Using FXD as the master

[Petri Sallinen]

We have made our first tests using Frosted Extreme Detail (FXD) as the master parts for resin castings (the scale is 1:87). After washing we painted parts using airbrush and Surfacer made by Gunze (the mixing was 1:1 using Gunzes own thinner). We painted parts four times — two times by using Surfacer 500 and two times using Surfacer 1200. After every painted layer we carefully brushed the surface by using the fibre brush. You are able to see the final parts in pictures. After that we will make the silicone molds. When we have got ready the first resin parts I will let you know so we are able to see the quality when making parts this way.

 

 

The FXD is much better than FUD but it is also more expensive. The price for these parts was 115 euros including postage costs to Finland. I think that FXD might be the good enough for the master when making small run kits — Micro Fine Green printed by Protolab is better but also very expensive. You need not to make any finishing when using Micro Fine Green. Please note that hulls are not exactly same — the new one is the other version of hulls.

 

 

Here is our first ready made bodies — parts (hulls) are made in resin and masters were made in Micro Fine Green. We have to make the new test body also ready (=painted) so we can compare details.

Petri Sallinen

Helsinki, Finland

[billbedford]

Some of the FXD patterns I've had recently have had very fine, but deep, vertical lines on opposite faces. Where FUD gave a fine diagonal pattern FXD has these line all over two of the faces. I'm afraid I'm beginning to loose patience with Shapeways and 3D System's machines.

[Quarryscapes]

Some of the FXD patterns I've had recently have had very fine, but deep, vertical lines on opposite faces. Where FUD gave a fine diagonal pattern FXD has these line all over two of the faces. I'm afraid I'm beginning to loose patience with Shapeways and 3D System's machines.

 

Same story here Bill, they're far too frugal with the print space - insisting on printing things on end causing the awful support wax surface disaster when it would have been better off printed lying flat. I am seriously considering making the leap to injection moulding. Yes the up front costs are astronomical, but the quality is far superior and far more end user friendly. 

[Pete Harvey]

Never had a bad experience using FUD or FXD for masters for resin or brass casting, to get a good master you have to clean it properly and have the tooling and the casting done by someone who knows what they are doing, i.e. a professional.

 

 

This is the CAD render of master for the resin parts for the Vix kit as Shapeways printed it and sent it to me before it went to my resin caster.

 

 

And the parts fitted.

 

Pete

 

[rue_d_etropal]

some valid comments and suggestions  there. I think many of the grumbles concerning Shapeways go back to how we do original design, and what we expect from it. Sometimes wonder if too many expect everything to be done for them. I prefer to settle for what I can do. If you want the finest detail done to highest standard then it is necessary to put a lot more in, possibly using different software.

My only concern , long term with , the new print option, is that it would be easier for someone to scan and use it to produce their own copy. Basically copyright issues. With the rougher prints this is far less likely to happen at the moment, until 3D scanning and other software gets a lot better. almost certainly will happen eventually.

 

Petri, just noticed your location. Hopefully it is not too cold over there at the moment. I have seen comments that temperature can affect painting, and how it dries.

My son was over there at new year, and commented on the minus 20 degrees. As he intends to move over there (assuming everything works out) then he will have to cope with it. Will mean I will probably get to Finland sometime, which will make an interesting contrast to where I intend to move to in south of France. At least there are local flights to Stockholm, and it should not be that difficult getting across to Helsinki from there.

[Petri Sallinen]

If you are making the small series kits then it is easy to make the investment for well detailed 3D prints like Micro Fine Green. Also many resin casting service companies are selling high detailed 3D-printings as the service when you are buying their casting services — this is their way to get you also making castings with them. If the price for the high detailed 3D-prints is about 1000-1500 euros and you are making 200 pcs of resin kits the cost per kit is only 3-5 euros (you are also able to compare this with CNC molds made in aluminum or brass etc). In these cases the high detailed prints are much better choice than Shapeways style prints. So the way to select the printing style depends on what you are making. At this case we are making only two models so it was the most cost effective way to use FXD (Micro Fine Green would have been too expensive) — we also made molds for this production exceptional ourselves this time.

 

Here you can see the double deck coach made in resin and using the high detailed 3D prints made by our resin casting service company. Yes, surfaces are mainly flat so there are not rivets etc. but the body of the coach is in technical meaning quite complicated and quite difficult to cast. In my opinion the quality of the model is quite good. You are not able to get this quality by using FUD of FXD.

 

 

 

 

 

 

Rue_d_etropal — you are right. Sometimes our winter time in Finland might be quite cold especially in Northern parts of Finland. Anyway the biggest problem is snow — then public transportation and trains have big problems. I am living in Southern Finland near by Helsinki. This winter time has been very easy for us and not cold at all. Last week we had also here in Southern areas minus 28 degrees frost — I am happy that I am not living in Northern areas, they had about minus 40 degrees frost. Our houses are typically very warm — the temperature in my house was in cold days about 22 degrees. It was very easy to paint models. BTW the winter time is the best time to make resin casting because the air in our rooms is very dry. The moisture of air is only 15 percent — in summer time it might be 80 percent.

 

In this picture you can see my house. Some years ago we had quite a lot snow (I hate the snow ). Fortunately this year we got snow in Southern Finland only just last week. I think it is very easy to travel from France to Finland. Myself I am travelling every year from Helsinki to Aulesbury to Scaleforum show. It takes only six hours from Helsinki to Aulesbury. From Helsinki to York Show is probably more easy to travel via Manchester airport.

 

Petri

 

[Knuckles]

What is wrong in using FXD as the master and then just putting a little tender loving care into the body. A bit of chiselling and sanding, add a wee primer or filler primer and go over it again etc.

 

I'm sure you can get the result you're after before casting.

 

Yay or nay?

 

If nay why?

 

I'd like to know as casting a full loco body something I may try one day. I've done bits of casting before but nothing epic.

[Rods_of_Revolution]

What is wrong in using FXD as the master and then just putting a little tender loving care into the body. A bit of chiselling and sanding, add a wee primer or filler primer and go over it again etc.

 

I'm sure you can get the result you're after before casting.

 

Yay or nay?

 

If nay why?

 

I'd like to know as casting a full loco body something I may try one day. I've done bits of casting before but nothing epic.

 

Some of the models above are possibly too big for Shapeways' print bed, so they may not be able to produce them. If you did produce parts for casting and were happy to spend a few hours cleaning up the Shapeways parts, I'm sure you could get comparable results. The clean up is lots of effort and if it was financially viable to pay more for a higher quality print, then that's probably what I would do, especially if it was the same company doing the casting.

 

All the best,

 

Jack

[Knuckles]

Ok many thanks. 

 

 

Could you please point me to a UK company if you know one, I've looked at a few but they all seem to be doing big stuff. 

Do companies charge a lot to make moulds for you? I've never looked into it but I'd imagine so, if it was affordable it'd solve a few issues for me though.

 

I have some silicone rubber and resin here and have made a few things but nothing like a loco body.

It's something I want to do but it also seems it would be a right pig to get right with lots of wasted material and failures and that in itself is what keeps putting me off trying currently.

 

Part of the reason for motivation is in my opinion Shapeways prices for FUD especially are a joke and until I get a good printer or maybe cast things myself I'm stuck with a stupid price tag on some of my stuff.  I don't like biting the hand that feeds me so to speak but I think their FUD price is over the top.  Not so bad for 009 modellers but standard gauge.....oowwwech.

[Revolution Mike]

Try CMA Moldform (they do the resin casting for the NGS (and others) and are used to rail models).

 

Cheers, Mike

[Petri Sallinen]

Try CMA Moldform (they do the resin casting for the NGS (and others) and are used to rail models).

 

I agree. They made us the first Finnish model railway kits as early as in the beginning of 1990´s. They have very good quality.

 

Petri

[Knuckles]

What sort of prices are you looking at though. Take a loco body shell roughly 12cm x 3 x 5. If you sent that too them and asked them to make a mould, they made it and posted everything back roughly what sort of figure could I expect? £50? 100? Less, more?

 

I might aswell ask as you have used them.

[Petri Sallinen]

I think it is better to make them the invitation for tenders. The price depends on very much how simple or how complicated your master parts are. Flat style parts are easy to cast but sometimes master parts might have negative cants and these are not so easy to cast — this appears for the price. Also the amount of your run have an effect on the unit price. The more you will order the lower the unit price will be. Flat rates are almost the same if you are ordering 50 pcs or 100 pcs. Typically 50 pcs is the minimum amount in resin casting services. I think competitiveness of resin casting is at its best when making under 500 pcs runs.

 

Petri

[billbedford]

CMA won't supply you with just a mould. They will supply you with castings. Moulds for something as complex as a loco body will last for 40-50 shots and cost something in the order of £10 each ± depending on the volume of resin used. If you order less than 30 units they will charge you at least £200 for the mould plus a casting charge. Delivery, at the moment is around 12 weeks.

 

They do all their casting in industrial machines, cast are done under vacuum so the quality is far superior to hand poured mouldings.

[Knuckles]

Ok sweet. Many thanks you two.

 

It's early days but that info will help me mull things over for sure.

[Petri Sallinen]

Now the special version of this locomotive type is ready. You might see that hulls are different than in the basic type of this kit  . Other parts are almost same in both models. As I have told we used FXD prints as the master parts and we made the silicon rubber molds ourselves. After that we also made castings ourselves using low pressure casting technique. It is well enough when making only some castings but not as well as high pressure casting technique like CMA used to used.

 

[Kelly]

Ok many thanks. 

 

 

Could you please point me to a UK company if you know one, I've looked at a few but they all seem to be doing big stuff. 

Do companies charge a lot to make moulds for you? I've never looked into it but I'd imagine so, if it was affordable it'd solve a few issues for me though.

 

I have some silicone rubber and resin here and have made a few things but nothing like a loco body.

It's something I want to do but it also seems it would be a right pig to get right with lots of wasted material and failures and that in itself is what keeps putting me off trying currently.

 

Part of the reason for motivation is in my opinion Shapeways prices for FUD especially are a joke and until I get a good printer or maybe cast things myself I'm stuck with a stupid price tag on some of my stuff.  I don't like biting the hand that feeds me so to speak but I think their FUD price is over the top.  Not so bad for 009 modellers but standard gauge.....oowwwech.

 

The other consideration if you're doing it yourself is the potential for shrinkage. When I spoke to a few traders about it in the past, they recommended adding 8% to allow for shrinkage of the resin. The larger the item the bigger the potential for shrinkage related warping too iirc as some parts will potentially set quicker than others.

[rue_d_etropal]

Before I got into designing for 3D printing, I looked at idea of creating a mold for the Simplex loco I wanted. A friend was a skilled model maker, including molding, and he told me it was now possible to take a mold of any master(or original model) and there was no shrinkage. Whats more the original was not damaged in any way. Apparently it is a commonly used technique within sci-fi modelling circles, as many classic sci-fi TV series and films, quite often used converted models, and sci-fi fans sought out the same models to build their replicas. As some of these models are quite rare, and collectable in their own right,using a resin copy is preferable to destroying the original model.

I have seen what was obviously a copy of a diecast model, and the resin even had the very slight but readable impression of the transfers on the original model.

It will be interesting to see how 3D scanning takes over, that first stage.

[Kelly]

Before I got into designing for 3D printing, I looked at idea of creating a mold for the Simplex loco I wanted. A friend was a skilled model maker, including molding, and he told me it was now possible to take a mold of any master(or original model) and there was no shrinkage. Whats more the original was not damaged in any way. Apparently it is a commonly used technique within sci-fi modelling circles, as many classic sci-fi TV series and films, quite often used converted models, and sci-fi fans sought out the same models to build their replicas. As some of these models are quite rare, and collectable in their own right,using a resin copy is preferable to destroying the original model.

I have seen what was obviously a copy of a diecast model, and the resin even had the very slight but readable impression of the transfers on the original model.

It will be interesting to see how 3D scanning takes over, that first stage.

 

This was fairly recently as I was discussing options for producing a Class 465 unit from a 466 and taking castings of bodyshells of 466s (due to them getting harder to get) to cast extra cars for extra units. I may still give it a go and see how it comes out at a later date though, but I suspect it is a case of trial/error and the type of resin used.

[Petri Sallinen]

The shrinkage of mold depends on what kind of silicone type you are using for making molds. There are mainly two types of silicones available: tin based silicones (=condensation cure) and platinum cure silicones (=addition cure). The shrinkage of tin based silicones is typically about one per cent or lower. When using platinum cure silicones there is no shrinkage at all or the shrinkage is very small. Tin based silicones are cheaper. You have to check the technical information of silicone when you are buying the stuff — there are differences with products — also with tin based and with platinum cure silicones. The shore hardness is also important thing when you are buying silicones — would you like to get "hard" or "soft" molds. The bigger the number of shore hardness is the harder the mold will be. Shore hardness 10 is very soft, shore hardness 60 is very hard. Shore hardness 25-30 is quite good for many cases. This depends on what kind of parts you would like to cast or what kind of construction of mold you are using. Some silicones need to use in vacuum chamber.

 

Some resins will shrink and some resins will swell when you are making castings. Sometimes it is very difficult to find the "stable resin" for casting. It is very frustrating if you make 100 casts and after that you will notice that parts are not in same size. Some resins are used to call "aggressive resins" — typically these are not very good for making bigger runs. These are good if you are making only some castings. In Finland model railway enthusiasts have used casting techniques until from 1970´s because the lack of commercial model railway items of Finnish prototypes.

 

Some years ago in Scaleforum exhibition was very interesting workshop where you were able to discuss with enthusiasts making castings. It was very useful to discuss with other ones who was interested in these things.

[MGR Hooper!]

Those look lovely! I am wondering if I should use 3D printed parts or resin cast parts to make my models (also in 1:87 scale)...

How did you make the silicone moulds? Any tutorial or step by step write up?

[jonhall]

The other thing about shrinkage is heat, as the resin sets it undergoes an exothermic reaction, this causes the liquid resin to expand slightly, and as it cools I tries to revert to its original volume (shrinkage). If you are using thick castings these get hotter, and the shrinkage is more, in thin section (like most of the parts I've ever demonstrated) the mould acts a bit like a heatsink and so the parts don't get as hot, and therefore don't shrink as much. My EWS MBA wagon has almost no shrinkage despite being nearly a foot long.

 

Jon

[Petri Sallinen]

The other thing about shrinkage is heat, as the resin sets it undergoes an exothermic reaction, this causes the liquid resin to expand slightly, and as it cools I tries to revert to its original volume (shrinkage).

 

I agree.

 

There is also other problem you have to remember. Molds might shrink over time more than the technical bulletin says. In picture you will see two molds. The master with both molds were same but over time other mold is shrunken very much.

[Kelly]

Some very informative/helpful replies thus far to this thread, thanks.