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seam filling w/ putty and acetone


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Hey everyone! I'm trucking away with my F/A-18 for the Hornet's Nest GB, and after several previous attempts at using acetone to smooth putty in seams, I finally had some (moderate) success :banana: ! This led to some curiosity about how others pull off those perfectly-filled seams in many of the WIP's!

This last attempt, I taped up around the seam and used a small putty knife to spread a bit of Tamiya white putty into the join, pressing it in to fill the whole seam. Then I removed the tape, and immediately used an acetone-soaked q-tip and rubbed in small circles all the way down the length of the seam. I had to use a couple q-tips to finally get all of the excess putty off, and I tend to remove a bit from the seam itself, so my technique isn't perfect.

My question is: what version of this technique works best for you? Do you thin the putty with acetone before applying it to the seam? Do you swipe the q-tip (or other tool?) from front to back, along the length of the seam? Side to side, across the seam? Do you remove the masking tape before removing the putty? Do you allow any time for the putty to dry before removal? Etc, etc! Any other pearls of wisdom I may not have thought of?

I'm always curious to see how others go about these techniques, if they'd like to share. Maybe myself or someone else will discover a hint or variation that works best for them. Thanks in advance, and happy building! :coolio:

-JL

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I found that it depends very much on the putty. With Revell putty you have to act quite quickly while it is still quite wet or the nail dissolvant will not have any effect. With Mr Dissolved Putty it is best to use the dissolvant a couple of hours after application: too soon and it will remove everything. I achieved the best results with Mr Dissolved Putty.

Hope this helps,

Arnaud

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I still use good old Green Stuff for filling seams and small voids. Some times I mask on either side of the seam. I'm generally pretty neat applying it, as I thin Squadron Green Stuff with Extra Thin Glue so that it's more like tooth paste. I can then carefully smear it along the seam pressing it down as I go, but leaving it slightly higher then the surface since it will shrink as it dries. I rather have to reapply a 2nd finish coat, then apply too much on the 1st coat.

For small filling jobs I Prefer to use Vallejo white acrylic putty. I smooth it on, then with a damp Q tip I gently remove the excess working at a angle, never directly down the seam. I give it 10 min or so to dry, and then I apply a 2nd coat. Usually that will fill the seam just fine. No sanding necessary.

Joel

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After carefully applying Tamiya or Mr Surfacer putty, I let it sit for about 10-15m then use 91% isopropyl on a cotton swab to first clean the putty away from the plastic before I deal with the actual seam. This allows me to minimize unintended/unwanted putty removal. Another good solvent is Mr Thinner, especially for Mr Surfacer. As for the seam itself, depending on the circumstances, I'll use either an isopropyl swab right after the plastic cleanup or wait until the putty cures and use a needle file.

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For more of a serious answer I do the following (In order):

1) Try very hard to prevent gaps or reduce them as much as possible.

2) Use strip styrene for large gaps.

3) Use CA for all other gaps (Small to tiny gaps).

It's very demoralizing when the putty that was applied, waited to dry, and then sanded to blend somehow falls off BANGHEAD2.jpg .

My sure 80% of that problem is operator-error, but non-the-less, I wanted a gap-filler that would eliminate said problem.

Between using a Dremal tool and a hand sander, my sanding time was greatly reduced as well.

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Stupid question maybe, but my experience with acetone is that it melts plastic (ABS/Styrene/whathaveyou) faster than you can say "D'Oh" ?

How can you rub this stuff along a seamline and not utterly destroy the kit part? :blink:

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After carefully applying Tamiya or Mr Surfacer putty, I let it sit for about 10-15m then use 91% isopropyl on a cotton swab to first clean the putty away from the plastic before I deal with the actual seam. This allows me to minimize unintended/unwanted putty removal. Another good solvent is Mr Thinner, especially for Mr Surfacer. As for the seam itself, depending on the circumstances, I'll use either an isopropyl swab right after the plastic cleanup or wait until the putty cures and use a needle file.

This has to be the best method -Mr Surfacer has been a revelation to me. Like Check Six says, if you have a really big gap turn it into a small one with strip styrene first then hit it with Mr S.

I have had some success with Pentel correcting fluid (the one that comes in a blue 'pen' applicator) -this can be wiped off with lighter fuel to avoid sanding, but sometimes dries looking a bit porous. Mr Surfacer 500 is really good and dries like...plastic!

There are favourable noises about Mr Dissolved Putty too; this may be even better but I have yet to get around to trying it.

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Putty? To fill gaps?

That is so 1970s monketdance4.gif !

i guess i'm stuck in the old ways! (despite not being alive in the 70's... :rofl:)

thanks for the reply!

Stupid question maybe, but my experience with acetone is that it melts plastic (ABS/Styrene/whathaveyou) faster than you can say "D'Oh" ?

How can you rub this stuff along a seamline and not utterly destroy the kit part? :blink:

sorry, ChrisRRR, should have specified it is nail polish remove w/ acetone, and not straight acetone

Edited by plasticWerks_JL
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I've had best luck with 90% alcohol (rubbing alcohol from a drug store) to wipe off excess putty (Acryl Blue or Mr. Putty).

My biggest problem has been that putty shrinks, especially the Mr Putty 1000 and 500. To counter this, I have to leave a raised bead then sand it down which is not optimal. Especially if you want to leave some detail in the surrounding areas. The other option is multiple applications to build it up to level which is tedious at best.

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I've had best luck with 90% alcohol (rubbing alcohol from a drug store) to wipe off excess putty (Acryl Blue or Mr. Putty).

My biggest problem has been that putty shrinks, especially the Mr Putty 1000 and 500. To counter this, I have to leave a raised bead then sand it down which is not optimal. Especially if you want to leave some detail in the surrounding areas. The other option is multiple applications to build it up to level which is tedious at best.

Just about all model putties shrink as they dry. If I wipe off the excess after applying, I automatically do a 2nd coat. Sometimes several applications are necessary. I use to use Bondo, which is a auto body filler. It dries rock hard, sands and polishes exceedingly well, and doesn't shrink. I really have to get another tube of the stuff and start using it again. It does solve a host of issues I have with Green stuff.

Joel

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This - apply Mr. Surfacer, wipe out excess/flush then do a 2nd coat which will later be reduced.

Just about all model putties shrink as they dry. If I wipe off the excess after applying, I automatically do a 2nd coat. Sometimes several applications are necessary. I use to use Bondo, which is a auto body filler. It dries rock hard, sands and polishes exceedingly well, and doesn't shrink. I really have to get another tube of the stuff and start using it again. It does solve a host of issues I have with Green stuff.

Joel

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thanks for all the input, fellas! :worship:

i've tried a number of these techniques (including CA, mr. surfacer, and melted sprue as well). i really liked using melted sprue, as that's the easiest to scribe through once dry, but it can be trying to clean certain seams up properly. i'm thinking i'll just keep all of these in mind and work on figuring out the best one for each unique situation. tools in the toolkit, and all!

i also happened upon this timely (and excellently-illustrated) tutorial on the Modern Hobbies blog that deals with the putty/acetone technique: Seam Filling F-16XL -- Modern Hobbies

if anyone else has more ideas, i'm all ears! i'm sure someone out there has some wacky method that none of us has heard! :wacko:

-JL

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Thank you for that link to the F-16XL article. :woot.gif:/>/>

I use three different techniques of seam/gap filling:

- For large gaps styrene strips or streches sprue glued in "wet" with lots of glue.

Another modeler suggested melting styrene in ethylacetate and using this as a filler. Have to try that the next time. Nitrocellulose thinner supposedly does not work.

- Automotive putty applied exactly like described in the above F-16XL article.

But instead of wiping the seam with solvent, I wet sand with 320 grit and finer. I have not yet mastered the wiping method. And I prefer 3M Acryl-Blue glazing putty.

- CA glue kicked off wth accelerator.

I sand the CA immediately. When the CA hasn't fully cured yet, it is much easier to sand than hardened CA.

Edited by Lancer512
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i really liked using melted sprue, as that's the easiest to scribe through once dry, but it can be trying to clean certain seams up properly.

I like using melted sprue in some situations as well. It takes a long time to cure and you have to be careful not to get air bubbles in it. But it's is very strong, sands and scribes beautifully. It doesn't shrink like putty either.

One thing I've found very helpful is to run masking tape along either side of the seam. That prevents getting that goopy melted plastic all over the detail of surrounding areas. Helps protect detail when sanding as well.

Edited by dmk0210
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JL, in my case, here's what I normally do:

1. Thin the putty *slightly* before applying (I also use Tamiya white putty)

2. I apply the slightly thinned putty with tooth pick. I normally work the putty around until it slightly dries up.

3. I normally wait until the putty dries up before wiping off with Q-tip *dampened* (NOT wet) with nail polish remover. This will minimise the amount of putty that may get wiped out from the seam.

Having said this, I don't always use this technique. There are times when I simply sand off the putty using 800-grit or 1200-grit sandpaper. Here's a sample... The right wing gap was wiped using Q-tip, the left wing gap was sanded off (wet sanding).

20140825_214700_zpsntjc4mm1.jpg

HTH.

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I've used Squadron Green and White Putty before, but they do shrink. I've also used Milliput for seam and gap filling, but this is expensive, and you have to mix two-parts together, but it doesn't shrink and cleans up with water, but there is some waste involved here, if you mix up too much for a small job. Super Glue also works for gap-filling,but the best product I've found has been Perfect Plastic Putty (see picture below) it works likes Milliput, in respect that it doesn't shrink when it dries, and it cleans up with water, but best of all, it is premixed and in a tube, so you can use as little or as much as you need without any wasted putty! I stumbled across it at my LHS (local hobby store) the shop owner found it at a doll house supply distributor! However, it is from England, and I just checked the Lucky Model web site and they have it in stock there now. I'm not sure if they have it at Hannants.

http://www.luckymodel.com/scale.aspx?item_no=DUX-BD44

20140120_193911_zpsf8d709cb.jpg

HTH

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I'm in the process of filling some gaps (OK, some are more like chasms) in my Italieri 1/72 AC-119 Gunship. I'm trying plain old Testors Contour Putty (in the gray tube) thinned with Tamiya Extra Thin Cement to the consistency of an easily spread paste. I've found that by using tape on just one side of the gap I can neatly apply putty from the taped side. I've been wiping it off right after application with Q-tips dampened with fingernail polish remover (Super Nail, orange). Seems to be working fine. A barely noticeable amount comes off with each swipe of the Q-tip. A couple of observations:

1) The acetone in nail polish remover evaporates quickly, so if you're using it in a small container (as I was), it becomes less effective after a few minutes. The first ingredient on the one I'm using is acetone, and the second is water. It helps to replace the old stuff with new stuff often.

2) There must be something better than Q-tips for doing this job. In my experience, they tend to be a bit coarse sometimes, and other times they shed fibers, leaving them in glue or putty. I've been using an old-fashioned men's handkerchief for some delicate wiping jobs. I'm not sure what it's made of, but I think it's finely woven cotton. I'm going to try using it to wipe puttied joints, and will let you know how that works.

Cheers,

Les

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This Perfect Plastic Putty stuff looks interesting. I found a tube on Amazon for less than $10. There are a few on Ebay as well.

I like Milliput also, mainly due to the water cleanup. This stuff looks more convenient and more liquid too. Milliput is a more clay like which is good sometimes, but sometimes a drawback too.

...but the best product I've found has been Perfect Plastic Putty (see picture below) it works likes Milliput, in respect that it doesn't shrink when it dries, and it cleans up with water, but best of all, it is premixed and in a tube, so you can use as little or as much as you need without any wasted putty! I stumbled across it at my LHS (local hobby store) the shop owner found it at a doll house supply distributor! However, it is from England, and I just checked the Lucky Model web site and they have it in stock there now. I'm not sure if they have it at Hannants.

Edited by dmk0210
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I'm in the process of filling some gaps (OK, some are more like chasms) in my Italieri 1/72 AC-119 Gunship.
One thing I'm finding is, it is often easier to glue strips of plastic(Evergreen or Plastruct) along the edges of poor fitting parts and then sand/file down to fit before gluing them together than it is to putty and sand after gluing together. With practice and patience (and a little luck) you can get parts to fit so no putty and scribing is required at all.
There must be something better than Q-tips for doing this job. In my experience, they tend to be a bit coarse sometimes, and other times they shed fibers, leaving them in glue or putty.
Don't laugh, but try "Eye Shadow Applicators" (little flat round sponge tips on a plastic stick) and "Makeup Sponge Wedges" from the beauty/makeup department of your local dollar store. They don't shed fibers like Q-tips. Edited by dmk0210
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Hey Gang,

I second the vote for Perfect Plastic Putty! No Noxious odor, dries in 15 minutes, and has a very fine surface when sanded. Here in the US, any LHS that buys from Horizon Hobby should be able to get it for you. You can do a similar technique for wing roots that this thread is about, But use water instead of acetone. Thus, no eating of plastic! I am a very happy customer! :banana:

David

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