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"Glazing Putty" for balsa?

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"Glazing Putty" for balsa?

Old 09-28-2012, 12:04 PM
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turbojoe
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Default "Glazing Putty" for balsa?

I can't believe how bad this is frustrating me. Over the years I've tried a LOT of filler materials from spackling to micro balloons to some really crazy concoctions including auto body glazing putty. Nothing sands easy enough to feather out without damaging the surrounding balsa. Every filler I've tried is always too hard for my taste. I finally found a filler I'm really happy with. Elmer's Carpenter's wood filler "natural" color and it's awesome but still doesn't feather as easy as I'd like. I need something to use for that final sanding to smooth and feather. Any suggestions for an EASY sanding final feather option? Have I said "feather" enough? A nice random orbital sander in a size for R/C would be perfect but I haven't seen one of those yet....

Joe
Old 09-28-2012, 12:22 PM
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91zulu
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I use light weight spackle. Go to Home Depot and get the spackle tub that feels like there is nothing in it. That`s the one.
Old 09-28-2012, 12:50 PM
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ORIGINAL: 91zulu

I use light weight spackle. Go to Home Depot and get the spackle tub that feels like there is nothing in it. That`s the one.

+100

i have even thinned it with water and slathered it all over a fuse to use as a leveler. Works great and weights nothing. Sands easier than balsa IMO.
Old 09-28-2012, 12:59 PM
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turbojoe
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Default RE: RE:

Thanks guys but I must have $30.00 worth of different spackle and I'm not happy with any of them. Even after thinning I don't get that smooth feather that I want. I just found a super old bottle of Pactra sanding sealer that will need some thinning to be useful. This is the direction I'm headed. A super smooth final surface. Not sure the sanding sealer is going to do it as the last time I tried it was on a mahogany boat. The mahogany was obviously harder than balsa. Gotta go to work now so will have to experiment some more this weekend.

Joe
Old 09-28-2012, 07:10 PM
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jester_s1
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Default RE:

The lightweight spackle will do what you're wanting, but don't put it on like you would normal wood putty. You can't press it in flat and make it stick. Slather the stuff on and let it dry, then sand it back off. It's really soft so it won't take long, and it will level out your finish.
Old 09-28-2012, 07:50 PM
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Charlie P.
 
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Default RE:

I use the Elmer's Carpenter filler.  Try watering it down for better feathering.
Old 09-29-2012, 12:12 AM
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ORIGINAL: Charlie P.

I use the Elmer's Carpenter filler. Try watering it down for better feathering.
Thanks. I was planning to try that next. I do like how smooth it is compared to spackle. The color almost matches the balsa as well. If thinning helps it feather better then I'll be set. Planning to try WBPU and talc too. We'll see what works best.

Joe
Old 09-29-2012, 01:34 AM
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Ding, ding, ding, ding. We have a winner! The thinned Elmer's is exactly what I've been looking for. I thinned it to the consistency of cake frosting and spread it with a credit card. Got antsy so I hit it with the heat gun to speed the cure. Knocked it flat with some 400 grit and it feathered out beautifully. The coolest part is the color match. From a foot or so away you can barely see where I put it. From now on spackle only goes on walls. I wish I'd found this Elmer's filler many years ago! You gotta try this stuff guys. A tube at Walmart is under $3.00!

Joe
Old 09-29-2012, 03:18 AM
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Toysareforkids
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Default RE: RE:

I also have used a lot of different types of filler, and never really liked any of them.Ihave been using Elmer's on mycabinets and things like thatfora long time and then one day, I tried it on balsa, and have been using it since. Great stuff!

Pat
Old 09-29-2012, 05:19 AM
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Default RE:

Two things that affect the feathering ability of any filler are proper application and sanding technique. If the filler doesn't bond well with the surface it won't feather well. Also you mention your desire for a small orbital sander but this would be exactly the wrong thing to achieve a nice level, feathered surface.

Before applying the filler, make sure the surface is clean and dust free. Since you have been sanding there is lots of dust on the surface and you want the filler to adhere to the wood, not to the dust. A good vacuuming or a blow from a compressor hose will leave a nice solid surface for the filler to bond with, increasing it's feathering ability.

When sanding for a level surface it is important to use a long sanding bar and fresh sandpaper. Older paper will still feel rough to the touch but the cutting edges of the grit will have been dulled requiring greater pressure to make it cut. This additional pressure will cause uneven cutting of different surfaces as well as pushing down unsupported wood, creating a scalloped surface. And of course hand sanding with just paper (no block or bar) is absolutely out as you can't keep the surface level. The proper technique when you start to fill and final sand is to use a good, flat sanding bar with absolutely fresh sandpaper, I use 220 grit on an aluminum sanding bar. Use the lightest touch you can muster, let the sandpaper do all the work. Flow the sanding bar around the curves and use an orbital motion (there's your model sized orbital sander!) It's amazing how quickly that fresh paper will cut and how nicely a properly applied and sanded filler will feather.

Dave
Old 09-29-2012, 07:40 AM
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Default RE:

I will add this even though ts slightly off topic. If you use the light weight spackle and you are applying sig stixit to hold fabric.. be aware that if you try to reposition the fabric over the spackle the adhesive will often pull the spackle and destroy the smooth finish.. Be careful of that...
Old 09-30-2012, 07:28 AM
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Default RE:

Carl Goldberg makes a product called "Model Magic" product number #795 Strong,lightweight,non-shrinking and works with wood, foam and fiberglass.....feathers out great. Not sure if it's still available.
Old 10-01-2012, 12:18 AM
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I THINK THE FINER GRIT SANDPAPER IS THE SECRET TO FEATHERING.....THAT AND NOT TRYING TO HURRY THE JOB.
I USE THE LIGHT SPACKLING AND THE KIND THAT IS PINK AND DRIES WHITE WHEN READY TO SAND. BOTH HAVE THEIR PLACES.

Old 10-01-2012, 08:32 AM
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Hi!
Why do you use filler without first having covered the balsa with 25g glass weave /24 epoxy???
There is nothing as good as brown micro balloons and 24 hour epoxy when it comes to spacling.
Old 10-01-2012, 10:33 AM
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Sorry, I've been using it for 20+years as a carpenter. I buy it in the tub and if it gets a little hard just add some water and stir.Lightweight spackle has it's place and so does epoxy and micro balloons. All depends on what your trying to accomplish. But for making fillets around tail and stab joints it's great.
Old 10-02-2012, 07:44 AM
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Hi!
But it's so weak and brittle!
Old 10-03-2012, 06:42 AM
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Default RE: RE:

No weakness at all. It's not the same as the lightweight balsa filler sold by hobbico and others. I've even used it outdoors as long as you paint over it later. It takes very little water to thin it so be careful. to each his own though, lots of ways to skin this cat.
Old 10-04-2012, 06:30 AM
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Default RE:

"Carl Goldberg makes a product called "Model Magic" product number #795 "

AKA Lightweight Vinyl Spackle:-)))))))))))) Available at Home Depot, Lowes, etc.

Les
Old 10-04-2012, 08:28 AM
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ORIGINAL: turbojoe

Ding, ding, ding, ding. We have a winner! The thinned Elmer's is exactly what I've been looking for. I thinned it to the consistency of cake frosting and spread it with a credit card. Got antsy so I hit it with the heat gun to speed the cure. Knocked it flat with some 400 grit and it feathered out beautifully. The coolest part is the color match. From a foot or so away you can barely see where I put it. From now on spackle only goes on walls. I wish I'd found this Elmer's filler many years ago! You gotta try this stuff guys. A tube at Walmart is under $3.00!

Joe
Bingo..... Been using it for several years myself. You will forget about the other items used for this job once you try Elmer's.
Old 12-16-2017, 05:37 PM
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Here`s a method I just happened to stumble across while doing some wing sheeting. I`m very careful sanding and it seems to make a good well bonded joint between some of those un-intended gaps between sheets.
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Old 12-16-2017, 05:47 PM
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I will come back into this thread and add this. I have been finding this elmer putty has a dang good adhesion to many things as long as its clean. I have even been using it as a putty over primed fiberglass,metal, etc.. Just try leaving it on your cheap plastic squeegees overnight for a test. On something like this I will spread it on scraps you would throw away just to see how it grips once dry. I am mostly building electrics these days so there is less vibration. But try this stuff out on some samples and see..

I have had good luck priming over it and painting with water based paints...
Old 12-17-2017, 06:55 AM
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You can also add a little water and some Rock Hard from home depot, to it and get a nice hard surface that is still easy to sand.
Old 12-17-2017, 08:41 AM
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Originally Posted by jaka View Post
Hi!
Why do you use filler without first having covered the balsa with 25g glass weave /24 epoxy???
There is nothing as good as brown micro balloons and 24 hour epoxy when it comes to spacling.
I find it best to do all your filling prior to applying fiberglass. This wing was stripped of covering, had quite a bit of filler applied to fix multiple low spots, then glassed and painted.
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Old 12-19-2017, 08:35 PM
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Originally Posted by speedracerntrixie View Post
I find it best to do all your filling prior to applying fiberglass. This wing was stripped of covering, had quite a bit of filler applied to fix multiple low spots, then glassed and painted.
As much as I hate to admit it, I agree with Shawn here. Much lighter to fill your balsa with lightweight filler before you glass the surface. Any filler above the glass is only to fill the weave of the fabric.

Scott
Old 12-20-2017, 12:00 PM
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Nonsense, you agree with me all the time.

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