building materials

[mickelsen]

I have two questions:

1. I've seen an epoxy product that is viscous like modeling clay. In fact, you have to mix the two parts together by kneading them with your fingers. I want to apply this in places where it can't be seen but where I need to reinforce some delicate structures. Do you know of this product, or can you recommend a product like this to me?

2. I want to use Evercoat Rage to repair some blemishes in the smooth surface of some models but, in some cases, the blemishes are so shallow that the Rage just won't stick when it cures. I've tried putting little dimples in the surface and/or roughing up the surface but these methods don't seem to help very much. Is there a way to treat or prepare the surface so that the Rage will bind with the plastic better? Or should I be using something different than Rage?

Thanks,
Mark

[He Who Shall Not Be Named]

Use an air-dry touch-up putty for the thin build-up task. I use Nitro-Stan putty. Rough up the surface with some #240 to produce the substrate 'tooth' that will help key the putty to the plastic.

David,

[Kazzer]

I have two questions:

1. I've seen an epoxy product that is viscous like modeling clay. In fact, you have to mix the two parts together by kneading them with your fingers. I want to apply this in places where it can't be seen but where I need to reinforce some delicate structures. Do you know of this product, or can you recommend a product like this to me?
Mark

http://www.caswellplating.com/aids/epoxies.htm

I particularly like this Quickwood product, its easy to mix and easy to sand.

2. I want to use Evercoat Rage to repair some blemishes in the smooth surface of some models but, in some cases, the blemishes are so shallow that the Rage just won't stick when it cures. I've tried putting little dimples in the surface and/or roughing up the surface but these methods don't seem to help very much. Is there a way to treat or prepare the surface so that the Rage will bind with the plastic better? Or should I be using something different than Rage?

Thanks,
Mark

Try EASYSAND


Easy Sand™
Two-part flowable polyester finishing and blending putty. Contains Hattonite™ for optimum sanding performance. Ideally suited for filling and skim coating body work, pinholes, grind marks, low spots and other surface imperfections. Includes ZNX-7™ for adhesion to galvanized metal, aluminum and steel. Part of the MetalWorks® System. Blue cream hardener included.
24oz Tube

[Anuci]

You may want to give a product called "Repair Putty by Locktite".
I've had good success and it is easy to work with as well. Simply cut off a piece from the roll of a two part epoxy, knead together, mold onto area of conern. Hardens like stone, is resistant to water and many chemicals, adheres well to plastics and fiberglass. Can be used in the repair of pvc water pipes as well as many other things. I've tried placing a photo into the test by transferring a photo from my Caswell photo files but had difficulties, however the product should be easily found if you so choose.

[mickelsen]

I looked this up on the web and says that it is not appropriate for "Polyethylene and polypropylene". I think that most models are made from styrene, is that correct? Does is work okay with that?

[Subculture]

You will find that very few adhesives will bond to Polyethylene and polypropylene. These plastics are inherently waxy, and tend to be welded together using heat (sometimes sonic welders). To bond to them, some companies like Loctite produce a special primer that you apply, and you can then use some of their glues to stick them together. However its best to avoid these plastics for modelling use.

For filling small scratches and blemishes follow Dave's advice and get the air dry putty. I use 3M Acryl red, which is used in the car trade. A tube will last you a very long time.

I only use epoxy putties for filling areas which need high strength, as it's more difficult to sand down and also takes much longer to cure than polyester putties.

[Anuci]

{ An epoxy product that is viscous like modeling clay. In fact, you have to mix the two parts together by kneading them with your fingers. I want to apply this in places where it can't be seen.
Mark,
If after reviewing the various suggestions you feel you may still want to go with something similar to what you had described, then you may want to give Loctite customer service a call for the final word on what in particular you intend to use it on.
Here is the phone # 1-800-624-7767 as printed on the packaging.

I agree, for small repair and filling of small blemishes, particularly on areas which will be readily visable, a fast drying Hobby Filler as suggested would probably work best. I like Green Putty by MMD, a fast drying easy sand filler that I have found good results with, and comes in a small tube if you find you won't need that much.

http://mfpilot.com/index.php?main_page=product_info&products_id=112

There are many such products in that regard that would work well. Hope this helps.

Al,

[mickelsen]

Hey Mike,
When looking for the putty-like epoxy to use to re-enforce plastic parts, why would you prefer the QuikWood to the QuikPlastik?
Mark

[Subculture]

Epoxy putties I've used come with different fillers, and different properties. Some remain flexible, some are finer consistency, so better for detail work, some dry rock hard etc.

[Kazzer]

Hey Mike,
When looking for the putty-like epoxy to use to re-enforce plastic parts, why would you prefer the QuikWood to the QuikPlastik?
Mark

I've always got some Quikwood around. I use it to glue coral onto rocks in my aquarium, fill holes in screw-ups I make around the house. Its easy to sand and does everything I want. To be honest, I don't think I've ever used Quikplastic, perhaps I should now! Andy is right of course, they have different fillers and properties