Hint when gluing styrene plastic (e.g. Mercury Redstone capsule)

Most of the Estes M-R capsule is best painted before assembly. Scraping paint from the parts where glue is to be applied is a fiddly operation, especially for holes and especially when your hands are as unsteady as mine...

A simple way to remove paint from holes/dimples: if you have one of those big (100+ bits) sets of drill bits, find the drill that best fits the hole. Hold the bit between thumb and finger and twiddle it back and forth in the hole. Takes off the paint both better and faster than using a knife.

If you don't have the big drill bit set, a set of wire-size #61-80 bits with a pin vise can be had on fleaBay for under $10.

Best -- Terry

Nice tip, but why not mask before painting?

Also, what glue do you use? I've been told by a couple of sources that Tertors red and the like have no use in rocketry, but they are made specifically for polystyrene.

jqavins said:

Testors red and the like have no use in rocketry, but they are made specifically for polystyrene.

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I have been using the Testors red tube to glue my plastic nose cone bases into the nose cone. Have I been doing it wrong all these years?

BABAR said:

I have been using the Testors red tube to glue my plastic nose cone bases into the nose cone. Have I been doing it wrong all these years?

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Not if it works.

jqavins said:

Nice tip, but why not mask before painting?

Also, what glue do you use? I've been told by a couple of sources that Tertors red and the like have no use in rocketry, but they are made specifically for polystyrene.

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Masking a hole that's less than 1/16" diameter is kinda hard. I know there's liquid masking but I don't have any and have never used it. I'm using Tamiya's cements, regular and extra-thin. The thick stuff in a tube is fine for some stuff but with the Mercury it's highly convenient to be able to place the part where it goes, then apply the thin stuff, which wicks into the joint and dries pretty quickly.

I like the Testors liquid cements (in abottle with brush), usually I use a toothpick to place small dots where I want them then put the parts together.

prfesser said:

Masking a hole that's less than 1/16" diameter is kinda hard. I know there's liquid masking but I don't have any and have never used it. I'm using Tamiya's cements, regular and extra-thin. The thick stuff in a tube is fine for some stuff but with the Mercury it's highly convenient to be able to place the part where it goes, then apply the thin stuff, which wicks into the joint and dries pretty quickly.

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What is the purpose of the 1/16" diameter hole?

One option would be stick a toothpick in it (for paint) or a piece of wire in it (for glue) prior to painting or gluing, and pull said piece out after it dries.

The hole matches a small stud on the adjoining piece for alignment. In most cases, the holes and studs (perhaps "nubs" is a better word) are on edges, and I was thinking that the whole edge could be masked. Using narrow tape, the tape would still hang over the corners, but could be left there without causing a problem, I should think.

The smaller-than-1/16" holes that the tower legs fit into are not on an edge; a toothpick probably would have worked on those but not on others such as the ones on the tower ladders and where the escape motor nozzles fit, they're more like dimples. See:
https://modelrocketbuilding.blogspot.com/2015/07/estes-mercury-redstone-1921-build-part_17.html?m=1
https://modelrocketbuilding.blogspot.com/2015/07/estes-mercury-redstone-1921-b-build.html?m=1

Plastic Weld by Plastruct is great stuff. For nearly all plastics, it actually welds the joint (melt the plastics into each other) I used it building my escape tower and then installing the tower on the capsule. Since its the consistency of water, it'll wick into joints and weld it together.

I can see where you would want to paint some parts before assembly, especially the inside faces of the tower structure and the top of the capsule which is inside the truss cage when fully assembled (if it's a different color). Very difficult to paint after assembly, even with a small paint brush.
I've assembled two of the red plastic Estes capsules. While I used the point of a #11 blade to scrape away the paint in the dimples/holes, I'm thinking maybe a tiny drop of white or yellow glue over the holes might work. It won't bond to the plastic, should be easy to peel off after painting. Also, it won't widen the hole accidentally which a knife point or drill bit could do.
Might be easier on your hands. Maybe someone can try it and let us know?
Laters.

I build a lot of plastic models and paint a lot of the parts before gluing.
Found the easiest way to keep the paint off the mating surfaces is to brush Elmer’s white glue on and let it dry. Paint part. Then when paint is dry just peel the Elmer’s off and glue.
Easy

KILTED COWBOY said:

I build a lot of plastic models and paint a lot of the parts before gluing.
Found the easiest way to keep the paint off the mating surfaces is to brush Elmer’s white glue on and let it dry. Paint part. Then when paint is dry just peel the Elmer’s off and glue.
Easy

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Thank you!

KILTED COWBOY said:

I build a lot of plastic models and paint a lot of the parts before gluing.
Found the easiest way to keep the paint off the mating surfaces is to brush Elmer’s white glue on and let it dry. Paint part. Then when paint is dry just peel the Elmer’s off and glue.
Easy

Click to expand...

Wish I'd known that a week or so ago... oh well, I know it now!

"More education is almost always better than less" -- T. McCreary, in Experimental Composite Propellant