Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

I seen this on insta but without an explanation

Yes, it's a good idea to wash all resin stuff.

Unlike modern plastic injection molding, resin casting still relies on mold release agents and not removing it from the surface of the model will cause paint adhesion issues.

Right, interesting thanks

Metal and resin models are made in a pressed mould - two halves that press together to form a seal to keep the material in when its poured in and then left to set. So that the two parts separate easily the inside is coated with an agent that restricts the resin/metal from sticking to the mould.

However the result is that all resins (they tend to retain the release agent more readily) and many metals (its not always needed/an issue as much with metals, but its good policy) need a warm wash; a tiny bit of soap and a scrub with a soft worn toothbrush.

This cleans off the mould release agent material and helps ensure that the model will glue together and that paint (both primer and regular) will stick to the surface correctly.





If you don't do it you might get lucky and not have an issue; or you'll get unlucky (more likely) and get paint that just won't stick and parts that just fall off.

From FW's A Guide to Building Resin Models -

Next, clean each part in warm water with a good degreasing agent, such as dish washing liquid, and an old toothbrush. This is to remove any excess
mould release agent which may still be on the surface of the parts. Any mould release agent left on the model may prevent the primer adhering to the
model. It may be required to leave the parts to soak for a while before scubbing if they feel very greasy.

Just to stir the pot a bit:
I rarely was my FW stuff, only if it feels 'slimy' & then sometimes I just hit it with a steel wire brush - it sounds extreme but it works for me especially on my FW Reaver titan.
However I have found sometimes when you try to wash & I try to scrub, there are small pockets that just won't loose their shine. I found this on one of my nurgle hellbeasts. I think it's where the resin hasn't mixed properly & needs to be gouged out. Even after hitting with varnish these areas were resisting paint so I went down the more extreme route then re-filled the areas with greenstuff. It doesn't occur a lot. I've only had it on a couple of minis from several years ago.

BTW a tip if you do wash your minis, buy a cheap Oral B rotary toothbrush. Saves a lot of elbow grease

 ScootyPuffJunior wrote:
Yes, it's a good idea to wash all resin stuff.

Unlike modern plastic injection molding, resin casting still relies on mold release agents and not removing it from the surface of the model will cause paint adhesion issues.

Modern plastic injection moulding ALSO relies on it, but it's more to cool/lubricate the dies and slides (some of it will find it's way onto the plastics, though, because of this), but it's not quite the same as the release agents used for resin casting (which don't NEED to be baby-gak-to-a-blanket stubborn like the one that FW uses).

But yeah, WASH the FW models. Something with good grease-cutting abilities (like a good detergent) and use a toothbrush (medium bristle).

I’ve bought many, many resin models from various model companies down the years, and I can tell you that Forge World models have the most difficult to remove mold release agent by a long, long way. I’ve been buying from FW for a long time, it’s always been this way.

I have a routine which I have to go through for each new model: soak in warm water with washing up liquid for a while, then scrub every area of every piece with more washing up liquid and a tough toothbrush. Then, once it is dried and then assembled, I spray it with a layer of varnish BEFORE priming.

If I don’t follow this routine there will be areas of the model where paint simply will not stick, it’s incredibly frustrating.

It’s a real nuisance, as I don’t have to do this for any other resin model that I have purchased, apart from one from the initial Creature Caster KS which was smothered in grease.

I wish that FW would use a different mold release agent, it would save me a lot of time and effort.

Also, I can’t help but feel surprised when people talk of not experiencing this problem with FW models. I tend to assume that they must have purchased recasts

I have many FW models for 30k and my DKoK. I haven't washed any of them, and they are all fine. Haven't noticed a single issue with the paint sticking to them.

Yeah it really depends. I've had no issues with any infantry or figures, but did have issues with the only vehicle I ever did from forge world.

I'll echo - always wash resin and metal.

Plastics, sometimes you can get away with, but I give sprues a soak in soapy water and a gentle scrub before priming. If the person packing had greasy fingers, you may well end up in for a rough time later.

In either case; cleanliness then becomes next to godliness - don't work on models with greasy hands or you'll just upset yourself later. A little effort in keeping things clean saves so much heartache later.

This is especially true if you're using polyurethane primers (Vallejo or Stynlrez) with an airbrush.
These have no solvent carrying them so they don't break down any surface film of grease leading to a primer coat that flakes or peels away with alarming ease even after you think it's cured.
And even more so if like most people you start working before primer's had a chance to cure.
More so again (!) if you're planning a paintjob that requires masking. If the tack on your tape exceeds the grip the primer has, you'll peel off the whole lot when you remove tape.

Huh. I've never washed metal before but always wash resin.

It is very well known that all of the people who work at forgeworld really enjoy fried chicken. They often eat it during lunch. Some times fat get stuck on the models. The paint does not grip well there. Washing in some warm soap water removes this oil.

 Undead_Love-Machine wrote:

Also, I can’t help but feel surprised when people talk of not experiencing this problem with FW models. I tend to assume that they must have purchased recasts

I don't like your implication here. I mostly buy from FW direct & can assure you that I've never knowingly bought a recast.
I bought one recast from a FB group. I reported it.

 Undead_Love-Machine wrote:

Also, I can’t help but feel surprised when people talk of not experiencing this problem with FW models. I tend to assume that they must have purchased recasts

There's no particular reason to assume that. The actual amount of mould release left on the model will vary, and will often not be enough to have a significant effect. Particularly if using a spraycan basecoat, some sprays will deal with residue on the models better than others.

Also, recasts would have just as much need for mould release as any other resin model.

Mould release agent is always a variable risk; sometimes you get lucky and sometimes you don't that's why its good to always wash.

Also not all models come out of the mould the same, some models need more agent to ensure they come out smoothly.



It's just like how some models will tear their moulds up faster than others. PP had one of tehir limited skorn models that would do that; they had to pull it from sale for ages (not even sure if it ever returned) because it simply destroyed the moulds far too quickly due to the placement of the detail on it.

bubber wrote:

 Undead_Love-Machine wrote:

Also, I can’t help but feel surprised when people talk of not experiencing this problem with FW models. I tend to assume that they must have purchased recasts

I don't like your implication here. I mostly buy from FW direct & can assure you that I've never knowingly bought a recast.
I bought one recast from a FB group. I reported it.

It was supposed to be a tongue in cheek comment, I’m sorry if I offended you.

insaniak wrote:

 Undead_Love-Machine wrote:

Also, I can’t help but feel surprised when people talk of not experiencing this problem with FW models. I tend to assume that they must have purchased recasts

There's no particular reason to assume that. The actual amount of mould release left on the model will vary, and will often not be enough to have a significant effect. Particularly if using a spraycan basecoat, some sprays will deal with residue on the models better than others.

Also, recasts would have just as much need for mould release as any other resin model.

Yes, they need mold release, but as I said in my original post, the type of mold release that FW use is much more difficult to remove than any other type used by other companies. I can only guess as to why this is the case.

 Undead_Love-Machine wrote:


Also, I can’t help but feel surprised when people talk of not experiencing this problem with FW models. I tend to assume that they must have purchased recasts

Direct from forge world, or indirect from egghead. I've only had the issue with the forge world tank. I've also had a bunch of recasts that haven't had any release agent on them. I guess it's just luck of the draw.

 queen_annes_revenge wrote:

 Undead_Love-Machine wrote:


Also, I can’t help but feel surprised when people talk of not experiencing this problem with FW models. I tend to assume that they must have purchased recasts

Direct from forge world, or indirect from egghead. I've only had the issue with the forge world tank. I've also had a bunch of recasts that haven't had any release agent on them. I guess it's just luck of the draw.

Yes always clean no matter where you get

PS rant, don't need to read.

Haven't had a FW model yet, but plenty of resin from third party companies (kickstarters, heresy labs, hitech miniature, wargames exclusive, raging heroes ...) and guess I got lucky with my half assed washing: I filled a bowl with warm water, added some dish soap, put the models in, then scrubbed a little with a toothbrush, swished them around and washed them off under running water afterwards.
Then let them dry at least over night.

I haven't bought FW, but, of the resin miniatures I've painted, I think only one or two I had difficulty priming. All I do is soak the miniature in soapy water for a few hours then dry. I'll use the soapy water as rinse (wash) water for my brushes, along with another container of rinse water for a second rinse.

I'll scrub next time I have a resin miniature that gives me problems priming.

EDIT: Folk Art Glass and Tile medium.has been tried on Reaper Bones as a brush-on primer (because of Bone's hydrophobic surface). Just used it today on some resin that brush-on primer didn't stick on.
http://www.coolminiornot.com/forums/showthread.php?7969