Smoothcast 65D and laser cut acrylic

[FIREWIRE]

Hey guys.

im looking to make a slush casting in which i sluish around 3mm acrylic parts i have. these will be used as mounting points for electronics i have ready to fit.

i have done several tests but the resin doesn't seem to want to adhere to the acrylic very well.

i have sanded the surface with rough paper and scored heavily. i also plan to drill lots oif anchor holes half way through for more surface area to grip. the acrylic will have one side where the resin will touch and the other side will be left untouched to mount my parts.

I was also planing to run a thin layer of bondo (.5mm) and mottle.

the resin sticks rock solid to glass which is weird as it is just as gloss a surface

any suggestions would be much appreciated.

Thanks

 

[FIREWIRE]

Another way i was thinking was to mold the parts into the resin without touching the surface. so that they basically snap out. then rough up the surface and glue back in with epoxy but id rather avoid this.

 

[Propsjonnyb]

What type of resin are you using , some Plastic resins will not bond to acrylic , so you may have to use epoxy to glue the parts in!!

I would suggest using an alternative fast cast , polyethylene style resin see if that makes a difference

 

[NormanF]

What type of resin are you using , some Plastic resins will not bond to acrylic , so you may have to use epoxy to glue the parts in!!

I would suggest using an alternative fast cast , polyethylene style resin see if that makes a difference

65D is a "polyurethane elastomer"

 

[mslz22]

Hard to say if this will work without seeing a pic of the part your want to cast, but what i have done in similar situations is to have something like a machine screw with an alternating stack of nuts and washers (nut, washer, nut washer etc..) protruding from the acrylic in the direction of the resin. The resin will sling around and "grab" the screws/washers very securely. It sounds like you will need to put it in an area that does not interfere with what you need to mount to the acrylic, but if you have enough room on the acrylic, this should work.

 

[FIREWIRE]

yeah it must be smoothcast 65d as its one of my helmets im slush casting. -

Daft Punk Thomas helmet kit Firewire V2 | eBay

if you look at the build thread or vi you will see that i made the front with laser cut parts when i made my sculpt.

well now i have made parts to hold my led matrix in place and other fans etc. heres the parts i plan to mold into the helmet -



Then the helmet will be prepped and chromed so really want a full bond rather than a friction fit if you know what i mean.

 

[Orbital Drydock]

What type of resin are you using , some Plastic resins will not bond to acrylic , so you may have to use epoxy to glue the parts in!!

I would suggest using an alternative fast cast , polyethylene style resin see if that makes a difference

65D is a "polyurethane elastomer"

polyurethane & polyethylene resins are not chemically the same thing & react differently.

I don't think your going to get a chemical bond between the resin & acrylic no matter what resin you use. Epoxy (JB weld only), or maybe put a few short screws in the acrylic. That way the resin forms around the screws & holds the acrylic in place. Then if your careful with the screws, your acrylic can be removed for more work if need be, & when you make the final install, glue the screws in place. BAM! permanent mechanical bond.

 

[FIREWIRE]

polyurethane & polyethylene resins are not chemically the same thing & react differently.

I don't think your going to get a chemical bond between the resin & acrylic no matter what resin you use. Epoxy (JB weld only), or maybe put a few short screws in the acrylic. That way the resin forms around the screws & holds the acrylic in place. Then if your careful with the screws, your acrylic can be removed for more work if need be, & when you make the final install, glue the screws in place. BAM! permanent mechanical bond.

Thanks think that ill test out the screw and jb weld

But thats why i was thinking the car body filler. would i get a chemical bond between set car body filler with resin poured over? so i would get my acrylic part and make a thin 0.5mm coat like this - http://www.floorheating.com/images/UltraProFlexSPSmall-grey.jpg and let it set. This sticks to acrylic really well. then do the slush casting onto that.

 

[NeonHybrid]

You could try a thin layer of plasto made by revell I use it to get a bond between styrene and body filler so it may bond to the resin as well. It also would give you a thinner layer as it is fairly runny when it comes out the tube.

 

[FIREWIRE]

iv bought some plasto so ill give that a go when i do more tests. cheers

 

[FIREWIRE]

So i have yet another idea.

i will score the plastic and rough it up. mount it in my mold then lay a bead of plasticine around the corners. pour my resin. then remove the plastice and there will be a void. lay a bead of jb weld. then a top coat of body filler
like so -



That pic is actually wrong as the resin will not run all the way over the acrylic but about quarter of the way up