Gt-12

[Navyrs]

Ok, I just spent the last couple of hrs reading this entire thread. You my friend are my hero and my inspiration to finish my build. I think I will be using this thread a lot to finish my Ranger.

 

[MountainMike]

it's definately a versatile method.you were using styrofoam(i know this because of the spray paint eating at it)which is very heavilly used by the movie industry for sets as it is very easy to form to any shape,and is very light weight,so is easy to move around.
the light weight is also a benifit of this method being used to make auto parts with urethane foam-the hood pictured above only weighs about 10 pounds,but can support a person jumping on it quite easilly.

Yeah, I was using pink insulation blocks layered and glued together. It worked surprisingly well and looked not bad when I was finished.

 

[gwaii]

Ok, I just spent the last couple of hrs reading this entire thread. You my friend are my hero and my inspiration to finish my build. I think I will be using this thread a lot to finish my Ranger.

welcome to the story of my life(lately).if anything here can help you out,you've made my day.SAR huh.that's quite a job,my hat's off to you

Yeah, I was using pink insulation blocks layered and glued together. It worked surprisingly well and looked not bad when I was finished.

that type,as well as the white pebbly stuff can be used the same way as the urethane foam i use but only with epoxy resin which is good stuff,but very expensive compared to polyester resin and when working with fiberglass matt(as opposed to cloth)i find it doesn't open up the fibers to let it form around curves as well.

what type of glue did you use?

for most of my work i use a hot-melt glue gun.it holds well,but you don't want to get it where you need to carve across a joint.it doesn't sand out so it leaves a nasty bump.

 

[MountainMike]

what type of glue did you use?

for most of my work i use a hot-melt glue gun.it holds well,but you don't want to get it where you need to carve across a joint.it doesn't sand out so it leaves a nasty bump.

I used hot glue as well. One every layer I plotted out where the cut was going to be and made sure to avoid those spots with the glue.

 

[gwaii]

I used hot glue as well. One every layer I plotted out where the cut was going to be and made sure to avoid those spots with the glue.

hmmmm.on one hand,it's cool to see we are using the same method,but on the other hand i was hoping you would have a better way that i hadn't thought of.
this one works,but it would be nice to find something that would hold it with a quick set and allow sanding across a seam.i've tried lots of things,but still keep coming back to the same thing.

 

[MountainMike]

Well I think "No More Nails" is sandable, that could work.

 

[AgPete139]

An adult jumping up & down on the glassed hood? Really? How many layers did you use, if it won't crack like that? Did you use more hardener, or what?

 

[gwaii]

Well I think "No More Nails" is sandable, that could work.

i've tried that too.it takes way too long to set up on foam-to-foam.i think the hot melt is probably going to be the best choice,just like we've both found you need to be careful about where cuts across the joint will be.

another one i've tried is mono foam,which works but is sort of rubbery,thus hard to sand for about a week.after that it works quite nice once it fully hardens.

 

[alwaysFlOoReD]

another one i've tried is mono foam,which works but is sort of rubbery,thus hard to sand for about a week.after that it works quite nice once it fully hardens.

You should try different brands, they are not all the same. I use a commercial gun applicator installing windows and have found that some dry quickly and to a hard consistency and others the opposite. I would look at a low expansion foam meant for windows/doors to avoid large voids and/or pushing the two pieces apart. I would suggest Hilti brand low expansion window foam for the character traits your looking for, but I'm sure there are others that might be as/more suitable.

Richard

 

[gwaii]

You should try different brands, they are not all the same. I use a commercial gun applicator installing windows and have found that some dry quickly and to a hard consistency and others the opposite. I would look at a low expansion foam meant for windows/doors to avoid large voids and/or pushing the two pieces apart. I would suggest Hilti brand low expansion window foam for the character traits your looking for, but I'm sure there are others that might be as/more suitable.

Richard

thanks for the suggestion...i'll see what i can find,around here the selection can be a bit limited(the saying on haida gwaii is that you don't use what you want,you use what you can get)but i'm sure there's more available than what i've used so far.

 

[YayItsJake]

i've tried that too.it takes way too long to set up on foam-to-foam.i think the hot melt is probably going to be the best choice,just like we've both found you need to be careful about where cuts across the joint will be.

another one i've tried is mono foam,which works but is sort of rubbery,thus hard to sand for about a week.after that it works quite nice once it fully hardens.

could you use the 3m spray adhesive? some of that stuff can be pretty sticky.

 

[gwaii]

could you use the 3m spray adhesive? some of that stuff can be pretty sticky.

i found that is good on flexible materials like vinyl,but with the rigid foam there is not full contact between the parts,so not much of the glue holds and the parts come apart while sanding and carving.
something with a bit more body to fill gaps is needed.i've also used 'gorilla glue',which is sort of like the mono foam in a smaller package.though it takes a while to set,it holds well but is kinda rubbery for a week or so.
once completely set it sands well.

 

[BONES]

An adult jumping up & down on the glassed hood? Really? How many layers did you use, if it won't crack like that? Did you use more hardener, or what?

Yeah what Pete asked, you can actually jump on it and it doesn't crack and break apart?? We're still talking about fiberglass or something else?

I always liked the fiberglass fenders with the wider flare and larger opening for the wheel. Basically what KopyKat built for fenders, but figured if they will break easily there's no point in doing the work on mine. But if they could take a good impact and shrug it off or pop back into shape after, hmmm, that's what I need. Is there such a material? Or are we talking vacuum boxing plastics?

I need to figure out what exactly a vacuum box is, lol. Sounds like a sealed box with your form in it and heated somehow to pull the plastic into the form, I guess the form would have holes for the vacuum?

 

[gwaii]

the hood only has two layers of 2oz matt and a layer of gelcoat,but gets it's rigidity from the foam core,and another two layers on the inside surface.regular fiberglass layups are fairly flexible,this type isn't.
so it won't take a point load like a rock hit well,but is very rigid and strong.you could jump on it with tennis shoes,but stillettoes would poke right through.

 

[gwaii]

I need to figure out what exactly a vacuum box is, lol. Sounds like a sealed box with your form in it and heated somehow to pull the plastic into the form, I guess the form would have holes for the vacuum?

yup,a vacuum box i basically that.the form doesnt need holes,and the heat is only applied to the plastic which is mounted in a frame.the form is mounted to the box,which is hooked to a shop vac,when the plastic is heated it is set in the box,the vac turned on and the plastic gets drawn against the form,where it cools to set it to it's new shape.
the excess is trimmed,and you have your new part.