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Modeling in General: Advice on...
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Working with Resin
Delta42
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Georgia, United States
Member Since: August 27, 2002
entire network: 616 Posts
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Posted: Wednesday, February 23, 2005 - 01:34 PM UTC
Hi Everyone,

I am presently working on a T-19 HMC conversion by Best Value Models. It has quite a bit of resin parts, and this is the first time I have worked with this much resin. Are there good articles or books out there that you would recommend that gives tips, pointers, etc. about working with resin parts. I'm doing a lot of trial and error (mostly error ), but think it's about time I got some pointers from the experts.

Thanks,

Dave
capnjock
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United States
Member Since: May 19, 2003
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Posted: Wednesday, February 23, 2005 - 03:16 PM UTC
The only book I am aware of that is devoted to resin is a book called something like BUILDING RESIN MODEL AIRPLANES. Most of what I have learned is from tidbits gleamed from articles, people that have used resin, and by working with it. The first item I learned was DRY FIT, DRY FIT, DRY FIT and then DRY fit some more. Second, learn how to use debonder. It is worth its weight in gold when you realize that something is not right and you must rebuild. Resin sands easily but is brittle.I use a mask when sanding and have a shopvac rigged up to pull the dust out of the air.The dust is NOT good for you.Warps are not that difficult to remove. I am partial to the hot water method. Super glue or epoxy are used to glue it together. I use both, depending on the strength of the joint I need. Painting is normal. The one problem with resin is usually the size of the casting gates. They can be HUGE.It all depends on the manufacture.
I hope some of this helps.
capnjock
bison126
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Correze, France
Member Since: June 10, 2004
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Posted: Wednesday, February 23, 2005 - 07:05 PM UTC
Hi,
the first step you should go in is a thorough wahsing of all the parts prior to anything else. It'll remove the greasy agent use to get them out the molds.

Then, identify the parts as unlike plastic kit ones, they
are scarcely coming with a frame/sprue with numbers.

Be careful when cutting the parts, be sure to have a new blade on your cutter, a saw may be of some use. To remove the big amount of resin sometimes remaining from the molding process I often use an electric circular saw like a Dremel one.

The dry fitting is really a must be done. The bond is tight with Cyano and even with a "debonder" you may encounter trouble to get the parts properly reglued.

The advice above about wearing a mask due to dust seems a good one especially if you work with electric tools which tend to blow more of it. This dust could be harmful if inhalated.

The warm water or hairdryer (avoid both together unless you've got a good insurance ;-) ) are used to get the twisted parts straight again and are useful as the tracks fitting is concerned.

I think these are the basics for a resin beginner. Others could tell more about it though.
Enjoy your building and keep us posted with pics of your model.

olivier
Delta42
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Georgia, United States
Member Since: August 27, 2002
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Posted: Thursday, February 24, 2005 - 06:57 AM UTC
Thanks to both bison126 and capnjock for your comments. With my trial and error method, I have learned alot. One big lesson that I learned was to think out the sanding and trimming before starting. I had a very delicate part that I cleaned up before removing the excess casting gate material. Took me an extra half a day to cut that stuff away with out damaging the actual part. Probably could have done the whole thing in 20 mins if I had thought out the process first. I will keep you posted, and will also post pictures and kit review when I finish.

Dave
18Bravo
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Colorado, United States
Member Since: January 20, 2005
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Posted: Friday, February 25, 2005 - 09:34 AM UTC
Ditto on what the others have said, except that I rarely use a mask when cutting off the parts with the dremel. (by the way, Dremel no longer sells their excellent little saws. I have to use Giros, which are at least five times thicker.) I do my cutting/grinding outside. There's usually enough of a breeze to blow the dust out far enough for my neighbors to enjoy the smell of a brand new resin model as well. If there's no breeze, then I use the mask. The dust can be so fine it'll circulate throughout your house no matter what you do, so I keep it outside.
One of the biggest problems I have with resin, which is about all I do these days, is sanding the parts square. I have several grits of wet/dry paper spray mounted to pieces of acrylic. I wet sand all of my parts on that, The surface is large enough that if I draw the part along in one direction, I can get a nice squared edge. For smaller parts I use a cirular motion to prevent the corners from rounding. The wet method also minimizes dust. I just keep washing the slurry down the drain.
One other thing I do when necessary or practical is to pin parts together with brass pins. Even after washing the parts, the bond between reson parts and CA is not as strong as I'd like. I don't use two part epoxy simply beause it seems more mafan. (First Cantonese word I ever learned, from my mother in law)
jRatz
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North Carolina, United States
Member Since: March 06, 2004
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Posted: Friday, February 25, 2005 - 01:44 PM UTC
Good info by all above; my 2 cents follows.

Use a mask to sand or heavy cut; or do it outside; or in your spray booth if bented outside. Once in your lungs, it stays there. I prefer outside; then my spray booth & I have an HEPA mini-vac to clean up the hobby area with.

Be careful sanding, stuff trims quickly & you can go too far, or damage detail, in a heartbeat.

Fit, fit, fit before you ever touch glue. Use tape, etc, to tie multi-parts together so you see/know the big picture.

Keep de-bonder right next to you -- not just for the parts but your fingers.

Study the part & instructions a few times before you cut/sand anything -- too many times I've lopped off something that looked like part of the plug & wasn't.

The quality of instructions with resin parts/kits varies from excellent to useless -- study carefuly & fit, fit, fit before you cut/sand/glue.

Welcome to the world of resin -- it's fun, really.

John
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