it to work wonderfully well. The Swordsman is now finished and sailing (motoring) well.
Lots of favourable comments. Will send some finished photos soon.
Any show of the 36" Huntsman plans?
Pomybill.

Hi Bill
Like I say, innit nice when a plan comes together?! Thanks for the comments, and I'm looking forward to seeing the photos. My dream - if I can ever get this flaming ACTion website finished - is to revisit the Huntsman in 1/12 scale (31"), for a couple of Speed 500 motors. Don't hold your breath, though!
FLJ
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pomybill

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Re: Obtaining a good finish on ply and balsa hulls with simple materials.
« Reply #20 on: March 25, 2008, 11:02:19 PM »

Hi Dave.
Getting worried now as I am not getting any younger. Your "Words and Music", (to coin an old LBSC saying.) make it all the easier.
New computer and still coming to grips with it. Pics as soon as I can make head or tail of it's workings.
Looking forward web site.
Bill O0
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