I've started a new thread in the "Mould making" section   http://www.talkcomposites.com/3221/Looking-for-best-way-to-make-this-mould

I'll still be updating this thread until the plug is finished and ready for mould making.

Got my Spraygun and 2K primer filler and will be giving the plug a few coats tonight.

Thinking about how to make the mould now, i'm considering making a 2 part split mould as illustrated cross section below, i haven't done this before so please add your comments on how you think it would work out or how i can do it better.

what would be the best material to use for the barriers?

Thanks for the advice Joe, i'm going to get myself a spraygun and 2k filler primer, more pics to come and progress of block sanding. 

Hi,

Yes the particular filler that I use will polish extremely well. I call it my "Piece of glass in a bottle".

For sanding curved areas (including edges), I use a rubber rectangle on which I wrap my sanding paper. Excelent results this way, if you remember to "cross sanding" to avoid bumps and recesses in the surface finish. Modify rubber thickness to your likings.

For guide coat I simply use your basic mat black spray can, I spray it more like a mist, not a real coat if you see what I mean. Yes, it's a spray can stuff, but since you're supposed to make it all go during sanding process, its ok. I use mat black cos gloss black takes too long to dry.

I start sanding the guide coated filler with 600 grit wet paper. Then I go all the way to 2500 grit before polishing. Always wet sanding, and I change the water in my cup after every stage, to avoid recreating scratches from bigger grit contamination.

For polishing I use a 75mm diameter polisher machine (mine is air pressure driven) with foam polishing pads from 3M, and 3M polishing compound. I go thru the 3 stages (coarse, fine and ultrafine). Some will say its too much, and I might agree with them. However, it's how I feel it is right to do, so I do it like that

Whatever polishing machine you want to use, please be aware than you should not use a machine that rotates in excess of 2000 rpm. My machine spins at 1000 rpm maximum, for example, and I never use it at full speed. Some would use a grinder or modify a tool they have, to save money, and they would prolly end burning their part or distort surface finish cos of excess heat. Be careful too if you are gonna use foam polishing pads, they tend to heat more than wool pads. However, if you keep on moving the pad on the whole part there is no problem. Plus I find them to create less swearls than wool.


Once again, this is not the only way, other people would have other methods and products that work as well.
Hope it helps.

 



 


    A $1000 electronic device will always protect a 10 cents fuse

Thanks Joe, I think I'll give it a try.

Hello,

For making my plugs, I use 2k Standox polyester filler that I shoot with a good quality 1.4mm tip HVLP gun. In the beginning, I made more than enough plugs with Euros 30 HVLP spray gun, and it works quite good as long as you clean it well each time.

One thing tho: filler is reduced a little with acetone to help flow thru the 1.4mm tip. I usually go over the whole part 3 or 4 times without it running. Then I let it cure overnight before I start block sanding and polishing.

If you intend making an epoxy mold on the polyester filler, I would suggest to stay on the safe side and let filler cure 48 hours. I do that and I never ever had a sticker with that particular filler.

Polyester filler is not the only answer, but it's quite inexpensive and it works for me.

Hope it helps.

 



 


    A $1000 electronic device will always protect a 10 cents fuse

sanding, filling, sanding, filling.....etc....

getting closer now so i put a light guide coat of primer over the whole spoiler and i can see immediatly areas that need some more attention that until now looked just fine, there are also small holes where there were bubbles in the filler.

I'm nearing the point at which i think i'll spray the whole thing in 2k primer filler before final sanding and polishing.

Looked at the 2k primer available in an aerosol, i have found several places to buy it from and the cost is around 20 pounds inc postage.

the problem is i'll need around 1/3rd of a can and once activated anything left in the can will be useless after 4 hours or so, if i need more after that it means buying another can.

So i'm looking at getting a cheap spray gun, if anyone can advise what set up will work best please let me know??

more pics

Surface coat on and cured, sanding now to get the shape right, and nice and smooth, sanding down the high spots and finding low spots that will need more filler, this is slow and dusty but i'm getting there.

i should really change the thread title as it's now a build?

Thats cool ! Cant wait to see the results. Good luck !

 



 


    A $1000 electronic device will always protect a 10 cents fuse

Things are moving along now, covered the bootlid in bagging film and mixed up some resin with glass microballoons

and silica, i used this to put my foam pieces in place on the bootlid.

once cured i'll put a surface coat over the whole spoiler.

when this has cured there will be plenty of final shaping and sanding before the next stage of taking a mould from it.