What type of plastic is a YF-19 made of, and how do you glue it?

[David Hingtgen]

Sigh, my YF-19 leg popped apart at the seam again. You know the place---just ahead of where the tailfin slides---there's a glued peg there that is guaranteed to break if you ever open up the leg. And that means its almost impossible to get it to close up nicely again.

Superglue is too brittle, doesn't work at all. Large quantities of standard model cement/glue allowed to dry for a week----works for a little while (up until tonight). And standard model glue clearly doesn't affect YF-19 plastic much--it doesn't "melt" it at all.

Is a YF-19 (tan parts) ABS? Will Plastruct glue work on it better? Is there a special ABS glue? (maybe for plumbers?) Perhaps epoxy? What the heck does Yamato use? I'm going to the hobby store tomorrow, so I'm open to suggestions---I want something that will REALLY hold the leg halves together. (part of the problem is the sliding fin--as it goes forward, it tries to split the halves apart---can't make it looser---then the fin won't hold in place--it's a fine balance between too loose and too tight---I tested it a dozen times while and after drying, but just tonight when I transformed it, I noticed it was open again)

I'm going to use a pin this time to try to help replace the peg, but there's so much stress on that seam--I bet the pin will pull out, rather than hold the leg halves together.

[Valk009]

If you are talking about the Yamato 1/60 YF-19, your best bet is to ask Graham.

When he showed us the prototype he mentioned that Yamato used various plastics and some fins were out of a new kind of plastic, very tough, yet flexible. i believe it is called "POM".

[David Hingtgen]

Graham's review says mostly ABS. The only POM is the canards, and possibly the "pale grey" parts.

Thing is, there's many types of ABS (just like there's many types of styrene). All react differently to different glues. Plastruct Weld is supposed to work with ABS well, but it's very thin and has no gap-filling ability. I have read raw acetone is good for ABS welding, but will not work on many variants of ABS that have anything else mixed in with them--and I have no spare YF-19 parts to experiment with really.

[Valkyrie addict]

oh man, the YF-19 just won't forgive some people with its problem... errrr...maybe you should try that glue that's black that's suppose to glue anything together, but I don't know the brand...sorry, wish I could be more help

[QuinJester]

I"m surprised a CA + accelerator combo doesn't work on it. That stuff will glue ANYTHING. Maybe a two-part epoxy, drilling a small brass pin into the broken pin area to hold it in place?

[David Hingtgen]

I'm currently pinning, that'll be superglued into the hole (as nothing really holds metal at all). Planning to try Plastruct Weld for the rest. If that doesn't work, probably an epoxy.

[GreatMoose]

You can never go wrong with JB Weld (or JB Qwik in this case).

[jardann]

You might try the stuff plumbers use for ABS pipe. I had some plastic cards (ID card blanks) that I wanted to use, and the plumber's adhesive was the only thing that could bite on them. It is quite "hot" though so you want to be careful.

Epoxy or JB Weld might be easier to work with and should work pretty well too. Is there any room on the back or inside of the parts to build up a little bit of epoxy? That might add strength.

Good luck!

[winterdyne]

Can you put up a pic of the damaged part and how it's meant to close? I don't have a '19 but I'm generally pretty good at making fairly invisible repairs...

EDIT: Do NOT attempt to make the repair with an untried solvent! If unsure, try a little with a q-tip / matchstick on an inside surface. If the plastic melts too much you'll just end up with a wider gap that's harder to hide.

Edited August 5, 2008 by winterdyne

[David Hingtgen]

Here's pics of the halves, "almost together" and fully together. It actually holds together quite stiffly by itself--it's when all the other parts come into play and transforming it that it splits open, right where the pin is (just to the left of center in the 2nd pic) (There's a glued plastic peg there from the factory to hold that spot closed---but if you ever open up the leg, that's destroyed)

[Valkyrie addict]

maybe you should contact MW member Ghostkiller who did a sweet looking supernova YF-19 custom and I'm sure he had to put this piece apart and reglue

[David Hingtgen]

A small test inside the leg shows that Plastruct Weld definitely is a solvent to it--it got soft in seconds. I just wonder about gap-filling abilities, etc, as it's one of those "evaporates instantly" glues.

[Wicked Ace]

I dealt with this issue, too; however, I cannot recall what glue I used. I no longer have the tube, because the contents dried out on me. Also, I used a pin.

[winterdyne]

From what I can see you've got plenty of space to work with. This is assuming that you want an 'invisible' fix. Takes a bit of work, but this should be pretty indestructible when you're done. I'm also sure some of this is second nature, but to some folks it might not be.

I'd suggest you glue (with epoxy or something else very strong) some blocks of plastic up to just under (.5mm) the level of the mating surfaces on both sides of the leg. Don't forget to roughen the surface first - scratch and burr it up with the point of a knife.

Next - Pinning. Pinning is best done by having the wire clipped into much longer lengths than needed (but small enough to handle - about 1inch / 2cm is fine), then once glued into the first set of holes, use a pair of wire cutters to snip 'em to the right length.

Drill pin holes straight in to a depth of about 5mm. Apply a small amount of epoxy to the holes, and insert pins. Clean any excess by drawing it with a toothpick toward the inside of the part. This stops strings being draped over the visible bits of the part.

Ensure they're straight, allow to dry then clip, leaving around 3-5 mm exposed. Now 'ink' the ends - put a spot of (oily) paint on the exposed end of the pin, and fit the part. This will mark on the other block where you need to drill for the pins to go in. Dunno where I learned this, nobody else I know does this, but I find it really useful.

Drill those *slightly* deeper than required and apply epoxy to the surface of the block with a toothpick, covering the holes, and bringing it to the mating surface level. Do NOT apply epoxy to the other block Again, work towards the inside of the part. What will happen is when you assemble the part the pins will push a little (enough) of the epoxy into the hole to hold them in place and the remainder should be displaced upward to contact the other block without having so much that it oozes out and makes a horrible seam.

Hope this helps. :-)

Edit: Just because the solvent softens the plastic doesn't mean it'll glue it. Otherwise everyone would use paint stripper instead of plastic cement. The question is does it go tacky, or just dissolved? I strongly suggest an inert adhesive like epoxy or CA.

Edited August 6, 2008 by winterdyne

[David Hingtgen]

Thanks much for the info/tips.

PS---I use paint on the tips to mark where to drill, too.

[MechTech]

Dave, the Plastruct stuff should work! I've been using a little ABS angle for the Daedalus and Duro superglue stuck right to it too! Not brittle or anything!

If you're having gap issues, you may be able to scrape some etchings from the inside of the part and mix it with solvent. Just putty it into place and sand a couple of days later. All that provided you haven't "Done the deed already. - MT

[David Hingtgen]

Part of the problem with the -19, is that the finish varies from part to part. Some are VERY pebbly, some like fine sandpaper, some "very smooth but not glossy smooth". Sanding has a very polishing effect on the plastic.

I have currently glued the blocks in like Winterdyne suggested, and added plastic pins. I did a test and the metal pin held in with CA came out way too easily. I figure using plastic pins in plastic blocks will actually have a better bond. Going to let things dry for a day, then will glue halves together tomorrow. Plus additional applications of Plastruct Weld to the blocks tonight to try to REALLY get the blocks to stick to the legs---that'll be the weak point I think. I'm also trying to encase the blocks in superglue as backup.

[David Hingtgen]

Well, Plastruct Weld's 3-sec working time was an insurmountable problem--even taping all the interior pieces in place so I didn't have to worry about them, it still took too long to apply cement, get things lined up, and get it together---the glue always dried before the pieces were in place (except for one spot). (applying glue "to the joint" was not an option here) I ended up using Testor's cement for the styrene-to-styrene pins, and Plastruct for everywhere else, hoping SOME Plastruct would work and hold.

A quick experiment from yesterday showed that while Plastruct Weld does make a much stronger bond for styrene to styrene, it will break cleanly and suddenly. Testor's will stretch and give long before breaking--which is actually what I think I need for this joint.

So in the end, I basically ended up using Plastruct to weld styrene onto the ABS leg parts, so I could then use "normal" glue to glue the styrene parts together, thus holding the leg parts together. Directly welding the ABS parts together just wasn't going to happen---not invisibly at least, and not without being able to access the interior while gluing.

Since I used copious amounts of Testor's in spots, I'll give it a week to dry. Or two. Heck, I might wait until September.