What to use as a filler?


goscrewyourselves

goscrewyourselves

I'm the one
What do you guys use to "Fill Gaps" in styrene joins?

I have read about a lot of things from melting styrene rods to Bondo to Tamiya Putty and so on. I've used Tamiya Putty on aircraft models and didn't really like how it ended up. I'e also used Bondo for its intended use but not sure how that will react with styrene or ABS.

I should add, the gaps I know will need to fill are going to be small. The plan is to "drill" a hole in styrene large enough for an SMD LED to fit into. Because the LED is rectangular, there are going to be very small gaps between it and the styrene. They are the gaps I want to fill. Whatever is recommended will also act as an adhesive for the LED, or at least that is the plan.
 
I just picked up some Plastalina non-hardening modeling clay last night. I was thinking about placing it the areas I wanted to fill to block light and even use it to hold the structure to the flooring. This will allow for movement of pieces, more for wood than plastic, with temperature expansion and contraction and a then the structure can be removed from the flooring which I will mount to the layout. I'm sure over time the clay will dry out and harden but shouldn't be much to remove and replace. I went this route due to the fact that this layout will be moving in the next couple of years and again 3-4 years after that so I wanted non-permanent. Just a thought.....
 
I'll butt in here seeing the question is about SMD's and ask if they can be glued by their emitting face to the end of a plastic light pipe and with what if so?
 
Tony,

Will these be visible? If there not than black silicone might work. It would let zero light through, and it would definitely be a good adhesive.

A quick question since you have Bondo experience. Does it sand well? Why I ask is on the seams of my backdrop I wanted to fill in the gaps between sheets before taping them. I heard bondo might be the ticket for this as it sticks to everything, and it dries solid.
 
tootnkumin said:
I'll butt in here seeing the question is about SMD's and ask if they can be glued by their emitting face to the end of a plastic light pipe and with what if so?
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Yep, they probably could be using CA to do so. The LED is only a few mil long and a couple wide, so they are anything but big or obtrusive.

I intend to "counter sink the lights" (like down lights) though. Firstly for aesthetics and, secondly and more importantly, so the LED is securely in place for when I solder the wiring to them. My "plan" is to have the face of the light flush (or close to it) to the styrene with the rear of it sticking up a bit for the wires, if that makes sense. So it will be the very small gaps around the sides of the LED that I want to fill.

One other thing, the lights will inserted to a non kit piece of styrene that will put in beneath the roof of the structure and painted (obviously) the same color as the roof.

migalyto said:
Tony,

Will these be visible? If there not than black silicone might work. It would let zero light through, and it would definitely be a good adhesive.

A quick question since you have Bondo experience. Does it sand well? Why I ask is on the seams of my backdrop I wanted to fill in the gaps between sheets before taping them. I heard bondo might be the ticket for this as it sticks to everything, and it dries solid.
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Some will and some wont be visible so your black silicone idea is a good idea.

Bondo ... yep, it sands very well BUT you need to start with a decent grit paper like 600 or 800 as it gets very hard. I then work my down to finer papers like 1200, 1600 and finally 2000 grit to get a very smooth finish. You probably wouldn't need to go that fine for your job though.

Bondo also "sticks well", as it should. I have never used it with wood but see no reason why it wouldn't adhere just as well. The only thing that "might be" an issue (over time) is it cracking if what it is adhered to moves a lot or dramatically. Theoretically though, if your fill work is good, meaning you get it leveled out and as smooth as the surrounding surfaces, then you possibly wouldn't need to tape over it.

One thing you need to keep in mind is Bondo needs something to adhere to - it is an automotive filler and is generally applied to the damaged area fairly thickly to attain that bond. The edges of the "damaged area" are also flared/beveled out with the Bondo over lapping the "solid" material. What I am getting at is I don't think it would be any good for small or shallow gaps in terms of longevity.

Generally, it looks as though this Squadron Putty (Green) is what I will use. One tube of it will last me a lifetime I think and hope :)
 
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It will not last a lifetime, I have gone through a few tubes of Squadron's Putty as the stuff seems to simply harden over time. Keep the cap on as tight as you can get it and clean the putty from the neck and cap threads as best as you can.
 
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I like Mark, aka NP2626, use Squadron's Putty which provides an excellent seam filler and can be sanded painted without effort.

Keep the cap on tight to ensure product freshness. I have a tube of the putty that is at least 10+ years old.

I use a finger to smooth the putty and once dry I use fine sanding medium.

Thanks.

Greg
 
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bnsf971 said:
Why not use Testors styrene cement? The stuff in the tube, not the real liquid stuff.
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Blobby, stringy and attacks/melts plastic. Probably not the best choice for filler.

Body putty (like Bondo) actually works pretty good, doesn't attack styrene, can work into precision areas with a toothpick or palette knife, sets well, can be filed/sanded down easily enough (although it is harder than the styrene).
 
I am also in the Squadron Putty camp. They make several kinds with different formulas and different "work" times. I always try to over fill and sand rather than trying to make it smooth to start. This is because it shrinks a tiny bit as it dries.
 
Okay, seems as though everyone is going with their Green Putty so that is what I ordered - 4 X tubes. Hopefully it'll turn up by the end of this coming week :)
 
wombat457 said:
Thanks Horseman, I'll make sure to take a careful look at the various types before buying. Which "variety" would you recommend?
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Ha! I don't remember... It gets to be too long between usages. I thought there there three variations. Green is definitely the most common, but I also have red and orange tubes. Looking closely now they both say "white putty" on them. I don't see any other difference. Must have just changed the packaging through the years. It must have been some other brand I was thinking of that was not "fast drying".
 
No problem as you said, the Green seems to be the most popular so that is what I went with. I also didn't see any difference between the Green and the White other than the color. I thought one may have been quicker drying than the other but if one is, I didn't see it written any where.
 
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