I'm workin on that bust I have a WIP for and for the life of me I just cant get it smooth, no matter how many times I sand it and put putty and thinned putty it just always seems to have mars and marks, how do you guys do it?

This is cured putty right?

I use a fine grit sand paper, then give it a once over with scotchbrite (grey) that clears up any scratches and marks. I used to use steel wool but it was wrecking the washer with rusty bits.

linky: http://www.amazon.com/Scotch-Brite-..._8?ie=UTF8&s=industrial&qid=1262977232&sr=8-8

For putties like Aves, Magic-sculpt and A&B it have always used a small, soft flat brush and Isopropyl alcohol (at least 90%). I find this is better than water because it evaporates faster. You can get the stuff very smooth using that method. I have even gotten my putty smooth enough using this method that it did not require any finish sanding.

One thing to be sure to do is to thuroughly clean the brush or the thinned putty will set it up hard as a rock. I also use it sparingly till I get the results (i.e. don't overload the brush with the alcohol). This keeps the surface from getting too slushy.

Cheers,

Mark.

I seem to be missing a complete step then. What are you using the brush for? When are you using it?

While the putty is uncured, you can smooth it. It's very similar in action to how you would smooth clay on a pottery wheel. Same idea just no rotaion. If it is cured putty then sand paper, files or machining is the route you go.

PM me your email and I'll send you a PDF of the documentation I hand out when I teach my epoxy putty class at Wonderfest every year. It includes images showing you what I mean...

Cheers,

Mark

Will do.

See, I am sanding it over and over with fine grit sandpaper and it isnt even taking fingerprints or anything off, some yea, but others no.

Also, for a medium, im using milliput to sculpt

Milliput is OK, but Magic Sculpt or Aves or even Kneadatite are all better putties for sculpting IMO. As far as smoothing, I'm using a mix of alcohol and oil in a hair tonic called Vitalis. I use the same technique of brushing it on like Mark. I also have to use steel wool once in a while.

All the best,
Dan

So you brush the alchahol and oil on it while its still curing to smooth it out?

I can't really advise you on the use of Miliput having never been able to master the stuff myself, so the following will be reference to those individual putties listed. But, first thing I thing would be to keep the finger prints from getting into the putty to begin with, make up some sort of handle and don't touch the actual work. A simple wood dowel with a pin in the end works nicely for smaller pieces, for larger ones it might be well to use a block of wood or even larger diameter dowel. Just remember that this thing is meant to be a handle so should fit comfortably in your hand.

Smoothing Magic-Sculp can be accomplished with water, saliva (bad practice I think), lip balm (this was Quang's idea and works well), and the various other things already mentioned. Water would be my personal preference, it doesn't cost anything to get from the tap and works wonderfully well so long as you keep your smoothing brush only damp with it and not wet. You won't want to flood your work with water it is a bother, sometimes damages the putty if still very soft, and makes it difficult to see what you are smoothing. All this applies as well to MS blended with GS (green stuff-kneaditite).

For A+B putty, water when soft, Acetone in a pinch, especially if the putty has begun to cure before you've had time to smooth. Just remember not to do more than dampen your brush with it, this stuff, like water, is a solvent and will dissolve your putty and make a mess if you use too much. In fact all the things, excepting perhaps the lip balm, I've heard recommended for smoothing are solvents in a way.

For myself I hardly ever file or sand, and almost never on a finished surface-But when I do I finish off with nothing finer than 320 grit sand paper. For a final glossy slick finish, which I don't think necessary if the original is to be painted, I simply spray-lightly, very lightly-with Testors Gloss Coat. This stuff, if properly used, puts on a very thin film of paint, thin enough that it has no discernable effect on the details of even the smallest pieces. The only reason I can think to seek a shiny finished surface is for reproduction and that only because molds used for resin casting seem to cast better with a slick, shiny surface than not. In all cases I don't think I'd be at all concerned about the putty being discolored or dirty in appearance. After all, the finished piece is either going to be used to make a mold or be itself painted so who cares, or will even know?

Were it me I would switch putties and use something like Magic-Sculp or Aves, or as a last resort A+B putty. However, as there are those that have great success with Miliput if you are one of these then I would stick with it even knowing that MS and Aves are a better bargain overall and will keep longer, thus making them more economical in the long term.

Finally, try to use a good quality brush-and keep it clean-for smoothing. Brush lightly in the direction of, say a fold, and across the thing only to remove any light brush marks you may have left with the main brushing. You might also do a little light shaping with a dampened brush when the putty is very soft, especially useful for truing up a seam or the edge of clothing.

Good luck, and I hope this hasn't been preachy and helps a little. If you have any additional questions please ask some one of us is likely to have an opinion or technique they favor.


Ray

I'm with Ray on this. I don't doubt that other solvents (or lubricants) work well or better; but for me, when a putty's already water-soluble there's not much of a contest.

This is especially true with milliput. The solubility was one of the properties that put me off it and IMO needs more patience and a delicate touch if you stick with it. Also, I'd say it's more easily smoothed when it's allowed to cure a little, but that's with more physical smoothing using metal tools and clay shapers.
(Although since I last mentioned milliput, I tried the five types and I'm coming round to it again. The black stuff has an interesting texture)

I used needle files on an apoxie mix yesterday, then polished it with 1200 grit paper. I have to say it left the areas around the file scratches very smooth. I think the both of us need to introduce another step or three. And avoid touching uncured sculpted areas.

I smooth Aves Apoxie Sculpt with hand cream or body lotion. I gave up on
Milliput years ago. After the putty has cured and I'm ready to spray with the
rattlecan the light grey primer, I first was the figure with soap and water
of course. I was surprised that the body lotion/hand cream does not leave a
residue.

Jaybird

Thanks for all the replies guys.

When I say smooth I mean more then the feel, but the look. I can hit it with a file then high grit, itl be smooth as a baby's bottom but the scratches are still a bit visible even after using a few coats of squadrin white putty for filling gaps and priming and sanding down...

Personally I think that Squadron putty (otherwise known as spot putty) sucks, I wouldn't use it for any application I can think of. For patching I'd much prefer A+B putty smoothed with acetone. Spot putty can also be smoothed with acetone, however your smoothing is a waste of time while wet because spot putty shrinks as it cures, A+B doesn't. From my experience, other's may have had different experiences, A+B is about the easiest putty to smooth and blend. Like all the air cured putties I've tried A+B can be burnished when almost hard with a hard smooth tool which results in a very slick smooth finish. But again, why struggle for a smoothness that is greater than the primer that is going to be used before painting?

I can't knock Sculpy or the other polymer putties because so many have gotten such excellent results using them, but for me they just don't work so well or easily as the air-dry stuff. Also, they do not set up as hard as air dry putties and seem always to be a bit porous even when cured, which would seem to make it more difficult to get a slick smooth finish. Another thing against Polymer putties that really favor the air dry varieties is the polymers don't have stages of hardness ranging from soft to hard as with a single mix of air dry putties. For me smoothing is easiest when the putty is nearing a stiff state, it is less soluble in this state and won't move around much with a quality brush dampened with water (that should be good quality synthetic brush).

In the end the important thing is to find the putty that works best for you and develop your techniques and tools around it. These things that work well for me may not work at all for others, as some of others techniques don't work at all for me. For instance, Gordy and Miliput, Gordy makes beautiful pieces with Miliput while all I am ever able to achieve with it is a formless mess, same with straight Green Stuff, if simply doesn't work for me. I suspect that those putties that do work for me, do because I started out with A+B got used to it and find the other putties like MS to have similar working properties.

Hope this helps some or at least gets a laugh,

Ray

I know it sounds a bit trite but my main advice on this front is to try not to have to - aim for a finished surface that doesn't require any further work. It's very doable and saves a lot of time and effort.

If you primarily use hard tools for shaping the putty when soft, then they need to be smooth (and free of dried bits of putty) as only a smooth tool can leave a smooth mark. If your tools are polished - shiny smooth - then you can achieve a similar finish on the cured putty, with the right methods.

Use water or other lubricants if necessary - sometimes a swipe with a wet fingertip works better than anything - but I would recommend not becoming over-reliant on a wet or damp brush to smooth things off, unless you then work over the surface a little with sculpting tools.

What grade of paper are you using? Dry or wet?

In addition to paper I too also strongly recommend steel wool and/or Scotchbrite or similar (the green nylon scrubbing pads for the kitchen can be essentially the same stuff as Scotchbrite, although maybe not as fine as you'd need, in which case you can then switch to 000 or 0000 steel wool).

FWIW you're doing the right thing here, judging visually, rather than by what you can feel with your fingertips - it's totally possible to have scratches that the skin can't feel but are clearly visible even after priming.

I too would suggest steering clear of filler putties when working in epoxy - aim to do everything with the putty, as much as possible.

Seconded - this is a surprisingly obvious thing that's very often not given as advice but it can be a huge help.

Einion

Enion,
Informative as always, thank you.

Now, to reiterate, I still 'almost' never resort to any kind of sanding on finished surfaces. when I do it is generally because I failed to adequately blend two separate applications of putty. This failure to blend is most often do to my attempting to stretch the life of a given batch of putty past the point where it is still easily workable, ending with a very slick and smooth surface on with the over hard putty but one that won't blend into previous applications.

When I do have to mechanically blend cured putty I'll use 320 grit sand paper and scraping with the edge of a sharp hobby knife. For hundreds of years cabinet makers only had 'cabinet scrapers' for smoothing as no sand paper existed, and they work wonderfully well on wood, and the same process (with an x-acto blade) works as well on putty when the knife blade will fit the area to be smoothed. Besides, as you know I'm mostly doing smaller scale figures so sanding, filing, and scraping just aren't going to fit most of the work, it being so small. This may be the actual reason more than any other that I've put so much effort into developing alternative techniques and work extra hard at not creating putty messes that need to be finished off mechanically.

As always I am not detracting from others techniques, instead I'm attempting to offer an alternative, one that works well for me.

One thing we do seem to have in common on the smoothing front is the use of hard tools, opposed to brushes, for the process. Absolutely you need a smooth shiny tool to achieve same on the putty being worked. It is a must to keep your tools clean and without dents or other blemishes. Also, once the brushing is done it is often useful to come back with that smooth shiny tool to do the final smoothing and shaping. Of course this is the time when a really light touch is most critical or tool marks will result and you'll have to get the water/solvent back out to try again.


Ray

It's amazing how much comment this thread has generated! Tremendously helpful stuff - things I want to try. Thanks everyone!

All the best,
Dan