using cyanoacrylate glue as a filler/putty replacement...November 14 2017 at 12:29 PM
|ilj (Login IanLJones)|
from IP address 220.127.116.11
I've tried using cyanoacrylate glue as a filler a few times - the result has been deposits of cured glue on the spot to be filled that are so hard as to be unsandable. Working on the CA glue spot with a sanding stick has resulted in damage to the plastic but not the glue - it seems to have hardened into something the stick can't smooth off. The glues used were Bob Smith Industries Maxi-Cure (extra-thick 10-25s) and Insta-Cure+ (gap-filling 5-15s). Any suggestions on how to use CA glue for filling? Am I using the wrong types of glue? I just noted the addition of talc on the 109 details just posted. What exactly are the benefits of CA glue over e.g., Squadron putty as a filler?
Re: using cyanoacrylate glue as a filler/putty replacement...
|November 14 2017, 12:37 PM |
You have to sand it while it's fresh. I rarely use it on anything larger than a seam line since it flows well into small crevices and is easy to work in small amounts.
You have to start sanding right after it sets.
|November 14 2017, 12:44 PM |
CA glues set then fully cure over time to reach the full hardness, 24 hours later it's a lot harder to sand than it would be 1 hour after it sets.
Talc can be added to make a putty/paste to fill larger gaps, it also has the benefit of being easier to sand than straight CA. Something I've done is to mix up a putty out of CA and talc and use it to remold the trailing edge of a wing for example, I'll let it set and then sand it to shape. Then I'll apply a thin coat of the extra thin CA over the area for strength. It fills in any small voids and helps to strengthen the area.
Since CA cures chemically and not by drying like any of the solvent putties you dn't have to worry about thick applications taking forever to dry or the underlying plastic staying soft because of the solvents. CA is much stronger than the solvent putties so it works well for making sharp edges, and it scribes with a much cleaner line than solvent putties.
You got the typical results
|November 14 2017, 12:52 PM |
Regardless of the brand, CA glue cures to a hardness typically greater than the surrounding material, so care must be exercised when sanding it. Many modelers who post build blogs and mention using CA as a filler will note this. You could try using tape to protect the areas surrounding the seam during sanding.
As for benefits, or rather, advantages over some other method, personally I can't think of one. I think it has more to do with personal preference and with a dislike of putties like Squadron white. Some note that Squadron putty shrinks as it cures and don't like the product for that reason.
I use Squadron white to fill seams and have no problems doing so. I thin it with acetone. Either I dissolve a blob of putty in a little glass jar, with a couple drops of acetone, and then apply it to the seam with an old brush. Or I apply the putty to the seam and then use a cotton swab soaked in acetone to remove the excess. Either way, I get the putty into the seam and remove excess, reducing the amount of sanding after the putty cures.
But it's preference. To me, it's less fuss using Squadron white, than to use CA glue. To someone else, the preferences are reversed. And others use other methods than these.
The bigger the government, the smaller the citizen.
I use it for sink marks and small blemishes. I hit it with accelerator.....
|November 14 2017, 2:30 PM |
and sand it immediately, within moments. I wouldn’t let it sit much past 15 minutes.
For me the main benefit
|November 14 2017, 2:49 PM |
is that it cures hard enough that it'll match the surrounding styrene under a NMF paint job. As others have said, it's important to sand/smooth it before it fully cures. I generally hit it with accelerator and start sanding immediately.
If it gets too hard, protect the surrounding plastic with Kabuki tape,
|November 14 2017, 2:56 PM |
and file it down. The rigidness of the metal file with grind through the raised glue and the Kabuki tape will keep the surrounding detail from scuffing. Weirdly, the waxy surface of the tape keeps the file from biting.
When it’s level, remove the tape and sand smooth. I prefer using CA as a filler because it won’t shrink and it won’t react to any paint solvents. With other fillers, often the lacquer in the paint will re-soften the putty and cause the seams or ejector pin marks to reappear.
thanks for all the tips
|November 14 2017, 3:15 PM |
I'm finding the Maxi-Cure and Insta-Cure+ are getting very hard very fast within a few minutes of hitting the spot with the accelerator. I suppose I need to work more quickly as I've been 'coming back later' to start the sanding. I'll do an experiment with a spare cheap kit and try talc, sanding immediately and with the tape to protect nearby area.
cheers to all!
Don't forget you safety-
|November 14 2017, 3:17 PM |
- I am extremely sensitive to sanded CA and general CA fumes, it can bring on a huge Asthma attack, far worse than any other triggers.
I don't know why. But just make sure you are aware
Quantity matters as well
|November 14 2017, 3:21 PM |
I generally don't use putty for any type of filler work. I like Bob Smith Medium Insta-Cure because it seems easier to sand down than the extra thick stuff. My process for filling a seam involves using a bottle cap to hold a dollop of CA and applying the glue to the area in question using a short length of metal wire. This way seems much neater and more precise than just applying straight from the container. After hitting the CA with some kicker (Insta-Set) I use a #15 scalpel blade to scrape away the upper surface of the CA before attacking the remains with some 320 or 400 grit wet sandpaper. For areas that have surrounding detail or are confined and difficult to sand (pin marks in wheel wells come to mind) I make a mini sanding pad using a hemostat. Cut a very narrow short strip of sandpaper and fold it over a couple of times. Grip the folded end of the sandpaper slightly above the fold with the hemostat. Press down on the fold and you have yourself a mini sanding pad that would otherwise be too small to hold and use with only your fingers. As my British friend Tony would say, "Works a treat".
|This message has been edited by davesherrill from IP address 18.104.22.168 on Nov 14, 2017 5:00 PM|
You need CHEAP superglue and talcum/baby powder
|November 14 2017, 5:21 PM |
Just like you see Bret used on the 109 in the kit review today...
You CANNOT use good (as in expensive hobby brand, etc.), thin, fast setting superglues for this!
I buy the 4/pk for $2 at Walmart. It's liquid, but not thin, and most importantly has the NORMAL working time of about 15-30seconds.
Put a small pile of baby powder/talcum powder on a plastic butter dish lid. Put a finger dent in the middle of the pile. Put a drop or two of the superglue into the dent. Mix it with a toothpick to the consistency YOU like: thinner for small fills, and thicker for filling gaps.
You'll have 30secs-1 minute to mix the paste and apply it. Once you master doing it, you can apply the mixture 2-3 times before it sets and you have to start over.
You'll find that you'll need to switch ends of the toothpick and use a new one after a couple of applications as the "set" mix on the end of the toothpick will make the next application set faster, lessening your working time.
The advantages to this mixture are that it's a little softer than straight superglue and can be sanded much easier, even after 24hrs. It also feathers out easier. It even scribes easier than straight super glue!
You can use accelerator, but in my experience, it's seldom needed.
If you've had trouble doing any of the above, it's usually because your superglue is TOO good and sets TOO fast. Go buy some cheaper stuff!
|This message has been edited by slowhandshodges from IP address 22.214.171.124 on Nov 14, 2017 5:22 PM|
|bobby in npt|
great results mixing CA with..
|November 14 2017, 5:28 PM |
resin acrylic powder to make a putty that is pretty soft, much softer than fully cured CA. The more powder added the softer/thicker the putty, more powder also seems to quicken drying time. I saw it in a vid by Paul Budzic(?) and use it for pretty much everything. Yesterdays '109 review also mentions mixing CA with talc powder to make putty...I just don't like the inconsistencies (i.e. screwed myself too many times) using straight CA as a putty..hth...
Wet Sanding CA filler Helps A Lot
|November 14 2017, 6:37 PM |
I keep a small spray bottle with distilled water in it on the bench and use it to moisten the cured filler before sanding it with wet-or-dry sanding pads, sticks or whatever. Water makes the sanding cleaner and faster, and the lubrication helps with the differential hardness if there is any. CA dissolves (slowly) in water, so there is some favorable chemistry too. Polish with an old toothbrush for a final burnish.
Use a nitro methane-based de-bonder.
|November 14 2017, 7:33 PM |
Squirt some debonder on a Q-tip.
Rub vigorously on the blob of CA you want to smooth.
When the Q-tip becomes gummy and saturated with softened CA, squirt debonder on a fresh Q-tip.
Repeat as necessary, until all excess CA is removed.
It's the same basic process as cleaning Mr. Surfacer with isopropanol. Just make sure your debonder is nitro-methane-based, not acetone based, because acetone-based debonders will attack and melt styrene. Nitro-methane-based debonders won't touch plastic (you can even use it on clear plastic)
mix it with talcum powder
|November 15 2017, 7:58 AM |
..the same stuff that was used for babies bottom.....
Put a small amount of talcum powder in a small container, add a drop of CA glue, mix with a toothpick or whatever you will use as an applicator.
The result is a good filler that dries fast, and is sandable, being approx as hard as the plastic...
The only drawback is you can only prepare small quantities at a time...
|November 15 2017, 9:27 AM |
Apparently this material is used by a lot of RC modelers. I tried it once, and just haven't gotten around to trying it again.
If I remember the application process (it's been a couple of decades, I guess), you put down a line of Micro Balloons and then apply thin superglue to the seam, supposedly the glue will travel right down the seam (capillary action?) and then you can sand.
Micro Balloons look like a powder in their container, but they're apparently some sort of microscopic spheres that work as a filler. IIRC, it can also be used to build up short shot wing tips, etc, as mentioned above with the super glue and talc method.
"The more I deal with people, the more I like my dog."
I do what Dave Sherril does...works great!
|November 16 2017, 4:24 AM |