Having managed to cast the first of Matt's moulds, the masonary wall, I have tried to give it some colouring just to try out different techniques. I have shared with Matt that I am having some problem maintaining the rigidity of the latex, possible due to the casting powder I am using generating a lot of heat when curing. I think it is better suited to the silicone rubber Linka used in their moulds. Destpite this, the detail from the mould is very good and any deficiencies are down to my cack handedness in getting the mixtures and depth of plaster right. I notice in another post the suggestion of utulising the powder plasterers use in covering the tape used to joing plaster boards. If I can source that then I will give it a go. I am also looking at the possibility of resin casting, to get an even thickness although I don't know how much the latex would stand up to this sort of treatment. In the meantime these are some shots of Matt's wall, without graffitti.





<a href="http://s303.photobucket.com/albums/nn136/mojo1-2008/?action=view&current=DSCF0007.jpg" target="_blank"><img></a>



The colouring has been done with pastel chalks ground down and just brushed on, except for the pinky colour on the extreme left which is a spray-on stone effect that I am experimenting with.

Mojo, looking good with the variances in colour.

I have use casting plaster but changed to patching plaster which, to me, appears to be better to work with. I think it is a bit finer like Polyfilla.

Very well done you guys 8) .further proof that this forum is the best thing since sliced bread , i cant imagine being without it now. :)  :)

I am also having some plroblems with the moulds keeping the shape, i am using casting plaster and whilst it is not brilliant, (which i am sure is due to the way i mix it, ie not enough or whatever) the moulds do come out ok sometimes. I have used some straight piece's of wood along the edge of the mould to try and see if i can get a straight edge, the design of the brickwork is excellent.

I am also having trouble with the paving slabs. The amount of plaster i have broke but i shall find a use for that with my layout. I need to work out how much plaster i need for these moulds due to them being alot thinner than the wall mould. I have just made 6 and i got 2 and a bit from them  :evil:  again its me getting the dam things out, cack handed but i get it right soon.  :D  I have just painted one pavement grey and so will post that result along with others at a later date. Also i have just done a stone wall which i think has come out really well, again pics at a later date.

All in all the moulds are excellent, Matt has done a fine job making them and i am sure its me who is getting the mix wrong but as i say i get it soon.
The good thing is you can make the retaining walls as big as the mould or any smaller size just by putting wood in the mould and making your own size.
phill

Mojo,

On the right hand side of the first picture the wall and especially the colouring look superb. What mix did you use to colour it - it really is excellent. :D

Les

Hi Les, from right to left the first quarter was burnt sienna powdered crayon as the base, rubbed in with kitchen towel, then a piece of charcoal rubbed across it, allowing the stone to catch it randomly.
The second quarter was just burnt sienna powder rubbed in, in anticipation of trying another finish on top, which I haven't got around to yet.
The third quarter was just matt black halfords car paint sprayed horizontally at the casting rather than face on, as suggested I think by Allan Downes. The paint catches the highlights but not quite as convincing a finish. Needs more work.
The last quarter is stone effect aerosol paint, sprayed on randomly. I found with the castings that they can come out a bit shiny so I used this to try roughening up the  surface a bit. Not convinced but as a spray-on ground surface, suitably coloured, it has a nice texture, something like fine gravel. I've seen it sprayed on peco underlay and it looks really effective at representing ballast.
As it continues to pour down in Rothbury UK it doesn't look as if I'm going to get a chance to go yomping, okay maybe sauntering this weekend down the old railway line for some further pictures, so that will have to wait. Still, gives me another chance to work on Matt's new moulds again.
Just shows how important research and development is before making stuff available to the general public. Hats off to Matt for giving it a go.

Having another go at trying to get a consistent mix and finish to do Matt's excellent moulds justice I am continuing to have problems, even with the scrimming plaster that I got from a builder friend, in maintaining an even thickness in order to match castings up with each other. Bracing is necessary to maintain the shape of the moulds but takes a lot of fettling in order to get a good result. Having said that the detail in the moulds comes across in the castings.


This is the dry stone wall. If you look carefully you can see the vertical capping stones. On the casting they can be picked out individually. This is the most consistent casting, I suspect because it is quite a thick and deep mould, and less likely to warp or break when being extracted.


This is the cast from the paving slab mould. It is quite difficult to extract as it has a tendency to break up due to thinness. This one depends very much on getting the type and mixture of plaster correct.


Sorry about the blurring of some of the pictures. This shows one of the retaining walls with capping stones on top. Again the detail is brilliant. I wish I knew the terminology for the way the stone is built up, but the capping stones are supported by smaller protruding stones. Anyone know what they are called? A lot of attention to detail from our master moulder.


Another shot of the previous wall hopefully showing in more detail Matt's painstaking work with the detail under the capping stones. Unfortunately, if you don't get the plaster type and mix right then some of this detail can be lost as the plaster does not follow the form of the mould. I have found that it is possible to add any bits by using DAS modelling clay.


This shows somewhat the thickness of the casting and there is a slight bow in it due to me not bracing the mould sufficiently. Again the plaster picks out the detail and takes powder colouring well. I would think that you would have to avoid anything that put a gloss finish on the surface unless you were aiming for a wet look surface.


Again one of the retaining walls. It is a shame that the plaster mix I used didn't find its way in to all the nooks and crannies under the capping stones. Looking at it again I think the extra thickness of stones at the base of the wall should be horizontal, and larger, in real life, in order to give the wall stability. Afraid the weathering was done in rather a hurry but gives an idea of what this medium is capable of.

Overall I have had a lot of fun with experimenting with this and have posted Matt with my observations on the product. Thanks Matt. It has a lot of potential but issues such as bracing the mould and advice about the consistency and type of casting plasters is necessary. Even allowing for my own inconstistencies in experimenting it's not as straightforward as you would first believe. The traditional casting plaster creates a lot of heat in curing and the latex does tend to distort during the process. Silicone rubber is much more resilient and firmer but I don't know how much it would cost to produce these moulds in a thicker form.
I hope the somewhat blurred photos (camera problems) do some justice to Matt's efforts. When I can afford it I will get hold of some casting resin and see what effect this has on the output.

i have put together a guide which i intend to send along with the moulds. This was put together with the help of Jeff who corrected my spelling mistakes and made the guide make sense 8) cheers Jeff. Forget the bits like you have just received your moulds as all I have done is copy and paste the doc. i thought it would be relevant to the thread and helpfull to members.

Hints and Tips

I have put together a guide rather than instructions on what to do with your moulds. You should have received the following moulds.

 1) 4x high wall 80mm
 2) 4x butt rest 80mm
 3) 1x corner 80mm
 4) 4x low wall 40mm
 5) 4x butt rest 40mm
 6) 1x corner
 7) low wall to high wall
 8 ) high wall to low wall
 9) high wall to 120mm

1. 120mm to high wall
2. sleeper fence
3. pavements x 8
4. pavement corner x4
5. pavement end x4
6. 1x dry stone wall
7. 1x dry stone wall with gap
8. dry stone wall gate posts

Moulds are made to order and by hand. They are 100% checked before posting but please note that occasional damage may occur whilst in the post.
We will be more than happy to replace any damaged mould free of charge.
Before attempting to cast your first mould please fully inspect the mould.

The following checks should be made: -
1) Check any distortion that has occurred during postage. Laying the moulds flat overnight can solve this.

2) Check for creases or folds in the latex. These can be teased or pulled out.  As the latex is a rubber substance it sticks to itself, but a light dusting with talcum powder will help with this.

3) Check for any small holes that may have appeared, as a result of postal damage. I will be more than happy to replace any damaged mould free of charge.
Any hole that has appeared will only be small and any small holes can be plugged with a bathroom sealant or something similar and should not affect the final casting.
 
4) Latex is air-drying, so in very rare instances, around corners and detailed parts of the mould, airflow may have been insufficient, resulting in the latex not setting fully.
Leave the mould upturned and the mould will set fully.

5) Once you are happy with your mould you can start the casting process.
Some moulds will require support around the edges and on the front face of the mould. An example of this would be the 80mm to 120mm incline wall. The wall is set back with a plinth at the base and a ledge overhanging at the top.
You will need to cut cardboard (or something similar) to support the wall (see FIG 1 & FIG 2)
Failing to support the wall will result in a bowed wall.

6) It is also advisable to support the edge of the mould; this is because of the weight of the casting material pushing against the sidewalls. This will keep the side of the casting straight and make aligning this against another casting easier (see FIG 3) Use any material with a straight edge for this.
It is also possible to manipulate the mould before casting. For example if you require a wall around a curved section. You can make a template of the curve using various materials (see FIG 4)
Cast 1 section at a time until you complete the wall.

fig 1



fig 2



fig 3



fig 4



Casting Method 1 (Modelling Plaster)

Tools Required
Mixing bowl
Fork\mixing utensil
Spoon
Knife
Talcum powder
Paintbrush
Latex mould
Water
Plaster
Sand paper

This is the way I do my moulds; it is not necessarily the only way. Different methods can be used to achieve the same goal, but my method works for me and can be used as a good guide.

1) Following the steps above, you should now have your mould with supports in front of you, with the detailed side of the mould facing upwards forming a bowl.

2) Lightly sprinkle ½ a teaspoon of talcum powder into the mould. Using a paintbrush ensure the mould has a very light covering of talcum powder. Blow away any surplus and ensure no build up of talcum powder has occurred.
This will help when removing the mould from the casting.

3) Following the manufacturers guidelines, mix the modelling plaster.

4) Using your spoon fill the mould about 25% full of plaster.

5) Use the paintbrush to move the plaster around in the bottom of the mould.             (What this does is to cover the bottom of the mould ensuring no air is trapped and all the detailed parts are covered)

6) Fill the mould level with the top using the remaining modelling plaster.

7) Using a knife level off the plaster ensuring the complete mould is covered.

8 ) Let the mould set as per manufactures guidelines.

9) When you come to remove the mould be patient, it will not come away with one pull. Hold the casting firmly ensuring you don’t apply too much pressure to one point as this may cause the casting to crack. Try to remove the latex from the casting and not the casting from the latex. (Rather like peeling a banana). Take a corner of the latex and slowly start to work the latex from the casting. Then work across one edge of the casting and then slowly pull the latex away from the face of the casting.

10) You should now have your casting separate from the latex, ensure the front face of the casting has set completely. It may feel damp to the touch due to the moisture in the plaster. Leave overnight to completely set.
Once you are happy that drying is thorough and complete, sand any bumps or clumps away from the edge and back of the casting.

11) Finally check for any holes in the front of your casting, caused by trapped air during the setting stage. (See 5 above). These will need to be filled with a little plaster or filler.

Your casting is now ready for painting and weathering.

 If you would like to add to this guide or would like to contact me regarding these moulds please feel free to email me.


Thanks, Matt
this is still work in progress and still at the early stages. i am trying to get my sections wired up on the layout, once this is done i can get some casting done.

Just what was needed, Matt, comprehensive and easily understood. I'll have another go, following the instructions!

If you are finding you are getting strengh problems with your castings how about adding some glass fibre fibres it gives the mix greater tensile strengh  you use this method in mixing render mixes which gives it a great deal more strengh and less cracking can occur .

if hairs stick out you burn them off wit a blow torch.

as a guide you use a teacupfull of fibres in 1 cement mixer mix

cheers Brian.W

henryparrot said

As a guide you use a teacupfull of fibres in 1 cement mixer mix
cheers Brian.W

Geeeez :!:  :!:  How many moulds was that Matt sent me to try :?:
           

nice one Jeff,          8)

Jeff
does that mean you don't have a cement mixer to mix your plaster :wink:   :?:  
i did try and figure out a way of strengthening the sides. But i think one of the advantages of latex is the flexibility of the mould. i think with silicone you would struggle to produce a  curve. one of the problems with the moulds is the thinness say for example the pavements. phil has had trouble removing these from the  mould. i have not yet had a problem so far. when i thought up this mould idea i brought 25kg HERCULITE NO 2 CASTING Plaster of Paris. you get the normal one and the number 2, the number 2 is a couple of quid more expensive. however when this has set ( it says 10 mins but i leave it for an hour ) it is hard as nails. i have only had 2 walls crack on me. one was too watery when i cast the wall and the other snapped when i was cutting an L shape from it (my dremell blade was broke and i was using a hacksaw blade :oops: ) i brought mine from fleebay for 27 quid but i have found this that does it for £26.38  including postage. you can use this for all sorts of stuff like tree trunks, land forms and roads. i have added colour whilst mixing with mixed results, i have a lovely pink retaining wall if anyone is interested :D  the plastr takes colour well as you have seen (just my skills let it down) and you can cut,sand and use filla on the moulds. i would recommend this stuff.

Casting Plaster, Plaster-Of-Paris Supplies, Casting Powder, Life-Casting, Stone powder, Life-casting Materials...

Jeff

If you have not got a cement mixer just use the wifes food mixer im sure she will be more than happy to let you use that    


cheers Brian.W

henryparrot said

Jeff
If you have not got a cement mixer just use the wifes food mixer im sure she will be more than happy to let you use that    
cheers Brian.W

I suppose any residue of fiberglass fibres would give some added strength to her next batch of soup :?:  :?:
          

Well the experts keep telling us we need more fibre in our diet.

Les

henryparrot said

Jeff

If you have not got a cement mixer just use the wifes food mixer im sure she will be more than happy to let you use that    


cheers Brian.W

Well and this is true i did use the mixer only we have 2 one old one and one new one, me not realising i used the new one, well it is the same for goodness sake. Anyhow i quickly washed it and put it back but i tell you it works ok, so later when i have time i shall post pics of them. As for the pavement i have now sussed it, i cardboard the sides and then fill, they seem ok as in coming out.
So if the wife do nopt find out what i did i shall post some pics at end of week.
Phill

i have done a couple of experiments
the first one was the pavements, i used the plaster i mentioned above. i used 2 table spoons per mould so i would get the same thickness. i left the mould to set for one hour. the moulds came out quite easy. no breakage or chipping. i can only put the braking of the plaster down to the type of plaster used. a couple of pics











no colour just out of the mould. i didn't support the mould as they are all in the same piece of latex (see pic) so would support themselves.

the next experiment was a tunnel.
i cut some ply to the shape of the tunnel mouth. this was placed inside the mould. i then made a casting (well 2 as the first one messed up). i had to split the casting in order to remove the ply. i then added filla around the tunnel mouth and over the crack. this will then be sanded down and i will scribe larger stones into this. i will then add side walls and hey presto hopefully a self built tunnel.

Those pavements look ok Matt and i like the tunnel idea as well.
Not had time to do any of my moulds as yet, been working and then these 2 days off i am finishing the decorating but hopefully in the next week i shall have some done.
Phill

phil
have a look at that plaster, it is worth the extra cost as you save in time and broken moulds :wink:  try what i did and use 2 table spoons for the pavements. it is just below the top of the mould. i have just got some railmatch concrete paint, only 2.50 a jar so i will have a go at painting later.