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Probably a tumbler with polishing media.
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Hi all, Not sure if this is the correct forum to post this so sorry if its in the wrong area..
I started making these clear resin soap dishes for a small craft shop near me, and to get the glass like finish I have to sand them by hand after pulling from the silicone mould using 320/600/100/1500 grit wet sandpaper and then polish them on a buffing wheel.
The problem now is I'm starting to get some large orders of 200-500. Obviously this would take too long to finish these by hand and so I'm wondering what type of tools/machinery I can buy to sand these pieces up to a grit of about 1500 so I can dramatically increase productivity. Any Ideas what the big factories use?
Thanks for any help.
Probably a tumbler with polishing media.
Thanks for the advice and I was thinking about a tumbler (if there was one big enough to fit quite a few soap dishes in), but the base of my pieces are flat with quite sharp edges and I would have thought a tumbler would take these edges away, aswell as the 3 little ridges on the centre top and end up creating a sort of big resin pebble shape?
I am not really understand,You want to polish or cut ？
http://www.morntech.com/: Laser engraving machine , CNC router
I want to sand and polish. When they come out of the mould they have surface defects like this picture.
http://i1108.photobucket.com/albums/...G_1526-1-1.jpg
I want to sand and polish a lot of them to finish like this.
http://i1108.photobucket.com/albums/...1/IMG_1533.jpg
That surface defect looks a lot like excessive mold release.
You should be able to get a pretty good surface direct from the mold, if you use a good casting resin.
Then as an alternative to hours of polishing (I have been there) you can simple spray with a good clear coat and have instant gloss.
They are some beautiful works of art too! I can see why you are getting big orders! Put your price UP right now!
Hey thanks for the compliments. Although this looks like it could be a lucrative business, I dont think I would be doing it if I didn't get satisfaction that I do when I finally finish buffing them and see'ing what I've created.
As for the mould release, I must have tried every type of release invented and found the best one to be baby talcum powder believe it or not.
Its funny that you should mention about the clear coat because After the first round of hand sanding 20 of them today with 320 grit wet&dry paper, and feeling pretty dismal about the thought of going over them with the rest of the grits before buffing. I decided to dip one of them in some old urethane floor sealing gloss. Will have to see what its like in the morning. Any ideas what would be a good clear tough UV resistant coating that I could dip them in?
I'd still love to know what machines the big casting companies use in there process's to make things like these.
I was thinking maybe some sort of mini air sander/polisher to use with wet sandpaper same as the auto bodyshop guys use would be a good idea. Or maybe it would be possible to use a desktop buffing/grinding wheel from start to finish using different grade flap abrasive wheels to start, and moving on to quite abrasive cutting compounds then finish with polishing/buffing compounds?
Just trying to find a solution to making as many as i can with the least effort (before I start feeling sick of the thought of hand sanding a few hundred a month)
You can buy UV resistant clear coat in convenient spray cans, you just need to spray it in a dust free room to get a finished gloss.
You may consider farming these out to a paint company that have a clean paint booth, expecially if you have hundreds.
I can;t say for big companies but if I had to do hundreds it would be with a clear coat! And yep I would probably farm it out, if they charge a dollar(?) per item it should not bite into your bottom line too much.
You are using a silicone mold. Why are you using a mold release? I did some silicone molding many decades ago and did not use any release. After all the mold itself is a silicone rubber which doesn't stick to anything.Originally Posted by jontidy
What is the surface finish of the pattern you make your mold from?
Do you thoroughly degass the silicone when you are making the mold?
Depending on what type of resin you are using to cast the parts I would expect you should be able to simply vapor polish them after molding to get a very nice finish.
An open mind is a virtue...so long as all the common sense has not leaked out.
Although the mold release is not needed with silicone as its self releasing. It's a good idea to use it because it extends the life of the mold as it creates a barrier between the resin and the silicone, preventing the silicone oils from being drawn out over time making the mold become brittle. Good mold releases will end up giving double the amount of pulls before the mold have to be replaced.
Baby powder has an extra benefit of stopping the odd stray bubble from sticking to the wall of the molds, which results in pit marks on the finished piece and a lot more sanding to get them out.
The surface finish of the pattern is flawlesss and glass like giving an excellent surface to the created platinum based silicone mold, which has been degassed beforehand using the pump and chamber which I just built with your help and advice Geof
Never heard of vapor polishing before. Had a little look on the interweb and it seems like the ideal solution. But not sure if it could be done with Polyester casted pieces?, and not sure I could find anywhere that had those kind of facilities to do it here in thailand.
Offhand I do not know whether polyester is softened by methylenechloride which is one of the vapor polishing solvents. It probably is, I think the only common plastics that are not are epoxies, acetals and polyethylene/polypropylene.
You might already have the equipment to try vapor polishing if an idea I am tooling up to try is a success; Vacuum Vapor Polishing.
The whole idea behind vapor polishing is to expose the parts to a high level of solvent vapor so it will condense on the parts softening the surface and allowing surface tension to make the surface 'flow' and smooth out imperfections.
The only way I have come across that this is done is to have the part in a chamber where a container of the solvent is heated to create a lot of vapors.
My idea is to put the part in a vacuum chamber with a small container of the solvent. When the vacuum is pumped down the solvent is going to vaporize, actually if the vacuum is taken too low the solvent will boil. The atmosphere inside the chamber will be mostly solvent vapors so the part should get vapor polished.
Actually my plan is to have two chambers connected by a large diameter ball valve. The part will be in one which is connected to the vacuum pump, and the solvent will be in the other. Once the part chamber has been pumped down I will open the ball valve which will allow solvent vapors to flow into the part chamber. This way I can limit the exposure of the part to vapors, my part chamber is glass so I can see what is going on. When the vapor polishing is complete I close the ball valve admitting solvent vapors and open a vent valve to flush out the vapors from the part chamber.
This idea works great in theory but I have not got to putting it into practise. I am stalled making an annealing oven because the parts I want to vapor polish are machined out of cast acrylic. I need to anneal them first, then vapor polish then bake them to drive of residual solvent.
And the reason I am stalled is my business is moving to new premises and I don't have time to fool around on weird ideas.
An open mind is a virtue...so long as all the common sense has not leaked out.
Sounds like a great idea Geof. I'd like to know how that turns out if you get round to doing it.
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