I posted in another thread that I think all of us scale buffs should do a thread on tips and tricks to share with each other. I think if newbies are needing help on how to make or do a scale something or other that this thread may help them so I decided to start this and see how it goes and hope that the rest of you would contribute also and lets see if we can come up with a good section on building and designing all those neat little scale Items for our aircraft.

I will start this with a design I have been working on for my B-25. this drop will drop 8 or 10 bombs in sequence. this is just basic and seems to work good in theory but I will take any advice on modifications.

The green section on the pic below is a pice of 3/32 lite ply. The yellow sections are 1/8th inch brass tube with a slightly larger than 1/4 inch gap in between. the thin red lines running through the brass is 1/8th inch music wire that is attached to a 1/8 x 1/4 inch piece of spruce (black bar). attached to the black bar is a linkage that a music wire is connected to and runs to a bellcrank then up to another one and over to a servo.

The wires are just slightly longer than the next one so as the bar is pulled the first bomb will drop then the next then the next and look more scale rather than all at once. Now the bomb will have a 1/8th inch x 1/4 brass tube mounted to its back like a model rocket lug and will fit into the gap between the tubes on the rack.

Now remember on bombers they have 2 racks facing each other so you will have to calculate wire length so that the right bomb then left bomb then next right next left etc drops in that order. this is still planning and next is to build a mockup and try it but I hope this gives some ideas and feedback.

as a note you can also adjust the length of tubes on the bomb for adjusting the drop sequence.

This isn't a "new" tip, and I certainly didn't invent it, but...

For the new scale builder who wants to add realistic panel lines to a model, here's an easy way. This works best on a model with a tough (i.e. fiberglass) surface.

First, get the model ready for final paint, by first priming, then wet-sanding most of that primer off. Now make your panel lines, using fine (1/8th or 1/6th) masking tape. Burnish the tape down firmly with a piece of soft balsa, or anything else that won't scratch the surface.

Then spray two light coats of primer (or one light coat of primer, followed by your base color coat) over the tape. Sand it LIGHTLY, (600 grit or so) to be sure that the tape will come up without pulling primer or paint with it. You're just trying to break the adhesion between the sides of the tape and your model. When you remove the tape, you will have nice recessed panel lines, which you can now paint over. These are deep enough to "print" into a mold, if you're going to use the part as a plug.
Opinons vary as to when you should remove the tape. I've had the best results letting the primer dry, then sanding, as described above. Others have had better luck with pulling the tape immediately after spraying. That would depend on paint types, tape types, etc..

I can help with some tips on making static props or vac forming those little details, etc. Just finished up a set of vac formed exhaust stacks for my current project. Not too difficult and they look good. Definitely not something you are going to buy from the LHS. Here's a peak:

Looking good chad I would be interested in how you make the mold for something so complex so when you suck it it gets into all the backdraft areas. I was plant manager at a fiberglass boat factory and built molds etc but never for vacuum forming. do you have to drill a bazillion microscopit holes in them or something? I just started my 118" Ziroli B-25 and have a few details I want to make for it and vacuum forming sounds interesting. right now I am vectorizing them in corel for my lazer guy.

ProFlooney, I'm putting together a little picture show detailing the highlights of how the exhaust stacks are made. Nothing exotic, believe me! As with glass work, undercuts are a no-no with vac forming so the stacks are molded in two halves and then assembled, each one seperately. The up side is that the glue joint looks just like the weld seem on the real item! Stay tuned...

for quick dying riviets use latex paint in a hyperdermic needle. I use white and thin it with a little water. It will dry in 15-20 minutes, glue riviets can take over an hour.

On my Fw190 I used 560 canopy glue in a little bottle from the car guys that was for "bushing buster" it has a nice metal tip and the bottle is easy to hold/squeeze for the rivets. By the time you rivet from the tip to root of the wing the tip was dry. Also easier to layout all rivets in pencil with a TopFlight stencil and then come back and apply rivets.

Hi ProfLonney,
Great idea for a thread, somewhat new to semi/scale, never to old to learn I hope, Chad exhaust stacks are exactly what I need, I checked with Richard Rawle this week about a set of dummy exhaust for my DH Hornet but with exchange rate and shipping from England bit too much, plus I rather make my own without having to butcher up something else to fit my needs.
By the looks of the hits so far I'm not the only one that could use some helpful tips.
Thanks Guys
Charlie Evans

For sliding canopy rails and runners consider using the Plastistruct
rectangular and I beam sections. On one of my P-47's I imbedded the rectangular section (with a lengthwise slot cut in it) in the turtle deck, glued I-beam to the canopy (runs in the slot) and had a sliding canopy without a lot of effort.

Here is a tip for those wanting to have more accurate panel line spacing and hatch sizes.


If you have an accurate 3-view you can use autocad to help.

1. start autocad and open a new file
2. choose insert and then raster image
3. find your folder with your 3-view and then select your file and click open
4. you will get a window called image open up
you will see 3 settings
a. insertion point b. scale c. rotation
5. uncheck the box that says specify onscreen under the scale heading
6. choose a scale factor ( here are a few factors to try to start as each picture will take a different factor) (for wingspans around 130 + try a fator of 150 for those around 100 try something around 100

NOTE: It is a trial and error method keep adjusting until you get the wingspan of your model. use the dimension button and choose linear click on one wingtip then over to the other and check the dimension. After you have your wingspan just use the dimension option and measure panel lines, distances between, hatch sizes and placement and anything else to may want. I find this an excellent help to making my planes lines and hatches more accurate in size and placement.

Corel Draw will work or any cad program you can import and resize a pic in also

WARNING: MAKE SURE YOU HAVE A GOOD SET OF DRAWINGS TO WORK FROM

Professionl drawings work best remember when you enlarge the drawings the lines will be thicker use the outermost lines as this is what autocad uses to enlarge from.

ProfLooney, thanks for the great tip. I have just put AutoCAD on my computer and it is very handy for lots of modeling stuff but I had not considered it as a measuring tool for laying out panel lines.

Charlie, I am trying to put together a little article on the basics of vac forming, including building your own machine. The actual vac forming is the easy part, making the plugs is where the work is. I have attached a pic of another part for my current project. The picture shows a stock Sullivan wheel on the right and the enhanced version on the left. Regards, Chad.

Chad,

Looking at the picture of your wheels bought to mind a technique I used for making scale wheel retainers for my T/F 1/5 scale Mustang.

To make the retainer I went to the local hardware store and found some of those drive on cap nuts like are used to retain wagon wheels. Found one of the approximate inside diameter to accept a 3/16 wheel collar. The collar had to be filed down a little to fit, and once in place I ran solder around the inside to secure the two. I then drilled a hole on the outside large enough to fit the set screw through to the wheel collar.

When looking at it compared to full scale pics it looks dead on.

Great idea Countryboy. As you can see in the pic above I originally molded the hub so that the center cap was large enough to fit over a wheel collar. The real airplane has the cap but it is larger than scale on the wheel above. I have since made a more scale version and am no longer using the wheel collars. Instead, I made a simple jig which allowed me to use my Dremel tool and a cutoff wheel to cut a groove around the end of the axle for a circlip. Have not flown the airplane yet but it seems like it will work just fine. Regards, Chad.

Glassing with Laquer Based Polyurethane

I use "DEFT" laquer based sanding sealer on my planes and put 3 coats on. I recently went to Lowes to get some more sealer and noticed that they just started carrying Laquer based Polyurethane. It is also by "DEFT" and costs 8 bucks a quart. I tried this and because I knew the properties wasnt surprised but pleased. For those not familiar with laquers they dry super fast and are extremely light weight finish as most of the carrier for the laquer based product evaporates off. You also have fumes to deal with but if you have a fan to draw the fumes outside or even do it outside you wont have a problem. Now this product states not to sand between layers and to put a layer on every 2 hrs. Within 15 minutes the entire surface was dry to the touch and the rest is time for it to breathe. I put a coat on every hour and had no problems and when I was done had a rock hard finish. you can get this in gloss or semigloss it doesnt really matter which you use. when I was done all I had to do was scuff the surface with 320 and apply me Nelson Hobbies Paint. For those of you that use nelsons one thing to remember is not to use laquer based primer for his paint but was told rustoleum has been used.

Question: Can you tell me more about this lacquer based polyurethane? I have searched several sites including DEFT.

Yes, there are a couple out there. I use "Deft" brand name which can be found at Lowes. A friend of mine, after I told him about it, found another laquer based at Tru-Value hardware stores but he couldn't remember the name. Basically, laquer based products especially paints have the product and a carrier. the carrier is 3/4 th volume of the product and evaporates away as it cures thus making it lighter. the polyurethane I have found works in the same way as I have tried sample pieces myself. I dont have a gram scale but could actually feel the difference in my hand. Laquer Based Polyurethane dries to the touch (by on the can) in 30 mins and is ready for second coat within 2 hrs. My personal experience is abt 10 to 15 minutes until dry to touch and I put a second coat on in 1 hr. You need at least 1 hour between coats to allow the carrier to evaporate. Now also if by chance you get a run it will sand extremely easy abt like you would do for hard balsa. now with 2 part epoxy or regular polyurethane you have the chance of getting a gummy surface that makes you go through several sheets of sandpaper to sand (not always but a lot of the time this is the case) with laquer based it dries hard and without the gumminess because the carrier evaporates. now if you finish glassing give it 24 hrs to make sure fully cured, sand with 320 to scuff it up and tack rag it off and paint its that easy. I will not be putting more than 3 coats on in a day and wait 24 hrs before doing final 3 coats. I have found it takes 6 coats to fill the weave on 1/2 oz glass. then after second 3 coats give another 24 hrs to breathe and paint. now 1 to 2 hours after you paint the final coat you can sand then leave to breathe its just you want it to have 24 hrs before you paint to make sure all carrier evaporated. thats abt it. It comes to a glass smooth finish and you are not supposed to sand in between layers only after the final layers dry.

Question: Why not lacquer based primer? Is that a problem for the paint to go over or for the polyurethane underneath?

Good question, and I got the answer for you. You can use a laquer based primer, but you have to be careful on the paints you use on top of it. let me explain: Laquer based paints and primers have a wax inside them called Styrene. What this wax does is help it when drying to get a good and hard and not have a soft gooey coating on top. It is the same thing and principals that are used when painting Gel Coat. Now on laquers you cant feel the wax coating as it is just a minute quantity, but trust me it's there. Ok now the reasons not to use certain paints on top of Laquers. First we will cover Laquers: Laquers have what is called a chemical bond. Basically what they do is (for lack of better word) is to melt or blend into the layer below it. You can paint certain laquers on top of each other and they will blend together to create a totally different color I also know this by experience because we use it like this in Taxidermy a lot when painting fish. that is a chemical bond Now for a Mechanical bond ie. Enamels and others A mechanical bond is one that you spray on top of something and it drys just as it was sprayed, it drys on top of something and doesnt join with it for a stronger bond. Now this is how it would work with a laquer based primer. The laquer sprayed on top the primer would melt into the primer joining with it creating a really strong bond. But an enamel like Nelsons Hobbies Paints will just sit on top the laquer based primer. Now what will happen is that the styrene in the laquer will work as a release agent. Just think of a fiberglass part in a mold. they use wax so the part doesnt stick in the mold, well same thing here. now it wont be over obvious it isnt sticking, but vibration during flight etc will shortly make your paint start flaking off. I hope this helps explain some things. Laquer is a good primer but only for paints with a chemical bond. now the laquer based polyurethane does not have this styrene in it so it will work as a mechanical bond thus all paints will stick to it.

theres so much to it, I like scale and pattern and 3d, but it will be a while before i get into this, cause first im in high school and i dont have THAT much time period with sports and study work... plus i need a job, but u know that yellow spitfire looks real tempting!

I just got my canopy set from Ziroli for my 11* B-25 and thought I would share a tip I use to take the flashing off the bottom of my canopies.

I have struggled to remove the offensive extra material before by cutting it away with an exacto and every other way I can think of and to tell ya the truth I have ruined many a canopy that way. When I worked for the boat factory we had to remove the glass lip from the hulls and rails after they came out of the mold before we could work on them. what we did was held th grinder flat and ground down till the lip just fell off.

Same technique with the canopy. lay a square of sandpaper 18 works or even 100 grit garnet paper. then hold the top of your canopy like it was a sanding block and sand that sandpaper with it and after a few seconds you will see the bottom flashing begin to fall off. This is where i just break it off by hand then taking some 220 on a piece of balsa lightly sand the bottom of the canopy until all signs of the lip is gone.

this works great and leaves you with a nice straight edge to boot so give it a try with your next canopy or turret.

Bump

I am glad to see this thread bumped up. I did a thread on staining wooden props to make them look (sorta) scale. Here is that thread:
http://www.rcuniverse.com/forum/m_45...tm.htm#4575578

Nice!

HI All

I have a composit kit which iam building now and i saw the foil metal cover does any one try this thing before??? and how could i make the detalies like bolts and screws over the fuslage and wing??

Thanks
Ahmed

Ahmed, that's a BIG question! Actually the answer could fill an entire book. Detailing WWII heavy-metal warbirds is an art all its own.

Thank you for your reply , well could you help me where i could find any tips for that??

ProfLooney. It does not have to be trial and error. If you import the raster image, then "scale", "reference", select a wing tip, then another wingtip and tell AutoCAD what your wingspan is, it will scale to your size.

Did that with a Top Flite P-40 some years ago.

Les

I mean can you help me with any books that i can get which shows how to make this??