
Builder Last Online: Mar 2021


Model Scale: 1/8
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Started: 02-06-07
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As promised, I wll add this addendum to the installment #2. We'll talk about using filler so you won't have to stop building.
People are always asking, and for good reason, which filler to use, which one is the best and how to make it work correctly. For my 2 cents, as long as your filler does what you want it to do, works well providing invisible seams, isn't too expensive and is stable, i.e. it doesn't change shape over time, handling or temperature; you can use any filler available. What works fantastic in one person's hand can be garbage in someone else's. In addition, many fillers
and techniques have a significant learning curve and require some practice for it to work correctly. So, again, if you get the results you want, then that's the final aim. Just make sure you do not wind up getting trapped by the "Holy Grail" syndrome, meaning that if you use this particular material, you just apply it, the material will smooth itself and your models will forever be perfect. That used to happen to me all the time. I'd read in a model magazine that everyone swears that this material, "Ultracrap" is the only thing you should ever use. The only place you could get the stuff was about 50 miles away from your house and my dad wouldn't take me there. Finally, I'd somehow get ahold of some and it's the worst stuff I could ever have used. Why? Because it was a bad material? A resounding NO. I never took the time to learn how to work with it. Always remember that you never let the material do what it wants to do. You make it do what [U]you[/U] want it to do and that's where I made my mistake.
Personally, I use several materials for fillers
depending on the situation. For broad, mildly deep defects, I like to use a two part system like Evercoat glazing
putty
, because it doesn't shrink, it sets fast and very hard and sands really smooth. Make sure you use an organic respirator with this stuff because it's toxic. For really shallow and small defects, I may use a smooth model
putty
like
Squadron
Green or White. I've even been known to use a hard dental wax for really fine defects. For really deep defects or seams that are wide open, I'll first glue in some scrap
styrene
to make up the largest part of the bulk and then over coat with the
two part putty
. You never want to try and span a gap with your
putty
because it will make a weaker repair which may crack while you're handling the part somewhere down the road. Your strongest filled area is one which is completely backed up by your structural material whether it's
styrene
,
resin
or metal. It would be like trying to solder a wide defect. It just doesn't work well. You also don't want to build up a modification like fins. You want to make a "framework" for the fins in
styrene
and then use the
putty
for the final shape. That's the way it's done in the
1:1
lead slinging world.
Where a lot of inexperieced modelers go wrong is in the preparation of the defect and shaping of the putty
. I do not apply the
putty
to an unsanded surface. It's like paint prep. Paint and
putty
won't stick to a slick, dirty or oily surface. When it's being shaped, many builders don't wait long enough for a good set. No matter what it says on the can, I usually let the part sit overnight after the filler is applied. BTW, it takes about that long for me to get the smell out of the hobby room so I can get to the next step. Dh
Another thing is that I start with gross removal tools like the Dremel
, knife or files but I do not go to final contour. I switch to a coarse
sand
stick,
sanding
wet and switching to finer sticks as I get close to contour. The final work is always done with the finest abrasives like 400 -600 grit wet paper backed up by a small block to contour and then finished to about 800 or 1000 grit. The edges should be feathered out leaving no seams. You check your results by spraying on your
primer
to "magnify" the defect. Then correct the same way. It takes time to get good results, So don't rush.
One thing I mentioned is that I sand
wet. This is better for several reasons.
1) Sanding
creates a lot of friction and thus a lot of heat. This can actually melt your surface and make the smoothing process impossible. Your surface can get gummy and tear. The water acts as a lubricant and coolant to reduce some of the friction and also the heat.
2) Dry sanding
always clogs up your abrasive paper and makes it harder for it to cut efficiently increasing your work, the friction and the heat. So you're working against yourself. You'll see that between
sanding
and trying to keep your abrasive clean, you spend much more time
sanding
.
3) When the sanding
debris starts to clog the abrasive, those areas then can pack down hard and become coarser abrasive areas and scratch, no! gouge the daylight out of your surface. You'll sit there and wonder why you can't get the stuff smooth. The water
washes
away the debris and keeps the cutting surface fresh. It extends the life of the abrasive paper.
Here is a quick repair of a sink hole on the front surface of the engine.

The first thing I do is take a round bur and slightly deepen and roughen the defect. I also round the edges so the material can feather out much easier.

I then wash the area well and let dry. I add my filler making sure I have good contact between my material and the plastic. In this case I'm using a hard dental wax for the sake of time. The handling principles are the same.

The part is allowed to set and is trimmed. In this case with wax, my abrasive is different "grits" of nylon fabric and silk.
Here are the results.

Next, we finish our prep and start to lay down some paint.
People are always asking, and for good reason, which filler to use, which one is the best and how to make it work correctly. For my 2 cents, as long as your filler does what you want it to do, works well providing invisible seams, isn't too expensive and is stable, i.e. it doesn't change shape over time, handling or temperature; you can use any filler available. What works fantastic in one person's hand can be garbage in someone else's. In addition, many fillers

Personally, I use several materials for fillers












Where a lot of inexperieced modelers go wrong is in the preparation of the defect and shaping of the putty



Another thing is that I start with gross removal tools like the Dremel




One thing I mentioned is that I sand

1) Sanding

2) Dry sanding



3) When the sanding


Here is a quick repair of a sink hole on the front surface of the engine.

The first thing I do is take a round bur and slightly deepen and roughen the defect. I also round the edges so the material can feather out much easier.

I then wash the area well and let dry. I add my filler making sure I have good contact between my material and the plastic. In this case I'm using a hard dental wax for the sake of time. The handling principles are the same.

The part is allowed to set and is trimmed. In this case with wax, my abrasive is different "grits" of nylon fabric and silk.
Here are the results.

Next, we finish our prep and start to lay down some paint.
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