How to Finish a Good Model

[HarvardIV]

Hi Folks:

I have the hardest time getting a good finish on an RC warbird. I was using bondo on the low spots of the balsa skin, but that is terrible trying to determine what is smooth enough finish-wise. Any ideas? It's so hard to determine a high or low spot too. I had to put the wings out in the sun and look at them from different angles. Nasty. It's almost easier to rebuild a full scale plane!


There have got to be some great "tricks to the trade" that I don't know yet.

Thanks,

Chris

[mrhenniger]

I am a new modeler. I have been taking my my time on my 1:24 P-51D. It isn't on the top of my priority list, but when I do get to spend time with it I have fun.

Anway... I would would really like it if the modelers here could share their most useful tip or two that they have learned the hard way in the past. It might save this newbie some headaches in the future?

Mike

[Ollie]

Can't help you with balsa models, but for plastic models, drop by http://modelingmadness.com, hit the forum and fire away!

[Chad Veich]

Chris, I feel your pain! Getting a smooth surface prior to finishing a balsa model is very time consuming but it sure pays dividends in the end. The difference between a so-so finish and a good one comes down to sand paper! Of course, being careful during the assembly process really helps so that a great deal of sanding/filler is not necessary. I use a light weight spackle or light weight model filler on the bare balsa. Whatever you use, make sure it sands as easy or easier than the balsa, otherwise you are just begging for trouble. Whenever possible it is best to sand with a sanding block when trying to even out the surface. When dealing with raw balsa, hand sanding generally leads to more lumps and bumps than it eliminates! And holding the surface out in strong light is a really great way to find imperfections. But the biggest problem I see on many flying models is that guys just stop sanding too soon. I guess it comes down to what is “good enough” for each individual. I probably have not told you anything you didn’t already know but there is my .02 cents. If you have any other specific finishing questions please post them and I’d be happy to share what I know. (which probably isn’t all that much!) Best regards, Chad Veich.



PS- Before anyone else points it out, I know EB-B should not have invasion stripes or full span wings! However, the customer is always right.

[HarvardIV]

Hi Chad:

Thanks!

[Chad Veich]

My pleasure Chris. One other thing that ocurred to me when thinking about the finishing process. On a model that is completely sheeted, be sure you are gluing your sheets together (such as for a wing panel) with a glue which is sandable. The instant glues are good other places but not where you need to sand later. I use Sigment or, even better, Alphatic wood glue for this. Same goes when you are planking a fuse. Anywhere that you may need to sand later to blend surfaces together. CA glues are incredibly hard and you will sand away the balsa around the CA much faster than the CA itself with the resulting low spot or flat spot. You can come back after the airframe is fiberglassed and fill low spots and imperfections with Bondo or spot putty but it is easier to get it right on the front end in my opinion. Here is my current project, a little smaller than my usual! A 34 inch span Yak-11 for electric power, from my own plans.

[HarvardIV]

Looks good, Chad!

[TonyI]

When I did models I did the "blocking" just like doing a car restoration. I would either use two LITE dustings of paint or two LITE dustings of primer. I prefered primer it normally dries faster. The term two meaning two COLORS of compatable paint/primer. So looking at your model you would have the base color(basla or fglass), whatever filler you started to use and two colors of primer. The idea is to sand off the primer so it shows you the low spots to fill in without adding all the weight of that primer. Fill the spots that still have primer and repeat and repeat and repeat.

Remember you do have to PAINT it on just a nice dusting can show the spots and also a final single color and one good light source to look for shaddows and highlights.

My .02
Cheers
Tony

[HarvardIV]

Hi Tony:

I did that too, so it sounds like we're all using the same building techniques.

[HarvardIV]

So another question I have is should a larger R.C. Model have fibreglass cloth on the wings for strength? Or is the wing sheeting, spars, ribs, and stringers enough for structural strength?

Thanks,

Chris

[Chad Veich]

Chris, the glass cloth is not necessary for strength in the sense that the wing may not be strong enough to take flight loads without it. The glass provides ding resistance to the sheeting and also the first step towards achieving a finish representative of an aluminum airplane. There is much less "voodoo" involved and glassing a model than the rumours would lead you to believe. It's time consuming but not difficult to learn and do properly.

[HarvardIV]

Thanks Chad!

[Eric Swabeck]

Hi Folks
I think I am on the same plane as some others here. I have rediscovered the joy of model airplanes. Right now I am going old school and building balsa and tissue models. But I am having dificulties getting a good finish. My wings are often somewhat warped. I am using white glue and water to attach tissue. I apply glue at all surfaces. After dry, I mist and then dope. Could anyone give me some tips to reduce warpage?

Thanks

[Chad Veich]

Eric, I have not done any stick and tissue in quite a few years but used to do quite a bit. I always used dope to attach wetted (just damp) tissue to the airframe. White glue should not pose any problems for you though. I only attache the covering to the perimeter to start with, then doped the entire structure once the tissue had dried and stretched tight. Minor warps could be taken out by steaming or wetting the structure and holding it straight while it dried. You can even over-twist the wing if needed to get it straight in the end. Probably the best advice I can give you is to visit www.rcuniverse.com or www.rcgroups.com and ask your questions to some guys who are still doing this on a regular basis. Good luck with your models and post some pics for us to look at. Regards, Chad Veich.