Using Light Balsa filler
 

Good Day All,
I'm completing my first kit build and have a question about how to get the sheeting on the wing smooth. I glued the sheeting along each seem with thin CA. Now I have that hard ridge and some bumps. I've use some coarse sandpaper to get the large lumps off, but I can still tell there is a ridge and I would like it to be smoother. Can anyone suggest or have some tips on using filler to achieve smoothness? Is it possible to mix the filler with some water (few drops only) to get it more pasty?

Thanks in advance

RE: Using Light Balsa filler
 

I put water in my filler and use those flexible "fake" credit cards they send in the mail to spread it. Build it up in thin coats.

Also, I've mixed a fair amount of water in and painted the filler on with a brush and then dragged the card across the surface removing the excess.

I've switched from using CA to yellow glue at sheet joints to eliminate the problem you describe.

RE: Using Light Balsa filler
 

And don't use that "Lite" filler. It's crap.

I use Elmer's Wood Filler (For Light colored wood), and yes, you can add water to it - but you don't need much.

I also like to wet my finger and smooth it out immediately after applying it.

RE: Using Light Balsa filler
 

A club mate and I have been using "lite" filler and it seems to work fine. One plane has flown a couple of years with it. What's the problem?

RE: Using Light Balsa filler
 

I use it too. The problem with it is that there are better products out there that go on better and easier.

I will use the lite filler I have until I use it up and then go to something else. I dont think its really that bad... but to each his own.

RE: Using Light Balsa filler
 

The best way to make a balsa skin:

[link=http://www.airfieldmodels.com/information_source/how_to_articles_for_model_builders/construction/edge_join_balsa_sheet_skins/index.htm]How to Edge join balsa sheet.[/link]

Whenever I decide to use CA for anything, I stop to think, and then I select the correct glue for the job. It never is CA. (But this is just my opinion.) :eek:

RE: Using Light Balsa filler
 

When you edge glue balsa sheets you need to be aware that with wood glue (even the "water proof" type) the glue joint WILL LOOSEN AND FAIL when you wet the sheet down for bending. It will fail when you attempt to bend the glue joint area.

What I do is edge glue the sheets with wood glue and sand the glue joint smooth. Then, ON THE INSIDE OF THE SHEET (the part that will be inside the plane ) I go over the glue joint with CA (wiping it down/off ). When you wet the sheet, provided you do not flex the glue joint too much, the glue joint will hold together.

If the joint does start to separate, you can use some lite weight filler after it is glued in place to fill the joint and have smooth sanding.

RE: Using Light Balsa filler
 

To me, the worst psrt of that Lite filler is that it melts under the heat of a covering iron. So the joint you so carefully smoothed over winds up showing through anyway.

And as far as it being lighter... Well, if you need so much filler that it makes a difference, you need to work on building better :D

RE: Using Light Balsa filler
 

I used to use that "lite" spackle filler and thought was great, until I found the Elmer's wood filler, mentioned above. As soon as I tried it, I threw the other away. Best part is, it's available at Walmart and cost less than the other stuff.
Campy, I have been using Elmer's wood glue, and Titebond wood glue for years, and have never seen water soften or release a joint.

RE: Using Light Balsa filler
 

Weldbond and Titebond II will not loosen when wetted after they have dried. I use Weldbond a lot because for an aliphatic it sands reasonably well.

I've only used light spackle under paint, and so I don't have covering iron issues. Nice to hear about the Elmers--maybe I'll try it when my light spackle is gone. But the spackle has lasted me four years and still going, cost 5 bucks, and works fine--it'll be tough to beat. When I need strength I use Sig Epoxolite, but I've had some trouble with it getting gritty in the pot after it sits a couple of years.

Jim

RE: Using Light Balsa filler
 

I tape the heets tightly together with green masking tape after TRUEING the edges, turn it over. fold the joint open, apply WELDBOND glue to the joint, fold it shut, scrape the excess with a chisel and wipe it clean with paper towel. Apply masking tape along the joint and let dry. Never had one fail from bending, wet or dry. I like lepage instafil lightweight filler; no problems.