Jump to content
This site uses cookies! Learn More

This site uses cookies!

You can find a list of those cookies here: mysite.com/cookies

By continuing to use this site, you agree to allow us to store cookies on your computer. :)

Codger

Assembly preparation??

Recommended Posts

In the 'dark ages' of modeling, it used to be sage advice to remove part trees from the box and wash with warm soapy water and rinse. This to remove the mold release coating.

But I see virtually everyone these days, open the box and shoot the paint job on immediately. No test fitting, no part washing, no surface sanding. I'm not sure how good those finishes are but it seems the thing to do today.

Does anyone prep the plastic anymore??

Share this post


Link to post
Share on other sites
Posted (edited)

There have been several posts on mould release agent and the need to clean or not on the site here. I recall someone - I forget who - who seemed to know a bit about the process of injection moulding plastic advising that mould release agent was not present, at least not after the first few pulls. 

I confess that I had not heard of or experienced any difficulty through the 60’s 70’s and 80’s in not washing kits and getting paint to adhere. However I do wash kits on a “just in case” basis. 

 

Resin parts are are a different ball game I gather

Edited by JohnT
Grammar and spellun

Share this post


Link to post
Share on other sites

I always wash the sprues still.  Have done ever since a Matchbox Strikemaster back in the day, where the paint crazed like crazy.  

Whether the parts need washing I don't know, it's more a sort of Zen preparation for the build process, receiving the kit from the stash into its purpose of becoming a scale model (ooh, heeavy man).  It's also a good opportunity to inspect the kit and consider any aspects that may need deeper review.

I would point out that unlike others' experience, masking tape doesn't seem to pull off paint when I've prepped this way, another good thing is to wipe down the built model with meths on a make up pad before priming.

Cheers

Will

Share this post


Link to post
Share on other sites

Another one here who washes the sprues off before beginning any work (chrome sprues excepted). Usually just a case of dropping them into warmish soapy water and leaving for 2-3 hours (EDIT: then rinsing under the tap) then letting them air dry. Can't say I've had any bad experiences to make me do that, and I never did this when younger, but I'd rather do that tiny little bit of work on every model than lose one to paint going bad.

Share this post


Link to post
Share on other sites
10 minutes ago, Spiny said:

Another one here who washes the sprues off before beginning any work (chrome sprues excepted). Usually just a case of dropping them into warmish soapy water and leaving for 2-3 hours then letting them air dry.

First, thanks much guys; was hoping to hear what are good practices being used today and what causes trouble.

Spiny, does that mean you don't rinse them? Just let soap air dry? I'm surprised that doesn't cause paint adhesion problems if so.

Share this post


Link to post
Share on other sites

Personally I wash the sprues straight out the box, then remove, prep, test fit and glue where possible/ necessary. 

After this I tend to wash the assembly’s again before going to paint as follows:

Handling is now done in gloves.... Warm soapy water and the wife’s toothbrush to scrub, a rinse under the warm tap, shake dry, then air through the airbrush to reach all the nooks and crannies etc. 

Then onto paint.

 

you notice a difference in the feel of the plastic after the first wash IMHO.

 

Share this post


Link to post
Share on other sites
43 minutes ago, Cooper645 said:

you notice a difference in the feel of the plastic after the first wash IMHO.

 

A very thorough prep and your paint work must be excellent.

I can remember in my early years that some kits (maybe AMT, Entex or Monogram) definitely had a coating of what seemed the consistency of WD-40. Ambroid glue or Testors cement would not join parts like that. I started washing early.

In the last two decades I noticed that was gone from new quality kits. They come very clean from China, Japan and Korea these day. Airfix too in UK I guess. So instead of washing, I got in the habit of sanding big scale parts with 600 grit and 4-O steel wool on smaller parts. Gives a nice scratch-free surface with 'bite' for primers or fillers.

Share this post


Link to post
Share on other sites

Yes, not long ago a post was made about the old school mould release not being used anymore so there’s not really much of a need.

 

Up until I restarted modelling I never bothered to wash and never had any issues, and I’ve been doing it since the 90’s.

 

Resin I use Polly plastic prep.  Those need it bad.

 

I think primer even doesn’t need to be used as much nowadays with the quality of paint.

 

 

Share this post


Link to post
Share on other sites

It depends whether parts are going to be painted on the sprue.  For large parts that I'm going to handle, test fit, fettle, fit etc I'd rather wash after the assembly is completed.

Share this post


Link to post
Share on other sites

Generally a rule with me to wash.

Soaking in water and dish soap is enough with a rinse of course.

Vinegar soak for p/e.

Soaking in alcohol for resin bits Just don't soak them too long as some resin will react.

Here the wheel spokes all took on a new shape as the resin was soaked overnight:

IMG-2334.jpg

It was an 'even' new shape so I went with it!

Share this post


Link to post
Share on other sites
21 hours ago, Codger said:

…  anyone prep the plastic anymore??

yes. prior to assembly & then again just before primer. I only use 50% mix of isopropyl alcohol & distilled water, so it might just be exercise.

 

i'm having fun, and that's what's important to me.

Share this post


Link to post
Share on other sites

Steve - a happy accident ! Can be good if you can control the effect. Adds character to your cart !

 

S.E. - Iso is not just an exercise. I've found it very effective on plastic and between coats.

Share this post


Link to post
Share on other sites
22 hours ago, Codger said:

First, thanks much guys; was hoping to hear what are good practices being used today and what causes trouble.

Spiny, does that mean you don't rinse them? Just let soap air dry? I'm surprised that doesn't cause paint adhesion problems if so.

Sorry, bit of numptiness crept in there. Yes I do a quick rinse under the tap to get rid of the soapiness - not sure why I didn't write that in in the first place. I've amended my post above, but glad you pointed it out - I'd hate to be responsible for ruining someone else's build.

Share this post


Link to post
Share on other sites

I ALWAYS wash everything first. My resolve was strengthened a year or so back when I picked up a couple of ICM 1:48 P-51Ds at a good price. On opening, I found that they were covered (to the point of dripping) with an amber oily liquid that made holding the parts almost impossible, never mind painting them!

Share this post


Link to post
Share on other sites

A great discussion and I thank all who contributed their experience.

 

Very useful to new and returning builders I hope.

Share this post


Link to post
Share on other sites

If building a kit, I always put chrome sprues straight into bleach. Everything else- what's the point???

ALL parts have to be have to be sanded, filled and sanded again before you can do anything, anyway, so I've tended to fettle an assembly's-worth of parts, then wash them. After that, I'll do whatever assy, clean, sand and wash again. Then, each assy at a time, when needed. (too many parts off the sprue at any one time can lead to many missing or broken/damaged parts...beware).

Share this post


Link to post
Share on other sites
22 minutes ago, harveyb258 said:

If building a kit, I always ...

Since when have you built 'a kit' ??? :crosseyed:  When you were 8 maybe?? :D

Share this post


Link to post
Share on other sites

I never wash kits at any point and have never had any problems as a result.

 

It was @hendie that posted the fascinating info about injection moulding, which mentioned that mould release agent on kits is pretty much a myth:

 

Share this post


Link to post
Share on other sites

I did wash the sprues at first, then stopped when I realized that I'll be handling each and every part for cleanup anyway so they'll have my greasy paw prints all over them as I'm not about to wear sweaty latex gloves all the time. I now wash or wipe down (with alcohol tissues for cleaning glasses) exterior parts or assemblies before primer, that seems to work. Although I forget to do so every now and then. I always use Tamiya's fine grey primer and it doesn't seem to mind. But, generally I wash visible parts before paint, because of the prints. 

Share this post


Link to post
Share on other sites
6 hours ago, Gorby said:

I never wash kits at any point and have never had any problems as a result.

 

It was @hendie that posted the fascinating info about injection moulding, which mentioned that mould release agent on kits is pretty much a myth:

 

I suspect time is a factor here; you may have started building after the fluid was no longer in widespread  use. And the geographic location of manufacture, like Japan, may have been a factor.. But I have clear memories of it from the late  1950's (when I started at age eight) until possibly the early '70's.

Share this post


Link to post
Share on other sites
3 minutes ago, Codger said:

until possibly the early '70's

That's pretty much when I started (for the first time).

Share this post


Link to post
Share on other sites

Open box, remove parts and begin - you're going to overwhelm any residue with your finger oils with a few minutes anyway, so why bother?  The short and shorter the run, the more likelihood of release agent, with resin at the top of the tree.  If you work like I do you seldom get to the point where you put any meaningful quantities of paint on it, so it's a moot point really :shrug:

 

If anything I prep the model for paint just before I paint.  A rub with IPA usually works (no, not beer), and in the case of resin, a light sand with your finest buffing stick (usually the grey/green one).

Share this post


Link to post
Share on other sites
3 minutes ago, Gorby said:

That's pretty much when I started (for the first time).

That would pretty much correlate with my experience then.

So the question becomes 'why did I raise the issue now?'.

Because we all have different ways to a fine quality finish and I hoped to have many ideas presented, which there are. Prepping a surface either by wash, chemical coat or abrading the surface is helpful. Those that do not can still produce excellent work but I learned that, if you didn't and lay down a perfect coat, the omission may ruin your skilled work. The term 'fisheyes' was born from such oversight in the 1:1 paint world.

BTW- this is not withstanding Hendie's comprehensive 'term paper' on injection molding. A tremendous work.

The answer I think is that there are several ways to skin the cat.

Share this post


Link to post
Share on other sites
5 minutes ago, Mike said:

Open box, remove parts and begin - you're going to overwhelm any residue with your finger oils with a few minutes anyway, so why bother? 

Which is why from the '90's on, I kept a bottle of IPA right on the bench. If I don't build with gloves on, I splash some IPA on my hands over time to handle delicate parts. It take no additional time or effort I've found.

Share this post


Link to post
Share on other sites
4 minutes ago, Codger said:

I splash some IPA on my hands over time to handle delicate parts. It take no additional time or effort I've found.

It's probably quite bad for your skin though, so I wouldn't recommend it to anyone with delicate skin.  Your fingers have oil secreted to keep them supple and soft, so removing that often isn't really recommended.  I occasionally use IPA to remove paint residue from my hands, but you can tell after that your skin is now bereft of oils :S

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...