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Why can't i ever fill gaps neatly!


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Hey guys, i'm having a bit of a nightmare at the moment filling some unsightly gaps on Revell's 1/48 F-117 nighthawk mainly between the fuselage and wings. I use the following methods:

1. masking tape either side along area to be filled to minimise excess filler

2. fill the gap

3. rub down with isoprophyl alcohol on a q-tip/cotton bud

4. sand any remaining stubborn filler with finer and finer sandpaper

BUT!!

I still have problems i seem to get ridges between the filler and the plastic or noticeable lines where the filler ends and the plastic begins no matter how much rubbing and sanding i do. I currently use squadron white putty. It's really bugging me because i kinda hoped i would by now have been able to make real nice flush smooth gap fills like most of the work on this site, yet i get these horrible (small but noticeable - to my eye anyway) ridges between filler and plastic. Is there something i am doing wrong or could do better?

many thanks sorry for the waffle.

al :cheers:

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First of all get rid of the squadron filler - that stuff is impossible to work with! I use automotive spot filler and I hear a lot of others here on ARC that use it too, I've also heard good things about tamiya filler but have'nt tried it myself Could it be that you're sanding too much of the filler away causing the "ridges"? or not sanding enough of it away? squadron putty is very hard when dry and it takes a lot of sanding to smooth it out. Automotive spot puttys sand very easily - If you'll try it you'll wonder how you ever used that crap. Hope this helps! Matt

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May be in the minority here, but I almost always sand the filler with well-used medium (400 - 600 grit) sandpaper first. The abrasiveness helps to knock down the high spots and "true up" the different elevations of the plastic and filler (especially if using super glue).

The isopropyl and fine sandpaper usually don't have enough "bite" to take the elevation down evenly. They polish up the high spots without feathering the outer edges well.

After the initial sanding, I'll lightly prime it and polish it out with finer grits of paper.

Also gree that Squadron putty may not be the best product to use. Definitely prefer Tamiya as it's less porous and shrinks very little.

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The isopropyl and fine sandpaper usually don't have enough "bite" to take the elevation down evenly. They polish up the high spots without feathering the outer edges well.

Yep. And the alcohol can tend to remove thinner where it's needed, around the edges, while leaving the bulk in the middle. I played around with the filling without sanding trick for a while, but in the end, the only way to really prefect a smooth join is with sandpaper, IMO.

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From my limitted experience with Tamiya putty (never used the Squadron one) I found that acetone (found in nail polish remover) works much better than IPA. Be careful not to use too much or it will eat the plastic. I think the Tamiya putty is fairly soft allowing it to be removed without removing much plastic.

Where I can I use the acetone/cotton bud method, but in other areas where that's not possible I fill the seam with putty (using tape either side if I remember). Then when that's dry, using a very coarse sandpaper (150 grit) I wet sand across the seam softly (to avoid removing any nearby detail). As mentioned by trojansamurai this removes the excess putty. Then when that's getting close to removing the ridge, I work my way towards finer grits and use a bit more force each time. I had read somewhere on the forums to sand at 45 degrees to the seam and when you change sandpaper, change the direction by 90 degrees (so you're still 45 to the seam, but the other way). This is to help remove the marks from the previous sandpaper used.

I used to sand along the seam hoping to avoid removing detail, but found this very ineffective at removing the ridges and some detail was inevitably lost anyway.

Hope that helps.

Brett

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I do not rub down the putty with acetone or achohol. I leave it as it is. Some putty shrinks and the gap will still be visible if you do this.

Here are some of my tips. I have a fetish for filling gaps :thumbsup:

1. Try to minimize the gap wherever you can. Assemble carefully.

2. If the gap is still too large after careful assembly, stuff in some styrene to fill as much gap as possible. Never depend solely on putty to fill gaps, especially big ones. They are weak and crack easily.

3. Fill above the surface level, even if your putty do not shrink. when applying putty.

4. When applying putty, its a good idea to dilute it a little. First of all, it can flow into small gaps. Secondly, it reduce the possiblity of 'antholes' in the putty. Oh, pressing the putty a little as you apply helps too.

5. Wet sanding is always better. Slower, yeah, but helps you see better as you sand.

6. When everything fails, flash out the epoxy filler!!

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Alistair, I use Tamiya putty (a paste). After application & drying, I wet-sand it with 400g then 800g (black) Wet n' Dry sanding paper. I, too, still get a distinct demarcation between the putty & plastic - and some pin-holes.

So, I go to a finer filling medium - Mr. Surface 500. This is a thick liquid medium. I dot it on with a toothpick (= economical) or a Q-Tip (= wastes a fair bit), let it dry (I allow overnight) then wet-sand it with 800g then 1200g.

Mr. Surfacer is also available in 1000. Other modelers use liquid paper, instead. Other modellers wipe the 500 with thinner or alcohol - I dunno what, and I don't myself.

Good luck. George, out................

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i use squadron white putty as well, but ive found that wet sanding is the way to go. gives a much better finish and really trues up the edge of the putty to the plastic. heck, sometimes ill take a few wings or a fuse into the shower with me and sand away. too much info?

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i use squadron white putty as well, but ive found that wet sanding is the way to go. gives a much better finish and really trues up the edge of the putty to the plastic. heck, sometimes ill take a few wings or a fuse into the shower with me and sand away. too much info?

:D

waaay too much info :D

I swear by Tamiya putty removed with a Q-Tip and Mr. Colour Thinner. Check out the gaps I'm filling

on the bf110 over in the In-Process group. I still sand a bit...600 quickly followed by 2000, but not

enough to lose detail. This is usually followed up with a brushing of Mr Surface along all of the seams.

When this drys after 40 minutes or so, I rub it off with a Q-Tip in good'ol Mr. Colour Thinner.

:banana:

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I've been working on a revell f-117 on and off and I ran into the same problem as you. I normally fill gaps with Bondo spot and glazing putty, but the gap between the wingos and fuselage was a bit strange.

I basically just filled it with super glue (so that there would actually be a good bond between these parts) and clamped it until the glue dried, and then i folded a piece of 400 grit sandpaper (so that i could make the correct angle needed). Once i painted over the top, it looks very good!

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Try gap filling super glue as your filler. I stopped using Squadron white years ago, and although I still use Tamiya putty at times, I find nothing finishes smoother, or takes re-scribing of lost details bettter than the likes of Zap a Gap.

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I could never see the point of taping either side of a join; all you end up with is a couple of ridges to remove. I use a piece of wooden dowel, about 1/8" across, and cut it down to a chisel point, about 1/16" across. Using that, to apply the filler, minimises any excess spread. Micromesh (wet,) or wet-and-dry paper (wet) follows, for sanding down. Using the paper(s) wet means that a coarse grade is unnecessary; using plain wet-and-dry, I don't go coarser than 600 grade (that's the UK grading.) Micromesh supply sanding sticks, with four grades attached; absolutely brilliant for normal seam work.

Edgar

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Along with Bondo, two other auto body products that can be used are:

DuPont's Spot-n-Glaze and

3M's Acryl Blue

They can be found at auto parts stores, you may have to ask. For auto use, these are designed as a finishing glaze to be applied in a thin coat for final smoothing. I haven't bought either for some time, but as I recall they each come in a 2 lb tube so one will last a very long time. Both will disolve in Testors liquid cement (the square bottles) if you want to make a thinner mix, although the shrink rate increases significantly when thinned this way.

These days I usually just use thick (or thin, depending on what needs filling) CA glue or Gunze's Mr Surfacer 500/1000. The downside of using superglue is that if you wait too long to snad down the filler, it will have dried harder then the plastic.

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I'll say that to my wife, sorry darling no showering together today, i have to sand my fuselage in the shower......

:)

Uhhh, yeah...OK EagleDriver :rofl: :rofl:!

Great thread! I have the same problems filling gaps, but thanks to this I think I've finally figured out what I was doing wrong...I was sanding the living sh*t out of the filler, making it too low, leaving a visible line between plastic and putty :thumbsup:.

Edited by TomcatFanatic123
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OK now I'm waiting for someone to ask:

1) "What shower head is better for wet-sanding? the Waterpik Ultimate Massage 3000 or the Lady Alston Omega II with 5 unique settings???"

2) "I need a replacement part for my Tamigawa Spit-phoon, I lost mine down the drain whilst showering"

carpet-monster has been replaced by the darned drain-monster...

:nanner::rofl::rofl::rofl::rofl:

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OK now I'm waiting for someone to ask:

1) "What shower head is better for wet-sanding? the Waterpik Ultimate Massage 3000 or the Lady Alston Omega II with 5 unique settings???"

2) "I need a replacement part for my Tamigawa Spit-phoon, I lost mine down the drain whilst showering"

carpet-monster has been replaced by the darned drain-monster...

Why don't take the fuselage/wings with you in your bath & sand it there , perhaps the putty residue is a good soap :blink: :D

I guess it would be a mess :) :D

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