Using Testors Molding Putty

Heat does mean the strength/penetration/reaction level of how the solvent interacts with the styrene. The hotter the more it actually melts the plastic.

Leave a tin of Weld-On open near a plastic model on your bench and two things are certain to happen. The contents of the tin will evaporate quickly and the plastic will melt like a chocolate Easter bunny in a microwave.

The faster liquid solvents/cements evaporate generally the "hotter" they are. I use a "working bottle" when I use Weld-On...I transfer a small amount to this bottle for two reasons.

One, most of you HAVE or WILL tip over a full or nearly full bottle of your solvent on your workbench. BTDT myself! By transferring a small amount to a smaller container, I reduce the chance of doing this 100 fold.

I refill my Touch N Flow from this amber working bottle, resealing it and setting it up in a spot near my bench where I won't knock it over! If you get in the habit of setting such things in a place where they are within easy reach but not subject to being knocked over and damaging or possibly ruining your project the happier you will be.

Like beer solvents will break down under light especially UV light. The amber bottle protects them. These are available from my website if you're interested. I transfer from the tin can to the bottle using a large/long glass eye dropper which I sourced from the local drug store. You can also use pipettes used for paint mixing. NEVER try to pour from can to bottle, you'll not like the consequences. You spill more than you transfer.

B52CrewDog

When you say "low heat" you are talking in the context of plastic models yes?

The  liquid cements work by chemically melting the plastic in the areas to be bonded. I believe Gerald's reference to "heat" in relation to liquid cements is not so much in relation to physical temperature, but more relative to how aggressive the solvents in the cement are to the styrene being bonded.

For example, the Testors "pink label" liquid cement is a relatively "low heat" cement meaning it's rather mild and slow acting, which gives you more working time but may not give the best bond. Tamiya l"Extra thin" iquid cement is "hotter" than Testors and the Weld-In and Tenax mentioned above are "hotter" still.

When you say "low heat" you are talking in the context of plastic models yes?

Tube glue definitely not. Most entry level liquid cements are mild and when you weld with low heat you don't get the penetration necessary for the strongest of welds. I use Weld-On #3 or Tenax .

I will take a look at 3M Actryl series.  About the article, doesn't Testors glue "weld" or melt two pieces of plastic together also?

First of all TOSS THAT CRAP! its junk!

Do your homework, read this post and its related links. Perfect Seams

Then acquire yourself some of the 3M Acryl series of automotive glazing putties...much better than that Testors peanut butter.

I am sure that just about everyone will give you a method for this, and I am by far no expert but here is my humble version of how I tackle the hated fuselage seam.

I follow the same basic procedure as you described above.  When the fuselage is dry I take a wide strip of sand paper on a block (1 inch or so) and sand the seam down until it feels relatively smooth.  I don’t worry too much about panel lines since I re-scribe any that I knock off later.

Next I run a light bead of putty, I usually use the Tamiya grey putty since it just seems smoother to me, and I mold it with my finger and let it dry.

Once that is dry I work with successively finer grit padded sanding sticks to shape the dried putty paying careful attention to (as best I can) feather the edges away from the seam.  This is the part that I consider the most key to the whole process.  If the putty seam only covers over the plastic joint it will hump-up slightly and may be visible under the paint.  Feathering it down as best I can helps to hide the profile of the putty and blend it into the curve of the fuselage.  I use the padded sticks because they usually give you a great softly rounded profile that hard surface sanders just can’t.  That is also how I compensate for the slight flattening when I do the initial sanding.

Once that is done I give the thing a quick shot of primer to see how it will look with paint on it.  If the results are not satisfactory I go back to work, use steel wool to remove the primer, and add another skim coat of putty working in small increments until it looks as smooth as I can get it.

When I finally get it to that near mythical perfect smoothness and profile I re-scribe the panel lines and move on to my other arch nemesis....wing roots.....

Hope that helps and I can’t wait to see what others do.  Good Luck!!