Resin Bodies

[Horrorshow]

I’ve never worked with a resin body. Are they that different from styrene? What are they like to sand, cut, paint ect.

Thanks

[Mark]

Different in that they cannot be cemented with plastic cement...super glue or epoxy must be used.  

When sanding (especially when grinding), breathing protection is an absolute must.  You don't want to breathe in that dust in any amount.

Most resins cut and sand about the same as plastic, maybe a little bit easier.  It's usually easier to scribe panel lines into (but then again, it's easy to scribe too deep also). 

When joining resin to resin, or resin to plastic, I don't want to prime or paint directly over the seam, no matter how smooth it seems to be.  I rout out that area and apply epoxy putty, so on the surface the transition becomes: plastic, putty, resin.

Clean all resin parts before doing any sanding, cutting, or grinding.  Many casters use a mold release product to prolong the useful life of the mold.  If you don't get rid of that, you'll be embedding it into the resin which will cause you grief later on.  The caster should suggest a suitable cleaning agent for their parts because they know what they used when making them.

[Horrorshow]

4 minutes ago, Mark said:

Different in that they cannot be cemented with plastic cement...super glue or epoxy must be used.  

When sanding (especially when grinding), breathing protection is an absolute must.  You don't want to breathe in that dust in any amount.

Most resins cut and sand about the same as plastic, maybe a little bit easier.  It's usually easier to scribe panel lines into (but then again, it's easy to scribe too deep also). 

When joining resin to resin, or resin to plastic, I don't want to prime or paint directly over the seam, no matter how smooth it seems to be.  I rout out that area and apply epoxy putty, so on the surface the transition becomes: plastic, putty, resin.

Clean all resin parts before doing any sanding, cutting, or grinding.  Many casters use a mold release product to prolong the useful life of the mold.  If you don't get rid of that, you'll be embedding it into the resin which will cause you grief later on.  The caster should suggest a suitable cleaning agent for their parts because they know what they used when making them.

Thanks for the tips!

[Mark]

Too, whatever part or body you get needs to be stored on a flat surface.  With bodies, I like to get them to fit the donor chassis, and store them with chassis and interior installed.

[Mopar maniac 74]

1 more tip I learned the hard way is the resin is not flexible like plastic and breaks easily so donor chassis etc will need to be trimmed exactly to fit resin body

[DRIPTROIT 71]

I always clean with Comet, warm water and a toothbrush. Clean until surface feels "squeaky."  Even when I soak a resin part in Wesley's Bleach White, I still have to scrub it with Comet. If a lot of mold release was used, you may have to clean before you can even sand it. 

[Horrorshow]

Thanks for the tips everyone ?

[Lone Wolf]

On 11/8/2022 at 8:11 AM, Mark said:

Different in that they cannot be cemented with plastic cement...super glue or epoxy must be used.  

When sanding (especially when grinding), breathing protection is an absolute must.  You don't want to breathe in that dust in any amount.

Most resins cut and sand about the same as plastic, maybe a little bit easier.  It's usually easier to scribe panel lines into (but then again, it's easy to scribe too deep also). 

When joining resin to resin, or resin to plastic, I don't want to prime or paint directly over the seam, no matter how smooth it seems to be.  I rout out that area and apply epoxy putty, so on the surface the transition becomes: plastic, putty, resin.

Clean all resin parts before doing any sanding, cutting, or grinding.  Many casters use a mold release product to prolong the useful life of the mold.  If you don't get rid of that, you'll be embedding it into the resin which will cause you grief later on.  The caster should suggest a suitable cleaning agent for their parts because they know what they used when making them.

Mark, obviously an older thread but I needed some resin related info, if you don't mind? When it comes to using "filler" on cast resin bodies, what will stick to it, that hopefully is not overly difficult to sand? I do have some Evercoat Metalglaze 2-part polyester glazing putty, some Tamiya white solvent putty, thick/medium/thin CA hobby glue, and 2-part hobby (clear) epoxy. Additionally I have PC-7 Epoxy (it's like thicker JB Weld) and some Milliput (both of which dry nearly rock hard)... I mostly need to fill some door seams (converting a 4-door to a 2-door coupe, w/the doors molded shut). Potentially, I may need to fill various  small flaws (just ordered kit)? Thanks!

Edited June 23, 2023 by Lone Wolf

[Mark]

I would use either two-part epoxy or catalyzed spot putty (like Evercoat) on the door lines, after routing them out a bit.  Pretty much any filler that works on styrene will work on most resins, provided the resin has been cleaned and prepped same as you would with styrene.  I once used PC-7 on an extensively modified plastic body that I used as a master for resin casting, both to fill seams and to build up the wall thickness of the body in some areas.  In fact, I used it on a master for a trailer body and lid also.  Still have both masters, both are in great shape.  

[Lone Wolf]

Mark, Thank You very much for the reply. Dang it, I didn't realize I needed to "follow" things, I thought making a comment automatically did that, oops. So, Evercoat glazing putty it will be. Yes, PC-7 is amazing, great stuff, I've been using it for many decades and have always kept some on hand. Although I'm not certain it was PC-7, in the 70's, some well known pro-stock racers used it, or a similar gray epoxy, to "reinforce" the outside of aluminum tunnel ram intake runners so they could port them out further than the aluminum would allow them.