# Sandpaper grits...



## charonjr (Mar 27, 2000)

Hi Guys, 

I'm a newbie with airliners (1/100) and am working on several. After gluing the hulls together with Testors, there is a bead running along the seams. I tried adzing them off, then tried shaving them off, only to bring nicks into the plastic and some inadvertent planing. I did try 120 grit only to learn that gouges as bad as the x-acto blade. What a mess! 400 is almost as bad and doesn't remove the bead at all.

What grit should I use that won't gouge the plastic with scratches and yet get rid of that bead? Also, while gluing such large pieces together, is there any way to do it in sections or am I stuck with running glue over the entire hull or wing seam and then doing my best to mate and rubber the parts together?


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## djnick66 (May 2, 2008)

YOu have a few issues going on here...

Testors tube glue (not bad but you get the glue ooze) dries very slowly. So, you cant try to remove the excess for a few days. Otherwise, its still soft, and the plastic that it melted to get a good bond, is still soft.

I use thin, liquid, brush on glues for 95% of my general plastic building. Stuff like Gunze Mr. Cement S Type, Tamiya Extra Thin Cement, or even Testors Liquid Cement (the stuff in a jar not the squeeze bottle). Those glues are quicker than tube glue, dry faster, and make for cleaner seams. You can also hold two parts together and flow them down the seam from the outside. For larger parts you can glue them in sections. Apply some glue, squeeze, align and then move on down the joint until its done. A plus with liquid glues too is that instead of getting oozy glue out of the joint, you (if you want it) can get a beat of melted plastic to form long the seam. Let that dry over night and just trim or sand it down and you have eliminated the need for putty/filler. One type of seam that I do use tube glue for, are very large halved parts like the hull halves of big warships, or the big Mongram 1/48 bombers. I apply a thin layer of tube glue to each half of the part, let it set up a minute or two, and then press the two halves together firmly. This is called dry gluing and its good for big seams. I figure on those kinds of joints I am going to have to putty and sand it down anyway, so this is a good way to get a fast, strong, holding bond.

As to sanding, You really want to use wet and dry paper. The black/grey stuff, and not the tan paper for wood. Water makes the sanding much smoother and more akin to polishing. I use 350-400 for most general sanding where I want to cut something down fairly fast. Finer grits are good for polishing and smoothing and removing the marks left by the coarse stuff. I buy my paper at Ace Hardware by the sheet.


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## John P (Sep 1, 1999)

I think sandpaper grits are best served with eggs.



What?


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## irishtrek (Sep 17, 2005)

When it comes to sand paper the lower the number the more course the sand paper, like 60 grit is more course and than say 120 grit. If you want an extremely smooth finish go with say 1500 grit which you can find at True-Value if I remember correctly. Anyway it's best to first sand with 60 grit and the 120 followed by 400 grit and so on....
Hope that helps.


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## charonjr (Mar 27, 2000)

Yes, guys, this helps a lot. I had forgotten much of that information, which was last used 19 years ago on an Excelsior kit. I am glad you guys are here. Hopefully I can rescue my L-1011, DC-10, 707, 727,737,767 kits from my ham-handedness!

Oh, and John, I prefer my eggs green....


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## charonjr (Mar 27, 2000)

Oh, found some Tenax 7R in a box, how is this stuff?


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## robn1 (Nov 17, 2012)

Tenax 7R is good stuff, dries very fast. But it evaporates like alcohol so don't leave the cap off longer than needed.


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## djnick66 (May 2, 2008)

Tenax is great when you can find it. It is pretty hot but dries and evaporates quickly. Apply it with a fine brush.


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## John P (Sep 1, 1999)

Tenax is the best. Hold the parts together, let the Tenax suck into the seam by capillary action. It's dry in minutes and you can sand the seam almost immediately.


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## charonjr (Mar 27, 2000)

Thank you! Will try the Tenax. Oops! I looked....


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## charonjr (Mar 27, 2000)

Nuts! Should have read the bottle. Not Tenax, bad memory engram. Used to have Tenax. This is Plastruct Weldene. Hopefully, in essence, the same stuff.


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## John P (Sep 1, 1999)

Slightly different, but just as good.


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## djnick66 (May 2, 2008)

Ehhh I don't care for Plastic Weldene. Plastic WELD is great. Weldene is their non toxic stuff and its crap, IMHO.

If you can find it, Ambroid Pro Weld is also very very good.

Or, cut to the chase and buy a quart of MEK Methyl Ethyl Ketone at a hardare store. It's essentiall the same stuff and is/was the active ingredient in a lot of the solvent type glues to start with.


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## charonjr (Mar 27, 2000)

Oh SWEET, djnick66! Ace Hardware is just down the street and has MEK. Thank you!


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## djnick66 (May 2, 2008)

I just put some MEK in an old Tamiya glue jar and use it that way. If you were using it in an industrial application, its pretty harsh stuff and you would want to take some precautions with it. But, as a cement, its no worse than, say, cement... I use it now and then to clean and degrease firearms too. It's pretty versitile stuff.


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## Owen E Oulton (Jan 6, 2012)

Tenax and Ambroid Pro-Weld are *NOT* the same as MEK. MEK is Methyl Ethyl Ketone, the same stuff as Testors Liquid Cement. The hotter ones like Tenax areMC, or Methylene Chloride, which can be found at plastics wholesalers where it is used to glue acrylic sheet. It also glues styrene and ABS. Itll glue these plastics to themselves or to each other, while MEK will only glue styrene to styrene and won't touch the other plastics. MC will evapourate very quickly and set fast, as described above. MEK bonds slowly, but just as permanently, and allows some time for positioning. I've found that with tiny parts, MC may melt the part, and MEK is more forgiving in this regard. If you buy a large jug of MC is a polyethylene jug, transfer it immediately to a glass jug, as it will evapourate right through the polyethylene jug.


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## Modlerbob (Feb 10, 2011)

Micro Mark sells MC aka Tenax7 or Ambroid Pro Weld in their own bottles and call it Same Stuff. It is a larger bottle and is cheaper unless you are only ordering the glue, then the shipping charges bring the price up. I have been using the Same Stuff from Micro Mark for about two years now and like it very much. You can also get a great variety of sandpapers and sanding sticks there as well.


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## djnick66 (May 2, 2008)

No one said it was chemically the same. But, for modeling purposes it is/does the same thing. And, MEK is/was the active ingredient in a lot of model cements like the old MEKpak glue. You can buy a tiny 1 or 2 oz jar of the branded glues for $5 or a quart of the stuff for $7. It's a good, economical purchase.

Micro Mark is an interesting place. They have a lot of stuff but also seem to be the pirates and recasters of the hobby tool business. Lots of branded stuff like specific tools, glues, 3D resin decals, etc. have started turning up as, what seem to be, bootleg knock offs sold by MM.


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## Owen E Oulton (Jan 6, 2012)

True, but I just wanted to make things quite explicit. Chemistry is funny stuff. There are some important differences between MEK and MC. MEK, the same stuff as Testors Liquid in the purple-labelled bottle is best for novice modellers, as it is more forgiving. Both have their uses, and most really advanced modellers like to use MC. Finescale Modeler did an article several years back evaluating the various liquid cements and decided that tyhe ultimate plastic glue was a 50/50 mix of MEK and MC. Never tried it, but that was their suggestion.


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## djnick66 (May 2, 2008)

To some extent I agree. But if the poster is buying welder type glues (that are expensive) he might as well buy a can of MEK and cut to the chase. Otherwise, the common Testors stuff is "okay". I think I quit using that back when it still came in a square bottle, though.

I find Gunze Mr. Cement S Type to be a great general glue. It flows, is fast acting and will bite into the plastic, and dries quickly.

You know, and oddly, Mr. Cement Limone Type (Lemon Type) is really really good. It's one of those citric acid type glues that smells (you guessed it) like Lemon. I'd rate it about like the Testors stuff. It is a bit slow to dry which can be good if you need to move the parts around. When cured though, I cant see where it is any weaker than Mr. Cement S Type. Normally I hate all those lemony, non toxic or less toxic glues because they are crap but Limone Type actually works. Go figure.


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## Modlerbob (Feb 10, 2011)

My experience with one of the new lemony smelling "welders" brand name Micro Weld was that it is useless. That is a pity since Micro Weld was the first of the MC welders. Back in the 1970's when Micro Weld was good I discovered that the compound sold by Addressograph multigraph to clean the rollers in their copy machines was in fact methylene chloride called multilith deglazing compound. Much cheaper by the quart than buying 1/2 oz. bottles in the hobby shop. That is until it was found to be a carcinogen and removed from the market.


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## charonjr (Mar 27, 2000)

I went to the hardware store and they had quart and gallon cans of MEK. At $10 and $24, respectively, which I discovered is beyond this month's budget! I am glad to hear about the MC, as I have the ABS Deep Space 9 kit and I'd rather not use CA. I found that, aside from zero sheer strength, CA came apart after ten years on an Enterprise I had spent a great deal of time working on. Temperature stress, I expect.


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## charonjr (Mar 27, 2000)

Can Testors glue be used in combination with the Weldene? Perhaps not, I was thinking the faster drying one would hold the plastic in place for the slower drying one to make an effective permanent weld. But then I realized the vapors of the Testors would likely keep the Weldene coating soft. Hmmm.


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## djnick66 (May 2, 2008)

I doubt you can mix them. Fast and slow drying really have no bearing on the type of bond in most cases. If you want fast, use a fast glue. If you want slow, use a slow one. 

Tamiya Extra Thin Cement works on ABS and styrene. Tamiya also does make an ABS model cement, although I have not seen it. In the end its good to have a few kinds of glues around. I probably have 10 different cements for plastic models and three or four different kinds of putty. There is not one type that is the best choice 100% of the time. 

If you are on a budget, the old Testors stuff in the glass jar is not half bad. I've had much worse.


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## charonjr (Mar 27, 2000)

Gotcha. On another note, I'm using some older Squadron White Putty that is coming out a bit on the dry side. I noticed it uses toluene. Since Testors cement uses toluene, can i use it to mix with the putty and make a bit more smooth or malleable?


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## djnick66 (May 2, 2008)

Yup - you can thin most tube type model cements with liquid model cement


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## charonjr (Mar 27, 2000)

thank you!


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## robn1 (Nov 17, 2012)

If you use glue to thin the putty do it sparingly, it can melt plastic if you use too much. It will also shrink more so be prepared to do an extra application.


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## djnick66 (May 2, 2008)

Solvent based, tube type, putties generally shrink a lot anyway. Let it dry overnight before sanding and reapply if necessary.


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## Owen E Oulton (Jan 6, 2012)

Best tghing to thin putty with is nail-polish remover (acetone-based). It can be had quite cheaply in the cosmetics area of any drug store.


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## charonjr (Mar 27, 2000)

Yes, I just found that Acetone and Toluene can be had in cans at Ace Hardware. Also MEK is available in a can. They also have a paint stripper that is made, in part, with Methylene Chloride. Hmmm.


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## djnick66 (May 2, 2008)

I have cans of MEK, lacquer thinner, denatured alcohol, odorless mineral spirits and acetone. All of them have their uses. None present any undue safety issue when used properly. Stuff like MEK I usually transfer into a small, work bench sized, glass jar for general use. No need to get into the big can all the time.


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## charonjr (Mar 27, 2000)

Ok...I was thinking something similar, since I have such a small space to work in.


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