Model Kit Gap filling tip

[Pat Payne]

I found this technique on the Aircraft Resource Center website (www.aircraftresourcecenter.com) and it works relatively well for filling gaps and seam lines on models.

What you need:

1) clear white paper glue (Elmers' or stuff like it -- you know like the glues they had in elementary school)

2) Warm water (for this, the warmer the better, so long as it's not just plain hot)

3) A paper towel or napkin (something strong--no Kleenex)

4) a model with seam lines or gaps.

What you do is put a bead of glue onto the seam line of the model (don't worry about getting on the outside) completely along the length of the gap. Once you've done this, dip the paper towel in the warm water and wring it out so it's just still damp. Then, run the damp towel over the seam, wiping off the excess glue on either side. (if you've done it right, the glue in the seam will remain.) Let the glue dry (you may have to repeat this process a couple of times for deep seams) and then paint as normal. The white glue will have filled the seam almost as well as putty.

[Gerwalker]

Simple and useful for some seams but you cannot sand vinyl (white) glue and it dries slowly.

For small gaps and even for making new shapes I use the old super glue (cyanoacrylate a.k.a. CA) + Royal oven powder (sp?)

Just put some drops of CA in the seam and some oven powder. The powder makes the curing of the CA to start immediatelly and serves as filler (i.e. adds volume) The resulting thing is soft at the begining and can be cut with an X-acto knife just as plastic. Later it can be sanded, with time it get very hard though not as hard as pure CA. You have a couple of minutes to work with the stuff before it gets hard (this depends on the ammount of powder and the CA quality) This a super fast gap filling technique for those of us that don't want to wait the putty to dry.

I used also for re-shaping: you can make volumes just layer by layer of CA+oven powder in just a few seconds. I repaired a VF-1 wing tip with this technique and finish it by cutting and sanding to the original (lost) shape.

[Less than Super Ostrich]

Just put some drops of CA in the seam and some oven powder. The powder makes the curing of the CA to start immediatelly and serves as filler (i.e. adds volume) 

Could you also use baking powder instead of oven powder? I think I heard someone say you can use it.

Edited March 3, 2004 by Less than Super Ostrich

[Grayson72]

I think you can use baking soda for just about anything, I hear it's the new fuel source for the shuttle as well.

[ewilen]

I've used CA and baking powder to fill rather large gaps and David H. recommends it as well. My problem with it though is that it's much harder than the surrounding plastic, so you must be careful when sanding. Based on one of the above posts, this may not be a problem if you sand before it fully cures. David H. offered another solution, which is to mask before sanding.

[Jung]

I use talcum powder

[David Hingtgen]

Yup, I use pure CA for ALL gap/seam filling. Never tried the baking powder version myself though.

And yes, you should mask to prevent loss of detail when sanding. (Though you often have to re-scribe detail regardless of how you fill seams) Also, always use a curved sanding implement, unless you've got an utterly flat surface. It'll help you sand just the CA, not the plastic.

CA dries funny when used in large quantities, I swear shape affects it more than area/thickness. Timing's important, check it every 30 mins or so. (I let it dry naturally, no accelerator---this way I can get to it when it's 80 or 90 percent hard)

[Gerwalker]

Just put some drops of CA in the seam and some oven powder. The powder makes the curing of the CA to start immediatelly and serves as filler (i.e. adds volume) 

Could you also use baking powder instead of oven powder? I think I heard someone say you can use it.

LTSO: It's baking soda not oven powder as I wrote, sorry. That's why I first wrote Royal oven powder (sp?) because I didn't remember the exact english term... My apologies for my poor english writting.

Just a little of chemistry: baking soda is an alkaline substance and CA cures faster in alkaline media (well at least the normal CA type, there are also acid curing CAs) But the resulting paste (?) is soft during some time.

And YES: you must sand the CA or CA+b. soda or CA + accelarator when they are still soft (as soft as plastic I mean) If you let it cure it gets harder than plastic and you would ruin the model (i did that with an old german sub using gap filling CA when I was first experimenting with this stuff)